/*
* Copyright 2007-2008 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.impalaframework.module.operation;
import org.impalaframework.module.ModuleDefinition;
import org.impalaframework.module.ModuleDefinitionSource;
import org.impalaframework.module.RootModuleDefinition;
import org.impalaframework.module.spi.ModificationExtractor;
import org.impalaframework.module.spi.ModificationExtractorType;
import org.impalaframework.module.spi.ModuleStateHolder;
import org.impalaframework.module.spi.TransitionSet;
import org.springframework.util.Assert;
/**
* Implementation of {@link ModuleOperation} which encapsulates mechanism for
* updating the module hierarchy to reflect the {@link ModuleDefinition}
* obtained from the {@link ModuleOperationInput#getModuleDefinitionSource()}
* instance. This operation can be used to supply a new module definition set to
* reflect a new desired module hierarchy.
*
* @author Phil Zoio
*/
public class UpdateRootModuleOperation extends BaseModuleOperation {
protected UpdateRootModuleOperation() {
super();
}
public ModuleOperationResult doExecute(ModuleOperationInput moduleOperationInput) {
Assert.notNull(moduleOperationInput, "moduleOperationInput cannot be null");
ModuleStateHolder moduleStateHolder = getModuleStateHolder();
//note that the module definition source is externally supplied
ModuleDefinitionSource newModuleDefinitionSource = moduleOperationInput.getModuleDefinitionSource();
Assert.notNull(newModuleDefinitionSource, "moduleDefinitionSource is required as it specifies the new module definition to apply in " + this.getClass().getName());
RootModuleDefinition newModuleDefinition = newModuleDefinitionSource.getModuleDefinition();
RootModuleDefinition oldModuleDefinition = getExistingModuleDefinitionSource();
ModificationExtractorType modificationExtractorType = getModificationExtractorType();
// figure out the modules to reload
ModificationExtractor calculator = getModificationExtractorRegistry().getModificationExtractor(modificationExtractorType);
TransitionSet transitions = calculator.getTransitions(oldModuleDefinition, newModuleDefinition);
moduleStateHolder.processTransitions(transitions);
return ModuleOperationResult.TRUE;
}
protected ModificationExtractorType getModificationExtractorType() {
return ModificationExtractorType.STRICT;
}
protected RootModuleDefinition getExistingModuleDefinitionSource() {
return null;
}
}