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 */ 020 package org.apache.directory.shared.asn1.ber.grammar; 021 022 023 import org.apache.directory.shared.asn1.util.Asn1StringUtils; 024 025 026 /** 027 * Define a transition between two states of a grammar. It stores the next 028 * state, and the action to execute while transiting. 029 * 030 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 031 * @version $Rev: 664290 $, $Date: 2008-06-07 08:28:06 +0200 (Sat, 07 Jun 2008) $ 032 */ 033 public class GrammarTransition 034 { 035 /** The action associated to the transition */ 036 private IAction action; 037 038 /** The previous state */ 039 private int previousState; 040 041 /** The current state */ 042 private int currentState; 043 044 /** The current tag */ 045 private int currentTag; 046 047 // ~ Constructors 048 // ------------------------------------------------------------------------------- 049 050 /** 051 * Creates a new GrammarTransition object. 052 * 053 * @param previousState the previous state 054 * @param currentState The current state 055 * @param currentTag the current TLV's tag 056 * @param action The action to execute. It could be null. 057 */ 058 public GrammarTransition( int previousState, int currentState, int currentTag, IAction action ) 059 { 060 this.previousState = previousState; 061 this.currentState = currentState; 062 this.action = action; 063 this.currentTag = currentTag; 064 } 065 066 /** 067 * Tells if the transition has an associated action. 068 * 069 * @return <code>true</code> if an action has been asociated to the 070 * transition 071 */ 072 public boolean hasAction() 073 { 074 return action != null; 075 } 076 077 /** 078 * @return Returns the action associated with the transition 079 */ 080 public IAction getAction() 081 { 082 return action; 083 } 084 085 /** 086 * @param statesEnum Starting state. 087 * @return A representation of the transition as a string. 088 */ 089 public String toString( IStates statesEnum ) 090 { 091 092 StringBuffer sb = new StringBuffer(); 093 094 sb.append( "Transition from state <" ).append( statesEnum.getState( previousState ) ).append( "> " ); 095 sb.append( "to state <" ).append( statesEnum.getState( currentState ) ).append( ">, " ); 096 sb.append( "tag <" ).append( Asn1StringUtils.dumpByte( (byte)currentTag ) ).append( ">, " ); 097 sb.append( "action : " ).append( ( ( action == null ) ? "no action" : action.toString() ) ).append( ">" ); 098 099 return sb.toString(); 100 } 101 102 /** 103 * @return The current state 104 */ 105 public int getCurrentState() 106 { 107 return currentState; 108 } 109 110 /** 111 * @return The previous state 112 */ 113 public int getPreviousState() 114 { 115 return previousState; 116 } 117 }