8011800: Add java.util.Objects.requireNonNull(T, Supplier<String>)
Reviewed-by: alanb, dholmes, mduigou
--- a/jdk/src/share/classes/java/util/Objects.java Mon Apr 15 14:07:17 2013 -0700
+++ b/jdk/src/share/classes/java/util/Objects.java Mon Apr 15 18:31:48 2013 -0700
@@ -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 @@
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;
+ }
}
--- a/jdk/test/java/util/Objects/BasicObjectsTest.java Mon Apr 15 14:07:17 2013 -0700
+++ b/jdk/test/java/util/Objects/BasicObjectsTest.java Mon Apr 15 18:31:48 2013 -0700
@@ -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 @@
errors += testToString();
errors += testToString2();
errors += testCompare();
- errors += testNonNull();
+ errors += testRequireNonNull();
if (errors > 0 )
throw new RuntimeException();
}
@@ -158,49 +159,54 @@
return errors;
}
- private static int testNonNull() {
+ private static int testRequireNonNull() {
int errors = 0;
- String s;
+
+ 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");
- // Test 1-arg variant
+ 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++;
}
}