org.springframework.webflow.engine.EndState 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 org.springframework.binding.mapping.AttributeMapper;
import org.springframework.core.style.ToStringCreator;
import org.springframework.util.Assert;
import org.springframework.webflow.core.collection.LocalAttributeMap;
import org.springframework.webflow.execution.Event;
import org.springframework.webflow.execution.FlowExecutionException;
import org.springframework.webflow.execution.FlowSession;
import org.springframework.webflow.execution.RequestContext;
import org.springframework.webflow.execution.ViewSelection;
/**
* A state that ends a flow when entered. More specifically, this state ends the
* active flow session of the active flow execution associated with the current
* request context.
*
* If the ended session is the "root flow session" the entire flow execution
* ends, signaling the end of a logical conversation.
*
* If the terminated session was acting as a subflow the flow execution
* continues and control is returned to the parent flow session. In that case,
* this state returns an ending result event the resuming parent flow is
* expected to respond to.
*
* An end state may optionally be configured with the name of a view to render
* when entered. This view will be rendered if the end state terminates the
* entire flow execution as a kind of flow ending "confirmation page".
*
* Note: if no viewName property is specified and this
* end state terminates the entire flow execution it is expected that some
* action has already written the response (or else a blank response will
* result). On the other hand, if no viewName is specified and
* this end state relinquishes control back to a parent flow, view selection
* responsibility falls on the parent flow.
*
* @see org.springframework.webflow.engine.ViewSelector
* @see org.springframework.webflow.engine.SubflowState
*
* @author Keith Donald
* @author Colin Sampaleanu
* @author Erwin Vervaet
*/
public class EndState extends State {
/**
* The optional view selector that will select a view to render if this end
* state terminates a root flow session.
*/
private ViewSelector viewSelector = NullViewSelector.INSTANCE;
/**
* Attribute mapper for mapping output attributes exposed by this end state
* when it is entered.
*/
private AttributeMapper outputMapper;
/**
* Create a new end state with no associated view.
* @param flow the owning flow
* @param id the state identifier (must be unique to the flow)
* @throws IllegalArgumentException when this state cannot be added to given
* flow, e.g. because the id is not unique
* @see State#State(Flow, String)
* @see #setViewSelector(ViewSelector)
* @see #setOutputMapper(AttributeMapper)
*/
public EndState(Flow flow, String id) throws IllegalArgumentException {
super(flow, id);
}
/**
* Returns the strategy used to select the view to render in this end state
* if it terminates a root flow.
*/
public ViewSelector getViewSelector() {
return viewSelector;
}
/**
* Sets the strategy used to select the view to render when this end state
* is entered and terminates a root flow.
*/
public void setViewSelector(ViewSelector viewSelector) {
Assert.notNull(viewSelector, "The view selector is required");
this.viewSelector = viewSelector;
}
/**
* Returns the configured attribute mapper for mapping output attributes
* exposed by this end state when it is entered.
*/
public AttributeMapper getOutputMapper() {
return outputMapper;
}
/**
* Sets the attribute mapper to use for mapping output attributes exposed by
* this end state when it is entered.
*/
public void setOutputMapper(AttributeMapper outputMapper) {
this.outputMapper = outputMapper;
}
/**
* Specialization of State's doEnter template method that
* executes behaviour specific to this state type in polymorphic fashion.
*
* This implementation pops the top (active) flow session off the execution
* stack, ending it, and resumes control in the parent flow (if neccessary).
* If the ended session is the root flow, a {@link ViewSelection} is
* returned.
* @param context the control context for the currently executing flow, used
* by this state to manipulate the flow execution
* @return a view selection signaling that control should be returned to the
* client and a view rendered
* @throws FlowExecutionException if an exception occurs in this state
*/
protected ViewSelection doEnter(RequestControlContext context) throws FlowExecutionException {
FlowSession activeSession = context.getFlowExecutionContext().getActiveSession();
if (activeSession.isRoot()) {
// entire flow execution is ending, return ending view if applicable
ViewSelection selectedView = viewSelector.makeEntrySelection(context);
context.endActiveFlowSession(createSessionOutput(context));
return selectedView;
}
else {
// there is a parent flow that will resume (this flow is a subflow)
LocalAttributeMap sessionOutput = createSessionOutput(context);
context.endActiveFlowSession(sessionOutput);
return context.signalEvent(new Event(this, getId(), sessionOutput));
}
}
/**
* Returns the subflow output map. This will invoke the output mapper (if any)
* to map data available in the flow execution request context into a newly
* creaed empty map.
*/
protected LocalAttributeMap createSessionOutput(RequestContext context) {
LocalAttributeMap outputMap = new LocalAttributeMap();
if (outputMapper != null) {
outputMapper.map(context, outputMap, null);
}
return outputMap;
}
protected void appendToString(ToStringCreator creator) {
creator.append("viewSelector", viewSelector).append("outputMapper", outputMapper);
}
}