io.jenetics.ext.internal.parser.TokenRing Maven / Gradle / Ivy
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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 java.util.stream.Collectors;
import java.util.stream.IntStream;
/**
* Ring-buffer for storing lookup tokens.
*
* @param the token value type
*
* @author Franz Wilhelmstötter
* @since 7.1
* @version 7.1
*/
final class TokenRing {
private final Object[] _tokens;
private int _pos = 0;
TokenRing(final int k) {
_tokens = new Object[k];
}
void add(final V token) {
_tokens[_pos] = token;
_pos = (_pos + 1)%_tokens.length;
}
@SuppressWarnings("unchecked")
public V LT(final int i) {
return (V)_tokens[(_pos + i - 1)%_tokens.length];
}
@Override
public String toString() {
return IntStream.rangeClosed(1, _tokens.length)
.mapToObj(i -> i + ":'" + LT(i) + "'")
.collect(Collectors.joining(", ", "[", "]"));
}
}