DefaultConverter.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.util.convert;
import com.twelvemonkeys.lang.BeanUtil;
import com.twelvemonkeys.lang.StringUtil;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
/**
* Converts strings to objects and back.
* <p>
* This converter first tries to create an object, using the class' single
* string argument constructor ({@code <type>(String)}) if found,
* otherwise, an attempt to call
* the class' static {@code valueOf(String)} method. If both fails, a
* {@link ConversionException} is thrown.
* </p>
*
* @author <A href="haraldk@iconmedialab.no">Harald Kuhr</A>
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/util/convert/DefaultConverter.java#2 $
*
*/
public final class DefaultConverter implements PropertyConverter {
/**
* Creates a {@code DefaultConverter}.
*/
public DefaultConverter() {
}
/**
* Converts the string to an object of the given type.
*
* @param pString the string to convert
* @param pType the type to convert to
* @param pFormat ignored.
*
* @return the object created from the given string.
*
* @throws ConversionException if the type is null, or if the string cannot
* be converted into the given type, using a string constructor or static
* {@code valueOf} method.
*/
public Object toObject(final String pString, final Class pType, final String pFormat) throws ConversionException {
if (pString == null) {
return null;
}
if (pType == null) {
throw new MissingTypeException();
}
if (pType.isArray()) {
return toArray(pString, pType, pFormat);
}
// TODO: Separate CollectionConverter?
// should however, be simple to wrap array using Arrays.asList
// But what about generic type?! It's erased...
// Primitive -> wrapper
Class type = unBoxType(pType);
try {
// Try to create instance from <Constructor>(String)
Object value = BeanUtil.createInstance(type, pString);
if (value == null) {
// createInstance failed for some reason
// Try to invoke the static method valueOf(String)
value = BeanUtil.invokeStaticMethod(type, "valueOf", pString);
if (value == null) {
// If the value is still null, well, then I cannot help...
throw new ConversionException(String.format(
"Could not convert String to %1$s: No constructor %1$s(String) or static %1$s.valueOf(String) method found!",
type.getName()
));
}
}
return value;
}
catch (InvocationTargetException ite) {
throw new ConversionException(ite.getTargetException());
}
catch (ConversionException ce) {
throw ce;
}
catch (RuntimeException rte) {
throw new ConversionException(rte);
}
}
private Object toArray(final String pString, final Class pType, final String pFormat) {
String[] strings = StringUtil.toStringArray(pString, pFormat != null ? pFormat : StringUtil.DELIMITER_STRING);
Class type = pType.getComponentType();
if (type == String.class) {
return strings;
}
Object array = Array.newInstance(type, strings.length);
try {
for (int i = 0; i < strings.length; i++) {
Array.set(array, i, Converter.getInstance().toObject(strings[i], type));
}
}
catch (ConversionException e) {
if (pFormat != null) {
throw new ConversionException(String.format("%s for string \"%s\" with format \"%s\"", e.getMessage(), pString, pFormat), e);
}
else {
throw new ConversionException(String.format("%s for string \"%s\"", e.getMessage(), pString), e);
}
}
return array;
}
/**
* Converts the object to a string, using {@code pObject.toString()}.
*
* @param pObject the object to convert.
* @param pFormat ignored.
*
* @return the string representation of the object, or {@code null} if {@code pObject == null}
*/
public String toString(final Object pObject, final String pFormat)
throws ConversionException {
try {
return pObject == null ? null : pObject.getClass().isArray() ? arrayToString(toObjectArray(pObject), pFormat) : pObject.toString();
}
catch (RuntimeException rte) {
throw new ConversionException(rte);
}
}
private String arrayToString(final Object[] pArray, final String pFormat) {
return pFormat == null ? StringUtil.toCSVString(pArray) : StringUtil.toCSVString(pArray, pFormat);
}
private Object[] toObjectArray(final Object pObject) {
// TODO: Extract util method for wrapping/unwrapping native arrays?
Object[] array;
Class<?> componentType = pObject.getClass().getComponentType();
if (componentType.isPrimitive()) {
if (int.class == componentType) {
array = new Integer[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (short.class == componentType) {
array = new Short[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (long.class == componentType) {
array = new Long[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (float.class == componentType) {
array = new Float[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (double.class == componentType) {
array = new Double[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (boolean.class == componentType) {
array = new Boolean[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (byte.class == componentType) {
array = new Byte[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else if (char.class == componentType) {
array = new Character[Array.getLength(pObject)];
for (int i = 0; i < array.length; i++) {
Array.set(array, i, Array.get(pObject, i));
}
}
else {
throw new IllegalArgumentException("Unknown type " + componentType);
}
}
else {
array = (Object[]) pObject;
}
return array;
}
private Class<?> unBoxType(final Class<?> pType) {
if (pType.isPrimitive()) {
if (pType == boolean.class) {
return Boolean.class;
}
if (pType == byte.class) {
return Byte.class;
}
if (pType == char.class) {
return Character.class;
}
if (pType == short.class) {
return Short.class;
}
if (pType == int.class) {
return Integer.class;
}
if (pType == float.class) {
return Float.class;
}
if (pType == long.class) {
return Long.class;
}
if (pType == double.class) {
return Double.class;
}
throw new IllegalArgumentException("Unknown type: " + pType);
}
return pType;
}
}