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8177290: add copy factory methods for unmodifiable List, Set, Map

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8184690: add Collectors for collecting into unmodifiable List, Set, and Map

Reviewed-by: alanb, briangoetz, dholmes, jrose, rriggs, scolebourne
This commit is contained in:
Stuart Marks 2017-12-04 11:50:04 -08:00
parent 6d82950756
commit f4db9575d1
10 changed files with 675 additions and 153 deletions
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100
src/java.base/share/classes/java/util/Collection.java
View File

@ -54,19 +54,15 @@ import java.util.stream.StreamSupport;
* constructors) but all of the general-purpose {@code Collection}
* implementations in the Java platform libraries comply.
*
* <p>The "destructive" methods contained in this interface, that is, the
* methods that modify the collection on which they operate, are specified to
* throw {@code UnsupportedOperationException} if this collection does not
* support the operation. If this is the case, these methods may, but are not
* required to, throw an {@code UnsupportedOperationException} if the
* invocation would have no effect on the collection. For example, invoking
* the {@link #addAll(Collection)} method on an unmodifiable collection may,
* but is not required to, throw the exception if the collection to be added
* is empty.
* <p>Certain methods are specified to be
* <i>optional</i>. If a collection implementation doesn't implement a
* particular operation, it should define the corresponding method to throw
* {@code UnsupportedOperationException}. Such methods are marked "optional
* operation" in method specifications of the collections interfaces.
*
* <p><a id="optional-restrictions">
* Some collection implementations have restrictions on the elements that
* they may contain.</a> For example, some implementations prohibit null elements,
* <p><a id="optional-restrictions"></a>Some collection implementations
* have restrictions on the elements that they may contain.
* For example, some implementations prohibit null elements,
* and some have restrictions on the types of their elements. Attempting to
* add an ineligible element throws an unchecked exception, typically
* {@code NullPointerException} or {@code ClassCastException}. Attempting
@ -111,6 +107,86 @@ import java.util.stream.StreamSupport;
* methods. Implementations may optionally handle the self-referential scenario,
* however most current implementations do not do so.
*
* <h2><a id="view">View Collections</a></h2>
*
* <p>Most collections manage storage for elements they contain. By contrast, <i>view
* collections</i> themselves do not store elements, but instead they rely on a
* backing collection to store the actual elements. Operations that are not handled
* by the view collection itself are delegated to the backing collection. Examples of
* view collections include the wrapper collections returned by methods such as
* {@link Collections#checkedCollection Collections.checkedCollection},
* {@link Collections#synchronizedCollection Collections.synchronizedCollection}, and
* {@link Collections#unmodifiableCollection Collections.unmodifiableCollection}.
* Other examples of view collections include collections that provide a
* different representation of the same elements, for example, as
* provided by {@link List#subList List.subList},
* {@link NavigableSet#subSet NavigableSet.subSet}, or
* {@link Map#entrySet Map.entrySet}.
* Any changes made to the backing collection are visible in the view collection.
* Correspondingly, any changes made to the view collection &mdash; if changes
* are permitted &mdash; are written through to the backing collection.
* Although they technically aren't collections, instances of
* {@link Iterator} and {@link ListIterator} can also allow modifications
* to be written through to the backing collection, and in some cases,
* modifications to the backing collection will be visible to the Iterator
* during iteration.
*
* <h2><a id="unmodifiable">Unmodifiable Collections</a></h2>
*
* <p>Certain methods of this interface are considered "destructive" and are called
* "mutator" methods in that they modify the group of objects contained within
* the collection on which they operate. They can be specified to throw
* {@code UnsupportedOperationException} if this collection implementation
* does not support the operation. Such methods should (but are not required
* to) throw an {@code UnsupportedOperationException} if the invocation would
* have no effect on the collection. For example, consider a collection that
* does not support the {@link #add add} operation. What will happen if the
* {@link #addAll addAll} method is invoked on this collection, with an empty
* collection as the argument? The addition of zero elements has no effect,
* so it is permissible for this collection simply to do nothing and not to throw
* an exception. However, it is recommended that such cases throw an exception
* unconditionally, as throwing only in certain cases can lead to
* programming errors.
*
* <p>An <i>unmodifiable collection</i> is a collection, all of whose
* mutator methods (as defined above) are specified to throw
* {@code UnsupportedOperationException}. Such a collection thus cannot be
* modified by calling any methods on it. For a collection to be properly
* unmodifiable, any view collections derived from it must also be unmodifiable.
* For example, if a List is unmodifiable, the List returned by
* {@link List#subList List.subList} is also unmodifiable.
*
* <p>An unmodifiable collection is not necessarily immutable. If the
* contained elements are mutable, the entire collection is clearly
* mutable, even though it might be unmodifiable. For example, consider
* two unmodifiable lists containing mutable elements. The result of calling
* {@code list1.equals(list2)} might differ from one call to the next if
* the elements had been mutated, even though both lists are unmodifiable.
* However, if an unmodifiable collection contains all immutable elements,
* it can be considered effectively immutable.
*
* <h2><a id="unmodview">Unmodifiable View Collections</a></h2>
*
* <p>An <i>unmodifiable view collection</i> is a collection that is unmodifiable
* and that is also a view onto a backing collection. Its mutator methods throw
* {@code UnsupportedOperationException}, as described above, while
* reading and querying methods are delegated to the backing collection.
* The effect is to provide read-only access to the backing collection.
* This is useful for a component to provide users with read access to
* an internal collection, while preventing them from modifying such
* collections unexpectedly. Examples of unmodifiable view collections
* are those returned by the
* {@link Collections#unmodifiableCollection Collections.unmodifiableCollection},
* {@link Collections#unmodifiableList Collections.unmodifiableList}, and
* related methods.
*
* <p>Note that changes to the backing collection might still be possible,
* and if they occur, they are visible through the unmodifiable view. Thus,
* an unmodifiable view collection is not necessarily immutable. However,
* if the backing collection of an unmodifiable view is effectively immutable,
* or if the only reference to the backing collection is through an
* unmodifiable view, the view can be considered effectively immutable.
*
* <p>This interface is a member of the
* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
* Java Collections Framework</a>.

