changeset 4652:c5c91589b126

5029031: Add Collections.checkedQueue() Reviewed-by: mduigou Contributed-by: darryl.mocek@oracle.com
author mduigou
date Wed, 19 Oct 2011 14:17:47 -0700
parents 15078025eed9
children 634cd6f050ba
files src/share/classes/java/util/Collections.java test/java/util/Collections/CheckedQueue.java
diffstat 2 files changed, 248 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/classes/java/util/Collections.java	Wed Oct 19 10:16:22 2011 -0400
+++ b/src/share/classes/java/util/Collections.java	Wed Oct 19 14:17:47 2011 -0700
@@ -2352,6 +2352,64 @@
     }
 
     /**
+     * Returns a dynamically typesafe view of the specified queue.
+     * Any attempt to insert an element of the wrong type will result in
+     * an immediate {@link ClassCastException}.  Assuming a queue contains
+     * no incorrectly typed elements prior to the time a dynamically typesafe
+     * view is generated, and that all subsequent access to the queue
+     * takes place through the view, it is <i>guaranteed</i> that the
+     * queue cannot contain an incorrectly typed element.
+     *
+     * <p>A discussion of the use of dynamically typesafe views may be
+     * found in the documentation for the {@link #checkedCollection
+     * checkedCollection} method.
+     *
+     * <p>The returned queue will be serializable if the specified queue
+     * is serializable.
+     *
+     * <p>Since {@code null} is considered to be a value of any reference
+     * type, the returned queue permits insertion of {@code null} elements
+     * whenever the backing queue does.
+     *
+     * @param queue the queue for which a dynamically typesafe view is to be
+     *             returned
+     * @param type the type of element that {@code queue} is permitted to hold
+     * @return a dynamically typesafe view of the specified queue
+     * @since 1.8
+     */
+    public static <E> Queue<E> checkedQueue(Queue<E> queue, Class<E> type) {
+        return new CheckedQueue<>(queue, type);
+    }
+
+    /**
+     * @serial include
+     */
+    static class CheckedQueue<E>
+        extends CheckedCollection<E>
+        implements Queue<E>, Serializable
+    {
+        private static final long serialVersionUID = 1433151992604707767L;
+        final Queue<E> queue;
+
+        CheckedQueue(Queue<E> queue, Class<E> elementType) {
+            super(queue, elementType);
+            this.queue = queue;
+        }
+
+        public E element()              {return queue.element();}
+        public boolean equals(Object o) {return o == this || c.equals(o);}
+        public int hashCode()           {return c.hashCode();}
+        public E peek()                 {return queue.peek();}
+        public E poll()                 {return queue.poll();}
+        public E remove()               {return queue.remove();}
+
+        public boolean offer(E e) {
+            typeCheck(e);
+            return add(e);
+        }
+    }
+
+    /**
      * Returns a dynamically typesafe view of the specified set.
      * Any attempt to insert an element of the wrong type will result in
      * an immediate {@link ClassCastException}.  Assuming a set contains
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/util/Collections/CheckedQueue.java	Wed Oct 19 14:17:47 2011 -0700
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2011, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 5020931
+ * @summary Unit test for Collections.checkedQueue
+ */
+
+import java.lang.reflect.Method;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Queue;
+import java.util.concurrent.ArrayBlockingQueue;
+
+public class CheckedQueue {
+    static int status = 0;
+
+    public static void main(String[] args) throws Exception {
+        new CheckedQueue();
+    }
+
+    public CheckedQueue() throws Exception {
+        run();
+    }
+
+    private void run() throws Exception {
+        Method[] methods = this.getClass().getDeclaredMethods();
+
+        for (int i = 0; i < methods.length; i++) {
+            Method method = methods[i];
+            String methodName = method.getName();
+
+            if (methodName.startsWith("test")) {
+                try {
+                    Object obj = method.invoke(this, new Object[0]);
+                } catch(Exception e) {
+                    throw new Exception(this.getClass().getName() + "." +
+                            methodName + " test failed, test exception "
+                            + "follows\n" + e.getCause());
+                }
+            }
+        }
+    }
+
+    /**
+     * This test adds items to a queue.
