--- /dev/null
+/*
+ * @(#)Hashtable.java 1.105 03/12/19
+ *
+ * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
+ * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ */
+
+package instrumented.java15.util;
+import java.io.*;
+
+/**
+ * This class implements a hashtable, which maps keys to values. Any
+ * non-<code>null</code> object can be used as a key or as a value. <p>
+ *
+ * To successfully store and retrieve objects from a hashtable, the
+ * objects used as keys must implement the <code>hashCode</code>
+ * method and the <code>equals</code> method. <p>
+ *
+ * An instance of <code>Hashtable</code> has two parameters that affect its
+ * performance: <i>initial capacity</i> and <i>load factor</i>. The
+ * <i>capacity</i> is the number of <i>buckets</i> in the hash table, and the
+ * <i>initial capacity</i> is simply the capacity at the time the hash table
+ * is created. Note that the hash table is <i>open</i>: in the case of a "hash
+ * collision", a single bucket stores multiple entries, which must be searched
+ * sequentially. The <i>load factor</i> is a measure of how full the hash
+ * table is allowed to get before its capacity is automatically increased.
+ * The initial capacity and load factor parameters are merely hints to
+ * the implementation. The exact details as to when and whether the rehash
+ * method is invoked are implementation-dependent.<p>
+ *
+ * Generally, the default load factor (.75) offers a good tradeoff between
+ * time and space costs. Higher values decrease the space overhead but
+ * increase the time cost to look up an entry (which is reflected in most
+ * <tt>Hashtable</tt> operations, including <tt>get</tt> and <tt>put</tt>).<p>
+ *
+ * The initial capacity controls a tradeoff between wasted space and the
+ * need for <code>rehash</code> operations, which are time-consuming.
+ * No <code>rehash</code> operations will <i>ever</i> occur if the initial
+ * capacity is greater than the maximum number of entries the
+ * <tt>Hashtable</tt> will contain divided by its load factor. However,
+ * setting the initial capacity too high can waste space.<p>
+ *
+ * If many entries are to be made into a <code>Hashtable</code>,
+ * creating it with a sufficiently large capacity may allow the
+ * entries to be inserted more efficiently than letting it perform
+ * automatic rehashing as needed to grow the table. <p>
+ *
+ * This example creates a hashtable of numbers. It uses the names of
+ * the numbers as keys:
+ * <p><blockquote><pre>
+ * Hashtable numbers = new Hashtable();
+ * numbers.put("one", new Integer(1));
+ * numbers.put("two", new Integer(2));
+ * numbers.put("three", new Integer(3));
+ * </pre></blockquote>
+ * <p>
+ * To retrieve a number, use the following code:
+ * <p><blockquote><pre>
+ * Integer n = (Integer)numbers.get("two");
+ * if (n != null) {
+ * System.out.println("two = " + n);
+ * }
+ * </pre></blockquote>
+ * <p>
+ * As of the Java 2 platform v1.2, this class has been retrofitted to
+ * implement Map, so that it becomes a part of Java's collection framework.
+ * Unlike the new collection implementations, Hashtable is synchronized.<p>
+ *
+ * The Iterators returned by the iterator and listIterator methods
+ * of the Collections returned by all of Hashtable's "collection view methods"
+ * are <em>fail-fast</em>: if the Hashtable is structurally modified
+ * at any time after the Iterator is created, in any way except through the
+ * Iterator's own remove or add methods, the Iterator will throw a
+ * ConcurrentModificationException. Thus, in the face of concurrent
+ * modification, the Iterator fails quickly and cleanly, rather than risking
+ * arbitrary, non-deterministic behavior at an undetermined time in the future.
+ * The Enumerations returned by Hashtable's keys and values methods are
+ * <em>not</em> fail-fast.