40
src/java.base/share/classes/java/util/Collections.java
View File

@ -989,9 +989,8 @@ public class Collections {
// Unmodifiable Wrappers
/**
* Returns an unmodifiable view of the specified collection. This method
* allows modules to provide users with "read-only" access to internal
* collections. Query operations on the returned collection "read through"
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified collection. Query operations on the returned collection "read through"
* to the specified collection, and attempts to modify the returned
* collection, whether direct or via its iterator, result in an
* {@code UnsupportedOperationException}.<p>
@ -1102,9 +1101,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified set. This method allows
* modules to provide users with "read-only" access to internal sets.
* Query operations on the returned set "read through" to the specified
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified set. Query operations on the returned set "read through" to the specified
* set, and attempts to modify the returned set, whether direct or via its
* iterator, result in an {@code UnsupportedOperationException}.<p>
*
@ -1132,9 +1130,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified sorted set. This method
* allows modules to provide users with "read-only" access to internal
* sorted sets. Query operations on the returned sorted set "read
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified sorted set. Query operations on the returned sorted set "read
* through" to the specified sorted set. Attempts to modify the returned
* sorted set, whether direct, via its iterator, or via its
* {@code subSet}, {@code headSet}, or {@code tailSet} views, result in
@ -1180,9 +1177,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified navigable set. This method
* allows modules to provide users with "read-only" access to internal
* navigable sets. Query operations on the returned navigable set "read
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified navigable set. Query operations on the returned navigable set "read
* through" to the specified navigable set. Attempts to modify the returned
* navigable set, whether direct, via its iterator, or via its
* {@code subSet}, {@code headSet}, or {@code tailSet} views, result in
@ -1269,9 +1265,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified list. This method allows
* modules to provide users with "read-only" access to internal
* lists. Query operations on the returned list "read through" to the
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified list. Query operations on the returned list "read through" to the
* specified list, and attempts to modify the returned list, whether
* direct or via its iterator, result in an
* {@code UnsupportedOperationException}.<p>
@ -1415,9 +1410,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified map. This method
* allows modules to provide users with "read-only" access to internal
* maps. Query operations on the returned map "read through"
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified map. Query operations on the returned map "read through"
* to the specified map, and attempts to modify the returned
* map, whether direct or via its collection views, result in an
* {@code UnsupportedOperationException}.<p>
@ -1765,9 +1759,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified sorted map. This method
* allows modules to provide users with "read-only" access to internal
* sorted maps. Query operations on the returned sorted map "read through"
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified sorted map. Query operations on the returned sorted map "read through"
* to the specified sorted map. Attempts to modify the returned
* sorted map, whether direct, via its collection views, or via its
* {@code subMap}, {@code headMap}, or {@code tailMap} views, result in
@ -1809,9 +1802,8 @@ public class Collections {
}
/**
* Returns an unmodifiable view of the specified navigable map. This method
* allows modules to provide users with "read-only" access to internal
* navigable maps. Query operations on the returned navigable map "read
* Returns an <a href="Collection.html#unmodview">unmodifiable view</a> of the
* specified navigable map. Query operations on the returned navigable map "read
* through" to the specified navigable map. Attempts to modify the returned
* navigable map, whether direct, via its collection views, or via its
* {@code subMap}, {@code headMap}, or {@code tailMap} views, result in

