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.io.input;
018
019import java.io.Reader;
020import java.util.Arrays;
021import java.util.Collections;
022import java.util.HashSet;
023import java.util.Set;
024import java.util.function.IntPredicate;
025
026/**
027 * A filter reader that removes a given set of characters represented as {@code int} code points, handy to remove known
028 * junk characters from CSV files for example.
029 * <p>
030 * This class must convert each {@code int} read to an {@link Integer}. You can increase the Integer cache with a system
031 * property, see {@link Integer}.
032 * </p>
033 */
034public class CharacterSetFilterReader extends AbstractCharacterFilterReader {
035
036    private static IntPredicate toIntPredicate(final Set<Integer> skip) {
037        if (skip == null) {
038            return SKIP_NONE;
039        }
040        final Set<Integer> unmodifiableSet = Collections.unmodifiableSet(skip);
041        return c -> unmodifiableSet.contains(Integer.valueOf(c));
042    }
043
044    /**
045     * Constructs a new reader.
046     *
047     * @param reader the reader to filter.
048     * @param skip the set of characters to filter out.
049     * @since 2.9.0
050     */
051    public CharacterSetFilterReader(final Reader reader, final Integer... skip) {
052        this(reader, new HashSet<>(Arrays.asList(skip)));
053    }
054
055    /**
056     * Constructs a new reader.
057     *
058     * @param reader the reader to filter.
059     * @param skip the set of characters to filter out.
060     */
061    public CharacterSetFilterReader(final Reader reader, final Set<Integer> skip) {
062        super(reader, toIntPredicate(skip));
063    }
064
065}