jdk8-mips64-public/corba: src/share/classes/com/sun/corba/se/impl/util/IdentityHashtable.java@643e7612cf6d (annotated)

src/share/classes/com/sun/corba/se/impl/util/IdentityHashtable.java@643e7612cf6d (annotated)

src/share/classes/com/sun/corba/se/impl/util/IdentityHashtable.java

Mon, 29 Oct 2012 14:10:49 +0100

author: ohrstrom
date: Mon, 29 Oct 2012 14:10:49 +0100
changeset 416: 643e7612cf6d
parent 158: 91006f157c46
child 748: 6845b95cba6b
permissions: -rw-r--r--

8000970: break out auxiliary classes that will prevent multi-core compilation of the JDK.
Reviewed-by: alanb, wetmore

 /*
  * Copyright (c) 1999, 2004, 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.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * 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.
  */
 /*
  * Licensed Materials - Property of IBM
  * RMI-IIOP v1.0
  * Copyright IBM Corp. 1998 1999  All Rights Reserved
  *
  */
 package com.sun.corba.se.impl.util;
 import java.util.Dictionary;
 import java.util.Enumeration;
 import java.util.NoSuchElementException;
 /**
  * IdentityHashtable is a modified copy of the 1.1.6 Hashtable class which
  * does not rely on the hashCode() and equals() methods of the key or value;
  * instead, it uses the System.identityHashcode() method and pointer comparison.
  * In addition, all synchronization has been removed.
  */
 public final class IdentityHashtable extends Dictionary {
     /**
      * The hash table data.
      */
     private transient IdentityHashtableEntry table[];
     /**
      * The total number of entries in the hash table.
      */
     private transient int count;
     /**
      * Rehashes the table when count exceeds this threshold.
      */
     private int threshold;
     /**
      * The load factor for the hashtable.
      */
     private float loadFactor;
     /**
      * Constructs a new, empty hashtable with the specified initial
      * capacity and the specified load factor.
      *
      * @param      initialCapacity   the initial capacity of the hashtable.
      * @param      loadFactor        a number between 0.0 and 1.0.
      * @exception  IllegalArgumentException  if the initial capacity is less
      *               than or equal to zero, or if the load factor is less than
      *               or equal to zero.
      * @since      JDK1.0
      */
     public IdentityHashtable(int initialCapacity, float loadFactor) {
         if ((initialCapacity <= 0) || (loadFactor <= 0.0)) {
             throw new IllegalArgumentException();
         }
         this.loadFactor = loadFactor;
         table = new IdentityHashtableEntry[initialCapacity];
         threshold = (int)(initialCapacity * loadFactor);
     }
     /**
      * Constructs a new, empty hashtable with the specified initial capacity
      * and default load factor.
      *
      * @param   initialCapacity   the initial capacity of the hashtable.
      * @since   JDK1.0
      */
     public IdentityHashtable(int initialCapacity) {
         this(initialCapacity, 0.75f);
     }
     /**
      * Constructs a new, empty hashtable with a default capacity and load
      * factor.
      *
      * @since   JDK1.0
      */
     public IdentityHashtable() {
         this(101, 0.75f);
     }
     /**
      * Returns the number of keys in this hashtable.
      *
      * @return  the number of keys in this hashtable.
      * @since   JDK1.0
      */
     public int size() {
         return count;
     }
     /**
      * Tests if this hashtable maps no keys to values.
      *
      * @return  <code>true</code> if this hashtable maps no keys to values;
      *          <code>false</code> otherwise.
      * @since   JDK1.0
      */
     public boolean isEmpty() {
         return count == 0;
     }
     /**
      * Returns an enumeration of the keys in this hashtable.
      *
      * @return  an enumeration of the keys in this hashtable.
      * @see     java.util.Enumeration
      * @see     java.util.Hashtable#elements()
      * @since   JDK1.0
      */
     public Enumeration keys() {
         return new IdentityHashtableEnumerator(table, true);
     }
     /**
      * Returns an enumeration of the values in this hashtable.
      * Use the Enumeration methods on the returned object to fetch the elements
      * sequentially.
      *
      * @return  an enumeration of the values in this hashtable.
      * @see     java.util.Enumeration
      * @see     java.util.Hashtable#keys()
      * @since   JDK1.0
      */
     public Enumeration elements() {
         return new IdentityHashtableEnumerator(table, false);
     }
     /**
      * Tests if some key maps into the specified value in this hashtable.
      * This operation is more expensive than the <code>containsKey</code>
      * method.
      *
      * @param      value   a value to search for.
      * @return     <code>true</code> if some key maps to the
      *             <code>value</code> argument in this hashtable;
      *             <code>false</code> otherwise.
      * @exception  NullPointerException  if the value is <code>null</code>.
      * @see        java.util.Hashtable#containsKey(java.lang.Object)
      * @since      JDK1.0
      */
     public boolean contains(Object value) {
         if (value == null) {
             throw new NullPointerException();
         }
         IdentityHashtableEntry tab[] = table;
         for (int i = tab.length ; i-- > 0 ;) {
             for (IdentityHashtableEntry e = tab[i] ; e != null ; e = e.next) {
                 if (e.value == value) {
                     return true;
                 }
             }
         }
         return false;
     }
     /**
      * Tests if the specified object is a key in this hashtable.
      *
      * @param   key   possible key.
      * @return  <code>true</code> if the specified object is a key in this
      *          hashtable; <code>false</code> otherwise.
      * @see     java.util.Hashtable#contains(java.lang.Object)
      * @since   JDK1.0
      */
     public boolean containsKey(Object key) {
         IdentityHashtableEntry tab[] = table;
         int hash = System.identityHashCode(key);
         int index = (hash & 0x7FFFFFFF) % tab.length;
         for (IdentityHashtableEntry e = tab[index] ; e != null ; e = e.next) {