86
src/java.base/share/classes/java/util/List.java
View File

@ -87,15 +87,16 @@ import java.util.function.UnaryOperator;
* Such exceptions are marked as "optional" in the specification for this
* interface.
*
* <h2><a id="immutable">Immutable List Static Factory Methods</a></h2>
* <p>The {@link List#of(Object...) List.of()} static factory methods
* provide a convenient way to create immutable lists. The {@code List}
* <h2><a id="unmodifiable">Unmodifiable Lists</a></h2>
* <p>The {@link List#of(Object...) List.of} and
* {@link List#copyOf List.copyOf} static factory methods
* provide a convenient way to create unmodifiable lists. The {@code List}
* instances created by these methods have the following characteristics:
*
* <ul>
* <li>They are <em>structurally immutable</em>. Elements cannot be added, removed,
* or replaced. Calling any mutator method will always cause
* {@code UnsupportedOperationException} to be thrown.
* <li>They are <a href="Collection.html#unmodifiable"><i>unmodifiable</i></a>. Elements cannot
* be added, removed, or replaced. Calling any mutator method on the List
* will always cause {@code UnsupportedOperationException} to be thrown.
* However, if the contained elements are themselves mutable,
* this may cause the List's contents to appear to change.
* <li>They disallow {@code null} elements. Attempts to create them with
@ -777,9 +778,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing zero elements.
* Returns an unmodifiable list containing zero elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @return an empty {@code List}
@ -791,9 +792,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing one element.
* Returns an unmodifiable list containing one element.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the single element
@ -807,9 +808,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing two elements.
* Returns an unmodifiable list containing two elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -824,9 +825,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing three elements.
* Returns an unmodifiable list containing three elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -842,9 +843,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing four elements.
* Returns an unmodifiable list containing four elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -861,9 +862,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing five elements.
* Returns an unmodifiable list containing five elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -881,9 +882,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing six elements.
* Returns an unmodifiable list containing six elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -903,9 +904,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing seven elements.
* Returns an unmodifiable list containing seven elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -926,9 +927,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing eight elements.
* Returns an unmodifiable list containing eight elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -950,9 +951,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing nine elements.
* Returns an unmodifiable list containing nine elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -975,9 +976,9 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing ten elements.
* Returns an unmodifiable list containing ten elements.
*
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @param <E> the {@code List}'s element type
* @param e1 the first element
@ -1001,8 +1002,8 @@ public interface List<E> extends Collection<E> {
}
/**
* Returns an immutable list containing an arbitrary number of elements.
* See <a href="#immutable">Immutable List Static Factory Methods</a> for details.
* Returns an unmodifiable list containing an arbitrary number of elements.
* See <a href="#unmodifiable">Unmodifiable Lists</a> for details.
*
* @apiNote
* This method also accepts a single array as an argument. The element type of
@ -1039,4 +1040,29 @@ public interface List<E> extends Collection<E> {
return new ImmutableCollections.ListN<>(elements);
}
}
/**
* Returns an <a href="#unmodifiable">unmodifiable List</a> containing the elements of
* the given Collection, in its iteration order. The given Collection must not be null,
* and it must not contain any null elements. If the given Collection is subsequently
* modified, the returned List will not reflect such modifications.
*
* @implNote
* If the given Collection is an <a href="#unmodifiable">unmodifiable List</a>,
* calling copyOf will generally not create a copy.
*
* @param <E> the {@code List}'s element type
* @param coll a {@code Collection} from which elements are drawn, must be non-null
* @return a {@code List} containing the elements of the given {@code Collection}
* @throws NullPointerException if coll is null, or if it contains any nulls
* @since 10
*/
@SuppressWarnings("unchecked")
static <E> List<E> copyOf(Collection<? extends E> coll) {
if (coll instanceof ImmutableCollections.AbstractImmutableList) {
return (List<E>)coll;
} else {
return (List<E>)List.of(coll.toArray());
}
}
}