+ *
+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
+ * as it is, generally speaking, impossible to make any hard guarantees in the
+ * presence of unsynchronized concurrent modification. Fail-fast iterators
+ * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
+ * Therefore, it would be wrong to write a program that depended on this
+ * exception for its correctness: <i>the fail-fast behavior of iterators
+ * should be used only to detect bugs.</i><p>
+ *
+ * This class is a member of the
+ * <a href="{@docRoot}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @author Arthur van Hoff
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @version 1.105, 12/19/03
+ * @see Object#equals(java.lang.Object)
+ * @see Object#hashCode()
+ * @see Hashtable#rehash()
+ * @see Collection
+ * @see Map
+ * @see HashMap
+ * @see TreeMap
+ * @since JDK1.0
+ */
+public class Hashtable<K,V>
+ extends Dictionary<K,V>
+ implements Map<K,V>, Cloneable, java.io.Serializable {
+
+ /**
+ * The hash table data.
+ */
+ private transient Entry[] table;
+
+ /**
+ * The total number of entries in the hash table.
+ */
+ private transient int count;
+
+ /**
+ * The table is rehashed when its size exceeds this threshold. (The
+ * value of this field is (int)(capacity * loadFactor).)
+ *
+ * @serial
+ */
+ private int threshold;
+
+ /**
+ * The load factor for the hashtable.
+ *
+ * @serial
+ */
+ private float loadFactor;
+
+ /**
+ * The number of times this Hashtable has been structurally modified
+ * Structural modifications are those that change the number of entries in
+ * the Hashtable or otherwise modify its internal structure (e.g.,
+ * rehash). This field is used to make iterators on Collection-views of
+ * the Hashtable fail-fast. (See ConcurrentModificationException).
+ */
+ private transient int modCount = 0;
+
+ /** use serialVersionUID from JDK 1.0.2 for interoperability */
+ private static final long serialVersionUID = 1421746759512286392L;
+
+ /**
+ * 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 the load factor of the hashtable.
+ * @exception IllegalArgumentException if the initial capacity is less
+ * than zero, or if the load factor is nonpositive.
+ */
+ public Hashtable(int initialCapacity, float loadFactor) {
+ if (initialCapacity < 0)
+ throw new IllegalArgumentException("Illegal Capacity: "+
+ initialCapacity);
+ if (loadFactor <= 0 || Float.isNaN(loadFactor))
+ throw new IllegalArgumentException("Illegal Load: "+loadFactor);
+
+ if (initialCapacity==0)
+ initialCapacity = 1;
+ this.loadFactor = loadFactor;
+ table = new Entry[initialCapacity];
+ threshold = (int)(initialCapacity * loadFactor);
+ }
+
+ /**
+ * Constructs a new, empty hashtable with the specified initial capacity
+ * and default load factor, which is <tt>0.75</tt>.
+ *
+ * @param initialCapacity the initial capacity of the hashtable.
+ * @exception IllegalArgumentException if the initial capacity is less
+ * than zero.
+ */
+ public Hashtable(int initialCapacity) {
+ this(initialCapacity, 0.75f);
+ }
+
+ /**
+ * Constructs a new, empty hashtable with a default initial capacity (11)
+ * and load factor, which is <tt>0.75</tt>.
+ */
+ public Hashtable() {
+ this(11, 0.75f);
+ }
+
+ /**
+ * Constructs a new hashtable with the same mappings as the given
+ * Map. The hashtable is created with an initial capacity sufficient to
+ * hold the mappings in the given Map and a default load factor, which is
+ * <tt>0.75</tt>.
+ *
+ * @param t the map whose mappings are to be placed in this map.
+ * @throws NullPointerException if the specified map is null.
+ * @since 1.2
+ */
+ public Hashtable(Map<? extends K, ? extends V> t) {
+ this(Math.max(2*t.size(), 11), 0.75f);
+ putAll(t);
+ }
+
+ /**
+ * Returns the number of keys in this hashtable.
+ *
+ * @return the number of keys in this hashtable.
+ */
+ public synchronized 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.
+ */
+ public synchronized boolean isEmpty() {
+ return count == 0;
+ }
+
+ /**
+ * Returns an enumeration of the keys in this hashtable.
+ *
+ * @return an enumeration of the keys in this hashtable.
