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 */
017
018
019package org.apache.commons.beanutils.converters;
020
021
022import java.util.List;
023import org.apache.commons.beanutils.ConversionException;
024
025
026/**
027 * Standard {@link org.apache.commons.beanutils.Converter} implementation that converts an incoming
028 * String into an array of String objects. On a conversion failure, returns
029 * a specified default value or throws a {@link ConversionException} depending
030 * on how this instance is constructed.
031 * <p>
032 * There is also some special handling where the input is of type int[].
033 * See method convert for more details.  
034 *
035 * @author Craig R. McClanahan
036 * @version $Revision: 556229 $ $Date: 2007-07-14 07:11:19 +0100 (Sat, 14 Jul 2007) $
037 * @since 1.4
038 * @deprecated Replaced by the new {@link ArrayConverter} implementation
039 */
040
041public final class StringArrayConverter extends AbstractArrayConverter {
042
043
044    // ----------------------------------------------------------- Constructors
045
046
047    /**
048     * Create a {@link org.apache.commons.beanutils.Converter} that will throw
049     * a {@link ConversionException} if a conversion error occurs.
050     */
051    public StringArrayConverter() {
052
053        this.defaultValue = null;
054        this.useDefault = false;
055
056    }
057
058
059    /**
060     * Create a {@link org.apache.commons.beanutils.Converter} that will return
061     * the specified default value if a conversion error occurs.
062     *
063     * @param defaultValue The default value to be returned
064     */
065    public StringArrayConverter(Object defaultValue) {
066
067        this.defaultValue = defaultValue;
068        this.useDefault = true;
069
070    }
071
072
073    // ------------------------------------------------------- Static Variables
074
075
076    /**
077     * <p>Model object for type comparisons.</p>
078     */
079    private static final String[] MODEL = new String[0];
080    
081    /**
082     * <p> Model object for int arrays.</p>
083     */
084    private static final int[] INT_MODEL = new int[0];
085
086
087
088    // --------------------------------------------------------- Public Methods
089
090
091    /**
092     * Convert the specified input object into an output object of the
093     * specified type.
094     * <p>
095     * If the value is already of type String[] then it is simply returned
096     * unaltered.
097     * <p>
098     * If the value is of type int[], then a String[] is returned where each
099     * element in the string array is the result of calling Integer.toString
100     * on the corresponding element of the int array. This was added as a
101     * result of bugzilla request #18297 though there is not complete
102     * agreement that this feature should have been added. 
103     * <p>
104     * In all other cases, this method calls toString on the input object, then
105     * assumes the result is a comma-separated list of values. The values are 
106     * split apart into the individual items and returned as the elements of an
107     * array. See class AbstractArrayConverter for the exact input formats
108     * supported.
109     * 
110     * @param type is the data type to which this value should be converted.
111     * It is expected to be the class for type String[] (though this parameter
112     * is actually ignored by this method).
113     * 
114     * @param value is the input value to be converted. If null then the
115     * default value is returned or an exception thrown if no default value
116     * exists.
117     * @return the converted value
118     *
119     * @exception ConversionException if conversion cannot be performed
120     * successfully, or the input is null and there is no default value set
121     * for this object.
122     */
123    public Object convert(Class type, Object value) {
124
125        // Deal with a null value
126        if (value == null) {
127            if (useDefault) {
128                return (defaultValue);
129            } else {
130                throw new ConversionException("No value specified");
131            }
132        }
133
134        // Deal with the no-conversion-needed case
135        if (MODEL.getClass() == value.getClass()) {
136            return (value);
137        }
138
139        // Deal with the input value as an int array
140        if (INT_MODEL.getClass() == value.getClass())
141        {
142            int[] values = (int[]) value;
143            String[] results = new String[values.length];
144            for (int i = 0; i < values.length; i++)
145            {
146                results[i] = Integer.toString(values[i]);
147            }
148
149            return (results);
150        }
151
152        // Parse the input value as a String into elements
153        // and convert to the appropriate type
154        try {
155            List list = parseElements(value.toString());
156            String[] results = new String[list.size()];
157            for (int i = 0; i < results.length; i++) {
158                results[i] = (String) list.get(i);
159            }
160            return (results);
161        } catch (Exception e) {
162            if (useDefault) {
163                return (defaultValue);
164            } else {
165                throw new ConversionException(value.toString(), e);
166            }
167        }
168    }
169
170}