JavaScript实现的ArrayList类[原创]

王朝html/css/js·作者佚名  2006-01-09
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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<elementCount;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<elementCount - 1;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<oldCapacity;i++ ){

elementData[i] = oldData[i];

}

}

}

}

 
 
 
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