+ * @see Enumeration
+ * @see #elements()
+ * @see #keySet()
+ * @see Map
+ */
+ public synchronized Enumeration<K> keys() {
+ return this.<K>getEnumeration(KEYS);
+ }
+
+ /**
+ * 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 benchmarks.instrumented.java15.util.Enumeration
+ * @see #keys()
+ * @see #values()
+ * @see Map
+ */
+ public synchronized Enumeration<V> elements() {
+ return this.<V>getEnumeration(VALUES);
+ }
+
+ /**
+ * Tests if some key maps into the specified value in this hashtable.
+ * This operation is more expensive than the <code>containsKey</code>
+ * method.<p>
+ *
+ * Note that this method is identical in functionality to containsValue,
+ * (which is part of the Map interface in the collections framework).
+ *
+ * @param value a value to search for.
+ * @return <code>true</code> if and only if some key maps to the
+ * <code>value</code> argument in this hashtable as
+ * determined by the <tt>equals</tt> method;
+ * <code>false</code> otherwise.
+ * @exception NullPointerException if the value is <code>null</code>.
+ * @see #containsKey(Object)
+ * @see #containsValue(Object)
+ * @see Map
+ */
+ public synchronized boolean contains(Object value) {
+ if (value == null) {
+ throw new NullPointerException();
+ }
+
+ Entry tab[] = table;
+ for (int i = tab.length ; i-- > 0 ;) {
+ for (Entry<K,V> e = tab[i] ; e != null ; e = e.next) {
+ if (e.value.equals(value)) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Returns true if this Hashtable maps one or more keys to this value.<p>
+ *
+ * Note that this method is identical in functionality to contains
+ * (which predates the Map interface).
+ *
+ * @param value value whose presence in this Hashtable is to be tested.
+ * @return <tt>true</tt> if this map maps one or more keys to the
+ * specified value.
+ * @throws NullPointerException if the value is <code>null</code>.
+ * @see Map
+ * @since 1.2
+ */
+ public boolean containsValue(Object value) {
+ return contains(value);
+ }
+
+ /**
+ * Tests if the specified object is a key in this hashtable.
+ *
+ * @param key possible key.
+ * @return <code>true</code> if and only if the specified object
+ * is a key in this hashtable, as determined by the
+ * <tt>equals</tt> method; <code>false</code> otherwise.
+ * @throws NullPointerException if the key is <code>null</code>.
+ * @see #contains(Object)
+ */
+ public synchronized boolean containsKey(Object key) {
+ Entry tab[] = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+ for (Entry<K,V> e = tab[index] ; e != null ; e = e.next) {
+ if ((e.hash == hash) && e.key.equals(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.
+ * @throws NullPointerException if the key is <code>null</code>.
+ * @see #put(Object, Object)
+ */
+ public synchronized V get(Object key) {
+ Entry tab[] = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+ for (Entry<K,V> e = tab[index] ; e != null ; e = e.next) {
+ if ((e.hash == hash) && e.key.equals(key)) {
+ return e.value;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Increases the capacity of and internally reorganizes this
+ * hashtable, in order to accommodate and access its entries more
+ * efficiently. This method is called automatically when the
+ * number of keys in the hashtable exceeds this hashtable's capacity
+ * and load factor.
+ */
+ protected void rehash() {
+ int oldCapacity = table.length;
+ Entry[] oldMap = table;
+
+ int newCapacity = oldCapacity * 2 + 1;
+ Entry[] newMap = new Entry[newCapacity];
+
+ modCount++;
+ threshold = (int)(newCapacity * loadFactor);
+ table = newMap;
+
+ for (int i = oldCapacity ; i-- > 0 ;) {
+ for (Entry<K,V> old = oldMap[i] ; old != null ; ) {
+ Entry<K,V> e = old;
+ old = old.next;
+
+ int index = (e.hash & 0x7FFFFFFF) % newCapacity;
+ e.next = newMap[index];
+ newMap[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 Object#equals(Object)
+ * @see #get(Object)
+ */
+ public synchronized V put(K key, V value) {
+ // Make sure the value is not null
+ if (value == null) {
+ throw new NullPointerException();
+ }
+
+ // Makes sure the key is not already in the hashtable.
