001    /*
002     * JBoss, Home of Professional Open Source.
003     * Copyright 2008, Red Hat Middleware LLC, and individual contributors
004     * as indicated by the @author tags. See the copyright.txt file in the
005     * distribution for a full listing of individual contributors. 
006     *
007     * This is free software; you can redistribute it and/or modify it
008     * under the terms of the GNU Lesser General Public License as
009     * published by the Free Software Foundation; either version 2.1 of
010     * the License, or (at your option) any later version.
011     *
012     * This software is distributed in the hope that it will be useful,
013     * but WITHOUT ANY WARRANTY; without even the implied warranty of
014     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015     * Lesser General Public License for more details.
016     *
017     * You should have received a copy of the GNU Lesser General Public
018     * License along with this software; if not, write to the Free
019     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
021     */
022    package org.jboss.dna.graph.commands;
023    
024    /**
025     * The base interface for all repository commands
026     * 
027     * @author Randall Hauch
028     */
029    public interface GraphCommand {
030    
031        /**
032         * Return whether this command has been cancelled.
033         * 
034         * @return true if this command has been cancelled, or false otherwise.
035         */
036        boolean isCancelled();
037    
038        /**
039         * Set the error for this command.
040         * 
041         * @param error the exception
042         * @see #getError()
043         * @see #hasError()
044         * @see #hasNoError()
045         */
046        void setError( Throwable error );
047    
048        /**
049         * Get the error for this command.
050         * 
051         * @return the error, or null if there is no error
052         * @see #setError(Throwable)
053         * @see #hasError()
054         * @see #hasNoError()
055         */
056        Throwable getError();
057    
058        /**
059         * Return true if this command has an {@link #getError() error}.
060         * 
061         * @return true if the command has an error, or false otherwise
062         * @see #getError()
063         * @see #setError(Throwable)
064         * @see #hasNoError()
065         */
066        boolean hasError();
067    
068        /**
069         * Convenience method that is equivalent to <code>!hasError()</code>.
070         * 
071         * @return true if the command has no error, or false otherwise
072         * @see #getError()
073         * @see #setError(Throwable)
074         * @see #hasError()
075         */
076        boolean hasNoError();
077    
078    }