utility | edwin's journey

How to Convert Java List or ArrayList into ResultSet

By edwin / 18 August 2010 18 August 2010 / Java, Programming / Java, object, Programming, utility

At this project i found an obstacle, which i need to convert a reporting module from fetching data from database into fetching data from Webservices. At first I think it was easy, I just fetch strings from Webservice, and put it in a bean or in a map and put it all in an ArrayList, just like JasperReport. But I forgot, this isn’t JasperReport I’m using, I’m using ~~bloody hell~~ CrystalReport. And my Crystal-Report-calling method only accepting ResultSet for parameter, so somehow I need to convert strings from webservice into ResultSet.

My idea is adding strings from webservices into an ArrayList<Object> and adding this ArrayList into ArrayList<ArrayList<Object>> and converting it into rows of ResultSet. And im using MockRunner library to help me. This is how I do it :

I create a class to convert a list into result set

package com.edw.rs;

import com.mockrunner.mock.jdbc.MockResultSet;
import java.sql.ResultSet;
import java.util.List;

/**
 *
 * @author edw
 */
public class MyResultSet {

    public ResultSet getResultSet(List<String> headers, List<List<Object>> data) throws Exception {

        // validation
        if (headers == null || data == null) {
            throw new Exception("null parameters");
        }

        if (headers.size() != data.size()) {
            throw new Exception("parameters size are not equals");
        }

        // create a mock result set
        MockResultSet mockResultSet = new MockResultSet("myResultSet");

        // add header
        for (String string : headers) {          
            mockResultSet.addColumn(string);
        }

        // add data
        for (List<Object> list : data) {
            mockResultSet.addRow(list);
        }

        return mockResultSet;
    }
}

and i tested it with my junit class

package com.edw.rs.test;

import com.edw.rs.MyResultSet;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
import org.junit.Test;

/**
 *
 * @author edw
 */
public class MyResultSetTest {

    private Logger logger = Logger.getLogger(MyResultSetTest.class);

    public MyResultSetTest() {
    }

    @Test
    public void testMyResultSet() throws Exception {
        MyResultSet myResultSet = new MyResultSet();
        List<String> headers = new ArrayList<String>();
        headers.add("id");
        headers.add("name");
        headers.add("salary");
        headers.add("age");

        List<List<Object>> data = new ArrayList<List<Object>>();
        for (int i = 0; i < 4; i++) {
            List<Object> objects = new ArrayList<Object>();
            objects.add(new Integer(i));
            objects.add("name " + i);
            objects.add(new Double(i));
            objects.add(new Integer(20 + i));
            data.add(objects);
        }

        ResultSet rs = myResultSet.getResultSet(headers, data);
        while (rs.next()) {
            logger.debug(rs.getString("id"));
            logger.debug(rs.getString(2));
            logger.debug(rs.getDouble("salary"));
            logger.debug(rs.getInt(4));
            logger.debug("------------------------");
        }

    }
}

this is the result on my IDE console

2010-08-18 18:13:09,112 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:42 - 0
2010-08-18 18:13:09,131 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:43 - name 0
2010-08-18 18:13:09,132 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:44 - 0.0
2010-08-18 18:13:09,132 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:45 - 20
2010-08-18 18:13:09,133 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:46 - ------------------------
2010-08-18 18:13:09,133 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:42 - 1
2010-08-18 18:13:09,189 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:43 - name 1
2010-08-18 18:13:09,189 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:44 - 1.0
2010-08-18 18:13:09,189 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:45 - 21
2010-08-18 18:13:09,190 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:46 - ------------------------
2010-08-18 18:13:09,190 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:42 - 2
2010-08-18 18:13:09,191 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:43 - name 2
2010-08-18 18:13:09,218 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:44 - 2.0
2010-08-18 18:13:09,219 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:45 - 22
2010-08-18 18:13:09,219 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:46 - ------------------------
2010-08-18 18:13:09,219 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:42 - 3
2010-08-18 18:13:09,220 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:43 - name 3
2010-08-18 18:13:09,225 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:44 - 3.0
2010-08-18 18:13:09,226 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:45 - 23
2010-08-18 18:13:09,226 [MyResultSetTest] DEBUG com.edw.rs.test.MyResultSetTest:46 - ------------------------

this is my project structure, FYI im using Netbeans 6.9.

all i can say is, Thank You mockrunner, you saved my life.

Random Date Generator dengan Java

By edwin / 28 April 2010 28 April 2010 / Java / basic, Java, Programming, utility

Iseng-iseng bikin class sederhana untuk menghasilkan suatu tanggal random yang terletak antara tanggalSebelum (Date) dan tanggalSesudah (Date). Rencananya ini mo gw pakek bwt testing aplikasi. Sorry klo classnya rada berantakan, bikinnya juga buru-buru, sembari nunggu adzan Maghrib.

package com.edw.random;

import java.math.BigDecimal;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * 
 * @author edwin
 */
public class RandomDateGenerator extends Thread {

	private Date sebelum;
	private Date sesudah;
	private int repetition;

	public Date getSebelum() {
		return sebelum;
	}

	public void setSebelum(Date sebelum) {
		this.sebelum = sebelum;
	}

	public Date getSesudah() {
		return sesudah;
	}

	public void setSesudah(Date sesudah) {
		this.sesudah = sesudah;
	}

	public int getRepetition() {
		return repetition;
	}

	public void setRepetition(int repetition) {
		this.repetition = repetition;
	}

	public RandomDateGenerator() {
	}

	@Override
	public void run() {
		try {
			for (int i = 0; i < repetition; i++) {
				Thread.sleep(1000);
				System.out.println(getRandomDateBetween(sebelum, sesudah));
			}
		} catch (InterruptedException interruptedException) {
			interruptedException.printStackTrace();
		}
	}

	private synchronized Date getRandomDateBetween(Date from, Date to) {
		Calendar cal = Calendar.getInstance();

		cal.setTime(from);
		BigDecimal decFrom = new BigDecimal(cal.getTimeInMillis());

		cal.setTime(to);
		BigDecimal decTo = new BigDecimal(cal.getTimeInMillis());

		BigDecimal selisih = decTo.subtract(decFrom);
		BigDecimal factor = selisih.multiply(new BigDecimal(Math.random()));

		return new Date((factor.add(decFrom)).longValue());
	}

	public static void main(String[] args) throws Exception {
		RandomDateGenerator rdg = new RandomDateGenerator();
		rdg.setSebelum(new SimpleDateFormat("dd MM yyyy").parse("17 08 1978"));
		rdg.setSesudah(new SimpleDateFormat("dd MM yyyy").parse("17 08 1990"));
		rdg.setRepetition(10);
		rdg.start();
	}
}

may the SOURCE be with you.

Wassalam.