/*
* Copyright 2010 Alibaba Group Holding Limited.
* All rights reserved.
*
* Licensed 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 com.alibaba.toolkit.util.typeconvert.converters;
import com.alibaba.toolkit.util.typeconvert.ConvertChain;
import com.alibaba.toolkit.util.typeconvert.ConvertFailedException;
import com.alibaba.toolkit.util.typeconvert.Converter;
import java.math.BigDecimal;
import java.math.BigInteger;
/**
* ������ת����<code>BigInteger</code>.
*
* <ul>
* <li>
* �������Ϊ<code>null</code>, ���׳���Ĭ��ֵ��<code>ConvertFailedException</code>.
* </li>
* <li>
* ��������Ѿ���<code>BigInteger</code>��, ֱ�ӷ���.
* </li>
* <li>
* ���������<code>BigDecimal</code>, ֱ��ת����<code>BigInteger</code>.
* </li>
* <li>
* ���������<code>Number</code>����, ������<code>BigInteger</code>ֵ.
* </li>
* <li>
* ��������ǿ��ַ���, ���׳���Ĭ��ֵ��<code>ConvertFailedException</code>.
* </li>
* <li>
* ����������ַ���, �����Ű���ת����<code>BigInteger</code>. ������ɹ�, ���׳�<code>ConvertFailedException</code>.
* </li>
* <li>
* ����, �Ѷ��ݸ���һ��<code>Converter</code>����.
* </li>
* </ul>
*
*
* @version $Id: BigIntegerConverter.java,v 1.1 2003/07/03 07:26:37 baobao Exp $
* @author Michael Zhou
*/
public class BigIntegerConverter implements Converter {
protected static final BigInteger DEFAULT_VALUE = BigInteger.ZERO;
public Object convert(Object value, ConvertChain chain) {
if (value == null) {
throw new ConvertFailedException().setDefaultValue(DEFAULT_VALUE);
}
if (value instanceof BigInteger) {
return value;
}
if (value instanceof BigDecimal) {
return ((BigDecimal) value).toBigInteger();
}
if (value instanceof Number) {
return new BigDecimal(value.toString()).toBigInteger();
}
if (value instanceof String) {
String strValue = ((String) value).trim();
try {
return new BigInteger(strValue);
} catch (NumberFormatException e) {
if (strValue.length() > 0) {
throw new ConvertFailedException(e);
}
throw new ConvertFailedException().setDefaultValue(DEFAULT_VALUE);
}
}
return chain.convert(value);
}
}