taskinfo.java

基于图形化的多线程下载器

import java.net.*;
import java.util.*;
import java.io.*;

/*
 * this class save the task info
 * only TaskThread can operate the instance content of this class's
 * others can only read it
 */
public class TaskInfo implements Serializable {
	public static final int TASK_STATE_FINISHED = 3;
	public static final int TASK_STATE_PAUSE = 2;
	public static final int TASK_STATE_RUN = 1;
	public static final int TASK_STATE_STOP = 0;

	transient private boolean debug = true;
	private File dstFile = null;
	// these parameters are deciding in runtime
	private HashSet<TaskPortionInfo> portionList = null;

	private int portionNumber = 0;
	// used for calculate speed...
	transient private long startTime = 0;
	transient private int state = TaskInfo.TASK_STATE_STOP;

	// these parameters are used for assistant
	private long totalLength = 0; // bytes

	// these parameters should be initiated when object first construct
	private URL url = null;

	// the only way to get instance of this class
	// if url is not correct or connect failed, return a null reference
	public static TaskInfo getInstance(String url, String dstFile,
			int portionNumber) {
		try {
			TaskInfo ti = new TaskInfo();
			ti.url = new URL(url);
			ti.dstFile = new File(dstFile);
			URLConnection conn = ti.url.openConnection();
			ti.totalLength = conn.getContentLength();
			ti.portionNumber = portionNumber;
			ti.allocatePortion();
			return ti;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	private TaskInfo() {
		URL url = null;
		File dstFile = null;
		portionNumber = 0;
		portionList = new HashSet<TaskPortionInfo>();
		totalLength = 0;
	}

	private void allocatePortion() {
		long portionSize = totalLength / portionNumber;
		long startPos = 0;
		// here use -1 to ensure first allocation set startPos to 0
		long endPos = -1;
		for (int i = 0; i < portionNumber - 1; i++) {
			TaskPortionInfo tpi = new TaskPortionInfo();
			startPos = endPos + 1;
			endPos = startPos + portionSize;
			tpi.setStartPos(startPos);
			tpi.setNowPos(startPos);
			tpi.setLastPos(startPos);
			tpi.setEndPos(endPos + 1);
			portionList.add(tpi);
		}
		TaskPortionInfo tpi = new TaskPortionInfo();
		tpi.setStartPos(endPos + 1);
		tpi.setNowPos(endPos + 1);
		tpi.setLastPos(endPos + 1);
		tpi.setEndPos(totalLength);
		portionList.add(tpi);
	}

	public boolean finished() {
		return (getRemaindSize() <= 0) ? true : false;
	}

	public long getAcquiredSize() {
		if (portionList.isEmpty())
			return 0;
		Iterator<TaskPortionInfo> it = portionList.iterator();
		long acquiredSize = 0;
		while (it.hasNext()) {
			long m = it.next().getAcquiredPortionSize();
			acquiredSize += m;
		}
		return acquiredSize;
	}

	public File getDstFile() {
		return dstFile;
	}

	public String getDstFileName() {
		return dstFile.getName();
	}

	public HashSet<TaskPortionInfo> getPortionList() {
		return portionList;
	}

	public int getPortionNumber() {
		return portionNumber;
	}

	public void setLastPos() {
		if (portionList.isEmpty())
			return;
		Iterator<TaskPortionInfo> it = portionList.iterator();
		TaskPortionInfo tpi = null;
		while (it.hasNext() && !portionList.isEmpty()) {
			tpi = it.next();
			tpi.setLastPos(tpi.getNowPos());
		}
	}
	public long getRemaindSize() {
		if (portionList.isEmpty())
			return totalLength;
		Iterator<TaskPortionInfo> it = portionList.iterator();
		long remaindSize = 0;
		while (it.hasNext()) {
			remaindSize += it.next().getRemaindPortionSize();
		}
		return remaindSize;

	}

	public long getStartTime() {
		return startTime;
	}

	public int getState() {
		return state;
	}

	public long getTotalLength() {
		return totalLength;
	}

	public URL getUrl() {
		return url;
	}

	public String getURLFileName() {
		String result = url.toString();
		result.substring(result.lastIndexOf("/"));
		return result;
	}

	public void setStartTime(long startTime) {
		this.startTime = startTime;
	}

	public void setState(int state) {
		this.state = state;
	}

	public long getLatestAcquiredSize() {
		if (portionList.isEmpty())
			return 0;
		Iterator<TaskPortionInfo> it = portionList.iterator();
		long latestAcquiredSize = 0;
		while (it.hasNext()) {
			latestAcquiredSize += it.next().getLatestAcquiredSize();
		}
		return latestAcquiredSize;
	}
}