001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.mina.statemachine.event;
021
022import org.apache.commons.lang.builder.ToStringBuilder;
023import org.apache.mina.statemachine.context.StateContext;
024
025/**
026 * Represents an event which typically corresponds to a method call on a proxy.
027 * An event has an id and zero or more arguments typically corresponding to
028 * the method arguments. 
029 *
030 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
031 */
032public class Event {
033    public static final String WILDCARD_EVENT_ID = "*";
034
035    private final Object id;
036
037    private final StateContext context;
038
039    private final Object[] arguments;
040
041    /**
042     * Creates a new {@link Event} with the specified id and no arguments.
043     * 
044     * @param id the event id.
045     * @param context the {@link StateContext} the event was triggered for.
046     */
047    public Event(Object id, StateContext context) {
048        this(id, context, new Object[0]);
049    }
050
051    /**
052     * Creates a new {@link Event} with the specified id and arguments.
053     * 
054     * @param id the event id.
055     * @param context the {@link StateContext} the event was triggered for.
056     * @param arguments the event arguments.
057     */
058    public Event(Object id, StateContext context, Object[] arguments) {
059        if (id == null) {
060            throw new IllegalArgumentException("id");
061        }
062        if (context == null) {
063            throw new IllegalArgumentException("context");
064        }
065        if (arguments == null) {
066            throw new IllegalArgumentException("arguments");
067        }
068        this.id = id;
069        this.context = context;
070        this.arguments = arguments;
071    }
072
073    /**
074     * Returns the {@link StateContext} this {@link Event} was triggered for.
075     * 
076     * @return the {@link StateContext}.
077     */
078    public StateContext getContext() {
079        return context;
080    }
081
082    /**
083     * Returns the id of this {@link Event}.
084     * 
085     * @return the id.
086     */
087    public Object getId() {
088        return id;
089    }
090
091    /**
092     * Returns the arguments of this {@link Event}.
093     * 
094     * @return the arguments. Returns an empty array if this {@link Event} has 
095     *         no arguments.
096     */
097    public Object[] getArguments() {
098        return arguments;
099    }
100
101    public String toString() {
102        return new ToStringBuilder(this).append("id", id).append("context", context).append("arguments", arguments)
103                .toString();
104    }
105}