org.springframework.webflow.engine.builder.TextToTargetStateResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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.springframework.webflow.engine.builder;
import org.springframework.binding.convert.ConversionContext;
import org.springframework.binding.convert.support.AbstractConverter;
import org.springframework.binding.expression.Expression;
import org.springframework.webflow.engine.TargetStateResolver;
import org.springframework.webflow.engine.support.DefaultTargetStateResolver;
/**
* Converter that takes an encoded string representation and produces a
* corresponding {@link TargetStateResolver} object.
*
* This converter supports the following encoded forms:
*
* - "stateId" - will result in a TargetStateResolver that always resolves
* the same state.
* - "${stateIdExpression} - will result in a TargetStateResolver that
* resolves the target state by evaluating an expression against the request
* context.
* - "bean:<id>" - will result in usage of a custom TargetStateResolver
* bean implementation configured in an external context.
*
*
* @author Keith Donald
* @author Erwin Vervaet
*/
public class TextToTargetStateResolver extends AbstractConverter {
/**
* Prefix used when the user wants to use a custom TargetStateResolver
* implementation managed by a factory.
*/
private static final String BEAN_PREFIX = "bean:";
/**
* Locator to use for loading custom TargetStateResolver beans.
*/
private FlowServiceLocator flowServiceLocator;
/**
* Create a new converter that converts strings to transition target state
* resolver objects. The given conversion service will be used to do all
* necessary internal conversion (e.g. parsing expression strings).
*/
public TextToTargetStateResolver(FlowServiceLocator flowServiceLocator) {
this.flowServiceLocator = flowServiceLocator;
}
public Class[] getSourceClasses() {
return new Class[] { String.class };
}
public Class[] getTargetClasses() {
return new Class[] { TargetStateResolver.class };
}
protected Object doConvert(Object source, Class targetClass, ConversionContext context) throws Exception {
String targetStateId = (String)source;
if (flowServiceLocator.getExpressionParser().isDelimitedExpression(targetStateId)) {
Expression expression = flowServiceLocator.getExpressionParser().parseExpression(targetStateId);
return new DefaultTargetStateResolver(expression);
}
else if (targetStateId.startsWith(BEAN_PREFIX)) {
return flowServiceLocator.getTargetStateResolver(targetStateId.substring(BEAN_PREFIX.length()));
}
else {
return new DefaultTargetStateResolver(targetStateId);
}
}
}