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JavaScript实现的ArrayList类[原创]

摘要: JavaScript实现的ArrayList类[原创]

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/**********************************************************
* JavaScript实现的ArrayList类
*
* @author yoinn {yoinn@21cn.com}
* @version $Revision: 0.5 $ $Date: 2004/09/28 15:00:00 $
* @description
* Method:
* add(element);
* addElementAt(index, element);
* contains(element);
* get(index);
* isEmpty(index);
* indexOf(element);
* lastIndexOf(element);
* remove()
* setElementAt(index, element);
* size();
* toString();
* @example
* var arrList = new ArrayList();
* //var arrList = new ArrayList(10);
* arrList.add("000");
* arrList.add("001");
* arrList.add("002");
*
*********************************************************/
var ArrayList = function(){

var args = ArrayList.arguments;

var initialCapacity = 10;

if( args!=null && args.length>0 ){
initialCapacity = args[0];
}

var elementData = new Array(initialCapacity);
var elementCount = 0;

this.size = function(){
return elementCount;
}

this.add = function (element) {
//alert("add");
ensureCapacity(elementCount + 1);
elementData[elementCount++] = element;
return true;
}

this.addElementAt = function (index, element ){
//alert("addElementAt");
if ( index > elementCount || index < 0 ){
alert( "IndexOutOfBoundsException, Index: " + index + ", Size: " + elementCount );
return;
//throw (new Error(-1,"IndexOutOfBoundsException, Index: "+index+", Size: " + elementCount));
}
ensureCapacity( elementCount+1 );
for( var i=elementCount+1; i>index; i-- ){
elementData[i] = elementData[i-1]
}
elementData[index] = element;
elementCount++;
}

this.setElementAt = function (index, element ){
//alert("setElementAt");
if ( index > elementCount || index < 0 ){
alert( "IndexOutOfBoundsException, Index: "+index+", Size: " + elementCount );
return;
//throw (new Error(-1,"IndexOutOfBoundsException, Index: "+index+", Size: " + elementCount));
}
elementData[index] = element;
}

this.toString = function(){
//alert("toString()");
var str = "{";
for(var i=0;i if( i>0 ){
str += ",";
}
str += elementData[i];
}
str += "}";
return str;
}

this.get = function(index){
//alert("elementAt");
if ( index >= elementCount ) {
alert( "ArrayIndexOutOfBoundsException, " + index + " >= " + elementCount );
return;
//throw ( new Error( -1,"ArrayIndexOutOfBoundsException, " + index + " >= " + elementCount ) );
}
return elementData[index];
}

this.remove = function(index){
if ( index >= elementCount ) {
alert( "ArrayIndexOutOfBoundsException, " + index + " >= " + elementCount );
//return;
throw ( new Error( -1,"ArrayIndexOutOfBoundsException, " + index + " >= " + elementCount ) );
}
var oldData = elementData[index];
for( var i=index;i elementData[i] = elementData[i+1];
}
elementData[elementCount - 1] = null;
elementCount--;
return oldData;
}

this.isEmpty = function() {
return elementCount == 0;
}

this.indexOf = function(elem) {
//alert("indexOf");
for ( var i=0; i < elementCount; i++ ){
if (elementData[i]==elem){
return i;
}
}
return -1;
}

this.lastIndexOf = function(elem) {
for (var i = elementCount-1; i >= 0; i--){
if ( elementData[i]==elem ){
return i;
}
}
return -1;
}

this.contains = function(elem) {
return this.indexOf(elem) >= 0;
}

function ensureCapacity (minCapacity) {
var oldCapacity = elementData.length;
if (minCapacity > oldCapacity) {
var oldData = elementData;
var newCapacity = parseInt( (oldCapacity * 3)/2 + 1 );
if (newCapacity < minCapacity){
newCapacity = minCapacity;
}
elementData = new Array(newCapacity);
for( var i=0;i elementData[i] = oldData[i];
}
}
}
}