01: /*
02: * <copyright>
03: *
04: * Copyright 2002-2004 BBNT Solutions, LLC
05: * under sponsorship of the Defense Advanced Research Projects
06: * Agency (DARPA).
07: *
08: * You can redistribute this software and/or modify it under the
09: * terms of the Cougaar Open Source License as published on the
10: * Cougaar Open Source Website (www.cougaar.org).
11: *
12: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
13: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
14: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
15: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
16: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
17: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
18: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
22: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: *
24: * </copyright>
25: */
26:
27: package org.cougaar.core.wp.resolver;
28:
29: import org.cougaar.core.component.Service;
30: import org.cougaar.core.mts.MessageAddress;
31:
32: /**
33: * This service is the "server selection service" advertised by
34: * the {@link SelectManager} that the {@link ClientTransport} uses
35: * to select a white pages server.
36: * <p>
37: * The primary job of this service is to locate servers and select
38: * the best one. The {@link #update} feedback can be used to
39: * aid selection.
40: */
41: public interface SelectService extends Service {
42:
43: /**
44: * Select a server for the specified name.
45: * <p>
46: * For example, this could be a lookup for the record of "AgentX".
47: * A server from the pool is selected and returned, or null is
48: * returned if no applicable server is listed.
49: */
50: MessageAddress select(boolean lookup, String name);
51:
52: /**
53: * Update the server list with measured performance statistics.
54: * <p>
55: * If the timeout flag is false then the duration is the measured
56: * round-trip-time for the message response, otherwise the
57: * duration is the timeout duration.
58: */
59: void update(MessageAddress addr, long duration, boolean timeout);
60:
61: /**
62: * @return true if the address is a listed white pages server
63: */
64: boolean contains(MessageAddress addr);
65:
66: interface Client {
67: /**
68: * The set of servers has changed, either with added or removed
69: * entries, so the client should scan their pending messages
70: * to see if the target is contained in the server's list.
71: */
72: void onChange();
73: }
74: }
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