/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.beanutils.converters;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.beanutils.ConversionException;
import org.apache.commons.beanutils.Converter;
/**
* <p>Convenience base class for converters that translate the String
* representation of an array into a corresponding array of primitives
* object. This class encapsulates the functionality required to parse
* the String into a list of String elements that can later be
* individually converted to the appropriate primitive type.</p>
*
* <p>The input syntax accepted by the <code>parseElements()</code> method
* is designed to be compatible with the syntax used to initialize arrays
* in a Java source program, except that only String literal values are
* supported. For maximum flexibility, the surrounding '{' and '}'
* characters are optional, and individual elements may be separated by
* any combination of whitespace and comma characters.</p>
*
* @author Craig R. McClanahan
* @version $Revision: 557808 $ $Date: 2007-07-20 00:05:03 +0100 (Fri, 20 Jul 2007) $
* @since 1.4
* @deprecated Replaced by the new {@link ArrayConverter} implementation
*/
public abstract class AbstractArrayConverter implements Converter {
// ----------------------------------------------------------- Constructors
/**
* Create a {@link Converter} that will throw a {@link ConversionException}
* if a conversion error occurs.
*/
public AbstractArrayConverter() {
this.defaultValue = null;
this.useDefault = false;
}
/**
* Create a {@link Converter} that will return the specified default value
* if a conversion error occurs.
*
* @param defaultValue The default value to be returned
*/
public AbstractArrayConverter(Object defaultValue) {
if (defaultValue == NO_DEFAULT) {
this.useDefault = false;
} else {
this.defaultValue = defaultValue;
this.useDefault = true;
}
}
// ------------------------------------------------------- Static Variables
/**
* This is a special reference that can be passed as the "default object"
* to the constructor to indicate that no default is desired. Note that
* the value 'null' cannot be used for this purpose, as the caller may
* want a null to be returned as the default.
*/
public static final Object NO_DEFAULT = new Object();
// ----------------------------------------------------- Instance Variables
/**
* <p>Model object for string arrays.</p>
*/
protected static String[] strings = new String[0];
/**
* The default value specified to our Constructor, if any.
*/
protected Object defaultValue = null;
/**
* Should we return the default value on conversion errors?
*/
protected boolean useDefault = true;
// --------------------------------------------------------- Public Methods
/**
* Convert the specified input object into an output object of the
* specified type. This method must be implemented by a concrete
* subclass.
*
* @param type Data type to which this value should be converted
* @param value The input value to be converted
* @return The converted value
*
* @exception ConversionException if conversion cannot be performed
* successfully
*/
public abstract Object convert(Class type, Object value);
// ------------------------------------------------------ Protected Methods
/**
* <p>Parse an incoming String of the form similar to an array initializer
* in the Java language into a <code>List</code> individual Strings
* for each element, according to the following rules.</p>
* <ul>
* <li>The string is expected to be a comma-separated list of values.</li>
* <li>The string may optionally have matching '{' and '}' delimiters
* around the list.</li>
* <li>Whitespace before and after each element is stripped.</li>
* <li>Elements in the list may be delimited by single or double quotes.
* Within a quoted elements, the normal Java escape sequences are valid.</li>
* </ul>
*
* @param svalue String value to be parsed
* @return The parsed list of String values
*
* @exception ConversionException if the syntax of <code>svalue</code>
* is not syntactically valid
* @exception NullPointerException if <code>svalue</code>
* is <code>null</code>
*/
protected List parseElements(String svalue) {
// Validate the passed argument
if (svalue == null) {
throw new NullPointerException();
}
// Trim any matching '{' and '}' delimiters
svalue = svalue.trim();
if (svalue.startsWith("{") && svalue.endsWith("}")) {
svalue = svalue.substring(1, svalue.length() - 1);
}
try {
// Set up a StreamTokenizer on the characters in this String
StreamTokenizer st =
new StreamTokenizer(new StringReader(svalue));
st.whitespaceChars(',',','); // Commas are delimiters
st.ordinaryChars('0', '9'); // Needed to turn off numeric flag
st.ordinaryChars('.', '.');
st.ordinaryChars('-', '-');
st.wordChars('0', '9'); // Needed to make part of tokens
st.wordChars('.', '.');
st.wordChars('-', '-');
// Split comma-delimited tokens into a List
ArrayList list = new ArrayList();
while (true) {
int ttype = st.nextToken();
if ((ttype == StreamTokenizer.TT_WORD) ||
(ttype > 0)) {
list.add(st.sval);
} else if (ttype == StreamTokenizer.TT_EOF) {
break;
} else {
throw new ConversionException
("Encountered token of type " + ttype);
}
}
// Return the completed list
return (list);
} catch (IOException e) {
throw new ConversionException(e);
}
}
}