/*****************************************************************************
* *
* This file is part of the tna framework distribution. *
* Documentation and updates may be get from biaoping.yin the author of *
* this framework *
* *
* Sun Public License Notice: *
* *
* The contents of this file are subject to the Sun Public License Version *
* 1.0 (the "License"); you may not use this file except in compliance with *
* the License. A copy of the License is available at http://www.sun.com *
* *
* The Original Code is tag. The Initial Developer of the Original *
* Code is biaoping yin. Portions created by biaoping yin are Copyright *
* (C) 2000. All Rights Reserved. *
* *
* GNU Public License Notice: *
* *
* Alternatively, the contents of this file may be used under the terms of *
* the GNU Lesser General Public License (the "LGPL"), in which case the *
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* biaoping.yin (yin-bp@163.com) *
* Author of Learning Java *
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*****************************************************************************/
package com.frameworkset.common.tag.pager;
import java.io.Serializable;
import java.util.Comparator;
import com.frameworkset.util.CompareUtil;
/**
* 继承java.util.Comparator接口，针对ClassData的，根据desc的值来确定排序的顺序，根?
* sortKey来确定排序的字段
* @author biaoping.yin
* 2005-3-25
* version 1.0
*/
public class DataComparatorImpl implements Comparator ,Serializable
{
/**
* 决定排序规则
* false:升序
* true :降序
*/
private boolean desc = true;
/**
* 排序关键字，为具体Field对象的名称
*/
private String sortKey = "";
private static DataComparatorImpl dataComparatorImpl;
/**
* 构建器，参数sortKey为排序的关键字
*/
private DataComparatorImpl()
{
}
/**
* Determines if the desc property is true.
*
* @return <code>true<code> if the desc property is true
*/
public boolean getDesc()
{
return desc;
}
/**
* Sets the value of the desc property.
*
* @param aDesc the new value of the desc property
*/
public void setDesc(boolean aDesc)
{
desc = aDesc;
}
/**
* Access method for the sortKey property.
*
* @return the current value of the sortKey property
*/
public String getSortKey()
{
return sortKey;
}
/**
* Sets the value of the sortKey property.
*
* @param aSortKey the new value of the sortKey property
*/
public void setSortKey(String aSortKey)
{
sortKey = aSortKey;
}
/**
* Compares its two arguments for order. Returns a negative integer,
* zero, or a positive integer as the first argument is less than, equal
* to, or greater than the second.
* @param left
* @param right
* @return int
*/
private int compareValue(Object left, Object right)
{
return CompareUtil.compareValue(left, right,desc);
}
/**
* @return com.westerasoft.khcerp.tag.pager.DataComparatorImpl
*/
public static DataComparatorImpl newInstance()
{
if(dataComparatorImpl == null)
dataComparatorImpl = new DataComparatorImpl();
return dataComparatorImpl;
}
/**
* @param arg0
* @param arg1
* @return int
*/
public int compare(Object arg0, Object arg1)
{
ClassData tleft = (ClassData)arg0;
ClassData tright = (ClassData)arg1;
//获取值对象中field名称为sortKey的值
Object lvalue = tleft.getValue(sortKey);
Object rvalue = tright.getValue(sortKey);
return compareValue(lvalue,rvalue);
//return 0;
}
/**
* 重置sortKey和desc的值
*/
public void reset()
{
this.desc = false;
this.sortKey = "";
}
}