[1991] | 1 | // Copyright 2012 Georg-August-Universität Göttingen, Germany |
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| 2 | // |
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| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
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| 4 | // you may not use this file except in compliance with the License. |
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| 5 | // You may obtain a copy of the License at |
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| 6 | // |
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| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
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| 8 | // |
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| 9 | // Unless required by applicable law or agreed to in writing, software |
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| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
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| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 12 | // See the License for the specific language governing permissions and |
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| 13 | // limitations under the License. |
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| 14 | |
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| 15 | package de.ugoe.cs.autoquest.httpmonitor.proxy; |
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| 16 | |
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| 17 | import java.util.logging.Level; |
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| 18 | |
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| 19 | import org.eclipse.jetty.client.api.Request; |
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| 20 | import org.eclipse.jetty.client.api.Result; |
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| 21 | import org.eclipse.jetty.client.api.Response.CompleteListener; |
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| 22 | import org.eclipse.jetty.http.HttpMethod; |
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| 23 | import org.eclipse.jetty.http.HttpVersion; |
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| 24 | |
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| 25 | import de.ugoe.cs.autoquest.httpmonitor.HttpMonitorComponent; |
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| 26 | import de.ugoe.cs.autoquest.httpmonitor.HttpMonitorException; |
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| 27 | import de.ugoe.cs.autoquest.httpmonitor.IdGenerator; |
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| 28 | import de.ugoe.cs.autoquest.httpmonitor.SimpleIdGenerator; |
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| 29 | import de.ugoe.cs.util.console.Console; |
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| 30 | |
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| 31 | /** |
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| 32 | * <p> |
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| 33 | * if a central monitoring server is used by the proxy, then this id generator is a connection to |
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| 34 | * the server to receive centrally unique ordering ids from the central server. If the central |
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| 35 | * server cannot be reached, this id generated uses a fallback internal {@link SimpleIdGenerator}. |
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| 36 | * </p> |
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| 37 | * |
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| 38 | * @author Patrick Harms |
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| 39 | */ |
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| 40 | public class HttpMonitorRemoteIdGenerator |
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| 41 | extends HttpMonitorRemoteConnection |
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| 42 | implements CompleteListener, IdGenerator, HttpMonitorComponent |
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| 43 | { |
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| 44 | /** the fall back id generator used internally if the server is not reachable*/ |
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| 45 | private IdGenerator fallBackIdGenerator = new SimpleIdGenerator(); |
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| 46 | |
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| 47 | /** |
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| 48 | * <p> |
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| 49 | * initializes the id generator with the host and port of the central server from which to |
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| 50 | * retrieve the ids |
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| 51 | * </p> |
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| 52 | * |
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| 53 | * @param httpMonitorServer the host name of the central server |
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| 54 | * @param httpMonitorPort the port of the central server |
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| 55 | */ |
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| 56 | public HttpMonitorRemoteIdGenerator(String httpMonitorServer, int httpMonitorPort) { |
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| 57 | super(httpMonitorServer, httpMonitorPort); |
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| 58 | } |
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| 59 | |
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| 60 | /* (non-Javadoc) |
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| 61 | * @see de.ugoe.cs.autoquest.httpmonitor.proxy.HttpMonitorRemoteConnection#init() |
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| 62 | */ |
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| 63 | @Override |
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| 64 | public void init() throws IllegalStateException, HttpMonitorException { |
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| 65 | fallBackIdGenerator.init(); |
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| 66 | super.init(); |
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| 67 | } |
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| 68 | |
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| 69 | /* (non-Javadoc) |
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| 70 | * @see de.ugoe.cs.autoquest.httpmonitor.proxy.HttpMonitorRemoteConnection#start() |
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| 71 | */ |
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| 72 | @Override |
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| 73 | public void start() throws IllegalStateException, HttpMonitorException { |
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| 74 | fallBackIdGenerator.start(); |
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| 75 | super.start(); |
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| 76 | } |
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| 77 | |
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| 78 | /* (non-Javadoc) |
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| 79 | * @see de.ugoe.cs.autoquest.httpmonitor.proxy.HttpMonitorRemoteConnection#stop() |
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| 80 | */ |
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| 81 | @Override |
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| 82 | public void stop() { |
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| 83 | super.stop(); |
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| 84 | fallBackIdGenerator.stop(); |
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| 85 | } |
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| 86 | |
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| 87 | /* (non-Javadoc) |
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| 88 | * @see de.ugoe.cs.autoquest.httpmonitor.IdGenerator#getNextId() |
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| 89 | */ |
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| 90 | @Override |
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| 91 | public synchronized long getNextId() { |
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| 92 | Request httpMonitorRequest = super.newRequest(); |
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| 93 | httpMonitorRequest.method(HttpMethod.GET); |
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| 94 | httpMonitorRequest.version(HttpVersion.HTTP_1_1); |
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| 95 | super.sendRequest(httpMonitorRequest); |
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| 96 | |
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| 97 | Result result = super.getResult(httpMonitorRequest); |
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| 98 | |
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| 99 | if (result.isFailed()) { |
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| 100 | Console.traceln |
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| 101 | (Level.WARNING, "could not retrieve next id correctly: " + result.getFailure()); |
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| 102 | Console.logException((Exception) result.getFailure()); |
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| 103 | |
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| 104 | Console.traceln(Level.WARNING, "using fallback, i.e., internal id generator"); |
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| 105 | return fallBackIdGenerator.getNextId(); |
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| 106 | } |
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| 107 | else { |
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| 108 | try { |
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| 109 | return result.getResponse().getHeaders().getLongField("X-AutoQUEST-OrderingId"); |
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| 110 | } |
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| 111 | catch (NumberFormatException e) { |
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| 112 | Console.traceln(Level.WARNING, "could not retrieve next id correctly: " + e); |
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| 113 | Console.logException(e); |
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| 114 | |
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| 115 | Console.traceln(Level.WARNING, "using fallback, i.e., internal id generator"); |
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| 116 | return fallBackIdGenerator.getNextId(); |
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| 117 | } |
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| 118 | } |
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| 119 | |
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| 120 | } |
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| 121 | |
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| 122 | } |
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