summaryrefslogtreecommitdiffstats
path: root/sandbox/fmoga/binding-comet-runtime/src/main/java/org/apache/tuscany/sca/binding/comet/runtime/ServletFactory.java
blob: c1244b31836e2eef663a850c1aa027fb410974ef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
/*
 * 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.    
 */

package org.apache.tuscany.sca.binding.comet.runtime;

import java.util.HashMap;
import java.util.Map;

import org.apache.tuscany.sca.host.http.ServletHost;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.runtime.RuntimeEndpoint;
import org.atmosphere.cpr.AtmosphereServlet;

/**
 * This class is used to create two servlets: one exposing all the comet
 * services, the other one exposing the javascript toolkit. Exposing all comet
 * services through a single servlet is needed as the browsers are undergone by
 * the two http connection limit so all comet services should send their
 * responses via the same http connection to the same client. Dispatching to the
 * corresponding endpoint and operation is done internally using Jersey RESTful
 * Web Services integration with the AtmosphereServlet. The Javascript toolkit
 * servlet is unique as it is not tied to any of the services - it offers a
 * global API.
 */
public final class ServletFactory {

    /**
     * Init-param key for the AtmosphereServlet defining where to look for
     * Jersey classes.
     */
    private static final String PACKAGE_KEY = "com.sun.jersey.config.property.packages";

    /**
     * Package of the class handling dispatching to endpoints.
     */
    private static final String PACKAGE_VALUE = "org.apache.tuscany.sca.binding.comet.runtime.handler";

    /**
     * Package of the class handling Javascript toolkit retrieval.
     */
    private static final String JS_PACKAGE_VALUE = "org.apache.tuscany.sca.binding.comet.runtime.javascript";

    /**
     * Property in the ServletContext where endpoints are added incrementally as
     * the Tuscany runtime calls the CometServiceBindingProvider for each comet
     * service.
     */
    public static final String ENDPOINTS_KEY = "org.apache.tuscany.sca.binding.comet.endpoints";

    /**
     * Property in the ServletContext where operations are added incrementally
     * as the CometServiceBindingProvider is calling the registerServlet method
     * for each comet service method.
     */
    public static final String OPERATIONS_KEY = "org.apache.tuscany.sca.binding.comet.operations";

    /**
     * Path where services will be exposed.
     */
    public static final String PATH = "/tuscany-comet/*";

    /**
     * Path where Javascript toolkit will be exposed.
     */
    public static final String JS_PATH = "/org.apache.tuscany.sca.cometComponentContext.js/*";

    /**
     * The servlet that is exposing the comet services.
     */
    private static AtmosphereServlet cometServlet = null;

    /**
     * The servlet that is exposing the Javascript toolkit.
     */
    private static AtmosphereServlet javascriptServlet = null;

    /**
     * Private constructor for the singleton class.
     */
    private ServletFactory() {
    }

    /**
     * Method called by CometServiceBindingProvider for each endpoint in order
     * to create the two singleton servlets.
     * 
     * @param servletHost the underlying servlet host
     */
    public static synchronized void registerServlet(final ServletHost servletHost) {
        if (ServletFactory.cometServlet == null) {
            ServletFactory.cometServlet = new AtmosphereServlet();
            ServletFactory.cometServlet.addInitParameter(ServletFactory.PACKAGE_KEY, ServletFactory.PACKAGE_VALUE);
            servletHost.addServletMapping(ServletFactory.PATH, ServletFactory.cometServlet);
            // store operations and corresponding endpoint in the ServletContext
            // so that they can be retrieved from inside the web service methods
            final Map<String, RuntimeEndpoint> endpoints = new HashMap<String, RuntimeEndpoint>();
            ServletFactory.cometServlet.getServletContext().setAttribute(ServletFactory.ENDPOINTS_KEY, endpoints);
            final Map<String, Operation> operations = new HashMap<String, Operation>();
            ServletFactory.cometServlet.getServletContext().setAttribute(ServletFactory.OPERATIONS_KEY, operations);
        }
        if (ServletFactory.javascriptServlet == null) {
            ServletFactory.javascriptServlet = new AtmosphereServlet();
            ServletFactory.javascriptServlet.addInitParameter(ServletFactory.PACKAGE_KEY,
                                                              ServletFactory.JS_PACKAGE_VALUE);
            servletHost.addServletMapping(ServletFactory.JS_PATH, ServletFactory.javascriptServlet);
        }
    }

    /**
     * Method called by CometServiceBindingProvider for each endpoint operation
     * in order to store all the operations the servlet will serve.
     * 
     * @param endpoint the endpoint
     * @param operation the operation
     */
    public static synchronized void addOperation(final RuntimeEndpoint endpoint, final Operation operation) {
        final String url = "/" + endpoint.getService().getName() + "/" + operation.getName();
        final Map<String, RuntimeEndpoint> endpoints =
            (Map<String, RuntimeEndpoint>)ServletFactory.cometServlet.getServletContext()
                .getAttribute(ServletFactory.ENDPOINTS_KEY);
        endpoints.put(url, endpoint);
        final Map<String, Operation> operations =
            (Map<String, Operation>)ServletFactory.cometServlet.getServletContext()
                .getAttribute(ServletFactory.OPERATIONS_KEY);
        operations.put(url, operation);
    }

    /**
     * Method called by CometServiceBindingProvider for each endpoint operation
     * in order to remove the two servlets.
     * 
     * @param servletHost the underlying servlet host
     */
    public static synchronized void unregisterServlet(final ServletHost servletHost) {
        servletHost.removeServletMapping(ServletFactory.PATH);
        servletHost.removeServletMapping(ServletFactory.JS_PATH);
    }

}