org.antlr.v4.runtime.atn.LexerSkipAction Maven / Gradle / Ivy
/*
* 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.atn;
import org.antlr.v4.runtime.Lexer;
import org.antlr.v4.runtime.misc.MurmurHash;
/**
* Implements the {@code skip} lexer action by calling {@link Lexer#skip}.
*
* The {@code skip} command does not have any parameters, so this action is
* implemented as a singleton instance exposed by {@link #INSTANCE}.
*
* @author Sam Harwell
* @since 4.2
*/
public final class LexerSkipAction implements LexerAction {
/**
* Provides a singleton instance of this parameterless lexer action.
*/
public static final LexerSkipAction INSTANCE = new LexerSkipAction();
/**
* Constructs the singleton instance of the lexer {@code skip} command.
*/
private LexerSkipAction() {
}
/**
* {@inheritDoc}
* @return This method returns {@link LexerActionType#SKIP}.
*/
@Override
public LexerActionType getActionType() {
return LexerActionType.SKIP;
}
/**
* {@inheritDoc}
* @return This method returns {@code false}.
*/
@Override
public boolean isPositionDependent() {
return false;
}
/**
* {@inheritDoc}
*
* This action is implemented by calling {@link Lexer#skip}.
*/
@Override
public void execute(Lexer lexer) {
lexer.skip();
}
@Override
public int hashCode() {
int hash = MurmurHash.initialize();
hash = MurmurHash.update(hash, getActionType().ordinal());
return MurmurHash.finish(hash, 1);
}
@Override
@SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
public boolean equals(Object obj) {
return obj == this;
}
@Override
public String toString() {
return "skip";
}
}