97
src/java.base/share/classes/java/util/Map.java
View File

@ -110,17 +110,18 @@ import java.io.Serializable;
* Implementations may optionally handle the self-referential scenario, however
* most current implementations do not do so.
*
* <h2><a id="immutable">Immutable Map Static Factory Methods</a></h2>
* <p>The {@link Map#of() Map.of()} and
* {@link Map#ofEntries(Map.Entry...) Map.ofEntries()}
* static factory methods provide a convenient way to create immutable maps.
* <h2><a id="unmodifiable">Unmodifiable Maps</a></h2>
* <p>The {@link Map#of() Map.of},
* {@link Map#ofEntries(Map.Entry...) Map.ofEntries}, and
* {@link Map#copyOf Map.copyOf}
* static factory methods provide a convenient way to create unmodifiable maps.
* The {@code Map}
* instances created by these methods have the following characteristics:
*
* <ul>
* <li>They are <em>structurally immutable</em>. Keys and values cannot be added,
* removed, or updated. Calling any mutator method will always cause
* {@code UnsupportedOperationException} to be thrown.
* <li>They are <a href="Collection.html#unmodifiable"><i>unmodifiable</i></a>. Keys and values
* cannot be added, removed, or updated. Calling any mutator method on the Map
* will always cause {@code UnsupportedOperationException} to be thrown.
* However, if the contained keys or values are themselves mutable, this may cause the
* Map to behave inconsistently or its contents to appear to change.
* <li>They disallow {@code null} keys and values. Attempts to create them with
@ -1276,8 +1277,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing zero mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing zero mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1290,8 +1291,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing a single mapping.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing a single mapping.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1307,8 +1308,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing two mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing two mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1327,8 +1328,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing three mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing three mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1349,8 +1350,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing four mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing four mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1373,8 +1374,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing five mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing five mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1399,8 +1400,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing six mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing six mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1429,8 +1430,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing seven mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing seven mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1461,8 +1462,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing eight mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing eight mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1495,8 +1496,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing nine mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing nine mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1531,8 +1532,8 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing ten mappings.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* Returns an unmodifiable map containing ten mappings.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
@ -1569,9 +1570,9 @@ public interface Map<K, V> {
}
/**
* Returns an immutable map containing keys and values extracted from the given entries.
* Returns an unmodifiable map containing keys and values extracted from the given entries.
* The entries themselves are not stored in the map.
* See <a href="#immutable">Immutable Map Static Factory Methods</a> for details.
* See <a href="#unmodifiable">Unmodifiable Maps</a> for details.
*
* @apiNote
* It is convenient to create the map entries using the {@link Map#entry Map.entry()} method.
@ -1602,15 +1603,17 @@ public interface Map<K, V> {
@SafeVarargs
@SuppressWarnings("varargs")
static <K, V> Map<K, V> ofEntries(Entry<? extends K, ? extends V>... entries) {
if (entries.length == 0) { // implicit null check of entries
if (entries.length == 0) { // implicit null check of entries array
return ImmutableCollections.Map0.instance();
} else if (entries.length == 1) {
// implicit null check of the array slot
return new ImmutableCollections.Map1<>(entries[0].getKey(),
entries[0].getValue());
} else {
Object[] kva = new Object[entries.length << 1];
int a = 0;
for (Entry<? extends K, ? extends V> entry : entries) {
// implicit null checks of each array slot
kva[a++] = entry.getKey();
kva[a++] = entry.getValue();
}
@ -1619,7 +1622,7 @@ public interface Map<K, V> {
}
/**
* Returns an immutable {@link Entry} containing the given key and value.
* Returns an unmodifiable {@link Entry} containing the given key and value.
* These entries are suitable for populating {@code Map} instances using the
* {@link Map#ofEntries Map.ofEntries()} method.
* The {@code Entry} instances created by this method have the following characteristics:
@ -1627,7 +1630,7 @@ public interface Map<K, V> {
* <ul>
* <li>They disallow {@code null} keys and values. Attempts to create them using a {@code null}
* key or value result in {@code NullPointerException}.
* <li>They are immutable. Calls to {@link Entry#setValue Entry.setValue()}
* <li>They are unmodifiable. Calls to {@link Entry#setValue Entry.setValue()}
* on a returned {@code Entry} result in {@code UnsupportedOperationException}.
* <li>They are not serializable.
* <li>They are <a href="../lang/doc-files/ValueBased.html">value-based</a>.
@ -1655,4 +1658,30 @@ public interface Map<K, V> {
// KeyValueHolder checks for nulls
return new KeyValueHolder<>(k, v);
}
/**
* Returns an <a href="#unmodifiable">unmodifiable Map</a> containing the entries
* of the given Map. The given Map must not be null, and it must not contain any
* null keys or values. If the given Map is subsequently modified, the returned
* Map will not reflect such modifications.
*
* @implNote
* If the given Map is an <a href="#unmodifiable">unmodifiable Map</a>,
* calling copyOf will generally not create a copy.
*
* @param <K> the {@code Map}'s key type
* @param <V> the {@code Map}'s value type
* @param map a {@code Map} from which entries are drawn, must be non-null
* @return a {@code Map} containing the entries of the given {@code Map}
* @throws NullPointerException if map is null, or if it contains any null keys or values
* @since 10
*/
@SuppressWarnings({"rawtypes","unchecked"})
static <K, V> Map<K, V> copyOf(Map<? extends K, ? extends V> map) {
if (map instanceof ImmutableCollections.AbstractImmutableMap) {
return (Map<K,V>)map;
} else {
return (Map<K,V>)Map.ofEntries(map.entrySet().toArray(new Entry[0]));
}
}
}

87
src/java.base/share/classes/java/util/Set.java
View File

@ -63,15 +63,16 @@ package java.util;
* Such exceptions are marked as "optional" in the specification for this
* interface.
*
* <h2><a id="immutable">Immutable Set Static Factory Methods</a></h2>
* <p>The {@link Set#of(Object...) Set.of()} static factory methods
* provide a convenient way to create immutable sets. The {@code Set}
* <h2><a id="unmodifiable">Unmodifiable Sets</a></h2>
* <p>The {@link Set#of(Object...) Set.of} and
* {@link Set#copyOf Set.copyOf} static factory methods
* provide a convenient way to create unmodifiable sets. The {@code Set}
* instances created by these methods have the following characteristics:
*
* <ul>
* <li>They are <em>structurally immutable</em>. Elements cannot be added or
* removed. Calling any mutator method will always cause
* {@code UnsupportedOperationException} to be thrown.
* <li>They are <a href="Collection.html#unmodifiable"><i>unmodifiable</i></a>. Elements cannot
* be added or removed. Calling any mutator method on the Set
* will always cause {@code UnsupportedOperationException} to be thrown.
* However, if the contained elements are themselves mutable, this may cause the
* Set to behave inconsistently or its contents to appear to change.
* <li>They disallow {@code null} elements. Attempts to create them with
@ -439,8 +440,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing zero elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing zero elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @return an empty {@code Set}
@ -452,8 +453,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing one element.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing one element.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the single element
@ -467,8 +468,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing two elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing two elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -484,8 +485,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing three elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing three elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -502,8 +503,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing four elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing four elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -521,8 +522,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing five elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing five elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -541,8 +542,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing six elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing six elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -563,8 +564,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing seven elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing seven elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -586,8 +587,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing eight elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing eight elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -610,8 +611,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing nine elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing nine elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -635,8 +636,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing ten elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing ten elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @param <E> the {@code Set}'s element type
* @param e1 the first element
@ -661,8 +662,8 @@ public interface Set<E> extends Collection<E> {
}
/**
* Returns an immutable set containing an arbitrary number of elements.
* See <a href="#immutable">Immutable Set Static Factory Methods</a> for details.
* Returns an unmodifiable set containing an arbitrary number of elements.
* See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*
* @apiNote
* This method also accepts a single array as an argument. The element type of
@ -700,4 +701,30 @@ public interface Set<E> extends Collection<E> {
return new ImmutableCollections.SetN<>(elements);
}
}
/**
* Returns an <a href="#unmodifiable">unmodifiable Set</a> containing the elements
* of the given Collection. The given Collection must not be null, and it must not
* contain any null elements. If the given Collection contains duplicate elements,
* an arbitrary element of the duplicates is preserved. If the given Collection is
* subsequently modified, the returned Set will not reflect such modifications.
*
* @implNote
* If the given Collection is an <a href="#unmodifiable">unmodifiable Set</a>,
* calling copyOf will generally not create a copy.
*
* @param <E> the {@code Set}'s element type
* @param coll a {@code Collection} from which elements are drawn, must be non-null
* @return a {@code Set} containing the elements of the given {@code Collection}
* @throws NullPointerException if coll is null, or if it contains any nulls
* @since 10
*/
@SuppressWarnings("unchecked")
static <E> Set<E> copyOf(Collection<? extends E> coll) {
if (coll instanceof ImmutableCollections.AbstractImmutableSet) {
return (Set<E>)coll;
} else {
return (Set<E>)Set.of(new HashSet<>(coll).toArray());
}
}
}

