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With inspiration from other libraries
/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.runtime;
import org.antlr.v4.runtime.atn.ATN;
import org.antlr.v4.runtime.atn.ATNSimulator;
import org.antlr.v4.runtime.atn.ParseInfo;
import org.antlr.v4.runtime.misc.Utils;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
public abstract class Recognizer {
public static final int EOF=-1;
private static final Map> tokenTypeMapCache =
new WeakHashMap>();
private static final Map> ruleIndexMapCache =
new WeakHashMap>();
private List _listeners =
new CopyOnWriteArrayList() {{
add(ConsoleErrorListener.INSTANCE);
}};
protected ATNInterpreter _interp;
private int _stateNumber = -1;
/** Used to print out token names like ID during debugging and
* error reporting. The generated parsers implement a method
* that overrides this to point to their String[] tokenNames.
*
* @deprecated Use {@link #getVocabulary()} instead.
*/
@Deprecated
public abstract String[] getTokenNames();
public abstract String[] getRuleNames();
/**
* Get the vocabulary used by the recognizer.
*
* @return A {@link Vocabulary} instance providing information about the
* vocabulary used by the grammar.
*/
@SuppressWarnings("deprecation")
public Vocabulary getVocabulary() {
return VocabularyImpl.fromTokenNames(getTokenNames());
}
/**
* Get a map from token names to token types.
*
* Used for XPath and tree pattern compilation.
*/
public Map getTokenTypeMap() {
Vocabulary vocabulary = getVocabulary();
synchronized (tokenTypeMapCache) {
Map result = tokenTypeMapCache.get(vocabulary);
if (result == null) {
result = new HashMap();
for (int i = 0; i <= getATN().maxTokenType; i++) {
String literalName = vocabulary.getLiteralName(i);
if (literalName != null) {
result.put(literalName, i);
}
String symbolicName = vocabulary.getSymbolicName(i);
if (symbolicName != null) {
result.put(symbolicName, i);
}
}
result.put("EOF", Token.EOF);
result = Collections.unmodifiableMap(result);
tokenTypeMapCache.put(vocabulary, result);
}
return result;
}
}
/**
* Get a map from rule names to rule indexes.
*
* Used for XPath and tree pattern compilation.
*/
public Map getRuleIndexMap() {
String[] ruleNames = getRuleNames();
if (ruleNames == null) {
throw new UnsupportedOperationException("The current recognizer does not provide a list of rule names.");
}
synchronized (ruleIndexMapCache) {
Map result = ruleIndexMapCache.get(ruleNames);
if (result == null) {
result = Collections.unmodifiableMap(Utils.toMap(ruleNames));
ruleIndexMapCache.put(ruleNames, result);
}
return result;
}
}
public int getTokenType(String tokenName) {
Integer ttype = getTokenTypeMap().get(tokenName);
if ( ttype!=null ) return ttype;
return Token.INVALID_TYPE;
}
/**
* If this recognizer was generated, it will have a serialized ATN
* representation of the grammar.
*
* For interpreters, we don't know their serialized ATN despite having
* created the interpreter from it.
*/
public String getSerializedATN() {
throw new UnsupportedOperationException("there is no serialized ATN");
}
/** For debugging and other purposes, might want the grammar name.
* Have ANTLR generate an implementation for this method.
*/
public abstract String getGrammarFileName();
/**
* Get the {@link ATN} used by the recognizer for prediction.
*
* @return The {@link ATN} used by the recognizer for prediction.
*/
public abstract ATN getATN();
/**
* Get the ATN interpreter used by the recognizer for prediction.
*
* @return The ATN interpreter used by the recognizer for prediction.
*/
public ATNInterpreter getInterpreter() {
return _interp;
}
/** If profiling during the parse/lex, this will return DecisionInfo records
* for each decision in recognizer in a ParseInfo object.
*
* @since 4.3
*/
public ParseInfo getParseInfo() {
return null;
}
/**
* Set the ATN interpreter used by the recognizer for prediction.
*
* @param interpreter The ATN interpreter used by the recognizer for
* prediction.
*/
public void setInterpreter(ATNInterpreter interpreter) {
_interp = interpreter;
}
/** What is the error header, normally line/character position information? */
public String getErrorHeader(RecognitionException e) {
int line = e.getOffendingToken().getLine();
int charPositionInLine = e.getOffendingToken().getCharPositionInLine();
return "line "+line+":"+charPositionInLine;
}
/** How should a token be displayed in an error message? The default
* is to display just the text, but during development you might
* want to have a lot of information spit out. Override in that case
* to use t.toString() (which, for CommonToken, dumps everything about
* the token). This is better than forcing you to override a method in
* your token objects because you don't have to go modify your lexer
* so that it creates a new Java type.
*
* @deprecated This method is not called by the ANTLR 4 Runtime. Specific
* implementations of {@link ANTLRErrorStrategy} may provide a similar
* feature when necessary. For example, see
* {@link DefaultErrorStrategy#getTokenErrorDisplay}.
*/
@Deprecated
public String getTokenErrorDisplay(Token t) {
if ( t==null ) return "";
String s = t.getText();
if ( s==null ) {
if ( t.getType()==Token.EOF ) {
s = "";
}
else {
s = "<"+t.getType()+">";
}
}
s = s.replace("\n","\\n");
s = s.replace("\r","\\r");
s = s.replace("\t","\\t");
return "'"+s+"'";
}
/**
* @exception NullPointerException if {@code listener} is {@code null}.
*/
public void addErrorListener(ANTLRErrorListener listener) {
if (listener == null) {
throw new NullPointerException("listener cannot be null.");
}
_listeners.add(listener);
}
public void removeErrorListener(ANTLRErrorListener listener) {
_listeners.remove(listener);
}
public void removeErrorListeners() {
_listeners.clear();
}
public List getErrorListeners() {
return _listeners;
}
public ANTLRErrorListener getErrorListenerDispatch() {
return new ProxyErrorListener(getErrorListeners());
}
// subclass needs to override these if there are sempreds or actions
// that the ATN interp needs to execute
public boolean sempred(RuleContext _localctx, int ruleIndex, int actionIndex) {
return true;
}
public boolean precpred(RuleContext localctx, int precedence) {
return true;
}
public void action(RuleContext _localctx, int ruleIndex, int actionIndex) {
}
public final int getState() {
return _stateNumber;
}
/** Indicate that the recognizer has changed internal state that is
* consistent with the ATN state passed in. This way we always know
* where we are in the ATN as the parser goes along. The rule
* context objects form a stack that lets us see the stack of
* invoking rules. Combine this and we have complete ATN
* configuration information.
*/
public final void setState(int atnState) {
// System.err.println("setState "+atnState);
_stateNumber = atnState;
// if ( traceATNStates ) _ctx.trace(atnState);
}
public abstract IntStream getInputStream();
public abstract void setInputStream(IntStream input);
public abstract TokenFactory getTokenFactory();
public abstract void setTokenFactory(TokenFactory input);
}