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.directory.api.asn1.ber.grammar; 021 022 023import org.apache.directory.api.asn1.DecoderException; 024import org.apache.directory.api.asn1.ber.Asn1Container; 025import org.apache.directory.api.asn1.util.Asn1StringUtils; 026import org.apache.directory.api.i18n.I18n; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030 031/** 032 * The abstract Grammar which is the Mother of all the grammars. It contains 033 * the transitions table. 034 * 035 * @param <C> The container type 036 * 037 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 038 */ 039public abstract class AbstractGrammar<C extends Asn1Container> implements Grammar<C> 040{ 041 /** The logger */ 042 private static final Logger LOG = LoggerFactory.getLogger( AbstractGrammar.class ); 043 044 /** Speedup for logs */ 045 private static final boolean IS_DEBUG = LOG.isDebugEnabled(); 046 047 /** 048 * Table of transitions. It's a two dimension array, the first dimension 049 * indices the states, the second dimension indices the Tag value, so it is 050 * 256 wide. 051 */ 052 protected GrammarTransition<C>[][] transitions; 053 054 /** The grammar name */ 055 private String name; 056 057 058 /** Default constructor */ 059 public AbstractGrammar() 060 { 061 } 062 063 064 /** 065 * {@inheritDoc} 066 */ 067 @Override 068 public String getName() 069 { 070 return name; 071 } 072 073 074 /** 075 * {@inheritDoc} 076 */ 077 @Override 078 public void setName( String name ) 079 { 080 this.name = name; 081 } 082 083 084 /** 085 * Get the transition associated with the state and tag 086 * 087 * @param state The current state 088 * @param tag The current tag 089 * @return A valid transition if any, or null. 090 */ 091 public GrammarTransition<C> getTransition( Enum<?> state, int tag ) 092 { 093 return transitions[state.ordinal()][tag & 0x00FF]; 094 } 095 096 097 /** 098 * {@inheritDoc} 099 */ 100 @Override 101 public void executeAction( C container ) throws DecoderException 102 { 103 104 Enum<?> currentState = container.getTransition(); 105 // We have to deal with the special case of a GRAMMAR_END state 106 if ( ( ( States ) currentState ).isEndState() ) 107 { 108 return; 109 } 110 111 byte tagByte = container.getCurrentTLV().getTag(); 112 113 // We will loop until no more actions are to be executed 114 @SuppressWarnings("unchecked") 115 GrammarTransition<C> transition = ( ( AbstractGrammar<C> ) container.getGrammar() ).getTransition( 116 currentState, 117 tagByte ); 118 119 if ( transition == null ) 120 { 121 String errorMessage = I18n.err( I18n.ERR_00001_BAD_TRANSITION_FROM_STATE, currentState, 122 Asn1StringUtils.dumpByte( tagByte ) ); 123 124 LOG.error( errorMessage ); 125 126 // If we have no more grammar on the stack, then this is an 127 // error 128 throw new DecoderException( errorMessage ); 129 } 130 131 if ( IS_DEBUG ) 132 { 133 LOG.debug( transition.toString() ); 134 } 135 136 if ( transition.hasAction() ) 137 { 138 Action<C> action = transition.getAction(); 139 action.action( container ); 140 } 141 142 container.setTransition( transition.getCurrentState() ); 143 } 144}