140
src/java.base/share/classes/java/util/stream/Collectors.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -116,6 +116,8 @@ public final class Collectors {
= Collections.unmodifiableSet(EnumSet.of(Collector.Characteristics.UNORDERED,
Collector.Characteristics.IDENTITY_FINISH));
static final Set<Collector.Characteristics> CH_NOID = Collections.emptySet();
static final Set<Collector.Characteristics> CH_UNORDERED_NOID
= Collections.unmodifiableSet(EnumSet.of(Collector.Characteristics.UNORDERED));
private Collectors() { }
@ -278,6 +280,26 @@ public final class Collectors {
CH_ID);
}
/**
* Returns a {@code Collector} that accumulates the input elements into an
* <a href="../List.html#unmodifiable">unmodifiable List</a> in encounter
* order. The returned Collector disallows null values and will throw
* {@code NullPointerException} if it is presented with a null value.
*
* @param <T> the type of the input elements
* @return a {@code Collector} that accumulates the input elements into an
* <a href="../List.html#unmodifiable">unmodifiable List</a> in encounter order
* @since 10
*/
@SuppressWarnings("unchecked")
public static <T>
Collector<T, ?, List<T>> toUnmodifiableList() {
return new CollectorImpl<>((Supplier<List<T>>) ArrayList::new, List::add,
(left, right) -> { left.addAll(right); return left; },
list -> (List<T>)List.of(list.toArray()),
CH_NOID);
}
/**
* Returns a {@code Collector} that accumulates the input elements into a
* new {@code Set}. There are no guarantees on the type, mutability,
@ -305,6 +327,36 @@ public final class Collectors {
CH_UNORDERED_ID);
}
/**
* Returns a {@code Collector} that accumulates the input elements into an
* <a href="../Set.html#unmodifiable">unmodifiable Set</a>. The returned
* Collector disallows null values and will throw {@code NullPointerException}
* if it is presented with a null value. If the input contains duplicate elements,
* an arbitrary element of the duplicates is preserved.
*
* <p>This is an {@link Collector.Characteristics#UNORDERED unordered}
* Collector.
*
* @param <T> the type of the input elements
* @return a {@code Collector} that accumulates the input elements into an
* <a href="../Set.html#unmodifiable">unmodifiable Set</a>
* @since 10
*/
@SuppressWarnings("unchecked")
public static <T>
Collector<T, ?, Set<T>> toUnmodifiableSet() {
return new CollectorImpl<>((Supplier<Set<T>>) HashSet::new, Set::add,
(left, right) -> {
if (left.size() < right.size()) {
right.addAll(left); return right;
} else {
left.addAll(right); return left;
}
},
set -> (Set<T>)Set.of(set.toArray()),
CH_UNORDERED_NOID);
}
/**
* Returns a {@code Collector} that concatenates the input elements into a
* {@code String}, in encounter order.
@ -1353,7 +1405,7 @@ public final class Collectors {
* <p>If the mapped keys contain duplicates (according to
* {@link Object#equals(Object)}), an {@code IllegalStateException} is
* thrown when the collection operation is performed. If the mapped keys
* may have duplicates, use {@link #toMap(Function, Function, BinaryOperator)}
* might have duplicates, use {@link #toMap(Function, Function, BinaryOperator)}
* instead.
*
* <p>There are no guarantees on the type, mutability, serializability,
@ -1410,6 +1462,45 @@ public final class Collectors {
CH_ID);
}
/**
* Returns a {@code Collector} that accumulates the input elements into an
* <a href="../Map.html#unmodifiable">unmodifiable Map</a>,
* whose keys and values are the result of applying the provided
* mapping functions to the input elements.
*
* <p>If the mapped keys contain duplicates (according to
* {@link Object#equals(Object)}), an {@code IllegalStateException} is
* thrown when the collection operation is performed. If the mapped keys
* might have duplicates, use {@link #toUnmodifiableMap(Function, Function, BinaryOperator)}
* to handle merging of the values.
*
* <p>The returned Collector disallows null keys and values. If either mapping function
* returns null, {@code NullPointerException} will be thrown.
*
* @param <T> the type of the input elements
* @param <K> the output type of the key mapping function
* @param <U> the output type of the value mapping function
* @param keyMapper a mapping function to produce keys, must be non-null
* @param valueMapper a mapping function to produce values, must be non-null
* @return a {@code Collector} that accumulates the input elements into an
* <a href="../Map.html#unmodifiable">unmodifiable Map</a>, whose keys and values
* are the result of applying the provided mapping functions to the input elements
* @throws NullPointerException if either keyMapper or valueMapper is null
*
* @see #toUnmodifiableMap(Function, Function, BinaryOperator)
* @since 10
*/
@SuppressWarnings({"rawtypes", "unchecked"})
public static <T, K, U>
Collector<T, ?, Map<K,U>> toUnmodifiableMap(Function<? super T, ? extends K> keyMapper,
Function<? super T, ? extends U> valueMapper) {
Objects.requireNonNull(keyMapper, "keyMapper");
Objects.requireNonNull(valueMapper, "valueMapper");
return collectingAndThen(
toMap(keyMapper, valueMapper),
map -> (Map<K,U>)Map.ofEntries(map.entrySet().toArray(new Map.Entry[0])));
}
/**
* Returns a {@code Collector} that accumulates elements into a
* {@code Map} whose keys and values are the result of applying the provided
@ -1473,6 +1564,51 @@ public final class Collectors {
return toMap(keyMapper, valueMapper, mergeFunction, HashMap::new);
}
/**
* Returns a {@code Collector} that accumulates the input elements into an
* <a href="../Map.html#unmodifiable">unmodifiable Map</a>,
* whose keys and values are the result of applying the provided
* mapping functions to the input elements.
*
* <p>If the mapped
* keys contain duplicates (according to {@link Object#equals(Object)}),
* the value mapping function is applied to each equal element, and the
* results are merged using the provided merging function.
*
* <p>The returned Collector disallows null keys and values. If either mapping function
* returns null, {@code NullPointerException} will be thrown.
*
* @param <T> the type of the input elements
* @param <K> the output type of the key mapping function
* @param <U> the output type of the value mapping function
* @param keyMapper a mapping function to produce keys, must be non-null
* @param valueMapper a mapping function to produce values, must be non-null
* @param mergeFunction a merge function, used to resolve collisions between
* values associated with the same key, as supplied
* to {@link Map#merge(Object, Object, BiFunction)},
* must be non-null
* @return a {@code Collector} that accumulates the input elements into an
* <a href="../Map.html#unmodifiable">unmodifiable Map</a>, whose keys and values
* are the result of applying the provided mapping functions to the input elements
* @throws NullPointerException if the keyMapper, valueMapper, or mergeFunction is null
*
* @see #toUnmodifiableMap(Function, Function)
* @since 10
*/
@SuppressWarnings({"rawtypes", "unchecked"})
public static <T, K, U>
Collector<T, ?, Map<K,U>> toUnmodifiableMap(Function<? super T, ? extends K> keyMapper,
Function<? super T, ? extends U> valueMapper,
BinaryOperator<U> mergeFunction) {
Objects.requireNonNull(keyMapper, "keyMapper");
Objects.requireNonNull(valueMapper, "valueMapper");
Objects.requireNonNull(mergeFunction, "mergeFunction");
return collectingAndThen(
toMap(keyMapper, valueMapper, mergeFunction, HashMap::new),
map -> (Map<K,U>)Map.ofEntries(map.entrySet().toArray(new Map.Entry[0])));
}
/**
* Returns a {@code Collector} that accumulates elements into a
* {@code Map} whose keys and values are the result of applying the provided

