// Copyright 2007 The Apache Software Foundation
//
// 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.apache.hivemind.annotations.internal;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.annotations.TypedRegistry;
import org.apache.hivemind.internal.Module;
import org.apache.hivemind.internal.RegistryInfrastructure;
import org.apache.hivemind.util.Defense;
import org.apache.hivemind.util.PropertyUtils;
/**
* Implementation of {@link ModuleInstanceProvider}.
*
* @author Achim Huegen
*/
public class ModuleInstanceProviderImpl implements ModuleInstanceProvider
{
private static final String REGISTRY_PROPERTY_NAME = "registry";
private Class _moduleClass;
private Object _instance;
private String _moduleId;
public ModuleInstanceProviderImpl(Class moduleClass, String moduleId)
{
_moduleClass = moduleClass;
_moduleId = moduleId;
}
public Object getModuleInstance()
{
Defense.fieldNotNull(_instance, "instance");
return _instance;
}
private void createModuleInstance(RegistryInfrastructure _registry)
{
try
{
_instance = _moduleClass.newInstance();
injectRegistry(_instance, _registry);
}
catch (Exception ex)
{
// TODO: more expressive error message
throw new ApplicationRuntimeException(ex.getMessage(), ex);
}
}
/**
* Checks if the module contains a property REGISTRY_PROPERTY_NAME and injects
* the registry interface provided to this class during construction.
*
* @param moduleInstance
*/
private void injectRegistry(Object moduleInstance, RegistryInfrastructure _registry)
{
if (PropertyUtils.isWritable(moduleInstance, REGISTRY_PROPERTY_NAME)
&& PropertyUtils.getPropertyType(moduleInstance, REGISTRY_PROPERTY_NAME).equals(TypedRegistry.class)) {
Module callingModule = _registry.getModule(_moduleId);
TypedRegistry annotatedRegistry = new TypedRegistryImpl(callingModule, _registry);
PropertyUtils.write(moduleInstance, REGISTRY_PROPERTY_NAME, annotatedRegistry);
}
}
/**
* Called after initialization of the registry infrastructure.
* This is a good moment to create the module instance. If any service defined in the module
* is initialized during startup (by the EagerLoad service) it will find the registry
* reference in place.
*
* @see org.apache.hivemind.events.RegistryInitializationListener#registryInitialized(org.apache.hivemind.internal.RegistryInfrastructure)
*/
public void registryInitialized(RegistryInfrastructure registry)
{
createModuleInstance(registry);
}
}