/interpreter/tags/at2dist170907/src/edu/vub/at/actors/net/cmd/VMCommand.java

 1/**
 2 * AmbientTalk/2 Project
 3 * VMCommand.java created on 22-feb-2007 at 13:03:56
 4 * (c) Programming Technology Lab, 2006 - 2007
 5 * Authors: Tom Van Cutsem & Stijn Mostinckx
 6 * 
 7 * Permission is hereby granted, free of charge, to any person
 8 * obtaining a copy of this software and associated documentation
 9 * files (the "Software"), to deal in the Software without
10 * restriction, including without limitation the rights to use,
11 * copy, modify, merge, publish, distribute, sublicense, and/or
12 * sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following
14 * conditions:
15 *
16 * The above copyright notice and this permission notice shall be
17 * included in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 * OTHER DEALINGS IN THE SOFTWARE.
27 */
28package edu.vub.at.actors.net.cmd;
29
30import edu.vub.at.actors.natives.ELVirtualMachine;
31import edu.vub.at.actors.net.comm.Address;
32
33import java.io.Serializable;
34
35/**
36 * VM Command objects are the message objects that AT/2 virtual machines send to one another.
37 * They are control objects sent by one VM and received by another. The receiving VM
38 * executes the VM Command object's uponReceiptBy method, which allows the command object to
39 * encapsulate the reception code itself.
40 * 
41 * By convention, all VM Command classes are prefixed with CMD.
42 *
43 * @author tvcutsem
44 */
45public abstract class VMCommand implements Serializable {
46	
47	private final String description_;
48	
49	/**
50	 * @param descr for debugging purposes
51	 */
52	public VMCommand(String descr) {
53		description_ = descr;
54	}
55	
56	public String toString() {
57		return "VMCMD["+description_+"]";
58	}
59	
60	/**
61	 * To be overridden by subclasses to specify the behaviour to execute upon reception
62	 * and execution of the command object at the recipient VM.
63	 * 
64	 * This code is still executed in a communication thread!
65	 * 
66	 * @param remoteHost the host at which the command arrived and is executed
67	 * @param senderAddress the address of the VM that sent this VM command object
68	 */
69	public abstract void uponReceiptBy(ELVirtualMachine remoteHost, Address senderAddress);
70	
71}