/*
* 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.util.Arrays;
import java.util.HashSet;
import java.util.Set;
/**
* ������ת���ɲ���ֵ.
*
* <ul>
* <li>
* �������Ϊ<code>null</code>, ���׳���Ĭ��ֵ��<code>ConvertFailedException</code>.
* </li>
* <li>
* ��������Ѿ���<code>Boolean</code>��, ֱ�ӷ���.
* </li>
* <li>
* ���������<code>Number</code>����, �Ҳ�Ϊ<code>0</code>, ��<code>true</code>, ����<code>false</code>.
* </li>
* <li>
* ����������ַ���, ���ַ�����������һ������, ����ֵ��Ϊ<code>0</code>, ��<code>true</code>, ����<code>false</code>.
* </li>
* <li>
* �������Ϊ���ַ���, ���׳���Ĭ��ֵ��<code>ConvertFailedException</code>.
* </li>
* <li>
* �������Ϊ����ֵ֮һ���ַ���(��Сд������): <code>"false", "null", "nul", "nil", "off", "no", "n"</code>
* ��Ϊ<code>false</code>.
* </li>
* <li>
* �������Ϊ����ֵ֮һ���ַ���(��Сд������): <code>"true", "on", "yes", "y"</code> ��Ϊ<code>true</code>.
* </li>
* <li>
* ����������ַ���, �Ҳ�����������������, ���׳�<code>ConvertFailedException</code>.
* </li>
* <li>
* ����, �Ѷ��ݸ���һ��<code>Converter</code>����.
* </li>
* </ul>
*
*
* @version $Id: BooleanConverter.java,v 1.1 2003/07/03 07:26:37 baobao Exp $
* @author Michael Zhou
*/
public class BooleanConverter implements Converter {
protected static final Boolean DEFAULT_VALUE = Boolean.FALSE;
protected static final Set TRUE_STRINGS = new HashSet(Arrays.asList(
new String[] {
"true",
"on",
"yes",
"y"
}));
protected static final Set FALSE_STRINGS = new HashSet(Arrays.asList(
new String[] {
"false",
"null",
"nul",
"nil",
"off",
"no",
"n"
}));
public Object convert(Object value, ConvertChain chain) {
if (value == null) {
throw new ConvertFailedException().setDefaultValue(DEFAULT_VALUE);
}
if (value instanceof Boolean) {
return value;
}
if (value instanceof Number) {
return (Math.abs(((Number) value).doubleValue()) < Float.MIN_VALUE)
? Boolean.FALSE
: Boolean.TRUE;
}
if (value instanceof String) {
String strValue = ((String) value).trim();
try {
return (Integer.decode(strValue).intValue() == 0) ? Boolean.FALSE
: Boolean.TRUE;
} catch (NumberFormatException e) {
if (strValue.length() == 0) {
throw new ConvertFailedException().setDefaultValue(DEFAULT_VALUE);
}
strValue = strValue.toLowerCase();
if (TRUE_STRINGS.contains(strValue)) {
return Boolean.TRUE;
}
if (FALSE_STRINGS.contains(strValue)) {
return Boolean.FALSE;
}
throw new ConvertFailedException(e);
}
}
return chain.convert(value);
}
}