+ Entry tab[] = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+ for (Entry<K,V> e = tab[index] ; e != null ; e = e.next) {
+ if ((e.hash == hash) && e.key.equals(key)) {
+ V old = e.value;
+ e.value = value;
+ return old;
+ }
+ }
+
+ modCount++;
+ if (count >= threshold) {
+ // Rehash the table if the threshold is exceeded
+ rehash();
+
+ tab = table;
+ index = (hash & 0x7FFFFFFF) % tab.length;
+ }
+
+ // Creates the new entry.
+ Entry<K,V> e = tab[index];
+ tab[index] = new Entry<K,V>(hash, key, value, 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.
+ * @throws NullPointerException if the key is <code>null</code>.
+ */
+ public synchronized V remove(Object key) {
+ Entry tab[] = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+ for (Entry<K,V> e = tab[index], prev = null ; e != null ; prev = e, e = e.next) {
+ if ((e.hash == hash) && e.key.equals(key)) {
+ modCount++;
+ if (prev != null) {
+ prev.next = e.next;
+ } else {
+ tab[index] = e.next;
+ }
+ count--;
+ V oldValue = e.value;
+ e.value = null;
+ return oldValue;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Copies all of the mappings from the specified Map to this Hashtable
+ * These mappings will replace any mappings that this Hashtable had for any
+ * of the keys currently in the specified Map.
+ *
+ * @param t Mappings to be stored in this map.
+ * @throws NullPointerException if the specified map is null.
+ * @since 1.2
+ */
+ public synchronized void putAll(Map<? extends K, ? extends V> t) {
+ Iterator<? extends Map.Entry<? extends K, ? extends V>> i = t.entrySet().iterator();
+ while (i.hasNext()) {
+ Map.Entry<? extends K, ? extends V> e = i.next();
+ put(e.getKey(), e.getValue());
+ }
+ }
+
+ /**
+ * Clears this hashtable so that it contains no keys.
+ */
+ public synchronized void clear() {
+ Entry tab[] = table;
+ modCount++;
+ for (int index = tab.length; --index >= 0; )
+ tab[index] = null;
+ count = 0;
+ }
+
+ /**
+ * Creates a shallow copy of this hashtable. All the structure of the
+ * hashtable itself is copied, but the keys and values are not cloned.
+ * This is a relatively expensive operation.
+ *
+ * @return a clone of the hashtable.
+ */
+ public synchronized Object clone() {
+ try {
+ Hashtable<K,V> t = (Hashtable<K,V>) super.clone();
+ t.table = new Entry[table.length];
+ for (int i = table.length ; i-- > 0 ; ) {
+ t.table[i] = (table[i] != null)
+ ? (Entry<K,V>) table[i].clone() : null;
+ }
+ t.keySet = null;
+ t.entrySet = null;
+ t.values = null;
+ t.modCount = 0;
+ return t;
+ } catch (CloneNotSupportedException e) {
+ // this shouldn't happen, since we are Cloneable
+ throw new InternalError();
+ }
+ }
+
+ /**
+ * Returns a string representation of this <tt>Hashtable</tt> object
+ * in the form of a set of entries, enclosed in braces and separated
+ * by the ASCII characters "<tt>, </tt>" (comma and space). Each
+ * entry is rendered as the key, an equals sign <tt>=</tt>, and the
+ * associated element, where the <tt>toString</tt> method is used to
+ * convert the key and element to strings. <p>Overrides to
+ * <tt>toString</tt> method of <tt>Object</tt>.
+ *
+ * @return a string representation of this hashtable.
