001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 * 
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 * 
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.text.translate;
018
019import java.io.IOException;
020import java.io.Writer;
021import java.util.ArrayList;
022import java.util.List;
023
024/**
025 * Executes a sequence of translators one after the other. Execution ends whenever 
026 * the first translator consumes codepoints from the input.
027 *
028 * @since 1.0
029 */
030public class AggregateTranslator extends CharSequenceTranslator {
031
032    private final List<CharSequenceTranslator> translators = new ArrayList<>();
033
034    /**
035     * Specify the translators to be used at creation time. 
036     *
037     * @param translators CharSequenceTranslator array to aggregate
038     */
039    public AggregateTranslator(final CharSequenceTranslator... translators) {
040        if (translators != null) {
041            for (CharSequenceTranslator translator : translators) {
042                if (translator != null) {
043                    this.translators.add(translator);
044                }
045            }
046        }
047    }
048
049    /**
050     * The first translator to consume codepoints from the input is the 'winner'. 
051     * Execution stops with the number of consumed codepoints being returned. 
052     * {@inheritDoc}
053     */
054    @Override
055    public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
056        for (final CharSequenceTranslator translator : translators) {
057            final int consumed = translator.translate(input, index, out);
058            if(consumed != 0) {
059                return consumed;
060            }
061        }
062        return 0;
063    }
064
065}