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Java example source code file (RouteTracker.java)

This example source code file (RouteTracker.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java tags/keywords

already, cloneable, hop, httphost, illegalargumentexception, illegalstateexception, inetaddress, layertype, net, network, no, override, proxy, routetracker, stringbuilder, tunneltype

The RouteTracker.java example source code

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.conn.routing;

import java.net.InetAddress;

import org.apache.http.annotation.NotThreadSafe;

import org.apache.http.HttpHost;

/**
 * Helps tracking the steps in establishing a route.
 * 
 * @since 4.0
 */
@NotThreadSafe
public final class RouteTracker implements RouteInfo, Cloneable {

    /** The target host to connect to. */
    private final HttpHost targetHost;

    /**
     * The local address to connect from.
     * <code>null indicates that the default should be used.
     */
    private final InetAddress localAddress;

    // the attributes above are fixed at construction time
    // now follow attributes that indicate the established route

    /** Whether the first hop of the route is established. */
    private boolean connected;

    /** The proxy chain, if any. */
    private HttpHost[] proxyChain;

    /** Whether the the route is tunnelled end-to-end through proxies. */
    private TunnelType tunnelled;

    /** Whether the route is layered over a tunnel. */
    private LayerType layered;

    /** Whether the route is secure. */
    private boolean secure;

    /**
     * Creates a new route tracker.
     * The target and origin need to be specified at creation time.
     *
     * @param target    the host to which to route
     * @param local     the local address to route from, or
     *                  <code>null for the default
     */
    public RouteTracker(HttpHost target, InetAddress local) {
        if (target == null) {
            throw new IllegalArgumentException("Target host may not be null.");
        }
        this.targetHost   = target;
        this.localAddress = local;
        this.tunnelled    = TunnelType.PLAIN;
        this.layered      = LayerType.PLAIN;
    }


    /**
     * Creates a new tracker for the given route.
     * Only target and origin are taken from the route,
     * everything else remains to be tracked.
     *
     * @param route     the route to track
     */
    public RouteTracker(HttpRoute route) {
        this(route.getTargetHost(), route.getLocalAddress());
    }

    /**
     * Tracks connecting to the target.
     *
     * @param secure    <code>true if the route is secure,
     *                  <code>false otherwise
     */
    public final void connectTarget(boolean secure) {
        if (this.connected) {
            throw new IllegalStateException("Already connected.");
        }
        this.connected = true;
        this.secure = secure;
    }

    /**
     * Tracks connecting to the first proxy.
     *
     * @param proxy     the proxy connected to
     * @param secure    <code>true if the route is secure,
     *                  <code>false otherwise
     */
    public final void connectProxy(HttpHost proxy, boolean secure) {
        if (proxy == null) {
            throw new IllegalArgumentException("Proxy host may not be null.");
        }
        if (this.connected) {
            throw new IllegalStateException("Already connected.");
        }
        this.connected  = true;
        this.proxyChain = new HttpHost[]{ proxy };
        this.secure     = secure;
    }

    /**
     * Tracks tunnelling to the target.
     *
     * @param secure    <code>true if the route is secure,
     *                  <code>false otherwise
     */
    public final void tunnelTarget(boolean secure) {
        if (!this.connected) {
            throw new IllegalStateException("No tunnel unless connected.");
        }
        if (this.proxyChain == null) {
            throw new IllegalStateException("No tunnel without proxy.");
        }
        this.tunnelled = TunnelType.TUNNELLED;
        this.secure    = secure;
    }

    /**
     * Tracks tunnelling to a proxy in a proxy chain.
     * This will extend the tracked proxy chain, but it does not mark
     * the route as tunnelled. Only end-to-end tunnels are considered there.
     *
     * @param proxy     the proxy tunnelled to
     * @param secure    <code>true if the route is secure,
     *                  <code>false otherwise
     */
    public final void tunnelProxy(HttpHost proxy, boolean secure) {
        if (proxy == null) {
            throw new IllegalArgumentException("Proxy host may not be null.");
        }
        if (!this.connected) {
            throw new IllegalStateException("No tunnel unless connected.");
        }
        if (this.proxyChain == null) {
            throw new IllegalStateException("No proxy tunnel without proxy.");
        }

        // prepare an extended proxy chain
        HttpHost[] proxies = new HttpHost[this.proxyChain.length+1];
        System.arraycopy(this.proxyChain, 0,
                         proxies, 0, this.proxyChain.length);
        proxies[proxies.length-1] = proxy;

        this.proxyChain = proxies;
        this.secure     = secure;
    }

    /**
     * Tracks layering a protocol.
     *
     * @param secure    <code>true if the route is secure,
     *                  <code>false otherwise
     */
    public final void layerProtocol(boolean secure) {
        // it is possible to layer a protocol over a direct connection,
        // although this case is probably not considered elsewhere
        if (!this.connected) {
            throw new IllegalStateException
                ("No layered protocol unless connected.");
        }
        this.layered = LayerType.LAYERED;
        this.secure  = secure;
    }

    public final HttpHost getTargetHost() {
        return this.targetHost;
    }

    public final InetAddress getLocalAddress() {
        return this.localAddress;
    }

    public final int getHopCount() {
        int hops = 0;
        if (this.connected) {
            if (proxyChain == null)
                hops = 1;
            else
                hops = proxyChain.length + 1;
        }
        return hops;
    }

    public final HttpHost getHopTarget(int hop) {
        if (hop < 0)
            throw new IllegalArgumentException
                ("Hop index must not be negative: " + hop);
        final int hopcount = getHopCount();
        if (hop >= hopcount) {
            throw new IllegalArgumentException
                ("Hop index " + hop +
                 " exceeds tracked route length " + hopcount +".");
        }

