treeviewcontainer.java

JTree的视图展示：记录树的展开状况

package fileTree;

import java.util.ArrayList;
import java.util.List;

/**
 * 记录树的历史视图
 * @author hyj
 *
 */
public class TreeViewContainer {
	
	// 储存对树的操作历史中每个树的视图对象
	private List viewList = new ArrayList();

	// 跟踪back,forward的索引
	private int index = 0;

	private static int LIST_SIZE = 3;

	private boolean isMost = false;
	
	public int getIndex() {
		return index;
	}

	public void setIndex(int index) {
		this.index = index;
	}

	public List getViewList() {
		return viewList;
	}
	
	public void setViewList(List viewList) {
		this.viewList = viewList;
	}

	public void privious(){
		this.index--;
	}
	
	public void next(){
		this.index++;
	}
	
	public boolean isFirst(){
		return index == 0;
	}
	
	public boolean isLast(){
		return index == (viewList.size() - 1);
	}
	
	public void addView(Object obj) {
		if(!isMost){
			if(index == LIST_SIZE){
				isMost = true;
				replaceValue(obj);
				return;
			}
			next();
			viewList.add(index, obj);
		} else {	// 如果容器已满，每次删除第一个，把新元素添加到最后，游标指向容器最后一个元素
			replaceValue(obj);
		}
	}

	/**
	 * 每次删除第一个，把新元素添加到最后，游标指向容器最后一个元素
	 * @param obj
	 */
	private void replaceValue(Object obj) {
		viewList.remove(0);
		viewList.add(obj);
		index = getSize() - 1;
	}
	
	public void addView(int index, Object obj){
		viewList.add(index, obj);
	}
	
	public Object getView(){
		return viewList.get(index);
	}
	
	public int getSize(){
		return viewList.size();
	}
}