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1 /* |
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2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package com.sun.xml.internal.ws.api.server; |
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27 |
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28 import com.sun.istack.internal.NotNull; |
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29 |
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30 import javax.xml.ws.Provider; |
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31 import javax.xml.ws.WebServiceContext; |
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32 import java.util.concurrent.Executor; |
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33 |
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34 /** |
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35 * Asynchronous version of {@link Provider}. |
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36 * |
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37 * <p> |
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38 * Applications that use the JAX-WS RI can implement this interface instead of |
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39 * {@link Provider} to implement asynchronous web services (AWS.) AWS enables |
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40 * applications to perform operations with long latency without blocking a thread, |
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41 * and thus particularly suitable for highly scalable service implementation, |
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42 * at the expesnce of implementation complexity. |
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43 * |
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44 * <h2>Programming Model</h2> |
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45 * <p> |
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46 * Whenever a new reuqest arrives, the JAX-WS RI invokes the {@link #invoke} method |
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47 * to notify the application. Normally, the application then schedules an execution |
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48 * of this request, and exit from this method immediately (the point of AWS is not |
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49 * to use this calling thread for request processing.) |
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50 * |
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51 * <p> |
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52 * Unlike the synchronous version, which requires the response to be given as the return value, |
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53 * with AWS the JAX-WS RI will keep the connection with client open, until the application |
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54 * eventually notifies the JAX-WS RI via {@link AsyncProviderCallback}. When that |
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55 * happens that causes the JAX-WS RI to send back a response to the client. |
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56 * |
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57 * <p> |
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58 * The following code shows a very simple AWS example: |
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59 * |
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60 * <pre> |
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61 * @WebService |
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62 * class MyAsyncEchoService implements AsyncProvider<Source> { |
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63 * private static final {@link Executor} exec = ...; |
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64 * |
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65 * public void invoke( final Source request, final AsyncProviderCallback<Source> callback, final WebServiceContext context) { |
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66 * exec.execute(new {@link Runnable}() { |
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67 * public void run() { |
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68 * Thread.sleep(1000); // kill time. |
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69 * callback.send(request); // just echo back |
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70 * } |
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71 * }); |
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72 * } |
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73 * } |
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74 * </pre> |
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75 * |
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76 * <p> |
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77 * Please also check the {@link Provider} and its programming model for general |
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78 * provider programming model. |
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79 * |
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80 * |
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81 * <h2>WebServiceContext</h2> |
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82 * <p> |
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83 * In synchronous web services, the injected {@link WebServiceContext} instance uses |
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84 * the calling {@link Thread} to determine which request it should return information about. |
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85 * This no longer works with AWS, as you may need to call {@link WebServiceContext} |
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86 * much later, possibly from entirely different thread. |
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87 * |
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88 * <p> |
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89 * For this reason, {@link AsyncProvider} passes in {@link WebServiceContext} as |
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90 * a parameter. This object remains usable until you invoke {@link AsyncProviderCallback}, |
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91 * and it can be invoked from any thread, even concurrently. AWS must not use the injected |
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92 * {@link WebServiceContext}, as its behavior is undefined. |
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93 * |
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94 * @see Provider |
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95 * @author Jitendra Kotamraju |
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96 * @author Kohsuke Kawaguchi |
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97 * @since 2.1 |
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98 */ |
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99 public interface AsyncProvider<T> { |
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100 /** |
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101 * Schedules an execution of a request. |
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102 * |
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103 * @param request |
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104 * Represents the request message or payload. |
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105 * @param callback |
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106 * Application must notify this callback interface when the processing |
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107 * of a request is complete. |
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108 * @param context |
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109 * The web service context instance that can be used to retrieve |
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110 * context information about the given request. |
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111 */ |
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112 public void invoke( |
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113 @NotNull T request, |
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114 @NotNull AsyncProviderCallback<T> callback, |
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115 @NotNull WebServiceContext context); |
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116 } |