org.apache.commons.beanutils.converters.StringConverter Maven / Gradle / Ivy
/*
* 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;
/**
* {@link org.apache.commons.beanutils.Converter}
* implementation that converts an incoming
* object into a java.lang.String object.
*
* Note that ConvertUtils really is designed to do string->object conversions,
* and offers very little support for object->string conversions. The
* ConvertUtils/ConvertUtilsBean methods only select a converter to apply
* based upon the target type being converted to, and generally assume that
* the input is a string (by calling its toString method if needed).
*
* This class is therefore just a dummy converter that converts its input
* into a string by calling the input object's toString method and returning
* that value.
*
* It is possible to replace this converter with something that has a big
* if/else statement that selects behaviour based on the real type of the
* object being converted (or possibly has a map of converters, and looks
* them up based on the class of the input object). However this is not part
* of the existing ConvertUtils framework.
*
*
* @version $Id: StringConverter.java 1540518 2013-11-10 19:04:04Z oheger $
* @since 1.3
*/
public final class StringConverter extends AbstractConverter {
/**
* Construct a java.lang.String Converter that throws
* a ConversionException if an error occurs.
*/
public StringConverter() {
super();
}
/**
* Construct a java.lang.String Converter that returns
* a default value if an error occurs.
*
* @param defaultValue The default value to be returned
* if the value to be converted is missing or an error
* occurs converting the value.
*/
public StringConverter(Object defaultValue) {
super(defaultValue);
}
/**
* Return the default type this Converter handles.
*
* @return The default type this Converter handles.
* @since 1.8.0
*/
@Override
protected Class getDefaultType() {
return String.class;
}
/**
* Convert the specified input object into an output object of the
* specified type.
*
* @param Target type of the conversion.
* @param type Data type to which this value should be converted.
* @param value The input value to be converted.
* @return The converted value.
* @throws Throwable if an error occurs converting to the specified type
* @since 1.8.0
*/
@Override
protected T convertToType(Class type, Object value) throws Throwable {
// We have to support Object, too, because this class is sometimes
// used for a standard to Object conversion
if (String.class.equals(type) || Object.class.equals(type)) {
return type.cast(value.toString());
}
throw conversionException(type, value);
}
}