Makefile.am: Add HashSet.java and java/lang/ref classes.

* Makefile.am: Add HashSet.java and java/lang/ref classes.
	Remove BasicMapEntry.java and Bucket.java.
	* Makefile.in: Rebuilt.
	* java/util/HashMap.java: Rewritten.
	* java/util/HashSet.java: Imported from classpath.
	* java/util/WeakHashMap.java: Imported from classpath.
	* java/util/Hashtable.java: Rewritten based on new HashMap code.
	* java/util/Bucket.java: Deleted.
	* java/util/BasicMapEntry.java: Deleted.
	* java/util/Collections.java (search): Use a for-loop, not iterator
	hasNext().
	(copy): Use a for-loop. Throw an IndexOutOfBoundsException if run out
	of elements in source.
	(max): Use a for-loop.
	(min): Ditto.
	(reverse): Keep track of positions instead of using Iterator's
	nextIndex() and previousIndex().
	(shuffle(List)): Initialize defaultRandom if required using
	double-check thread safety idiom. Call two-argument shuffle method
	using defaultRandom.
	(defaultRandom): New field.
	(shuffle(List, Random)): Use a for-loop. Keep track of pos instead
	of using previousIndex() and nextIndex().
	(singletonMap(iterator)): Use a HashMap.Entry, not BasicMapEntry.
	* java/util/AbstractCollection.java (toString): Use a StringBuffer.
	* java/util/AbstractMap.java (toString): Use StringBuffer.
	* java/lang/ref/PhantomReference.java: Imported from classpath.
	* java/lang/ref/SoftReference.java: Ditto.
	* java/lang/ref/Reference.java: Ditto.
	* java/lang/ref/WeakReference.java: Ditto.
	* java/lang/ref/ReferenceQueue.java: Ditto.

From-SVN: r38183

libjava/java/lang/ref/SoftReference.java

@@ -0,0 +1,73 @@
+/* java.lang.ref.SoftReference
+   Copyright (C) 1999 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., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+As a special exception, if you link this library with other files to
+produce an executable, this library does not by itself cause the
+resulting executable to be covered by the GNU General Public License.
+This exception does not however invalidate any other reasons why the
+executable file might be covered by the GNU General Public License. */
+
+
+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 
+  extends Reference
+{
+  /**
+   * Create a new soft reference, that is not registered to any queue.
+   * @param referent the object we refer to.
+   */
+  public SoftReference(Object 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(Object referent, ReferenceQueue 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 Object get()
+  {
+    /* Why is this overloaded??? 
+     * Maybe for a kind of LRU strategy. */
+    return super.get();
+  }
+}