pig自定义UDF

自定义ＵＤＦ，由此可见，ｐｉｇ还是很值得一用的，它也提供插入python代码

package com.zhangdan.ykt;

import java.io.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;

import org.apache.pig.EvalFunc;
import org.apache.pig.data.BagFactory;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;

/**
 * 
 * @author xunying 为每个有关系可能有关系的学生生成数据对
 */
public class GetConnection extends EvalFunc<DataBag> {
    TupleFactory tupleFactory = TupleFactory.getInstance();
    BagFactory bagFactory = BagFactory.getInstance();
    static long dis = 3 * 60;// 时间设定，超过三分钟就不存在联系
    int maxP = 20;// 设定20个相关联的人,将会有40个相关联的人
    Person[] line = new Person[maxP];// 设定maxp个相关联的人
    int indexS = 0;// 标记开始和结束队列
    int indexE = 0;
    boolean notice = false;// 标记

    public class Person {
        String account;
        String jntime;
    }

    public static boolean isFriendM(String jn1, String jn2) {
        // 获取两个时间参数
        DateFormat format = new SimpleDateFormat("yyyyMMdd HH:mm:ss");
        Date date1 = null;
        Date date2 = null;
        try {
            date1 = format.parse(jn1);
            date2 = format.parse(jn2);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        long diff = (int) ((date2.getTime() - date1.getTime()) / 1000);
        return diff < dis ? true : false;
    }

    @Override
    public DataBag exec(Tuple input) throws IOException {
        ArrayList<Tuple> tuples = new ArrayList<Tuple>();
        DataBag values = (DataBag) input.get(0);
        String account = null;
        String jntime = null;

        if (input == null || input.size() == 0) {
            return null;
        }
        for (int i = 0; i < maxP; i++)
            line[i] = new Person();
        for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
            Tuple t = it.next();
            account = (String) t.get(0);
            jntime = (String) t.get(2) + (String) t.get(3) + (String) t.get(4) + " " + (String) t.get(5);
            if (indexE == indexS && notice)
                indexS = (indexS + 1) % maxP;
            line[indexE].account = account;
            line[indexE].jntime = jntime;
            try {
                for (; indexS != indexE;) { // 修改开始索引
                    if (isFriendM(line[indexS].jntime, line[indexE].jntime))
                        break;
                    indexS = (indexS + 1) % maxP;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            String tmp1, tmp2;
            for (int i = indexS; i != indexE;) {
                Tuple tuple = tupleFactory.newTuple();
                tmp1 = line[i].account;
                tmp2 = line[indexE].account;
                try {
                    if (Integer.parseInt(line[i].account) > Integer.parseInt(line[indexE].account)) {
                        tmp2 = line[i].account;
                        tmp1 = line[indexE].account;
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (tmp1 != null && tmp2 != null && tmp1.trim() != "" && tmp2.trim() != "") {
                    tuple.append(tmp1);
                    tuple.append(tmp2);
                    tuple.append(line[i].jntime);
                    tuple.append(line[indexE].jntime);
                    tuples.add(tuple);
                }
                i = (i + 1) % maxP;
            }
            indexE = (indexE + 1) % maxP;
            notice = true;
        }
        DataBag bag = bagFactory.newDefaultBag(tuples);
        return bag;
    }

}