+     */
+    private void test00() {
+        int arrayLength = 10;
+        ArrayBlockingQueue<String> abq = new ArrayBlockingQueue(arrayLength);
+
+        for (int i = 0; i < arrayLength; i++) {
+            abq.add(new String(Integer.toString(i)));
+        }
+    }
+
+    /**
+     * This test tests the CheckedQueue.add method.  It creates a queue of
+     * {@code String}s gets the checked queue, and attempt to add an Integer to
+     * the checked queue.
+     */
+    private void test01() throws Exception {
+        int arrayLength = 10;
+        ArrayBlockingQueue<String> abq = new ArrayBlockingQueue(arrayLength + 1);
+
+        for (int i = 0; i < arrayLength; i++) {
+            abq.add(new String(Integer.toString(i)));
+        }
+
+        Queue q = Collections.checkedQueue(abq, String.class);
+
+        try {
+            q.add(new Integer(0));
+            throw new Exception(this.getClass().getName() + "." + "test01 test"
+                    + " failed, should throw ClassCastException.");
+        } catch(ClassCastException cce) {
+            // Do nothing.
+        }
+    }
+
+    /**
+     * This test tests the CheckedQueue.add method.  It creates a queue of one
+     * {@code String}, gets the checked queue, and attempt to add an Integer to
+     * the checked queue.
+     */
+    private void test02() throws Exception {
+        ArrayBlockingQueue<String> abq = new ArrayBlockingQueue(1);
+        Queue q = Collections.checkedQueue(abq, String.class);
+
+        try {
+            q.add(new Integer(0));
+            throw new Exception(this.getClass().getName() + "." + "test02 test"
+                    + " failed, should throw ClassCastException.");
+        } catch(ClassCastException e) {
+            // Do nothing.
+        }
+    }
+
+    /**
+     * This test tests the Collections.checkedQueue method call for nulls in
+     * each and both of the parameters.
+     */
+    private void test03() throws Exception {
+        ArrayBlockingQueue<String> abq = new ArrayBlockingQueue(1);
+        Queue q;
+
+        try {
+            q = Collections.checkedQueue(null, String.class);
+            throw new Exception(this.getClass().getName() + "." + "test03 test"
+                    + " failed, should throw NullPointerException.");
+        } catch(NullPointerException npe) {
+            // Do nothing
+        }
+
+        try {
+            q = Collections.checkedQueue(abq, null);
+            throw new Exception(this.getClass().getName() + "." + "test03 test"
+                    + " failed, should throw NullPointerException.");
+        } catch(Exception e) {
+            // Do nothing
+        }
+
+        try {
+            q = Collections.checkedQueue(null, null);
+            throw new Exception(this.getClass().getName() + "." + "test03 test"
+                    + " failed, should throw NullPointerException.");
+        } catch(Exception e) {
+            // Do nothing
+        }
+    }
+
+    /**
+     * This test tests the CheckedQueue.offer method.
+     */
+    private void test04() throws Exception {
+        ArrayBlockingQueue<String> abq = new ArrayBlockingQueue(1);
+        Queue q = Collections.checkedQueue(abq, String.class);
+
+        try {
+            q.offer(null);
+            throw new Exception(this.getClass().getName() + "." + "test04 test"
+                    + " failed, should throw NullPointerException.");
+        } catch (NullPointerException npe) {
+            // Do nothing
+        }
+
+        try {
+            q.offer(new Integer(0));
+            throw new Exception(this.getClass().getName() + "." + "test04 test"
+                    + " failed, should throw ClassCastException.");
+        } catch (ClassCastException cce) {
+            // Do nothing
+        }
+
+        q.offer(new String("0"));
+
+        try {
+            q.offer(new String("1"));
+            throw new Exception(this.getClass().getName() + "." + "test04 test"
+                    + " failed, should throw IllegalStateException.");
+        } catch(IllegalStateException ise) {
+            // Do nothing
+        }
+    }
+
+    private void test05() {
+
+    }
+}