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[Jnode-svn-commits] SF.net SVN: jnode: [2899] trunk/core/src/classpath/java/java/lang
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From: <ls...@us...> - 2006-12-12 21:13:42
|
Revision: 2899
http://jnode.svn.sourceforge.net/jnode/?rev=2899&view=rev
Author: lsantha
Date: 2006-12-12 13:13:38 -0800 (Tue, 12 Dec 2006)
Log Message:
-----------
Migrating to Java 5 level classpath.
Added Paths:
-----------
trunk/core/src/classpath/java/java/lang/ref/
trunk/core/src/classpath/java/java/lang/ref/PhantomReference.java
trunk/core/src/classpath/java/java/lang/ref/Reference.java
trunk/core/src/classpath/java/java/lang/ref/ReferenceQueue.java
trunk/core/src/classpath/java/java/lang/ref/SoftReference.java
trunk/core/src/classpath/java/java/lang/ref/WeakReference.java
trunk/core/src/classpath/java/java/lang/ref/package.html
Added: trunk/core/src/classpath/java/java/lang/ref/PhantomReference.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/PhantomReference.java (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/PhantomReference.java 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,73 @@
+/* java.lang.ref.PhantomReference
+ Copyright (C) 1999, 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang.ref;
+
+/**
+ * A phantom reference is useful, to get notified, when an object got
+ * finalized. You can't access that object though, since it is
+ * finalized. This is the reason, why <code>get()</code> always
+ * returns null.
+ *
+ * @author Jochen Hoenicke
+ */
+public class PhantomReference<T>
+ extends Reference<T>
+{
+ /**
+ * Creates a new phantom reference.
+ * @param referent the object that should be watched.
+ * @param q the queue that should be notified, if the referent was
+ * finalized. This mustn't be <code>null</code>.
+ * @exception NullPointerException if q is null.
+ */
+ public PhantomReference(T referent, ReferenceQueue<? super T> q)
+ {
+ super(referent, q);
+ }
+
+ /**
+ * Returns the object, this reference refers to.
+ * @return <code>null</code>, since the refered object may be
+ * finalized and thus not accessible.
+ */
+ public T get()
+ {
+ return null;
+ }
+}
Added: trunk/core/src/classpath/java/java/lang/ref/Reference.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/Reference.java (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/Reference.java 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,177 @@
+/* java.lang.ref.Reference
+ Copyright (C) 1999, 2002, 2003, 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang.ref;
+
+/**
+ * This is the base class of all references. A reference allows
+ * refering to an object without preventing the garbage collector to
+ * collect it. The only way to get the referred object is via the
+ * <code>get()</code>-method. This method will return
+ * <code>null</code> if the object was collected. <br>
+ *
+ * A reference may be registered with a queue. When a referred
+ * element gets collected the reference will be put on the queue, so
+ * that you will be notified. <br>
+ *
+ * There are currently three types of references: soft reference,
+ * weak reference and phantom reference. <br>
+ *
+ * Soft references will be cleared if the garbage collector is told
+ * to free some memory and there are no unreferenced or weakly referenced
+ * objects. It is useful for caches. <br>
+ *
+ * Weak references will be cleared as soon as the garbage collector
+ * determines that the refered object is only weakly reachable. They
+ * are useful as keys in hashtables (see <code>WeakHashtable</code>) as
+ * you get notified when nobody has the key anymore.
+ *
+ * Phantom references don't prevent finalization. If an object is only
+ * phantom reachable, it will be finalized, and the reference will be
+ * enqueued, but not cleared. Since you mustn't access an finalized
+ * object, the <code>get</code> method of a phantom reference will never
+ * work. It is useful to keep track, when an object is finalized.
+ *
+ * @author Jochen Hoenicke
+ * @see java.util.WeakHashMap
+ */
+public abstract class Reference<T>
+{
+ /**
+ * The underlying object. This field is handled in a special way by
+ * the garbage collector.
+ */
+ T referent;
+
+ /**
+ * The queue this reference is registered on. This is null, if this
+ * wasn't registered to any queue or reference was already enqueued.
+ */
+ ReferenceQueue<? super T> queue;
+
+ /**
+ * Link to the next entry on the queue. If this is null, this
+ * reference is not enqueued. Otherwise it points to the next
+ * reference. The last reference on a queue will point to itself
+ * (not to null, that value is used to mark a not enqueued
+ * reference).