56
test/jdk/java/util/Collection/MOAT.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -57,6 +57,8 @@ import java.util.*;
import java.util.concurrent.*;
import static java.util.Collections.*;
import java.lang.reflect.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class MOAT {
// Collections under test must not be initialized to contain this value,
@ -230,6 +232,17 @@ public class MOAT {
testListMutatorsAlwaysThrow(list);
}
List<Integer> listCopy = List.copyOf(Arrays.asList(1, 2, 3));
testCollection(listCopy);
testImmutableList(listCopy);
testListMutatorsAlwaysThrow(listCopy);
List<Integer> listCollected = Stream.of(1, 2, 3).collect(Collectors.toUnmodifiableList());
equal(listCollected, List.of(1, 2, 3));
testCollection(listCollected);
testImmutableList(listCollected);
testListMutatorsAlwaysThrow(listCollected);
// Immutable Set
testEmptySet(Set.of());
testCollMutatorsAlwaysThrow(Set.of());
@ -252,6 +265,18 @@ public class MOAT {
testCollMutatorsAlwaysThrow(set);
}
Set<Integer> setCopy = Set.copyOf(Arrays.asList(1, 2, 3));
testCollection(setCopy);
testImmutableSet(setCopy);
testCollMutatorsAlwaysThrow(setCopy);
Set<Integer> setCollected = Stream.of(1, 1, 2, 3, 2, 3)
.collect(Collectors.toUnmodifiableSet());
equal(setCollected, Set.of(1, 2, 3));
testCollection(setCollected);
testImmutableSet(setCollected);
testCollMutatorsAlwaysThrow(setCollected);
// Immutable Map
@SuppressWarnings("unchecked")
@ -280,6 +305,35 @@ public class MOAT {
testImmutableMap(map);
testMapMutatorsAlwaysThrow(map);
}
Map<Integer,Integer> mapCopy = Map.copyOf(new HashMap<>(Map.of(1, 101, 2, 202, 3, 303)));
testMap(mapCopy);
testImmutableMap(mapCopy);
testMapMutatorsAlwaysThrow(mapCopy);
Map<Integer,Integer> mapCollected1 =
Stream.of(1, 2, 3)
.collect(Collectors.toUnmodifiableMap(i -> i, i -> 101 * i));
equal(mapCollected1, Map.of(1, 101, 2, 202, 3, 303));
testMap(mapCollected1);
testImmutableMap(mapCollected1);
testMapMutatorsAlwaysThrow(mapCollected1);
try {
Stream.of(1, 1, 2, 3, 2, 3)
.collect(Collectors.toUnmodifiableMap(i -> i, i -> 101 * i));
fail("duplicates should have thrown an exception");
} catch (IllegalStateException ise) {
pass();
}
Map<Integer,Integer> mapCollected2 =
Stream.of(1, 1, 2, 3, 2, 3)
.collect(Collectors.toUnmodifiableMap(i -> i, i -> 101 * i, Integer::sum));
equal(mapCollected2, Map.of(1, 202, 2, 404, 3, 606));
testMap(mapCollected2);
testImmutableMap(mapCollected2);
testMapMutatorsAlwaysThrow(mapCollected2);
}
private static void checkContainsSelf(Collection<Integer> c) {

