org.springframework.webflow.engine.NullViewSelector 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;
import java.io.ObjectStreamException;
import java.io.Serializable;
import org.springframework.webflow.execution.RequestContext;
import org.springframework.webflow.execution.ViewSelection;
/**
* Makes a null view selection, indicating no response should be issued.
*
* @see org.springframework.webflow.execution.ViewSelection#NULL_VIEW
*
* @author Keith Donald
*/
public final class NullViewSelector implements ViewSelector, Serializable {
/*
* Implementation note: not located in webflow.execution.support package to
* avoid a cyclic dependency between webflow.execution and webflow.execution.support.
*/
/**
* The shared singleton {@link NullViewSelector} instance.
*/
public static final ViewSelector INSTANCE = new NullViewSelector();
/**
* Private constructor since this is a singleton.
*/
private NullViewSelector() {
}
public boolean isEntrySelectionRenderable(RequestContext context) {
return true;
}
public ViewSelection makeEntrySelection(RequestContext context) {
return ViewSelection.NULL_VIEW;
}
public ViewSelection makeRefreshSelection(RequestContext context) {
return makeEntrySelection(context);
}
// resolve the singleton instance
private Object readResolve() throws ObjectStreamException {
return INSTANCE;
}
}