+ */
+ public synchronized String toString() {
+ int max = size() - 1;
+ StringBuffer buf = new StringBuffer();
+ Iterator<Map.Entry<K,V>> it = entrySet().iterator();
+
+ buf.append("{");
+ for (int i = 0; i <= max; i++) {
+ Map.Entry<K,V> e = it.next();
+ K key = e.getKey();
+ V value = e.getValue();
+ buf.append((key == this ? "(this Map)" : (""+key)) + "=" +
+ (value == this ? "(this Map)" : (""+value)));
+
+ if (i < max)
+ buf.append(", ");
+ }
+ buf.append("}");
+ return buf.toString();
+ }
+
+
+ private <T> Enumeration<T> getEnumeration(int type) {
+ if (count == 0) {
+ return (Enumeration<T>)emptyEnumerator;
+ } else {
+ return new Enumerator<T>(type, false);
+ }
+ }
+
+ private <T> Iterator<T> getIterator(int type) {
+ if (count == 0) {
+ return (Iterator<T>) emptyIterator;
+ } else {
+ return new Enumerator<T>(type, true);
+ }
+ }
+
+ // Views
+
+ /**
+ * Each of these fields are initialized to contain an instance of the
+ * appropriate view the first time this view is requested. The views are
+ * stateless, so there's no reason to create more than one of each.
+ */
+ private transient volatile Set<K> keySet = null;
+ private transient volatile Set<Map.Entry<K,V>> entrySet = null;
+ private transient volatile Collection<V> values = null;
+
+ /**
+ * Returns a Set view of the keys contained in this Hashtable. The Set
+ * is backed by the Hashtable, so changes to the Hashtable are reflected
+ * in the Set, and vice-versa. The Set supports element removal
+ * (which removes the corresponding entry from the Hashtable), but not
+ * element addition.
+ *
+ * @return a set view of the keys contained in this map.
+ * @since 1.2
+ */
+ public Set<K> keySet() {
+ if (keySet == null)
+ keySet = Collections.synchronizedSet(new KeySet(), this);
+ return keySet;
+ }
+
+ private class KeySet extends AbstractSet<K> {
+ public Iterator<K> iterator() {
+ return getIterator(KEYS);
+ }
+ public int size() {
+ return count;
+ }
+ public boolean contains(Object o) {
+ return containsKey(o);
+ }
+ public boolean remove(Object o) {
+ return Hashtable.this.remove(o) != null;
+ }
+ public void clear() {
+ Hashtable.this.clear();
+ }
+ }
+
+ /**
+ * Returns a Set view of the entries contained in this Hashtable.
+ * Each element in this collection is a Map.Entry. The Set is
+ * backed by the Hashtable, so changes to the Hashtable are reflected in
+ * the Set, and vice-versa. The Set supports element removal
+ * (which removes the corresponding entry from the Hashtable),
+ * but not element addition.
+ *
+ * @return a set view of the mappings contained in this map.
+ * @see Map.Entry
+ * @since 1.2
+ */
+ public Set<Map.Entry<K,V>> entrySet() {
+ if (entrySet==null)
+ entrySet = Collections.synchronizedSet(new EntrySet(), this);
+ return entrySet;
+ }
+
+ private class EntrySet extends AbstractSet/*<Map.Entry<K,V>>*/ {
+ public Iterator/*<Map.Entry<K,V>>*/ iterator() {
+ return getIterator(ENTRIES);
+ }
+
+ public boolean add(Object/*Map.Entry<K,V>*/ o) {
+ return super.add(o);
+ }
+
+ public boolean contains(Object o) {
+ if (!(o instanceof Map.Entry))
+ return false;
+ Map.Entry entry = (Map.Entry)o;
+ Object key = entry.getKey();
+ Entry[] tab = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+
+ for (Entry e = tab[index]; e != null; e = e.next)
+ if (e.hash==hash && e.equals(entry))
+ return true;
+ return false;
+ }
+
+ public boolean remove(Object o) {
+ if (!(o instanceof Map.Entry))
+ return false;
+ Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
+ K key = entry.getKey();
+ Entry[] tab = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+
+ for (Entry<K,V> e = tab[index], prev = null; e != null;
+ prev = e, e = e.next) {
+ if (e.hash==hash && e.equals(entry)) {
+ modCount++;
+ if (prev != null)
+ prev.next = e.next;
+ else
+ tab[index] = e.next;
+
+ count--;
+ e.value = null;
+ return true;
+ }
+ }
+ return false;
+ }
+
+ public int size() {
+ return count;
+ }
+
+ public void clear() {
+ Hashtable.this.clear();
+ }
+ }
+
+ /**
+ * Returns a Collection view of the values contained in this Hashtable.