58
test/jdk/java/util/Collection/SetFactories.java
View File

@ -40,6 +40,9 @@ import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotEquals;
import static org.testng.Assert.assertNotSame;
import static org.testng.Assert.assertSame;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;
@ -275,9 +278,9 @@ public class SetFactories {
static <T> T serialClone(T obj) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(obj);
oos.close();
try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
oos.writeObject(obj);
}
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
ObjectInputStream ois = new ObjectInputStream(bais);
return (T) ois.readObject();
@ -285,4 +288,53 @@ public class SetFactories {
throw new AssertionError(e);
}
}
Set<Integer> genSet() {
return new HashSet<>(Arrays.asList(1, 2, 3));
}
@Test
public void copyOfResultsEqual() {
Set<Integer> orig = genSet();
Set<Integer> copy = Set.copyOf(orig);
assertEquals(orig, copy);
assertEquals(copy, orig);
}
@Test
public void copyOfModifiedUnequal() {
Set<Integer> orig = genSet();
Set<Integer> copy = Set.copyOf(orig);
orig.add(4);
assertNotEquals(orig, copy);
assertNotEquals(copy, orig);
}
@Test
public void copyOfIdentity() {
Set<Integer> orig = genSet();
Set<Integer> copy1 = Set.copyOf(orig);
Set<Integer> copy2 = Set.copyOf(copy1);
assertNotSame(orig, copy1);
assertSame(copy1, copy2);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullCollection() {
Set<Integer> set = Set.copyOf(null);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullElements() {
Set<Integer> set = Set.copyOf(Arrays.asList(1, null, 3));
}
@Test
public void copyOfAcceptsDuplicates() {
Set<Integer> set = Set.copyOf(Arrays.asList(1, 1, 2, 3, 3, 3));
assertEquals(set, Set.of(1, 2, 3));
}
}

54
test/jdk/java/util/List/ListFactories.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -39,6 +39,9 @@ import static java.util.Arrays.asList;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotEquals;
import static org.testng.Assert.assertNotSame;
import static org.testng.Assert.assertSame;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;
@ -221,9 +224,9 @@ public class ListFactories {
static <T> T serialClone(T obj) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(obj);
oos.close();
try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
oos.writeObject(obj);
}
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
ObjectInputStream ois = new ObjectInputStream(bais);
return (T) ois.readObject();
@ -231,4 +234,47 @@ public class ListFactories {
throw new AssertionError(e);
}
}
List<Integer> genList() {
return new ArrayList<>(Arrays.asList(1, 2, 3));
}
@Test
public void copyOfResultsEqual() {
List<Integer> orig = genList();
List<Integer> copy = List.copyOf(orig);
assertEquals(orig, copy);
assertEquals(copy, orig);
}
@Test
public void copyOfModifiedUnequal() {
List<Integer> orig = genList();
List<Integer> copy = List.copyOf(orig);
orig.add(4);
assertNotEquals(orig, copy);
assertNotEquals(copy, orig);
}
@Test
public void copyOfIdentity() {
List<Integer> orig = genList();
List<Integer> copy1 = List.copyOf(orig);
List<Integer> copy2 = List.copyOf(copy1);
assertNotSame(orig, copy1);
assertSame(copy1, copy2);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullCollection() {
List<Integer> list = List.copyOf(null);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullElements() {
List<Integer> list = List.copyOf(Arrays.asList(1, null, 3));
}
}