             if ((e.hash == hash) && e.key == key) {
                 return true;
             }
         }
         return false;
     }
     /**
      * Returns the value to which the specified key is mapped in this hashtable.
      *
      * @param   key   a key in the hashtable.
      * @return  the value to which the key is mapped in this hashtable;
      *          <code>null</code> if the key is not mapped to any value in
      *          this hashtable.
      * @see     java.util.Hashtable#put(java.lang.Object, java.lang.Object)
      * @since   JDK1.0
      */
     public Object get(Object key) {
         IdentityHashtableEntry tab[] = table;
         int hash = System.identityHashCode(key);
         int index = (hash & 0x7FFFFFFF) % tab.length;
         for (IdentityHashtableEntry e = tab[index] ; e != null ; e = e.next) {
             if ((e.hash == hash) && e.key == key) {
                 return e.value;
             }
         }
         return null;
     }
     /**
      * Rehashes the contents of the hashtable into a hashtable with a
      * larger capacity. This method is called automatically when the
      * number of keys in the hashtable exceeds this hashtable's capacity
      * and load factor.
      *
      * @since   JDK1.0
      */
     protected void rehash() {
         int oldCapacity = table.length;
         IdentityHashtableEntry oldTable[] = table;
         int newCapacity = oldCapacity * 2 + 1;
         IdentityHashtableEntry newTable[] = new IdentityHashtableEntry[newCapacity];
         threshold = (int)(newCapacity * loadFactor);
         table = newTable;
         //System.out.println("rehash old=" + oldCapacity + ", new=" + newCapacity + ", thresh=" + threshold + ", count=" + count);
         for (int i = oldCapacity ; i-- > 0 ;) {
             for (IdentityHashtableEntry old = oldTable[i] ; old != null ; ) {
                 IdentityHashtableEntry e = old;
                 old = old.next;
                 int index = (e.hash & 0x7FFFFFFF) % newCapacity;
                 e.next = newTable[index];
                 newTable[index] = e;
             }
         }
     }
     /**
      * Maps the specified <code>key</code> to the specified
      * <code>value</code> in this hashtable. Neither the key nor the
      * value can be <code>null</code>.
      * <p>
      * The value can be retrieved by calling the <code>get</code> method
      * with a key that is equal to the original key.
      *
      * @param      key     the hashtable key.
      * @param      value   the value.
      * @return     the previous value of the specified key in this hashtable,
      *             or <code>null</code> if it did not have one.
      * @exception  NullPointerException  if the key or value is
      *               <code>null</code>.
      * @see     java.util.Hashtable#get(java.lang.Object)
      * @since   JDK1.0
      */
     public Object put(Object key, Object value) {
         // Make sure the value is not null
         if (value == null) {
             throw new NullPointerException();
         }
         // Makes sure the key is not already in the hashtable.
         IdentityHashtableEntry tab[] = table;
         int hash = System.identityHashCode(key);
         int index = (hash & 0x7FFFFFFF) % tab.length;
         for (IdentityHashtableEntry e = tab[index] ; e != null ; e = e.next) {
             if ((e.hash == hash) && e.key == key) {
                 Object old = e.value;
                 e.value = value;
                 return old;
             }
         }
         if (count >= threshold) {
             // Rehash the table if the threshold is exceeded
             rehash();
             return put(key, value);
         }
         // Creates the new entry.
         IdentityHashtableEntry e = new IdentityHashtableEntry();
         e.hash = hash;
         e.key = key;
         e.value = value;
         e.next = tab[index];
         tab[index] = e;
         count++;
         return null;
     }
         /**
      * Removes the key (and its corresponding value) from this
      * hashtable. This method does nothing if the key is not in the hashtable.
      *
      * @param   key   the key that needs to be removed.
      * @return  the value to which the key had been mapped in this hashtable,
      *          or <code>null</code> if the key did not have a mapping.
      * @since   JDK1.0
      */
     public Object remove(Object key) {
         IdentityHashtableEntry tab[] = table;
         int hash = System.identityHashCode(key);
         int index = (hash & 0x7FFFFFFF) % tab.length;
         for (IdentityHashtableEntry e = tab[index], prev = null ; e != null ; prev = e, e = e.next) {
             if ((e.hash == hash) && e.key == key) {
                 if (prev != null) {
                     prev.next = e.next;
                 } else {
                     tab[index] = e.next;
                 }
                 count--;
                 return e.value;
             }
         }
         return null;
     }
     /**
      * Clears this hashtable so that it contains no keys.
      *
      * @since   JDK1.0
      */
     public void clear() {
         IdentityHashtableEntry tab[] = table;
         for (int index = tab.length; --index >= 0; )
             tab[index] = null;
         count = 0;
     }
     /**
      * Returns a rather long string representation of this hashtable.
      *
      * @return  a string representation of this hashtable.
      * @since   JDK1.0
      */
     public String toString() {
         int max = size() - 1;
         StringBuffer buf = new StringBuffer();
         Enumeration k = keys();
         Enumeration e = elements();
         buf.append("{");
         for (int i = 0; i <= max; i++) {
             String s1 = k.nextElement().toString();
             String s2 = e.nextElement().toString();
             buf.append(s1 + "=" + s2);
             if (i < max) {
                 buf.append(", ");
             }
         }
         buf.append("}");
         return buf.toString();
     }
 }

Mercurial > jdk8-mips64-public > corba / annotate

src/share/classes/com/sun/corba/se/impl/util/IdentityHashtable.java@643e7612cf6d (annotated)

src/share/classes/com/sun/corba/se/impl/util/IdentityHashtable.java