/*
* Copyright (c) 2002-2012 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.citrus.service.form.impl.condition;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.StringUtil.*;
import com.alibaba.citrus.expr.Expression;
import com.alibaba.citrus.expr.ExpressionContext;
import com.alibaba.citrus.expr.ExpressionFactory;
import com.alibaba.citrus.expr.ExpressionParseException;
import com.alibaba.citrus.expr.jexl.JexlExpressionFactory;
import com.alibaba.citrus.service.form.MessageContext;
import com.alibaba.citrus.service.form.Validator.Context;
import com.alibaba.citrus.service.form.support.AbstractCondition;
import com.alibaba.citrus.service.form.support.AbstractConditionDefinitionParser;
import com.alibaba.citrus.util.StringEscapeUtil;
import com.alibaba.citrus.util.ToStringBuilder;
import com.alibaba.citrus.util.ToStringBuilder.MapBuilder;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.ParserContext;
import org.w3c.dom.Element;
/**
* 用jexl表达式来计算条件。
* <p>
* JEXL语法参见：<a href="http://commons.apache.org/jexl/reference/syntax.html">JEXL
* Reference</a>
* </p>
*
* @author Michael Zhou
*/
public class JexlCondition extends AbstractCondition {
protected static final ExpressionFactory EXPRESSION_FACTORY = new JexlExpressionFactory();
private String conditionString;
private Expression condition;
public JexlCondition(String condition) {
this.conditionString = trimToNull(condition);
}
@Override
protected void init() throws Exception {
assertNotNull(conditionString, "missing condition expression");
try {
condition = EXPRESSION_FACTORY.createExpression(conditionString);
} catch (ExpressionParseException e) {
throw new IllegalArgumentException("Invalid if condition: \""
+ StringEscapeUtil.escapeJava(conditionString) + "\"", e);
}
}
public boolean isSatisfied(final Context context) {
TypeConverter converter = context.getField().getGroup().getForm().getTypeConverter();
ExpressionContext expressionContext = new MessageContext() {
@Override
protected Object internalGet(String key) {
return null;
}
@Override
public ExpressionContext getParentContext() {
return context.getMessageContext();
}
@Override
protected void buildToString(ToStringBuilder sb) {
sb.append("JexlConditionContext");
}
@Override
protected void buildToString(MapBuilder mb) {
}
};
Object value = condition.evaluate(expressionContext);
if (value == null) {
return false;
} else if (value instanceof Boolean) {
return (Boolean) value;
} else {
return (Boolean) converter.convertIfNecessary(value, Boolean.class);
}
}
public static class DefinitionParser extends AbstractConditionDefinitionParser<JexlCondition> {
@Override
protected void doParseElement(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
builder.addConstructorArgValue(element.getTextContent());
}
}
}