110
test/jdk/java/util/Map/MapFactories.java
View File

@ -42,6 +42,9 @@ import org.testng.annotations.Test;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotEquals;
import static org.testng.Assert.assertNotSame;
import static org.testng.Assert.assertSame;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;
@ -70,6 +73,12 @@ public class MapFactories {
}
// for varargs Map.Entry methods
@SuppressWarnings("unchecked")
Map.Entry<Integer,String>[] genEmptyEntryArray1() {
return (Map.Entry<Integer,String>[])new Map.Entry<?,?>[1];
}
@SuppressWarnings("unchecked")
Map.Entry<Integer,String>[] genEntries(int n) {
return IntStream.range(0, n)
@ -322,21 +331,41 @@ public class MapFactories {
}
@Test(expectedExceptions=NullPointerException.class)
public void nullKeyDisallowedN() {
Map.Entry<Integer,String>[] entries = genEntries(MAX_ENTRIES);
entries[0] = new AbstractMap.SimpleImmutableEntry(null, "a");
public void nullKeyDisallowedVar1() {
Map.Entry<Integer,String>[] entries = genEmptyEntryArray1();
entries[0] = new AbstractMap.SimpleImmutableEntry<>(null, "a");
Map<Integer, String> map = Map.ofEntries(entries);
}
@Test(expectedExceptions=NullPointerException.class)
public void nullValueDisallowedN() {
Map.Entry<Integer,String>[] entries = genEntries(MAX_ENTRIES);
entries[0] = new AbstractMap.SimpleImmutableEntry(0, null);
public void nullValueDisallowedVar1() {
Map.Entry<Integer,String>[] entries = genEmptyEntryArray1();
entries[0] = new AbstractMap.SimpleImmutableEntry<>(0, null);
Map<Integer, String> map = Map.ofEntries(entries);
}
@Test(expectedExceptions=NullPointerException.class)
public void nullEntryDisallowedN() {
public void nullEntryDisallowedVar1() {
Map.Entry<Integer,String>[] entries = genEmptyEntryArray1();
Map<Integer, String> map = Map.ofEntries(entries);
}
@Test(expectedExceptions=NullPointerException.class)
public void nullKeyDisallowedVarN() {
Map.Entry<Integer,String>[] entries = genEntries(MAX_ENTRIES);
entries[0] = new AbstractMap.SimpleImmutableEntry<>(null, "a");
Map<Integer, String> map = Map.ofEntries(entries);
}
@Test(expectedExceptions=NullPointerException.class)
public void nullValueDisallowedVarN() {
Map.Entry<Integer,String>[] entries = genEntries(MAX_ENTRIES);
entries[0] = new AbstractMap.SimpleImmutableEntry<>(0, null);
Map<Integer, String> map = Map.ofEntries(entries);
}
@Test(expectedExceptions=NullPointerException.class)
public void nullEntryDisallowedVarN() {
Map.Entry<Integer,String>[] entries = genEntries(MAX_ENTRIES);
entries[5] = null;
Map<Integer, String> map = Map.ofEntries(entries);
@ -344,7 +373,7 @@ public class MapFactories {
@Test(expectedExceptions=NullPointerException.class)
public void nullArrayDisallowed() {
Map.ofEntries(null);
Map.ofEntries((Map.Entry<?,?>[])null);
}
@Test(dataProvider="all")
@ -359,9 +388,9 @@ public class MapFactories {
static <T> T serialClone(T obj) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(obj);
oos.close();
try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
oos.writeObject(obj);
}
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
ObjectInputStream ois = new ObjectInputStream(bais);
return (T) ois.readObject();
@ -370,6 +399,62 @@ public class MapFactories {
}
}
Map<Integer, String> genMap() {
Map<Integer, String> map = new HashMap<>();
map.put(1, "a");
map.put(2, "b");
map.put(3, "c");
return map;
}
@Test
public void copyOfResultsEqual() {
Map<Integer, String> orig = genMap();
Map<Integer, String> copy = Map.copyOf(orig);
assertEquals(orig, copy);
assertEquals(copy, orig);
}
@Test
public void copyOfModifiedUnequal() {
Map<Integer, String> orig = genMap();
Map<Integer, String> copy = Map.copyOf(orig);
orig.put(4, "d");
assertNotEquals(orig, copy);
assertNotEquals(copy, orig);
}
@Test
public void copyOfIdentity() {
Map<Integer, String> orig = genMap();
Map<Integer, String> copy1 = Map.copyOf(orig);
Map<Integer, String> copy2 = Map.copyOf(copy1);
assertNotSame(orig, copy1);
assertSame(copy1, copy2);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullMap() {
Map<Integer, String> map = Map.copyOf(null);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullKey() {
Map<Integer, String> map = genMap();
map.put(null, "x");
Map<Integer, String> copy = Map.copyOf(map);
}
@Test(expectedExceptions=NullPointerException.class)
public void copyOfRejectsNullValue() {
Map<Integer, String> map = genMap();
map.put(-1, null);
Map<Integer, String> copy = Map.copyOf(map);
}
// Map.entry() tests
@Test(expectedExceptions=NullPointerException.class)
@ -386,7 +471,7 @@ public class MapFactories {
public void entryBasicTests() {
Map.Entry<String,String> kvh1 = Map.entry("xyzzy", "plugh");
Map.Entry<String,String> kvh2 = Map.entry("foobar", "blurfl");
Map.Entry<String,String> sie = new AbstractMap.SimpleImmutableEntry("xyzzy", "plugh");
Map.Entry<String,String> sie = new AbstractMap.SimpleImmutableEntry<>("xyzzy", "plugh");
assertTrue(kvh1.equals(sie));
assertTrue(sie.equals(kvh1));
@ -404,5 +489,4 @@ public class MapFactories {
Map<Number,Number> map = Map.ofEntries(e1, e2);
assertEquals(map.size(), 2);
}
}