/*
* @(#)ArrayTable.java 1.4 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.swing;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.Hashtable;
/*
* Private storage mechanism for Action key-value pairs.
* In most cases this will be an array of alternating
* key-value pairs. As it grows larger it is scaled
* up to a Hashtable.
* <p>
* This does no synchronization, if you need thread safety synchronize on
* another object before calling this.
*
* @version 1.4 12/19/03
* @author Georges Saab
* @author Scott Violet
*/
class ArrayTable implements Cloneable {
// Our field for storage
private Object table = null;
private static final int ARRAY_BOUNDARY = 8;
/**
* Writes the passed in ArrayTable to the passed in ObjectOutputStream.
* The data is saved as an integer indicating how many key/value
* pairs are being archived, followed by the the key/value pairs. If
* <code>table</code> is null, 0 will be written to <code>s</code>.
* <p>
* This is a convenience method that ActionMap/InputMap and
* AbstractAction use to avoid having the same code in each class.
*/
static void writeArrayTable(ObjectOutputStream s, ArrayTable table) throws IOException {
Object keys[];
if (table == null || (keys = table.getKeys(null)) == null) {
s.writeInt(0);
}
else {
// Determine how many keys have Serializable values, when
// done all non-null values in keys identify the Serializable
// values.
int validCount = 0;
for (int counter = 0; counter < keys.length; counter++) {
if ((keys[counter] instanceof Serializable) &&
(table.get(keys[counter]) instanceof Serializable)) {
validCount++;
}
else {
keys[counter] = null;
}
}
// Write ou the Serializable key/value pairs.
s.writeInt(validCount);
if (validCount > 0) {
for (int counter = 0; counter < keys.length; counter++) {
if (keys[counter] != null) {
s.writeObject(keys[counter]);
s.writeObject(table.get(keys[counter]));
if (--validCount == 0) {
break;
}
}
}
}
}
}
/*
* Put the key-value pair into storage
*/
public void put(Object key, Object value){
if (table==null) {
table = new Object[] {key, value};
} else {
int size = size();
if (size < ARRAY_BOUNDARY) { // We are an array
if (containsKey(key)) {
Object[] tmp = (Object[])table;
for (int i = 0; i<tmp.length-1; i+=2) {
if (tmp[i].equals(key)) {
tmp[i+1]=value;
break;
}
}
} else {
Object[] array = (Object[])table;
int i = array.length;
Object[] tmp = new Object[i+2];
System.arraycopy(array, 0, tmp, 0, i);
tmp[i] = key;
tmp[i+1] = value;
table = tmp;
}
} else { // We are a hashtable
if ((size==ARRAY_BOUNDARY) && isArray()) {
grow();
}
((Hashtable)table).put(key, value);
}
}
}
/*
* Gets the value for key
*/
public Object get(Object key) {
Object value = null;
if (table !=null) {
if (isArray()) {
Object[] array = (Object[])table;
for (int i = 0; i<array.length-1; i+=2) {
if (array[i].equals(key)) {
value = array[i+1];
break;
}
}
} else {
value = ((Hashtable)table).get(key);
}
}
return value;
}
/*
* Returns the number of pairs in storage
*/
public int size() {
int size;
if (table==null)
return 0;
if (isArray()) {
size = ((Object[])table).length/2;
} else {
size = ((Hashtable)table).size();
}
return size;
}
/*
* Returns true if we have a value for the key
*/
public boolean containsKey(Object key) {
boolean contains = false;
if (table !=null) {
if (isArray()) {
Object[] array = (Object[])table;
for (int i = 0; i<array.length-1; i+=2) {
if (array[i].equals(key)) {
contains = true;
break;
}
}
} else {
contains = ((Hashtable)table).containsKey(key);
}
}
return contains;
}
/*
* Removes the key and its value
* Returns the value for the pair removed
*/
public Object remove(Object key){
Object value = null;
if (key==null) {
return null;
}
if (table !=null) {
if (isArray()){
// Is key on the list?
int index = -1;
Object[] array = (Object[])table;
for (int i = array.length-2; i>=0; i-=2) {
if (array[i].equals(key)) {
index = i;
value = array[i+1];
break;
}
}
// If so, remove it
if (index != -1) {
Object[] tmp = new Object[array.length-2];
// Copy the list up to index
System.arraycopy(array, 0, tmp, 0, index);
// Copy from two past the index, up to
// the end of tmp (which is two elements
// shorter than the old list)
if (index < tmp.length)
System.arraycopy(array, index+2, tmp, index,
tmp.length - index);
// set the listener array to the new array or null
table = (tmp.length == 0) ? null : tmp;
}
} else {
value = ((Hashtable)table).remove(key);
}
if (size()==ARRAY_BOUNDARY - 1 && !isArray()) {
shrink();
}
}
return value;
}
/**
* Removes all the mappings.
*/
public void clear() {
table = null;
}
/*
* Returns a clone of the <code>ArrayTable</code>.
*/
public Object clone() {
ArrayTable newArrayTable = new ArrayTable();
if (isArray()) {
Object[] array = (Object[])table;
for (int i = 0 ;i < array.length-1 ; i+=2) {
newArrayTable.put(array[i], array[i+1]);
}
} else {
Hashtable tmp = (Hashtable)table;
Enumeration keys = tmp.keys();
while (keys.hasMoreElements()) {
Object o = keys.nextElement();
newArrayTable.put(o,tmp.get(o));
}
}
return newArrayTable;
}
/**
* Returns the keys of the table, or <code>null</code> if there
* are currently no bindings.
* @param keys array of keys
* @return an array of bindings
*/
public Object[] getKeys(Object[] keys) {
if (table == null) {
return null;
}
if (isArray()) {
Object[] array = (Object[])table;
if (keys == null) {
keys = new Object[array.length / 2];
}
for (int i = 0, index = 0 ;i < array.length-1 ; i+=2,
index++) {
keys[index] = array[i];
}
} else {
Hashtable tmp = (Hashtable)table;
Enumeration enum_ = tmp.keys();
int counter = tmp.size();
if (keys == null) {
keys = new Object[counter];
}
while (counter > 0) {
keys[--counter] = enum_.nextElement();
}
}
return keys;
}
/*
* Returns true if the current storage mechanism is
* an array of alternating key-value pairs.
*/
private boolean isArray(){
return (table instanceof Object[]);
}
/*
* Grows the storage from an array to a hashtable.
*/
private void grow() {
Object[] array = (Object[])table;
Hashtable tmp = new Hashtable(array.length/2);
for (int i = 0; i<array.length; i+=2) {
tmp.put(array[i], array[i+1]);
}
table = tmp;
}
/*
* Shrinks the storage from a hashtable to an array.
*/
private void shrink() {
Hashtable tmp = (Hashtable)table;
Object[] array = new Object[tmp.size()*2];
Enumeration keys = tmp.keys();
int j = 0;
while (keys.hasMoreElements()) {
Object o = keys.nextElement();
array[j] = o;
array[j+1] = tmp.get(o);
j+=2;
}
table = array;
}
}
|
