org.springframework.webflow.engine.model.builder.FlowModelBuilder 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.model.builder;
import org.springframework.core.io.Resource;
import org.springframework.webflow.engine.model.FlowModel;
/**
* Builder interface used to build a flow model. The process of building a flow model consists of the following steps:
*
* - Initialize this builder by calling {@link #init()}.
*
- Call {@link #build()} to create the flow model.
*
- Call {@link #getFlowModel()} to return the fully-built {@link FlowModel} model.
*
- Dispose this builder, releasing any resources allocated during the building process by calling {@link #dispose()}.
*
*
* Implementations should encapsulate flow construction logic, either for a specific kind of flow, for example, an
* XmlFlowModelBuilder, for building flows from an XML-definition.
*
* This is a good example of the classic GoF builder pattern.
*
* @see FlowModel
*
* @author Keith Donald
* @author Erwin Vervaet
* @author Scott Andrews
*/
public interface FlowModelBuilder {
/**
* Initialize this builder. This could cause the builder to open a stream to an externalized resource representing
* the flow definition, for example.
* @throws FlowModelBuilderException an exception occurred building the flow
*/
public void init() throws FlowModelBuilderException;
/**
* Builds any variables initialized by the flow when it starts.
* @throws FlowModelBuilderException an exception occurred building the flow
*/
public void build() throws FlowModelBuilderException;
/**
* Get the fully constructed flow model. Called by the builder's assembler (director) after assembly. When this
* method is called by the assembler, it is expected flow construction has completed and the returned flow model is
* ready for use.
* @throws FlowModelBuilderException an exception occurred building this flow
*/
public FlowModel getFlowModel() throws FlowModelBuilderException;
/**
* Shutdown the builder, releasing any resources it holds. A new flow construction process should start with another
* call to the {@link #init()} method.
* @throws FlowModelBuilderException an exception occurred disposing this flow
*/
public void dispose() throws FlowModelBuilderException;
/**
* Get the underlying flow model resource accessed to build this flow model. Returns null if this builder does not
* construct the flow model from a resource.
* @return the flow model resource
*/
public Resource getFlowModelResource();
/**
* Returns true if the underlying flow model resource has changed since the last call to {@link #init()}. Always
* returns false if the flow model is not build from a resource.
* @return true if the resource backing the flow model has changed
*/
public boolean hasFlowModelResourceChanged();
}