JDK 1.1 Source Code Directory
JDK 1.1 source code directory contains Java source code for JDK 1.1 core classes:
"C:\fyicenter\jdk-1.1.8\src".
Here is the list of Java classes of the JDK 1.1 source code:
✍: FYIcenter
⏎ java/util/Hashtable.java
/*
* @(#)Hashtable.java 1.43 01/12/10
*
* Copyright 2002 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.util;
import java.io.*;
/**
* Hashtable collision list.
*/
class HashtableEntry {
int hash;
Object key;
Object value;
HashtableEntry next;
protected Object clone() {
HashtableEntry entry = new HashtableEntry();
entry.hash = hash;
entry.key = key;
entry.value = value;
entry.next = (next != null) ? (HashtableEntry)next.clone() : null;
return entry;
}
}
/**
* 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 efficiency: its <i>capacity</i> and its <i>load
* factor</i>. The load factor should be between 0.0 and 1.0. When
* the number of entries in the hashtable exceeds the product of the
* load factor and the current capacity, the capacity is increased by
* calling the <code>rehash</code> method. Larger load factors use
* memory more efficiently, at the expense of larger expected time
* per lookup.
* <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>
*
* @author Arthur van Hoff
* @version 1.43, 12/10/01
* @see java.lang.Object#equals(java.lang.Object)
* @see java.lang.Object#hashCode()
* @see java.util.Hashtable#rehash()
* @since JDK1.0
*/
public
class Hashtable extends Dictionary implements Cloneable, java.io.Serializable {
/**
* The hash table data.
*/
private transient HashtableEntry 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;
/** 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 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 Hashtable(int initialCapacity, float loadFactor) {
if ((initialCapacity <= 0) || (loadFactor <= 0.0)) {
throw new IllegalArgumentException();
}
this.loadFactor = loadFactor;
table = new HashtableEntry[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 Hashtable(int initialCapacity) {
this(initialCapacity, 0.75f);
}
/**
* Constructs a new, empty hashtable with a default capacity and load
* factor.
*
* @since JDK1.0
*/
public Hashtable() {
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 synchronized Enumeration keys() {
return new HashtableEnumerator(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 synchronized Enumeration elements() {
return new HashtableEnumerator(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 synchronized boolean contains(Object value) {
if (value == null) {
throw new NullPointerException();
}
HashtableEntry tab[] = table;
for (int i = tab.length ; i-- > 0 ;) {
for (HashtableEntry e = tab[i] ; e != null ; e = e.next) {
if (e.value.equals(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 synchronized boolean containsKey(Object key) {
HashtableEntry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry 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.
* @see java.util.Hashtable#put(java.lang.Object, java.lang.Object)
* @since JDK1.0
*/
public synchronized Object get(Object key) {
HashtableEntry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry e = tab[index] ; e != null ; e = e.next) {
if ((e.hash == hash) && e.key.equals(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;
HashtableEntry oldTable[] = table;
int newCapacity = oldCapacity * 2 + 1;
HashtableEntry newTable[] = new HashtableEntry[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 (HashtableEntry old = oldTable[i] ; old != null ; ) {
HashtableEntry 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.lang.Object#equals(java.lang.Object)
* @see java.util.Hashtable#get(java.lang.Object)
* @since JDK1.0
*/
public synchronized 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.
HashtableEntry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry e = tab[index] ; e != null ; e = e.next) {
if ((e.hash == hash) && e.key.equals(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.
HashtableEntry e = new HashtableEntry();
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 synchronized Object remove(Object key) {
HashtableEntry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry e = tab[index], prev = null ; e != null ; prev = e, e = e.next) {
if ((e.hash == hash) && e.key.equals(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 synchronized void clear() {
HashtableEntry tab[] = table;
for (int index = tab.length; --index >= 0; )
tab[index] = null;
count = 0;
}
/**
* Creates a shallow copy of this hashtable. The keys and values
* themselves are not cloned.
* This is a relatively expensive operation.
*
* @return a clone of the hashtable.
* @since JDK1.0
*/
public synchronized Object clone() {
try {
Hashtable t = (Hashtable)super.clone();
t.table = new HashtableEntry[table.length];
for (int i = table.length ; i-- > 0 ; ) {
t.table[i] = (table[i] != null)
? (HashtableEntry)table[i].clone() : null;
}
return t;
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError();
}
}
/**
* Returns a rather long string representation of this hashtable.
*
* @return a string representation of this hashtable.
* @since JDK1.0
*/
public synchronized 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();
}
/**
* WriteObject is called to save the state of the hashtable to a stream.
* Only the keys and values are serialized since the hash values may be
* different when the contents are restored.
* iterate over the contents and write out the keys and values.
*/
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--) {
HashtableEntry entry = table[index];
while (entry != null) {
s.writeObject(entry.key);
s.writeObject(entry.value);
entry = entry.next;
}
}
}
/**
* readObject is called to restore the state of the hashtable from
* a stream. Only the keys and values are serialized since the
* hash values may be different when the contents are restored.
* Read count elements and insert into the hashtable.
*/
private synchronized 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 HashtableEntry[length];
count = 0;
// Read the number of elements and then all the key/value objects
for (; elements > 0; elements--) {
Object key = s.readObject();
Object value = s.readObject();
put(key, value);
}
}
}
/**
* A hashtable enumerator class. This class should remain opaque
* to the client. It will use the Enumeration interface.
*/
class HashtableEnumerator implements Enumeration {
boolean keys;
int index;
HashtableEntry table[];
HashtableEntry entry;
HashtableEnumerator(HashtableEntry table[], boolean keys) {
this.table = table;
this.keys = keys;
this.index = table.length;
}
public boolean hasMoreElements() {
if (entry != null) {
return true;
}
while (index-- > 0) {
if ((entry = table[index]) != null) {
return true;
}
}
return false;
}
public Object nextElement() {
if (entry == null) {
while ((index-- > 0) && ((entry = table[index]) == null));
}
if (entry != null) {
HashtableEntry e = entry;
entry = e.next;
return keys ? e.key : e.value;
}
throw new NoSuchElementException("HashtableEnumerator");
}
}
⏎ java/util/Hashtable.java
Or download all of them as a single archive file:
File name: jdk-1.1.8-src.zip File size: 1574187 bytes Release date: 2018-11-16 Download
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