/*
* Copyright 2004-2005 the original author or authors.
*
* 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 org.springmodules.validation.bean.rule.resolver;
import java.io.StringReader;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springmodules.validation.valang.functions.Function;
import org.springmodules.validation.valang.functions.TargetBeanFunction;
import org.springmodules.validation.valang.parser.ParseException;
import org.springmodules.validation.valang.parser.ValangParser;
/**
* Resolves error arguments based on valang expressions.
*
* @author Uri Boness
*/
public class ValangErrorArgumentsResolver implements ErrorArgumentsResolver {
private final static Log logger = LogFactory.getLog(ValangErrorArgumentsResolver.class);
private Function[] functions;
/**
* Creates a new ValangErrorArgumentsResolver with no argument expressions, that is, there will be no arguments.
*/
public ValangErrorArgumentsResolver() {
this(new String[0]);
}
/**
* Creates a new ValangErrorArgumentsResolver with the given argument expressions. This constructor uses the default
* {@link ValangParser).
*
* @param expressions The argument valang expressions.
*/
public ValangErrorArgumentsResolver(String[] expressions) {
this(expressions, null);
}
/**
* Creates a new ValangErrorArgumentsResolver with given argument expressions and custom functions that will be used
* by the valang parser.
*
* @param expressions The arguments valang expressions.
* @param functionsByName A map of custom valang functiosns where the key is the function name and the value is
* the name of the function class.
*/
public ValangErrorArgumentsResolver(String[] expressions, Map functionsByName) {
if (expressions == null) {
expressions = new String[0];
}
functions = new Function[expressions.length];
for (int i = 0; i < expressions.length; i++) {
functions[i] = parseFunction(expressions[i], functionsByName);
}
}
/**
* Returns the error arguments that are resolved by the configured valang expressions.
*
* @see org.springmodules.validation.bean.rule.resolver.ErrorArgumentsResolver#resolveArguments(Object)
*/
public Object[] resolveArguments(Object obj) {
Object[] args = new Object[functions.length];
for (int i = 0; i < args.length; i++) {
args[i] = functions[i].getResult(obj);
}
return args;
}
//=============================================== Helper Methods ===================================================
/**
* Parses a valang {@link Function} from the given argument expression and custom functions.
*
* @param expression The given argument expression.
* @param functionsByName The custom valang functions.
* @return The parsed function.
*/
protected Function parseFunction(String expression, Map functionsByName) {
ValangParser parser = new ValangParser(new StringReader(expression));
parser.setFunctionsByName(functionsByName);
try {
return parser.function(new TargetBeanFunction());
} catch (ParseException pe) {
logger.error("Could not parse valang expression '" + expression + "' to a function", pe);
throw new IllegalArgumentException("Could not parse valang expression '" + expression + "' to a function");
}
}
}