001 /*
002 * Copyright 2003-2004 The Apache Software Foundation
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package org.apache.commons.convert1.string;
017
018 import java.io.File;
019
020 import org.apache.commons.convert1.ConversionException;
021 import org.apache.commons.convert1.Converter;
022
023 /**
024 * <p>Standard {@link Converter} implementation that converts an incoming
025 * String into a <code>java.io.FileL</code> object, optionally using a
026 * default value or throwing a {@link ConversionException} if a conversion
027 * error occurs.</p>
028 *
029 * @author James Strachan
030 * @version $Id: FileConverter.java 155441 2005-02-26 13:19:22Z dirkv $
031 * @since 0.1
032 */
033 public final class FileConverter implements Converter {
034
035 // ----------------------------------------------------- Instance Variables
036
037
038 /**
039 * The default value specified to our Constructor, if any.
040 */
041 private Object defaultValue = null;
042
043
044 /**
045 * Should we return the default value on conversion errors?
046 */
047 private boolean useDefault = true;
048
049
050 // ----------------------------------------------------------- Constructors
051
052
053 /**
054 * Create a {@link Converter} that will throw a {@link ConversionException}
055 * if a conversion error occurs.
056 */
057 public FileConverter() {
058
059 this.defaultValue = null;
060 this.useDefault = false;
061
062 }
063
064
065 /**
066 * Create a {@link Converter} that will return the specified default value
067 * if a conversion error occurs.
068 *
069 * @param defaultValue The default value to be returned
070 */
071 public FileConverter(Object defaultValue) {
072
073 this.defaultValue = defaultValue;
074 this.useDefault = true;
075
076 }
077
078
079
080 // --------------------------------------------------------- Public Methods
081
082
083 /**
084 * Convert the specified input object into an output object of the
085 * specified type.
086 *
087 * @param type Data type to which this value should be converted
088 * @param value The input value to be converted
089 *
090 * @exception ConversionException if conversion cannot be performed
091 * successfully
092 */
093 public Object convert(Class type, Object value) {
094
095 if (value == null) {
096 if (useDefault) {
097 return (defaultValue);
098 } else {
099 throw new ConversionException("No value specified");
100 }
101 }
102
103 if (value instanceof File) {
104 return (value);
105 }
106
107 return new File(value.toString());
108 }
109 }