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8011800: Add java.util.Objects.requireNonNull(T, Supplier<String>)

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Reviewed-by: alanb, dholmes, mduigou
This commit is contained in:
Joe Darcy 2013-04-15 18:31:48 -07:00
parent 67e05359fc
commit dbb722dfb0
2 changed files with 68 additions and 34 deletions
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30
jdk/src/share/classes/java/util/Objects.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2009, 2013, 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
@ -25,6 +25,8 @@
package java.util;
import java.util.function.Supplier;
/**
* This class consists of {@code static} utility methods for operating
* on objects. These utilities include {@code null}-safe or {@code
@ -226,4 +228,30 @@ public final class Objects {
throw new NullPointerException(message);
return obj;
}
/**
* Checks that the specified object reference is not {@code null} and
* throws a customized {@link NullPointerException} if it is.
*
* <p>Unlike the method {@link requireNonNull(Object, String},
* this method allows creation of the message to be deferred until
* after the null check is made. While this may confer a
* performance advantage in the non-null case, when deciding to
* call this method care should be taken that the costs of
* creating the message supplier are less than the cost of just
* creating the string message directly.
*
* @param obj the object reference to check for nullity
* @param messageSupplier supplier of the detail message to be
* used in the event that a {@code NullPointerException} is thrown
* @param <T> the type of the reference
* @return {@code obj} if not {@code null}
* @throws NullPointerException if {@code obj} is {@code null}
* @since 1.8
*/
public static <T> T requireNonNull(T obj, Supplier<String> messageSupplier) {
if (obj == null)
throw new NullPointerException(messageSupplier.get());
return obj;
}
}

72
jdk/test/java/util/Objects/BasicObjectsTest.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2009, 2013, 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
@ -23,12 +23,13 @@
/*
* @test
* @bug 6797535 6889858 6891113
* @bug 6797535 6889858 6891113 8011800
* @summary Basic tests for methods in java.util.Objects
* @author Joseph D. Darcy
*/
import java.util.*;
import java.util.function.*;
public class BasicObjectsTest {
public static void main(String... args) {
@ -40,7 +41,7 @@ public class BasicObjectsTest {
errors += testToString();
errors += testToString2();
errors += testCompare();
errors += testNonNull();
errors += testRequireNonNull();
if (errors > 0 )
throw new RuntimeException();
}
@ -158,49 +159,54 @@ public class BasicObjectsTest {
return errors;
}
private static int testNonNull() {
private static int testRequireNonNull() {
int errors = 0;
String s;
// Test 1-arg variant
final String RNN_1 = "1-arg requireNonNull";
final String RNN_2 = "2-arg requireNonNull";
final String RNN_3 = "Supplier requireNonNull";
Function<String, String> rnn1 = s -> Objects.requireNonNull(s);
Function<String, String> rnn2 = s -> Objects.requireNonNull(s, "trousers");
Function<String, String> rnn3 = s -> Objects.requireNonNull(s, () -> "trousers");
errors += testRNN_NonNull(rnn1, RNN_1);
errors += testRNN_NonNull(rnn2, RNN_2);
errors += testRNN_NonNull(rnn3, RNN_3);
errors += testRNN_Null(rnn1, RNN_1, null);
errors += testRNN_Null(rnn2, RNN_2, "trousers");
errors += testRNN_Null(rnn3, RNN_3, "trousers");
return errors;
}
private static int testRNN_NonNull(Function<String, String> testFunc,
String testFuncName) {
int errors = 0;
try {
s = Objects.requireNonNull("pants");
String s = testFunc.apply("pants");
if (s != "pants") {
System.err.printf("1-arg non-null failed to return its arg");
System.err.printf(testFuncName + " failed to return its arg");
errors++;
}
} catch (NullPointerException e) {
System.err.printf("1-arg nonNull threw unexpected NPE");
System.err.printf(testFuncName + " threw unexpected NPE");
errors++;
}
return errors;
}
private static int testRNN_Null(Function<String, String> testFunc,
String testFuncName,
String expectedMessage) {
int errors = 0;
try {
s = Objects.requireNonNull(null);
System.err.printf("1-arg nonNull failed to throw NPE");
String s = testFunc.apply(null);
System.err.printf(testFuncName + " failed to throw NPE");
errors++;
} catch (NullPointerException e) {
// Expected
}
// Test 2-arg variant
try {
s = Objects.requireNonNull("pants", "trousers");
if (s != "pants") {
System.err.printf("2-arg nonNull failed to return its arg");
errors++;
}
} catch (NullPointerException e) {
System.err.printf("2-arg nonNull threw unexpected NPE");
errors++;
}
try {
s = Objects.requireNonNull(null, "pantaloons");
System.err.printf("2-arg nonNull failed to throw NPE");
errors++;
} catch (NullPointerException e) {
if (e.getMessage() != "pantaloons") {
System.err.printf("2-arg nonNull threw NPE w/ bad detail msg");
if (e.getMessage() != expectedMessage) {
System.err.printf(testFuncName + " threw NPE w/ bad detail msg");
errors++;
}
}