org.d2ab.iterator.chars.BackPeekingMappingCharIterator Maven / Gradle / Ivy
/*
* Copyright 2016 Daniel Skogquist Åborg
*
* 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.
*/
package org.d2ab.iterator.chars;
import org.d2ab.function.CharBinaryOperator;
/**
* An iterator over chars that also maps each element by looking at the current AND the previous element.
*/
public class BackPeekingMappingCharIterator extends DelegatingUnaryCharIterator {
private final char firstPrevious;
private final CharBinaryOperator mapper;
private int previous = -1;
public BackPeekingMappingCharIterator(CharIterator iterator, char firstPrevious, CharBinaryOperator mapper) {
super(iterator);
this.firstPrevious = firstPrevious;
this.mapper = mapper;
}
@Override
public char nextChar() {
char next = iterator.nextChar();
char result = mapper.applyAsChar(previous == -1 ? firstPrevious : (char) previous, next);
previous = next;
return result;
}
}