+ * The Collection is backed by the Hashtable, so changes to the Hashtable
+ * are reflected in the Collection, and vice-versa. The Collection
+ * supports element removal (which removes the corresponding entry from
+ * the Hashtable), but not element addition.
+ *
+ * @return a collection view of the values contained in this map.
+ * @since 1.2
+ */
+ public Collection<V> values() {
+ if (values==null)
+ values = Collections.synchronizedCollection(new ValueCollection(),
+ this);
+ return values;
+ }
+
+ private class ValueCollection extends AbstractCollection<V> {
+ public Iterator<V> iterator() {
+ return getIterator(VALUES);
+ }
+ public int size() {
+ return count;
+ }
+ public boolean contains(Object o) {
+ return containsValue(o);
+ }
+ public void clear() {
+ Hashtable.this.clear();
+ }
+ }
+
+ // Comparison and hashing
+
+ /**
+ * Compares the specified Object with this Map for equality,
+ * as per the definition in the Map interface.
+ *
+ * @param o object to be compared for equality with this Hashtable
+ * @return true if the specified Object is equal to this Map.
+ * @see Map#equals(Object)
+ * @since 1.2
+ */
+ public synchronized boolean equals(Object o) {
+ if (o == this)
+ return true;
+
+ if (!(o instanceof Map))
+ return false;
+ Map<K,V> t = (Map<K,V>) o;
+ if (t.size() != size())
+ return false;
+
+ try {
+ Iterator<Map.Entry<K,V>> i = entrySet().iterator();
+ while (i.hasNext()) {
+ Map.Entry<K,V> e = i.next();
+ K key = e.getKey();
+ V value = e.getValue();
+ if (value == null) {
+ if (!(t.get(key)==null && t.containsKey(key)))
+ return false;
+ } else {
+ if (!value.equals(t.get(key)))
+ return false;
+ }
+ }
+ } catch(ClassCastException unused) {
+ return false;
+ } catch(NullPointerException unused) {
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Returns the hash code value for this Map as per the definition in the
+ * Map interface.
+ *
+ * @see Map#hashCode()
+ * @since 1.2
+ */
+ public synchronized int hashCode() {
+ /*
+ * This code detects the recursion caused by computing the hash code
+ * of a self-referential hash table and prevents the stack overflow
+ * that would otherwise result. This allows certain 1.1-era
+ * applets with self-referential hash tables to work. This code
+ * abuses the loadFactor field to do double-duty as a hashCode
+ * in progress flag, so as not to worsen the space performance.
+ * A negative load factor indicates that hash code computation is
+ * in progress.
+ */
+ int h = 0;
+ if (count == 0 || loadFactor < 0)
+ return h; // Returns zero
+
+ loadFactor = -loadFactor; // Mark hashCode computation in progress
+ Entry[] tab = table;
+ for (int i = 0; i < tab.length; i++)
+ for (Entry e = tab[i]; e != null; e = e.next)
+ h += e.key.hashCode() ^ e.value.hashCode();
+ loadFactor = -loadFactor; // Mark hashCode computation complete
+
+ return h;
+ }
+
+ /**
+ * Save the state of the Hashtable to a stream (i.e., serialize it).
+ *
+ * @serialData The <i>capacity</i> of the Hashtable (the length of the
+ * bucket array) is emitted (int), followed by the
+ * <i>size</i> of the Hashtable (the number of key-value
+ * mappings), followed by the key (Object) and value (Object)
+ * for each key-value mapping represented by the Hashtable
+ * The key-value mappings are emitted in no particular order.
+ */
+ private synchronized void writeObject(java.io.ObjectOutputStream s)
+ throws IOException
+ {
+ // Write out the length, threshold, loadfactor
+ s.defaultWriteObject();
+
+ // Write out length, count of elements and then the key/value objects
+ s.writeInt(table.length);
+ s.writeInt(count);
+ for (int index = table.length-1; index >= 0; index--) {
+ Entry entry = table[index];
+
+ while (entry != null) {
+ s.writeObject(entry.key);
+ s.writeObject(entry.value);
+ entry = entry.next;
+ }
+ }
+ }
+
+ /**
+ * Reconstitute the Hashtable from a stream (i.e., deserialize it).
