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/*
* Java Genetic Algorithm Library (jenetics-8.1.0).
* Copyright (c) 2007-2024 Franz Wilhelmstötter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Author:
* Franz Wilhelmstötter ([email protected])
*/
package io.jenetics.ext.internal.parser;
import static java.lang.String.format;
import io.jenetics.ext.internal.parser.Token.Type;
/**
* Parser implementation for parsing explicit {@link Token} sequences.
*
* @param the token value type
*
* @author Franz Wilhelmstötter
* @since 7.1
* @version 7.1
*/
public class TokenParser extends Parser> {
/**
* Create a new parser object with the given {@code tokenizer} and lookahead
* count {@code k}.
*
* @param tokenizer the token source {@code this} parser uses
* @param k the lookahead count
*/
public TokenParser(final Tokenizer> tokenizer, final int k) {
super(tokenizer, k);
}
/**
* Return the token type code for the given lookahead index.
*
* @param index lookahead index
* @return the token type code for the given lookahead index
*/
public int LA(final int index) {
final var token = LT(index);
return token != null ? token.type().code() : Type.EOF.code();
}
/**
* Try to match and consume the next token of the given
* {@code type}. If the current token is not from the given type, a
* {@link ParsingException} is thrown.
*
* @param type the token type to match
* @return the matched token
* @throws NullPointerException if the given token {@code type} is
* {@code null}
* @throws ParsingException if the current token doesn't match the desired
* token {@code type}
*/
public Token match(final Type type) {
if (LA(1) == type.code()) {
final var token = LT(1);
consume();
return token;
} else {
throw new ParsingException(format(
"Expecting %s but found %s.",
type, LT(1)
));
}
}
}