        HttpHost result = null;
        if (hop < hopcount-1)
            result = this.proxyChain[hop];
        else
            result = this.targetHost;

        return result;
    }

    public final HttpHost getProxyHost() {
        return (this.proxyChain == null) ? null : this.proxyChain[0];
    }

    public final boolean isConnected() {
        return this.connected;
    }

    public final TunnelType getTunnelType() {
        return this.tunnelled;
    }

    public final boolean isTunnelled() {
        return (this.tunnelled == TunnelType.TUNNELLED);
    }

    public final LayerType getLayerType() {
        return this.layered;
    }

    public final boolean isLayered() {
        return (this.layered == LayerType.LAYERED);
    }

    public final boolean isSecure() {
        return this.secure;
    }

    /**
     * Obtains the tracked route.
     * If a route has been tracked, it is {@link #isConnected connected}.
     * If not connected, nothing has been tracked so far.
     *
     * @return  the tracked route, or
     *          <code>null if nothing has been tracked so far
     */
    public final HttpRoute toRoute() {
        return !this.connected ?
            null : new HttpRoute(this.targetHost, this.localAddress,
                                 this.proxyChain, this.secure,
                                 this.tunnelled, this.layered);
    }

    /**
     * Compares this tracked route to another.
     *
     * @param o         the object to compare with
     *
     * @return  <code>true if the argument is the same tracked route,
     *          <code>false
     */
    @Override
    public final boolean equals(Object o) {
        if (o == this)
            return true;
        if (!(o instanceof RouteTracker))
            return false;

        RouteTracker that = (RouteTracker) o;
        boolean equal = this.targetHost.equals(that.targetHost);
        equal &=
            ( this.localAddress == that.localAddress) ||
            ((this.localAddress != null) &&
              this.localAddress.equals(that.localAddress));
        equal &=
            ( this.proxyChain        == that.proxyChain) ||
            ((this.proxyChain        != null) &&
             (that.proxyChain        != null) &&
             (this.proxyChain.length == that.proxyChain.length));
        // comparison of actual proxies follows below
        equal &=
            (this.connected == that.connected) &&
            (this.secure    == that.secure) &&
            (this.tunnelled == that.tunnelled) &&
            (this.layered   == that.layered);

        // chain length has been compared above, now check the proxies
        if (equal && (this.proxyChain != null)) {
            for (int i=0; equal && (i<this.proxyChain.length); i++)
                equal = this.proxyChain[i].equals(that.proxyChain[i]);
        }

        return equal;
    }

    /**
     * Generates a hash code for this tracked route.
     * Route trackers are modifiable and should therefore not be used
     * as lookup keys. Use {@link #toRoute toRoute} to obtain an
     * unmodifiable representation of the tracked route.
     *
     * @return  the hash code
     */
    @Override
    public final int hashCode() {

        int hc = this.targetHost.hashCode();

        if (this.localAddress != null)
            hc ^= localAddress.hashCode();
        if (this.proxyChain != null) {
            hc ^= proxyChain.length;
            for (int i=0; i<proxyChain.length; i++)
                hc ^= proxyChain[i].hashCode();
        }

        if (this.connected)
            hc ^= 0x11111111;
        if (this.secure)
            hc ^= 0x22222222;

        hc ^= this.tunnelled.hashCode();
        hc ^= this.layered.hashCode();

        return hc;
    }

    /**
     * Obtains a description of the tracked route.
     *
     * @return  a human-readable representation of the tracked route
     */
    @Override
    public final String toString() {
        StringBuilder cab = new StringBuilder(50 + getHopCount()*30);

        cab.append("RouteTracker[");
        if (this.localAddress != null) {
            cab.append(this.localAddress);
            cab.append("->");
        }
        cab.append('{');
        if (this.connected)
            cab.append('c');
        if (this.tunnelled == TunnelType.TUNNELLED)
            cab.append('t');
        if (this.layered == LayerType.LAYERED)
            cab.append('l');
        if (this.secure)
            cab.append('s');
        cab.append("}->");
        if (this.proxyChain != null) {
            for (int i=0; i<this.proxyChain.length; i++) {
                cab.append(this.proxyChain[i]);
                cab.append("->");
            }
        }
        cab.append(this.targetHost);
        cab.append(']');

        return cab.toString();
    }


    // default implementation of clone() is sufficient
    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

}

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