+ */
+ private void readObject(java.io.ObjectInputStream s)
+ throws IOException, ClassNotFoundException
+ {
+ // Read in the length, threshold, and loadfactor
+ s.defaultReadObject();
+
+ // Read the original length of the array and number of elements
+ int origlength = s.readInt();
+ int elements = s.readInt();
+
+ // Compute new size with a bit of room 5% to grow but
+ // no larger than the original size. Make the length
+ // odd if it's large enough, this helps distribute the entries.
+ // Guard against the length ending up zero, that's not valid.
+ int length = (int)(elements * loadFactor) + (elements / 20) + 3;
+ if (length > elements && (length & 1) == 0)
+ length--;
+ if (origlength > 0 && length > origlength)
+ length = origlength;
+
+ table = new Entry[length];
+ count = 0;
+
+ // Read the number of elements and then all the key/value objects
+ for (; elements > 0; elements--) {
+ K key = (K)s.readObject();
+ V value = (V)s.readObject();
+ // synch could be eliminated for performance
+ reconstitutionPut(key, value);
+ }
+ }
+
+ /**
+ * The put method used by readObject. This is provided because put
+ * is overridable and should not be called in readObject since the
+ * subclass will not yet be initialized.
+ *
+ * <p>This differs from the regular put method in several ways. No
+ * checking for rehashing is necessary since the number of elements
+ * initially in the table is known. The modCount is not incremented
+ * because we are creating a new instance. Also, no return value
+ * is needed.
+ */
+ private void reconstitutionPut(K key, V value)
+ throws StreamCorruptedException
+ {
+ if (value == null) {
+ throw new java.io.StreamCorruptedException();
+ }
+ // Makes sure the key is not already in the hashtable.
+ // This should not happen in deserialized version.
+ Entry[] tab = table;
+ int hash = key.hashCode();
+ int index = (hash & 0x7FFFFFFF) % tab.length;
+ for (Entry<K,V> e = tab[index] ; e != null ; e = e.next) {
+ if ((e.hash == hash) && e.key.equals(key)) {
+ throw new java.io.StreamCorruptedException();
+ }
+ }
+ // Creates the new entry.
+ Entry<K,V> e = tab[index];
+ tab[index] = new Entry<K,V>(hash, key, value, e);
+ count++;
+ }
+
+ /**
+ * Hashtable collision list.
+ */
+ private static class Entry<K,V> implements Map.Entry<K,V> {
+ int hash;
+ K key;
+ V value;
+ Entry<K,V> next;
+
+ protected Entry(int hash, K key, V value, Entry<K,V> next) {
+ this.hash = hash;
+ this.key = key;
+ this.value = value;
+ this.next = next;
+ }
+
+ protected Object clone() {
+ return new Entry<K,V>(hash, key, value,
+ (next==null ? null : (Entry<K,V>) next.clone()));
+ }
+
+ // Map.Entry Ops
+
+ public K getKey() {
+ return key;
+ }
+
+ public V getValue() {
+ return value;
+ }
+
+ public V setValue(V value) {
+ if (value == null)
+ throw new NullPointerException();
+
+ V oldValue = this.value;
+ this.value = value;
+ return oldValue;
+ }
+
+ public boolean equals(Object o) {
+ if (!(o instanceof Map.Entry))
+ return false;
+ Map.Entry e = (Map.Entry)o;
+
+ return (key==null ? e.getKey()==null : key.equals(e.getKey())) &&
+ (value==null ? e.getValue()==null : value.equals(e.getValue()));
+ }
+
+ public int hashCode() {
+ return hash ^ (value==null ? 0 : value.hashCode());
+ }
+
+ public String toString() {
+ return key.toString()+"="+value.toString();
+ }
+ }
+
+ // Types of Enumerations/Iterations
+ private static final int KEYS = 0;
+ private static final int VALUES = 1;
+ private static final int ENTRIES = 2;
+
+ /**
+ * A hashtable enumerator class. This class implements both the
+ * Enumeration and Iterator interfaces, but individual instances
+ * can be created with the Iterator methods disabled. This is necessary
+ * to avoid unintentionally increasing the capabilities granted a user
+ * by passing an Enumeration.
