org.springframework.webflow.engine.ViewVariable Maven / Gradle / Ivy
/*
* 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.webflow.core.AnnotatedObject;
import org.springframework.webflow.execution.RequestContext;
/**
* A variable scoped to a particular view. Such a variable is allocated when a view-state is entered and destroyed when
* that view-state exits. The flow scope map is used as the backing variable store.
*
* @author Keith Donald
*/
public class ViewVariable extends AnnotatedObject {
private String name;
private VariableValueFactory valueFactory;
/**
* Creates a new view variable.
* @param name the name of the variable
* @param valueFactory the source for the variable value
*/
public ViewVariable(String name, VariableValueFactory valueFactory) {
this.name = name;
this.valueFactory = valueFactory;
}
/**
* Returns the name of this view variable.
*/
public String getName() {
return name;
}
/**
* Returns the source of the variable's initial value.
*/
public VariableValueFactory getValueFactory() {
return valueFactory;
}
// name and scope based equality
public boolean equals(Object o) {
if (!(o instanceof ViewVariable)) {
return false;
}
ViewVariable other = (ViewVariable) o;
return name.equals(other.name) && valueFactory.equals(other.valueFactory);
}
public int hashCode() {
return name.hashCode() + valueFactory.hashCode();
}
/**
* Creates this view variable. This method allocates the variable's value in flow scope.
* @param context the executing flow
*/
public void create(RequestContext context) {
Object value = valueFactory.createInitialValue(context);
context.getViewScope().put(name, value);
}
/**
* Restores this view 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.getViewScope().get(name);
valueFactory.restoreReferences(value, context);
}
/**
* Destroy this view variable. This method removes the variable's value in flow scope.
* @param context the executing flow
*/
public Object destroy(RequestContext context) {
return context.getViewScope().remove(name);
}
}