1 /*
2 * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
3 * the spring framework, http://el4j.sf.net
4 * Copyright (C) 2006 by ELCA Informatique SA, Av. de la Harpe 22-24,
5 * 1000 Lausanne, Switzerland, http://www.elca.ch
6 *
7 * EL4J is published under the GNU Lesser General Public License (LGPL)
8 * Version 2.1. See http://www.gnu.org/licenses/
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU Lesser General Public License for more details.
14 *
15 * For alternative licensing, please contact info@elca.ch
16 */
17 package ch.elca.el4j.services.remoting.protocol.loadbalancing.policy;
18
19 import ch.elca.el4j.services.remoting.AbstractRemotingProtocol;
20 import ch.elca.el4j.services.remoting.protocol.loadbalancing.NoProtocolAvailableRTException;
21
22 /**
23 *
24 * Abstract class that defines the policy of the protocol selection.
25 * Protocol comparison must be done using "=="!
26 *
27 * @svnLink $Revision: 3873 $;$Date: 2009-08-04 13:59:45 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/remoting_core/src/main/java/ch/elca/el4j/services/remoting/protocol/loadbalancing/policy/AbstractPolicy.java $
28 *
29 * @author Stefan Pleisch (SPL)
30 */
31 public abstract class AbstractPolicy {
32
33 /**
34 * Array of protocols, each represented by an array of Strings, using
35 * a [protocolTag, arg1, arg2, ...] representation.
36 */
37 protected AbstractRemotingProtocol[] m_protocols;
38
39 /**
40 * This method is called before any other method is called. It passes the
41 * protocol information.
42 * @param protocols Array of currently defined protocols.
43 */
44 public void setProtocols(AbstractRemotingProtocol[] protocols) {
45 m_protocols = protocols;
46 }
47
48 /**
49 * This method is called if the use of one of the protocols has failed.
50 * Protocol comparison must be done using "=="!
51 * @param protocol The protocol that has lead to a failure.
52 */
53 public void notifyFailure(AbstractRemotingProtocol protocol) {
54 // Do nothing
55 }
56
57 /**
58 * @return Number of available protocols
59 */
60 public int getProtocolCount() {
61 return m_protocols.length;
62 }
63
64 /**
65 * Note that protocol comparison must be done using "=="!
66 *
67 * @return The next protocol to be used.
68 * @throws NoProtocolAvailableRTException
69 * If no protocol is available any more
70 */
71 public abstract AbstractRemotingProtocol getNextProtocol()
72 throws NoProtocolAvailableRTException;
73
74
75 /**
76 * Removes protocol 'pi' from {@link #m_protocols}. Does nothing if 'pi'
77 * does not exist.
78 *
79 * @param protocol
80 * Protocol to be removed.
81 */
82 protected void removeProtocol(AbstractRemotingProtocol protocol) {
83 int index = -1;
84 for (int i = 0; i < m_protocols.length; i += 1) {
85 if (m_protocols[i] == protocol) {
86 index = i;
87 break;
88 }
89 }
90 if (index >= 0) {
91 // Element found
92 AbstractRemotingProtocol[] tmp
93 = new AbstractRemotingProtocol[m_protocols.length - 1];
94 for (int k = 0; k < index; k += 1) {
95 tmp[k] = m_protocols[k];
96 }
97 for (int j = index + 1; j < m_protocols.length; j += 1) {
98 tmp[j - 1] = m_protocols[j];
99 }
100 m_protocols = tmp;
101 }
102 }
103
104
105 } // CLASS AbstractPolicy