1 /*
2 Copyright (c) 2003, Laurent Caillette.
3 All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without modifica-
6 tion, are permitted provided that the following conditions are met:
7
8 1. Redistributions of source code must retain the above copyright notice,
9 this list of conditions and the following disclaimer.
10
11 2. Redistributions in binary form must reproduce the above copyright notice,
12 this list of conditions and the following disclaimer in the documentation
13 and/or other materials provided with the distribution.
14
15 3. The end-user documentation included with the redistribution, if any, must
16 include the following acknowledgment: "This product includes software
17 written by Laurent Caillette."
18 Alternately, this acknowledgment may appear in the software itself, if
19 and wherever such third-party acknowledgments normally appear.
20
21 4. The name "Laurent Caillette" must not be used to endorse or
22 promote products derived from this software without
23 prior written permission. For written permission, please contact
24 laurent.caillette@laposte.net
25
26 5. Products derived from this software may not be called
27 "Laurent Caillette", nor may "Laurent Caillette" appear
28 in their name, without prior written permission of the
29 author.
30
31 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
32 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
33 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
34 AUTHOR (LAURENT CAILLETTE) BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
36 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
37 OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 */
42 package tweed.invocation;
43 import java.io.IOException;
44 import org.apache.avalon.framework.logger.Logger;
45 import tweed.context.Context;
46
47
48 /***
49 * A <code>CommandInvoker</code> is supposed to run client-side.
50 * It makes a <code>Command</code> instance execute server-side.
51 * Concrete implementations of an <code>CommandInvoker</code> will rely on
52 * a particular middleware.
53 * Command implementors should not manipulate this class directly.
54 *
55 * @author Laurent Caillette
56 * @version $Id$
57 */
58 public abstract class CommandInvoker {
59
60 public final static String CHILDLOGGER_NAME = "invoker" ;
61
62 private final Context context ;
63 private final Logger logger ;
64
65 public CommandInvoker( Context context ) {
66 if( context == null ) {
67 throw new IllegalArgumentException( "context == null" ) ;
68 }
69 this.context = context ;
70 logger = context.getLogger().getChildLogger( CHILDLOGGER_NAME ) ;
71 }
72
73 protected final Logger getLogger() {
74 return logger ;
75 }
76
77 protected final Context getContext() {
78 return context ;
79 }
80
81 public void invoke( Command command ) {
82
83 getLogger().debug( "Preparing execution of command " + command ) ;
84 ExternalizedCommand toExecute = new ExternalizedCommand() ;
85 toExecute.enableLogging( getLogger() ) ;
86 toExecute.prepareServerInvocationOnClient( command ) ;
87
88 getLogger().debug(
89 "Launching server-side execution of command " + command ) ;
90
91 toExecute.enableLogging( getLogger().getChildLogger( "ext-command" ) ) ;
92 ExternalizedCommand returned ; // = new ExternalizedCommand() ;
93
94 try {
95 returned = doInvoke( toExecute ) ;
96 } catch( IOException ex ) {
97 // TODO find something smarter than this
98 throw new RuntimeException( ex ) ;
99 }
100
101 returned.enableLogging( getLogger().getChildLogger( "ext-command" ) ) ;
102 getLogger().debug(
103 "Server-side execution complete for command " + command ) ;
104
105 returned.reconfigureOnClient( command ) ;
106
107 if( command.wasSuccess() ) {
108 getLogger().debug( "Execution successful for command " + command ) ;
109 } else {
110 getLogger().debug(
111 "Functional exception caught while executing command " + command,
112 command.getFunctionalException()
113 ) ;
114 }
115 }
116
117 protected abstract ExternalizedCommand doInvoke(
118 ExternalizedCommand externalizedCommand
119 ) throws IOException ;
120
121 }
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