com.turn.ttorrent.tracker.TrackedPeer.java Source code

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Here is the source code for com.turn.ttorrent.tracker.TrackedPeer.java

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/**
 * Copyright (C) 2011-2012 Turn, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.turn.ttorrent.tracker;

import com.google.common.base.Objects;
import com.google.common.collect.Iterables;

import com.turn.ttorrent.protocol.TorrentUtils;
import java.net.InetSocketAddress;
import java.util.HashSet;
import java.util.Set;
import javax.annotation.Nonnull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A BitTorrent tracker peer.
 *
 * <p>
 * Represents a peer exchanging on a given torrent. In this implementation,
 * we don't really care about the status of the peers and how much they
 * have downloaded / exchanged because we are not a torrent exchange and
 * don't need to keep track of what peers are doing while they're
 * downloading. We only care about when they start, and when they are done.
 * </p>
 *
 * <p>
 * We also never expire peers automatically. Unless peers send a STOPPED
 * announce request, they remain as long as the torrent object they are a
 * part of.
 * </p>
 */
public class TrackedPeer {

    private static final Logger LOG = LoggerFactory.getLogger(TrackedPeer.class);
    private final byte[] peerId;
    private final Set<InetSocketAddress> peerAddresses = new HashSet<InetSocketAddress>();
    private TrackedPeerState state = TrackedPeerState.UNKNOWN;
    private long uploaded = 0;
    private long downloaded = 0;
    private long left = 0;
    private long lastAnnounce = System.currentTimeMillis();
    // We need a happen-before relationship for multiple threads.
    private final Object lock = new Object();

    /**
     * Instantiate a new tracked peer for the given torrent.
     *
     * @param peer The remote peer.
     * @param torrent The torrent this peer exchanges on.
     */
    public TrackedPeer(@Nonnull byte[] peerId) {
        this.peerId = peerId;
    }

    @Nonnull
    public byte[] getPeerId() {
        return peerId;
    }

    @Nonnull
    public String getPeerName() {
        return TorrentUtils.toText(getPeerId());
    }

    @Nonnull
    public Set<? extends InetSocketAddress> getPeerAddresses() {
        return peerAddresses;
    }

    /**
     * Update this peer's state and information.
     *
     * <p>
     * <b>Note:</b> if the peer reports 0 bytes left to download, its state will
     * be automatically be set to COMPLETED.
     * </p>
     *
     * @param torrent The torrent. This should be the same on every call.
     * @param state The peer's state.
     * @param uploaded Uploaded byte count, as reported by the peer.
     * @param downloaded Downloaded byte count, as reported by the peer.
     * @param left Left-to-download byte count, as reported by the peer.
     */
    public void update(@Nonnull TrackedTorrent torrent, TrackedPeerState state,
            Iterable<? extends InetSocketAddress> peerAddresses, long uploaded, long downloaded, long left) {
        if (TrackedPeerState.STARTED.equals(state) && left == 0)
            state = TrackedPeerState.COMPLETED;

        if (!state.equals(this.state)) {
            if (LOG.isDebugEnabled())
                LOG.debug("Peer {} {} download of {}.", new Object[] { this, state.name().toLowerCase(), torrent });
        }

        synchronized (lock) {
            Iterables.addAll(this.peerAddresses, peerAddresses);
            this.state = state;
            this.uploaded = uploaded;
            this.downloaded = downloaded;
            this.left = left;
            this.lastAnnounce = System.currentTimeMillis();
        }
    }

    /**
     * Tells whether this peer has completed its download and can thus be
     * considered a seeder.
     */
    public boolean isCompleted() {
        return TrackedPeerState.COMPLETED.equals(this.state);
    }

    /**
     * Returns how many bytes the peer reported it has uploaded so far.
     */
    public long getUploaded() {
        return this.uploaded;
    }

    /**
     * Returns how many bytes the peer reported it has downloaded so far.
     */
    public long getDownloaded() {
        return this.downloaded;
    }

    /**
     * Returns how many bytes the peer reported it needs to retrieve before
     * its download is complete.
     */
    public long getLeft() {
        return this.left;
    }

    /**
     * Tells whether this peer has checked in with the tracker recently.
     *
     * <p>
     * Non-fresh peers are automatically terminated and collected by the
     * Tracker.
     * </p>
     * 
     * @param now The current time.
     * @param refresh The interval after which a peer is considered stale.
     */
    public boolean isFresh(long now, long refresh) {
        synchronized (lock) {
            return (this.lastAnnounce > 0 && (this.lastAnnounce + refresh > now));
        }
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("name", getPeerName()).add("addresses", getPeerAddresses())
                .toString();
    }
}