+ */
+ Reference nextOnQueue;
+
+ /**
+ * This lock should be taken by the garbage collector, before
+ * determining reachability. It will prevent the get()-method to
+ * return the reference so that reachability doesn't change.
+ */
+ static Object lock = new Object();
+
+ /**
+ * Creates a new reference that is not registered to any queue.
+ * Since it is package private, it is not possible to overload this
+ * class in a different package.
+ * @param ref the object we refer to.
+ */
+ Reference(T ref)
+ {
+ referent = ref;
+ }
+
+ /**
+ * Creates a reference that is registered to a queue. Since this is
+ * package private, it is not possible to overload this class in a
+ * different package.
+ * @param ref the object we refer to.
+ * @param q the reference queue to register on.
+ * @exception NullPointerException if q is null.
+ */
+ Reference(T ref, ReferenceQueue<? super T> q)
+ {
+ if (q == null)
+ throw new NullPointerException();
+ referent = ref;
+ queue = q;
+ }
+
+ /**
+ * Returns the object, this reference refers to.
+ * @return the object, this reference refers to, or null if the
+ * reference was cleared.
+ */
+ public T get()
+ {
+ synchronized (lock)
+ {
+ return referent;
+ }
+ }
+
+ /**
+ * Clears the reference, so that it doesn't refer to its object
+ * anymore. For soft and weak references this is called by the
+ * garbage collector. For phantom references you should call
+ * this when enqueuing the reference.
+ */
+ public void clear()
+ {
+ referent = null;
+ }
+
+ /**
+ * Tells if the object is enqueued on a reference queue.
+ * @return true if it is enqueued, false otherwise.
+ */
+ public boolean isEnqueued()
+ {
+ return nextOnQueue != null;
+ }
+
+ /**
+ * Enqueue an object on a reference queue. This is normally executed
+ * by the garbage collector.
+ */
+ public boolean enqueue()
+ {
+ if (queue != null && nextOnQueue == null)
+ {
+ queue.enqueue(this);
+ queue = null;
+ return true;
+ }
+ return false;
+ }
+}
Added: trunk/core/src/classpath/java/java/lang/ref/ReferenceQueue.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/ReferenceQueue.java (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/ReferenceQueue.java 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,145 @@
+/* java.lang.ref.ReferenceQueue
+ Copyright (C) 1999, 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang.ref;
+
+/**
+ * This is the queue, where references can enqueue themselve on. Each
+ * reference may be registered to a queue at initialization time and
+ * will be appended to the queue, when the enqueue method is called.
+ *
+ * The enqueue method may be automatically called by the garbage
+ * collector if it detects, that the object is only reachable through
+ * the Reference objects.
+ *
+ * @author Jochen Hoenicke
+ * @see Reference#enqueue()
+ */
+public class ReferenceQueue<T>
+{
+ /**
+ * This is a linked list of references. If this is null, the list is
+ * empty. Otherwise this points to the first reference on the queue.
+ * The first reference will point to the next reference via the
+ * <code>nextOnQueue</code> field. The last reference will point to
+ * itself (not to null, since <code>nextOnQueue</code> is used to
+ * determine if a reference is enqueued).
+ */
+ private Reference<? extends T> first;
+
+ /**
+ * Creates a new empty reference queue.
+ */
+ public ReferenceQueue()
+ {
+ }
+
+ /**
+ * Checks if there is a reference on the queue, returning it
+ * immediately. The reference will be dequeued.
+ *
+ * @return a reference on the queue, if there is one,
+ * <code>null</code> otherwise.
+ */
+ public synchronized Reference<? extends T> poll()
+ {
+ return dequeue();
+ }
+
+ /**
+ * This is called by reference to enqueue itself on this queue.
+ * @param ref the reference that should be enqueued.
+ */
+ synchronized void enqueue(Reference<? extends T> ref)
+ {
+ /* last reference will point to itself */
+ ref.nextOnQueue = first == null ? ref : first;
+ first = ref;
+ /* this wakes only one remove thread. */
+ notify();
+ }
+
+ /**
+ * Remove a reference from the queue, if there is one.
+ * @return the first element of the queue, or null if there isn't any.
+ */
+ private Reference<? extends T> dequeue()
+ {
+ if (first == null)
+ return null;
+
+ Reference<? extends T> result = first;
+ first = (first == first.nextOnQueue) ? null : first.nextOnQueue;
+ result.nextOnQueue = null;
+ return result;
+ }
+
+ /**
+ * Removes a reference from the queue, blocking for <code>timeout</code>
+ * until a reference is enqueued.
