LoadOnGetList.java

package com.jiuqi.mobile.nigo.comeclose.bean;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.annotations.Expose;
import com.google.gson.internal.$Gson$Types;
import com.jiuqi.mobile.nigo.comeclose.exception.IndexOutException;
import com.jiuqi.mobile.nigo.comeclose.manager.ILoadDataHandler;

/**
 * 返回结果集封装，此类包含数据请求。不利于用户远程使用。<br/>
 * 客户端访问时，请谨慎使用。。。使用前请于本人沟通<br/>
 * 客户端使用方法：<br/>
 * void handler(){<br/>
 * String session = "";<br/>
 * INewsManager manager = ManagerFactory.instanceManager(INewsManager.class,
 * session );<br/>
 * int pageSize = 15;<br/>
 * long startIndex = 0;<br/>
 * SelectNewsKey key = new SelectNewsKey(pageSize);<br/>
 * key.setStartIndex(startIndex);<br/>
 * iterateList(manager, pageSize, startIndex, key);<br/>
 * //第二次请求<br/>
 * startIndex += pageSize;<br/>
 * key.setStartIndex(startIndex);<br/>
 * iterateList(manager, pageSize, startIndex, key);<br/>
 * ...<br/>
 * }<br/>
 * private void iterateList(INewsManager manager, int pageSize,<br/>
 * long startIndex, SelectNewsKey key) {<br/>
 * LoadOnGetList<CarTaskNewsBean> list = manager.get(CarTaskNewsBean.class,
 * key);<br/>
 * for(long i=startIndex; i<Math.min(pageSize+startIndex,
 * list.getTotalCount());i++){<br/>
 * CarTaskNewsBean bean = list.get(startIndex);<br/>
 * }<br/>
 * }<br/>
 * 
 * @author modi
 * 
 * @param <T>
 */
public class LoadOnGetList<T> {
	@Expose(deserialize = false, serialize = false)
	private ILoadDataHandler<T> loadData;
	private int size;
	// private final SelectKey key;
	private List<T> list = new ArrayList<T>();
	private Map<Long, T>  map= new HashMap<Long,T>();
	private long startIndex;
	private long totalCount;

	public LoadOnGetList() {
	}

	public LoadOnGetList(List<T> list) {
		this.list = list;
		this.totalCount = list.size();
		this.startIndex = list.size();
		this.size = list.size();
	}

	public LoadOnGetList(ILoadDataHandler<T> loadData, SelectKey key) {
		this.size = key.getSize();
		this.loadData = loadData;
		this.startIndex = key.getStartIndex()<0?0:key.getStartIndex();
		setTotalCount(initTotalCount());
		list = loadData.getData(startIndex,size);
	}

	public T get(long index) throws IndexOutException {
		if(list!=null&&list.size()==0){//第一次初始化
			list = loadData.getData(startIndex, size);
		}
		if(list!=null&&list.size()==totalCount){//将集合转化为loadongetlist使用 不是分页！使用的是第一个构造函数
			return list.get((int)index);
		}else{
			if(list!=null&&list.size()!=0){
				long startTemp = startIndex;
				if(!map.containsKey(startTemp)){//初始化map从stratindex 到size 的条数
					for(int i=0;i<list.size();i++){
						synchronized (map) {
							map.put(startTemp++, list.get(i));
						}
					}
				}else{//取得是 startindex到size意外的条数 比如 取0-15条记录 但是get（16）放入map
					startTemp = index;
					for(int i=0;i<list.size();i++){
						synchronized (map) {
						map.put(startTemp++, list.get(i));
						}
					}
				}
				
			}
			list = null;
			if(!map.containsKey(index)){//取得是 startindex到size意外的条数 比如 取0-15条记录 但是get（16）重新再数据库取
				list = loadData.getData(index, size);
				return get(index);
			}else{
				return map.get(index);
			}
		}
	}
	private long initTotalCount(){
		return loadData.getTotalCount();
	}
	public long getTotalCount() {
		return totalCount;
	}

	public void setTotalCount(long totalCount) {
		this.totalCount = totalCount;
	}

	/**
	 * 服务端禁用，仅限android客户端使用
	 * 只允许查询范围之内的
	 * @return
	 */
	public List<T> getList() {
//		list = loadData.getData(startIndex, size);
		return list;
	}

	public Type getType() {
		Type superclass = getClass().getGenericSuperclass();
		if (superclass instanceof Class) {
			throw new RuntimeException("Missing type parameter.");
		}
		ParameterizedType parameterized = (ParameterizedType) superclass;
		return $Gson$Types
				.canonicalize(parameterized.getActualTypeArguments()[0]);
	}
}