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.Collections; 021import java.util.Set; 022 023/** 024 * A filter reader that removes a given set of characters represented as <code>int</code> code points, handy to remove 025 * known junk characters from CSV files for example. 026 * <p> 027 * This class must convert each <code>int</code> read to an <code>Integer</code>. You can increase the Integer cache 028 * with a system property, see {@link Integer}. 029 * </p> 030 */ 031public class CharacterSetFilterReader extends AbstractCharacterFilterReader { 032 033 private static final Set<Integer> EMPTY_SET = Collections.emptySet(); 034 private final Set<Integer> skipSet; 035 036 /** 037 * Constructs a new reader. 038 * 039 * @param reader 040 * the reader to filter. 041 * @param skip 042 * the set of characters to filter out. 043 */ 044 public CharacterSetFilterReader(final Reader reader, final Set<Integer> skip) { 045 super(reader); 046 this.skipSet = skip == null ? EMPTY_SET : Collections.unmodifiableSet(skip); 047 } 048 049 @Override 050 protected boolean filter(final int ch) { 051 // Note WRT Integer.valueOf(): You can increase the Integer cache with a system property, see {@link Integer}. 052 return skipSet.contains(Integer.valueOf(ch)); 053 } 054 055}