org.apache.openjpa.util.StoreFacadeTypeRegistry Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.openjpa.util;
import java.util.Map;
import org.apache.openjpa.kernel.StoreManager;
import java.util.concurrent.ConcurrentHashMap;
/**
* Repository of store-specific facade classes. This is used by facade
* implementations to wrap store-specific components without knowing
* about all possible back-ends.
*/
public class StoreFacadeTypeRegistry {
private Map _impls = new ConcurrentHashMap();
/**
* Register a facade implementation.
*
* @param facadeType the facade interface
* @param storeType the store's
* {@link org.apache.openjpa.kernel.StoreManager} type, or null for generic
* @param implType the class implementing the facade
*/
public void registerImplementation(Class facadeType, Class storeType,
Class implType) {
Object key = (storeType == null) ? (Object) facadeType
: new Key(facadeType, storeType);
_impls.put(key, implType);
}
/**
* Return the implementation for the given facade and store.
*
* @param facadeType the facade interface
* @param storeType the store's
* {@link org.apache.openjpa.kernel.StoreManager} type, or null for generic
* @param implType the registered implementor
*/
public Class getImplementation(Class facadeType, Class storeType) {
// traverse store type hierarchy to store manager to find most specific
// store avaialble
Class impl;
for (; storeType != null && storeType != StoreManager.class;
storeType = storeType.getSuperclass()) {
impl = (Class) _impls.get(new Key(facadeType, storeType));
if (impl != null)
return impl;
}
return (Class) _impls.get(facadeType);
}
/**
* Return the implementation for the given facade and store. If no
* registered implementation is found then returns the given default type
* provided it the facade type is assignable from the deafult type.
*
* @param facadeType the facade interface
* @param storeType the store's
* {@link org.apache.openjpa.kernel.StoreManager} type, or null for generic
* @param implType the registered implementor
* @param defaultType class if no registered implementation is available.
*/
public Class getImplementation(Class facadeType, Class storeType,
Class defaultType) {
Class result = getImplementation(facadeType, storeType);
if (result == null)
result = defaultType;
if (facadeType == null || !facadeType.isAssignableFrom(result))
throw new InternalException();
return result;
}
/**
* Lookup key for facade+store hash.
*/
private static class Key {
public final Class _facadeType;
public final Class _storeType;
public Key(Class facadeType, Class storeType) {
_facadeType = facadeType;
_storeType = storeType;
}
public int hashCode() {
return _facadeType.hashCode() ^ _storeType.hashCode();
}
public boolean equals(Object other) {
if (other == this)
return true;
Key k = (Key) other;
return _facadeType == k._facadeType && _storeType == k._storeType;
}
}
}