+ */
+ private class Enumerator<T> implements Enumeration<T>, Iterator<T> {
+ Entry[] table = Hashtable.this.table;
+ int index = table.length;
+ Entry<K,V> entry = null;
+ Entry<K,V> lastReturned = null;
+ int type;
+
+ /**
+ * Indicates whether this Enumerator is serving as an Iterator
+ * or an Enumeration. (true -> Iterator).
+ */
+ boolean iterator;
+
+ /**
+ * The modCount value that the iterator believes that the backing
+ * List should have. If this expectation is violated, the iterator
+ * has detected concurrent modification.
+ */
+ protected int expectedModCount = modCount;
+
+ Enumerator(int type, boolean iterator) {
+ this.type = type;
+ this.iterator = iterator;
+ }
+
+ public boolean hasMoreElements() {
+ Entry<K,V> e = entry;
+ int i = index;
+ Entry[] t = table;
+ /* Use locals for faster loop iteration */
+ while (e == null && i > 0) {
+ e = t[--i];
+ }
+ entry = e;
+ index = i;
+ return e != null;
+ }
+
+ public T nextElement() {
+ Entry<K,V> et = entry;
+ int i = index;
+ Entry[] t = table;
+ /* Use locals for faster loop iteration */
+ while (et == null && i > 0) {
+ et = t[--i];
+ }
+ entry = et;
+ index = i;
+ if (et != null) {
+ Entry<K,V> e = lastReturned = entry;
+ entry = e.next;
+ return type == KEYS ? (T)e.key : (type == VALUES ? (T)e.value : (T)e);
+ }
+ throw new NoSuchElementException("Hashtable Enumerator");
+ }
+
+ // Iterator methods
+ public boolean hasNext() {
+ return hasMoreElements();
+ }
+
+ public T next() {
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ return nextElement();
+ }
+
+ public void remove() {
+ if (!iterator)
+ throw new UnsupportedOperationException();
+ if (lastReturned == null)
+ throw new IllegalStateException("Hashtable Enumerator");
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+
+ synchronized(Hashtable.this) {
+ Entry[] tab = Hashtable.this.table;
+ int index = (lastReturned.hash & 0x7FFFFFFF) % tab.length;
+
+ for (Entry<K,V> e = tab[index], prev = null; e != null;
+ prev = e, e = e.next) {
+ if (e == lastReturned) {
+ modCount++;
+ expectedModCount++;
+ if (prev == null)
+ tab[index] = e.next;
+ else
+ prev.next = e.next;
+ count--;
+ lastReturned = null;
+ return;
+ }
+ }
+ throw new ConcurrentModificationException();
+ }
+ }
+ }
+
+
+ private static Enumeration emptyEnumerator = new EmptyEnumerator();
+ private static Iterator emptyIterator = new EmptyIterator();
+
+ /**
+ * A hashtable enumerator class for empty hash tables, specializes
+ * the general Enumerator
+ */
+ private static class EmptyEnumerator implements Enumeration<Object> {
+
+ EmptyEnumerator() {
+ }
+
+ public boolean hasMoreElements() {
+ return false;
+ }
+
+ public Object nextElement() {
+ throw new NoSuchElementException("Hashtable Enumerator");
+ }
+ }
+
+
+ /**
+ * A hashtable iterator class for empty hash tables
+ */
+ private static class EmptyIterator implements Iterator<Object> {
+
+ EmptyIterator() {
+ }
+
+ public boolean hasNext() {
+ return false;
+ }
+
+ public Object next() {
+ throw new NoSuchElementException("Hashtable Iterator");
+ }
+
+ public void remove() {
+ throw new IllegalStateException("Hashtable Iterator");
+ }
+
+ }
+
+}
projects / Benchmarks_CSolver.git / blobdiff