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/*-
* ============LICENSE_START=======================================================
* SDC
* ================================================================================
* Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.openecomp.core.factory.impl;
import static org.openecomp.core.utilities.CommonMethods.isEmpty;
import static org.openecomp.core.utilities.CommonMethods.newInstance;
import org.openecomp.sdc.common.errors.CoreException;
import org.openecomp.sdc.common.errors.ErrorCategory;
import org.openecomp.sdc.common.errors.ErrorCode;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public abstract class AbstractFactoryBase {
/**
* Temporary registry of default implementations. The map keeps class names rather then class
* types to allow unloading of those classes from memory by garbage collector if factory is not
* actually used.
*/
private static Map<String, String> registry = new ConcurrentHashMap<String, String>();
/**
* Cached factory instances.
*/
private static Map<String, AbstractFactoryBase> factoryMap =
new ConcurrentHashMap<String, AbstractFactoryBase>();
/**
* Registers implementor for an abstract factory. The method accepts Java classes rather then
* class names to ensure type safety at compilation time.
*
* @param <I> Java interface type instantiated by abstract factory
* @param <F> Type specific abstract factory for concrete Java interface
* @param factory Java class of a type specific abstract factory
* @param impl Java class of type specific factory implementor
*/
public static <I, F extends AbstractFactoryBase> void registerFactory(Class<F> factory,
Class<? extends F> impl) {
if (factory == null) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001").withMessage("Mandatory input factory.")
.withCategory(ErrorCategory.SYSTEM).build());
}
if (impl == null) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001").withMessage("Mandatory input impl.")
.withCategory(ErrorCategory.SYSTEM).build());
}
if (factoryMap != null && factoryMap.containsKey(factory.getName())) {
factoryMap.remove(factory.getName());
}
registry.put(factory.getName(), impl.getName());
} // registerFactory
// TODO: Remove
protected static void registerFactory(String factoryName, String implName) {
registry.put(factoryName, implName);
} // registerFactory
/**
* Unregister factory.
*
* @param <F> the type parameter
* @param factory the factory
*/
public static <F extends AbstractFactoryBase> void unregisterFactory(Class<F> factory) {
if (factory == null) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001").withMessage("Mandatory input factory.")
.withCategory(ErrorCategory.SYSTEM).build());
}
if (factoryMap != null) {
factoryMap.remove(factory.getName());
}
}
/**
* Instantiates the configured implementation of an abstract factory.
*
* @param <I> Java interface type instantiated by abstract factory
* @param <F> Type specific abstract factory for concrete Java interface
* @param factoryType Java class of type specific abstract factory
* @return Instance of implementation class
*/
@SuppressWarnings("unchecked")
public static <I, F extends AbstractFactoryBase> F getInstance(Class<F> factoryType) {
if (factoryType == null) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001")
.withMessage("Mandatory input factory type.").withCategory(ErrorCategory.SYSTEM)
.build());
}
// Pick up factory instance from cache
F factory = (F) factoryMap.get(factoryType.getName());
// Check for the first time access
if (factory == null) {
// Synchronize factory instantiation
synchronized (factoryType) {
// Re-check the factory instance
factory = (F) factoryMap.get(factoryType.getName());
if (factory == null) {
// Get the implementation class name
String implName = registry.get(factoryType.getName());
if (isEmpty(implName)) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001")
.withMessage("Mandatory input factory implementation.")
.withCategory(ErrorCategory.SYSTEM).build());
}
factory = newInstance(implName, factoryType);
factory.init();
// Cache the instantiated singleton
factoryMap.put(factoryType.getName(), factory);
}
}
}
return factory;
} // getInstance
/**
* Is factory registered boolean.
*
* @param <F> the type parameter
* @param factoryType the factory type
* @return the boolean
*/
public static <F extends AbstractFactoryBase> boolean isFactoryRegistered(Class<F> factoryType) {
boolean isFactoryRegistered = false;
if (factoryType == null) {
throw new CoreException(
new ErrorCode.ErrorCodeBuilder().withId("E0001")
.withMessage("Mandatory input factory type.").withCategory(ErrorCategory.SYSTEM)
.build());
}
// Pick up factory instance from cache
F factory = (F) factoryMap.get(factoryType.getName());
// Check for the first time access
if (factory != null) {
isFactoryRegistered = true;
} else {
// Get the implementation class name
String implName = registry.get(factoryType.getName());
if (!isEmpty(implName)) {
isFactoryRegistered = true;
}
}
return isFactoryRegistered;
}
/**
* Stop all.
*/
public static void stopAll() {
Collection<AbstractFactoryBase> factorylist = factoryMap.values();
for (AbstractFactoryBase factory : factorylist) {
factory.stop();
}
}
protected void init() {
}
protected void stop() {
}
}
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