+ * @param timeout the timeout period in milliseconds, <code>0</code> means
+ * wait forever.
+ * @return the reference removed from the queue, or
+ * <code>null</code> if timeout period expired.
+ * @exception InterruptedException if the wait was interrupted.
+ */
+ public synchronized Reference<? extends T> remove(long timeout)
+ throws InterruptedException
+ {
+ if (first == null)
+ {
+ wait(timeout);
+ }
+
+ return dequeue();
+ }
+
+
+ /**
+ * Removes a reference from the queue, blocking until a reference is
+ * enqueued.
+ *
+ * @return the reference removed from the queue.
+ * @exception InterruptedException if the wait was interrupted.
+ */
+ public Reference<? extends T> remove()
+ throws InterruptedException
+ {
+ return remove(0L);
+ }
+}
Added: trunk/core/src/classpath/java/java/lang/ref/SoftReference.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/SoftReference.java (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/SoftReference.java 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,84 @@
+/* java.lang.ref.SoftReference
+ Copyright (C) 1999, 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang.ref;
+
+/**
+ * A soft reference will be cleared, if the object is only softly
+ * reachable and the garbage collection needs more memory. The garbage
+ * collection will use an intelligent strategy to determine which soft
+ * references it should clear. This makes a soft reference ideal for
+ * caches.<br>
+ *
+ * @author Jochen Hoenicke
+ */
+public class SoftReference<T>
+ extends Reference<T>
+{
+ /**
+ * Create a new soft reference, that is not registered to any queue.
+ * @param referent the object we refer to.
+ */
+ public SoftReference(T referent)
+ {
+ super(referent);
+ }
+
+ /**
+ * Create a new soft reference.
+ * @param referent the object we refer to.
+ * @param q the reference queue to register on.
+ * @exception NullPointerException if q is null.
+ */
+ public SoftReference(T referent, ReferenceQueue<? super T> q)
+ {
+ super(referent, q);
+ }
+
+ /**
+ * Returns the object, this reference refers to.
+ * @return the object, this reference refers to, or null if the
+ * reference was cleared.
+ */
+ public T get()
+ {
+ /* Why is this overloaded???
+ * Maybe for a kind of LRU strategy. */
+ return super.get();
+ }
+}
Added: trunk/core/src/classpath/java/java/lang/ref/WeakReference.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/WeakReference.java (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/WeakReference.java 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,79 @@
+/* java.lang.ref.WeakReference
+ Copyright (C) 1999, 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang.ref;
+
+/**
+ * A weak reference will be cleared, if the object is only weakly
+ * reachable. It is useful for lookup tables, where you aren't
+ * interested in an entry, if the key isn't reachable anymore.
+ * <code>WeakHashtable</code> is a complete implementation of such a
+ * table. <br>
+ *
+ * It is also useful to make objects unique: You create a set of weak
+ * references to those objects, and when you create a new object you
+ * look in this set, if the object already exists and return it. If
+ * an object is not referenced anymore, the reference will
+ * automatically cleared, and you may remove it from the set. <br>
+ *
+ * @author Jochen Hoenicke
+ * @see java.util.WeakHashMap
+ */
+public class WeakReference<T>
+ extends Reference<T>
+{
+ /**
+ * Create a new weak reference, that is not registered to any queue.
+ * @param referent the object we refer to.
+ */
+ public WeakReference(T referent)
+ {
+ super(referent);
+ }
+
+ /**
+ * Create a new weak reference.
+ * @param referent the object we refer to.
+ * @param q the reference queue to register on.
+ * @exception NullPointerException if q is null.
+ */
+ public WeakReference(T referent, ReferenceQueue<? super T> q)
+ {
+ super(referent, q);
+ }
+}
Added: trunk/core/src/classpath/java/java/lang/ref/package.html
===================================================================
--- trunk/core/src/classpath/java/java/lang/ref/package.html (rev 0)
+++ trunk/core/src/classpath/java/java/lang/ref/package.html 2006-12-12 21:13:38 UTC (rev 2899)
@@ -0,0 +1,46 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<!-- package.html - describes classes in java.lang.ref package.
+ Copyright (C) 2002 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. -->
+
+<html>
+<head><title>GNU Classpath - java.lang.ref</title></head>
+
+<body>
+<p>Low level manipulation and monitoring of object references.</p>
+
+</body>
+</html>
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