/*
* Copyright 2004-2008 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;
import org.springframework.core.style.ToStringCreator;
import org.springframework.util.Assert;
import org.springframework.webflow.core.AnnotatedObject;
import org.springframework.webflow.execution.RequestContext;
/**
* A value object that defines a specification for a flow variable. Such a variable is allocated when a flow starts and
* destroyed when that flow ends. This class encapsulates information about the variable and the behavior necessary to
* allocate the variable instance in flow scope.
*
* @author Keith Donald
*/
public class FlowVariable extends AnnotatedObject {
/**
* The variable name.
*/
private String name;
/**
* The value factory that provides this variable's value.
*/
private VariableValueFactory valueFactory;
/**
* Creates a new flow variable.
* @param name the variable name
*/
public FlowVariable(String name, VariableValueFactory valueFactory) {
Assert.hasText(name, "The variable name is required");
Assert.notNull(valueFactory, "The variable value factory is required");
this.name = name;
this.valueFactory = valueFactory;
}
/**
* Returns the name of this variable.
*/
public String getName() {
return name;
}
// name and scope based equality
public boolean equals(Object o) {
if (!(o instanceof FlowVariable)) {
return false;
}
FlowVariable other = (FlowVariable) o;
return name.equals(other.name) && valueFactory.equals(other.valueFactory);
}
public int hashCode() {
return name.hashCode() + valueFactory.hashCode();
}
/**
* Creates this flow variable. This method allocates the variable's value in the correct flow scope.
* @param context the executing flow
*/
public void create(RequestContext context) {
Object value = valueFactory.createInitialValue(context);
context.getFlowScope().put(name, value);
}
/**
* Restores this variable's dependencies. This method asks the variable's value factory to restore any references
* the variable has to transient objects.
* @param context the executing flow
*/
public void restore(RequestContext context) {
Object value = context.getFlowScope().get(name);
valueFactory.restoreReferences(value, context);
}
/**
* Destroys this flow variable. This method removes the variable's value in the correct flow scope.
* @param context the executing flow
*/
public Object destroy(RequestContext context) {
return context.getFlowScope().remove(name);
}
public String toString() {
return new ToStringCreator(this).append("name", name).append("valueFactory", valueFactory).toString();
}
}