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 public String getName() 068 { 069 return name; 070 } 071 072 073 /** 074 * {@inheritDoc} 075 */ 076 public void setName( String name ) 077 { 078 this.name = name; 079 } 080 081 082 /** 083 * Get the transition associated with the state and tag 084 * 085 * @param state The current state 086 * @param tag The current tag 087 * @return A valid transition if any, or null. 088 */ 089 public GrammarTransition<C> getTransition( Enum<?> state, int tag ) 090 { 091 return transitions[state.ordinal()][tag & 0x00FF]; 092 } 093 094 095 /** 096 * {@inheritDoc} 097 */ 098 public void executeAction( C container ) throws DecoderException 099 { 100 101 Enum<?> currentState = container.getTransition(); 102 // We have to deal with the special case of a GRAMMAR_END state 103 if ( ( ( States ) currentState ).isEndState() ) 104 { 105 return; 106 } 107 108 byte tagByte = container.getCurrentTLV().getTag(); 109 110 // We will loop until no more actions are to be executed 111 @SuppressWarnings("unchecked") 112 GrammarTransition<C> transition = ( ( AbstractGrammar<C> ) container.getGrammar() ).getTransition( 113 currentState, 114 tagByte ); 115 116 if ( transition == null ) 117 { 118 String errorMessage = I18n.err( I18n.ERR_00001_BAD_TRANSITION_FROM_STATE, currentState, 119 Asn1StringUtils.dumpByte( tagByte ) ); 120 121 LOG.error( errorMessage ); 122 123 // If we have no more grammar on the stack, then this is an 124 // error 125 throw new DecoderException( errorMessage ); 126 } 127 128 if ( IS_DEBUG ) 129 { 130 LOG.debug( transition.toString() ); 131 } 132 133 if ( transition.hasAction() ) 134 { 135 Action<C> action = transition.getAction(); 136 action.action( container ); 137 } 138 139 container.setTransition( transition.getCurrentState() ); 140 } 141}