Engine


1   /*
2    * Copyright 2005 Joe Walker
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.directwebremoting.proxy.dwr;
17  
18  import java.util.Collection  ;
19  
20  import org.directwebremoting.ScriptBuffer;
21  import org.directwebremoting.ScriptSession;
22  import org.directwebremoting.proxy.ScriptProxy;
23  
24  /**
25   * Engine is a server-side proxy that allows Java programmers to call client
26   * side Javascript from Java.
27   * @see Util for more documenation on server-side proxies
28   * @author Joe Walker [joe at getahead dot ltd dot uk]
29   */
30  public class Engine extends ScriptProxy
31  {
32      /**
33       * Http thread constructor, that affects no browsers.
34       * Calls to {@link Engine#addScriptSession(ScriptSession)} or to
35       * {@link Engine#addScriptSessions(Collection)} will be needed
36       */
37      public Engine()
38      {
39          super();
40      }
41  
42      /**
43       * Http thread constructor that alters a single browser
44       * @param scriptSession The browser to alter
45       */
46      public Engine(ScriptSession scriptSession)
47      {
48          super(scriptSession);
49      }
50  
51      /**
52       * Http thread constructor that alters a number of browsers
53       * @param scriptSessions A collection of ScriptSessions that we should act on.
54       */
55      public Engine(Collection   scriptSessions)
56      {
57          super(scriptSessions);
58      }
59  
60      /**
61       * XHR remoting type constant. See dwr.engine.set[Rpc|Poll]Type()
62       */
63      public static final int XMLHttpRequest = 1;
64  
65      /**
66       * XHR remoting type constant. See dwr.engine.set[Rpc|Poll]Type()
67       */
68      public static final int IFrame = 2;
69  
70      /**
71       * XHR remoting type constant. See dwr.engine.setRpcType()
72       */
73      public static final int ScriptTag = 3;
74  
75      /**
76       * Set a default timeout value for all calls. 0 (the default) turns timeouts off.
77       * @param timeout The time to wait in milliseconds
78       * @see <a HREF="http://getahead.org/dwr/browser/engine/errors">Error handling documentation</a>
79       */
80      public void setTimeout(int timeout)
81      {
82          ScriptBuffer script = new ScriptBuffer();
83          script.appendScript("dwr.engine.setTimeout(")
84                .appendData(timeout)
85                .appendScript(");");
86          addScript(script);
87      }
88  
89      /**
90       * Set the preferred remoting type.
91       * @param newType One of dwr.engine.XMLHttpRequest or dwr.engine.IFrame or dwr.engine.ScriptTag
92       * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
93       */
94      public void setRpcType(int newType)
95      {
96          ScriptBuffer script = new ScriptBuffer();
97          script.appendScript("dwr.engine.setRpcType(")
98                .appendData(newType)
99                .appendScript(");");
100         addScript(script);
101     }
102 
103     /**
104      * Which HTTP method do we use to send results? Must be one of "GET" or "POST".
105      * @param httpMethod One of {@link #XMLHttpRequest}, {@link #IFrame} or {@link #ScriptTag}
106      * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
107      */
108     public void setHttpMethod(String   httpMethod)
109     {
110         ScriptBuffer script = new ScriptBuffer();
111         script.appendScript("dwr.engine.setHttpMethod(")
112               .appendData(httpMethod)
113               .appendScript(");");
114         addScript(script);
115     }
116 
117     /**
118      * Ensure that remote calls happen in the order in which they were sent? (Default: false)
119      * @param ordered True to set call ordering.
120      * @see <a HREF="http://getahead.org/dwr/browser/engine/ordering">Ordering documentation</a>
121      */
122     public void setOrdered(boolean ordered)
123     {
124         ScriptBuffer script = new ScriptBuffer();
125         script.appendScript("dwr.engine.setOrdered(")
126               .appendData(ordered)
127               .appendScript(");");
128         addScript(script);
129     }
130 
131     /**
132      * Do we ask the XHR object to be asynchronous? (Default: true)
133      * @param async False to become synchronous (not recommended)
134      * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
135      */
136     public void setAsync(boolean async)
137     {
138         ScriptBuffer script = new ScriptBuffer();
139         script.appendScript("dwr.engine.setAsync(")
140               .appendData(async)
141               .appendScript(");");
142         addScript(script);
143     }
144 
145     /**
146      * Does DWR poll the server for updates? (Default: false)
147      * @param activeReverseAjax True/False to turn RA on/off
148      * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
149      */
150     public void setActiveReverseAjax(boolean activeReverseAjax)
151     {
152         ScriptBuffer script = new ScriptBuffer();
153         script.appendScript("dwr.engine.setActiveReverseAjax(")
154               .appendData(activeReverseAjax)
155               .appendScript(");");
156         addScript(script);
157     }
158 
159     /**
160      * Does DWR us comet polling? (Default: true)
161      * @param pollComet True/False to use Comet where supported
162      * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
163      */
164     public void setPollUsingComet(boolean pollComet)
165     {
166         ScriptBuffer script = new ScriptBuffer();
167         script.appendScript("dwr.engine.setPollUsingComet(")
168               .appendData(pollComet)
169               .appendScript(");");
170         addScript(script);
171     }
172 
173     /**
174      * Set the preferred polling type.
175      * @param newPollType One of {@link #XMLHttpRequest}, {@link #IFrame} or {@link #ScriptTag}
176      * @see <a HREF="http://getahead.org/dwr/browser/engine/options">Options documentation</a>
177      */
178     public void setPollType(int newPollType)
179     {
180         ScriptBuffer script = new ScriptBuffer();
181         script.appendScript("dwr.engine.setPollUsingComet(")
182               .appendData(newPollType)
183               .appendScript(");");
184         addScript(script);
185     }
186 }
187
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