001/*
002 * HA-JDBC: High-Availability JDBC
003 * Copyright (c) 2004-2007 Paul Ferraro
004 * 
005 * This library is free software; you can redistribute it and/or modify it 
006 * under the terms of the GNU Lesser General Public License as published by the 
007 * Free Software Foundation; either version 2.1 of the License, or (at your 
008 * option) any later version.
009 * 
010 * This library is distributed in the hope that it will be useful, but WITHOUT
011 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
012 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License 
013 * for more details.
014 * 
015 * You should have received a copy of the GNU Lesser General Public License
016 * along with this library; if not, write to the Free Software Foundation, 
017 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
018 * 
019 * Contact: ferraro@users.sourceforge.net
020 */
021package net.sf.hajdbc.distributable;
022
023import java.io.Externalizable;
024import java.io.IOException;
025import java.io.ObjectInput;
026import java.io.ObjectOutput;
027
028/**
029 * Represents a database command to be executed on a given database cluster.
030 * @author  Paul Ferraro
031 * @since   1.0
032 */
033public abstract class AbstractCommand implements Command<Boolean>, Externalizable
034{
035        protected String databaseId;
036        
037        /**
038         * Constructs a new AbstractDatabaseCommand.
039         */
040        protected AbstractCommand()
041        {
042                // Do nothing
043        }
044        
045        /**
046         * Constructs a new AbstractDatabaseCommand.
047         * @param databaseId a database identifier
048         */
049        public AbstractCommand(String databaseId)
050        {
051                this.databaseId = databaseId;
052        }
053        
054        /**
055         * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
056         */
057        @Override
058        public void writeExternal(ObjectOutput output) throws IOException
059        {
060                output.writeUTF(this.databaseId);
061        }
062
063        /**
064         * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
065         */
066        @Override
067        public void readExternal(ObjectInput input) throws IOException
068        {
069                this.databaseId = input.readUTF();
070        }
071        
072        /**
073         * @see java.lang.Object#toString()
074         */
075        @Override
076        public String toString()
077        {
078                return this.getClass().getName() + " [" + this.databaseId + "]"; //$NON-NLS-1$ //$NON-NLS-2$
079        }
080
081        /**
082         * @see net.sf.hajdbc.distributable.Command#marshalResult(java.lang.Object)
083         */
084        @Override
085        public Object marshalResult(Boolean result)
086        {
087                return result;
088        }
089
090        /**
091         * @see net.sf.hajdbc.distributable.Command#unmarshalResult(java.lang.Object)
092         */
093        @Override
094        public Boolean unmarshalResult(Object result)
095        {
096                return (Boolean) result;
097        }
098}