01: // Space4J(TM) - Object Persistence in RAM
02: // Copyright (C) 2003 Sergio Oliveira Junior
03: // This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License version 2.1 as published by the Free Software Foundation. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
04:
05: package org.space4j;
06:
07: import java.io.*;
08: import java.net.*;
09:
10: import org.space4j.indexing.*;
11:
12: /**
13: * Our database of objects in RAM. Clients will use the Space4J object to execute Commands in the
14: * underlying space. Space4J will be running in the same Virtual Machine the client is running, in other words, the client will be
15: * able to access the Space4J directly in memomy. No need for remote calls !!!
16: */
17: public interface Space4J {
18:
19: /**
20: * Executes a command on the underlying Space.<br>
21: * The client must use this method to perform any update on the Space.<br>
22: * The client must never do any modifications on the Space objects without using this method.<br>
23: * Space4J will execute the command and log the changes for future recovery if needed.<br>
24: * OBS: Logging is done AFTER the command is executed. If, for some reason, a CommandException is thrown, the command will not be logged.<br>
25: *
26: * @param cmd The command to execute.
27: * @param log A flag indicating whether this command should be logged or not.
28: * @return An int containing the number of objects modified by this operation.
29: * @throws CommandException if there is a problem executing this command
30: * @throws LoggerException if there is a problem logging thie command
31: */
32: public int executeCommand(Command cmd, boolean log)
33: throws CommandException, LoggerException;
34:
35: /**
36: * Executes a command on the underlying Space.<br>
37: * The client must use this method to perform any update on the Space.<br>
38: * The client must never do any modifications on the Space objects without using this method.<br>
39: * Space4J will execute the command and log the changes for future recovery if needed.<br>
40: * OBS: Logging is done AFTER the command is executed. If, for some reason, a CommandException is thrown, the command will not be logged.<br>
41: *
42: * @param cmd The command to execute.
43: * @return An int containing the number of objects modified by this operation.
44: * @throws CommandException if there is a problem executing this command
45: * @throws LoggerException if there is a problem logging thie command
46: */
47: public int executeCommand(Command cmd) throws CommandException,
48: LoggerException;
49:
50: /**
51: * Take a snapshot of the Space to disk. The Space will be serialized and written to disk.<br>
52: */
53: public void executeSnapshot() throws LoggerException;
54:
55: /**
56: * Returns the Space where the Objects are stored, so the client can direct access them.<br>
57: * @return a Space if Space4J is running locally or null otherwise
58: */
59: public Space getSpace();
60:
61: /**
62: * Starts the Space4J. This is only necessary for a replicated Space4J.
63: */
64: public void start() throws UnknownHostException, IOException,
65: ClassNotFoundException;
66:
67: /**
68: * Get the directory name where this Space4J is saving its data.
69: * @return The name of the dir
70: */
71: public String getDirName();
72:
73: /**
74: * Get the IndexManager for this Space4J.
75: * A IndexManager is responsible for managing Indexes.
76: * @return The IndexManager for this Space4J.
77: */
78: public IndexManager getIndexManager();
79:
80: }
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