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ObjectIterator

Kind of class:	public class
Package:	com.bourre.collection
Inherits from:	none
Implements:	Iterator
Author:	Cédric Néhémie
Classpath:	com.bourre.collection.ObjectIterator
File last modified:	Monday, 24 November 2008, 11:36:49

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/*
 * Copyright the original author or authors.
 * 
 * Licensed under the MOZILLA PUBLIC LICENSE, Version 1.1 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.mozilla.org/MPL/MPL-1.1.html
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.bourre.collection 
{
    import com.bourre.log.PixlibDebug;    
    import com.bourre.collection.Iterator;
    import com.bourre.error.IllegalStateException;
    import com.bourre.error.NoSuchElementException;
    import com.bourre.error.UnsupportedOperationException;    

    /**
     * The <code>ObjectIterator</code> class provides a convenient way
     * to iterate through each property of an <code>Object</code> instance 
     * as you could do with a <code>Collection</code> instance.
     * <p>
     * Order of returned elements are not guaranteed, the order is the
     * same as the <code>for...in</code> one.
     * </p><p>
     * The object iterator can only iterate thorugh public properties
     * of an object, as the <code>for...in</code> loop does.
     * </p> 
     * @author     C√©dric N√©h√©mie
     * @see        Iterator
     */
    public class ObjectIterator 
        implements Iterator 
    {
        protected var _oObject     : Object;
        protected var _aKeys     : Array;
        protected var _nSize     : Number;
        protected var _nIndex     : Number;
        protected var _bRemoved : Boolean;
        
        /**
         * Creates a new iterator to iterate through
         * each property of the passed-in object.
         * 
         * @param    o    <code>Object</code> iterator's target
         */
        public function ObjectIterator ( o : Object )
        {
            _oObject     = o;
            _aKeys         = new Array();
            
            for( var k : String in _oObject ) { _aKeys.push( k ); }
            
            _nIndex     = -1;
            _nSize         = _aKeys.length;
            _bRemoved     = false;
        }
        
        /**
         * @inheritDoc
         */
        public function hasNext () : Boolean
        {
             return ( _nIndex + 1 < _nSize );
        }
        
        /**
         * @inheritDoc
         */        
        public function next () : *
        {
            if ( !hasNext() )
            {
                var msg : String = this + " has no more element at '" + ( _nIndex + 1 ) + "' index.";
                PixlibDebug.ERROR ( msg );
                throw new NoSuchElementException ( msg );
            }
                
            _bRemoved = false;
            return _oObject[ _aKeys[ ++_nIndex ] ];
        }
        
        /**
         * @inheritDoc
         */        
        public function remove () : void
        {
            if( !_bRemoved )
            {
                if( delete _oObject[ _aKeys[ _nIndex ] ] )
                {
                    _nIndex--;
                    _bRemoved = true;

                } else
                {
                    var msg0 : String = this + ".remove() can't delete " + _oObject + "." + _aKeys[ _nIndex ];
                    PixlibDebug.ERROR ( msg0 );
                    throw new UnsupportedOperationException ( msg0 );
                }

            } else
            {
                var msg1 : String = this + ".remove() has been already called in this iteration.";
                PixlibDebug.ERROR ( msg1 );
                throw new IllegalStateException ( msg1 );
            }
        }
    }
}

The ObjectIterator class provides a convenient way
to iterate through each property of an Object instance
as you could do with a Collection instance.

Order of returned elements are not guaranteed, the order is the
same as the for...in one.

The object iterator can only iterate thorugh public properties
of an object, as the for...in loop does.

Summary

Constructor

ObjectIterator (o:Object)
- Creates a new iterator to iterate through

Instance methods

hasNext : Boolean
next : *
remove : void

Constructor

ObjectIterator

public function ObjectIterator (

o:Object)

Creates a new iterator to iterate through
each property of the passed-in object.

Parameters:

Object iterator's target

Instance methods

hasNext

public function hasNext (

) : Boolean

Returns:

ObjectIterator if the iterator has more elements.
#

Specified by:

Iterator.hasNext

public function next (

) : *

Returns:

the next element in the iteration.
#

Throws:

{VISDOC_LINK_0}Object — iteration has no more elements.
#

Specified by:

Iterator.next

remove

public function remove (

) : void

Throws:

{VISDOC_LINK_0}Collection — if the remove operation is not
supported by this Iterator.
#
{VISDOC_LINK_1}for...in — if the next method has not yet been called,
or the remove method has already been called after the last
call to the next method.
#

Specified by:

Iterator.remove