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/*
* Copyright 2008-2012 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. 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.
*/
package com.amazon.carbonado.gen;
import java.util.EnumSet;
import java.util.Map;
import org.cojen.classfile.ClassFile;
import org.cojen.classfile.CodeBuilder;
import org.cojen.classfile.MethodInfo;
import org.cojen.classfile.Modifiers;
import org.cojen.classfile.TypeDesc;
import org.cojen.util.ClassInjector;
import org.cojen.util.KeyFactory;
import com.amazon.carbonado.Storable;
import com.amazon.carbonado.SupportException;
import com.amazon.carbonado.util.SoftValuedCache;
/**
* Generates and caches concrete implementations of {@link Storable} types
* which delegate to {@link DelegateSupport}. The delegating classes extend
* those generated by {@link MasterStorableGenerator}.
*
* @author Brian S O'Neill
* @since 1.2
*/
public class DelegateStorableGenerator<S extends Storable> {
private static final SoftValuedCache<Object, Class> cCache;
static {
cCache = SoftValuedCache.newCache(11);
}
/**
* Delegate class has a constructor that accepts a {@link DelegateSupport}
* instance.
*
* <pre>
* public <init>(DelegateSupport);
* </pre>
*
*/
public static <S extends Storable> Class<? extends S>
getDelegateClass(Class<S> type, EnumSet<MasterFeature> features)
throws SupportException
{
if (features == null) {
features = EnumSet.noneOf(MasterFeature.class);
}
Object key = KeyFactory.createKey(new Object[] {type, features});
synchronized (cCache) {
Class<? extends S> generatedClass = (Class<? extends S>) cCache.get(key);
if (generatedClass != null) {
return generatedClass;
}
generatedClass = new DelegateStorableGenerator<S>(type, features)
.generateAndInjectClass();
cCache.put(key, generatedClass);
return generatedClass;
}
}
private final Class<S> mStorableType;
private final ClassInjector mClassInjector;
private final ClassFile mClassFile;
private DelegateStorableGenerator(Class<S> type, EnumSet<MasterFeature> features)
throws SupportException
{
mStorableType = type;
final Class<? extends S> abstractClass =
MasterStorableGenerator.getAbstractClass(mStorableType, features);
mClassInjector = ClassInjector.create(mStorableType.getName(),
abstractClass.getClassLoader());
mClassFile = new ClassFile(mClassInjector.getClassName(), abstractClass);
mClassFile.markSynthetic();
mClassFile.setSourceFile(DelegateStorableGenerator.class.getName());
mClassFile.setTarget("1.5");
}
private Class<? extends S> generateAndInjectClass() {
TypeDesc masterSupportType = TypeDesc.forClass(MasterSupport.class);
TypeDesc delegateSupportType = TypeDesc.forClass(DelegateSupport.class);
// Add constructor that accepts a DelegateSupport.
{
TypeDesc[] params = {delegateSupportType};
MethodInfo mi = mClassFile.addConstructor(Modifiers.PUBLIC, params);
CodeBuilder b = new CodeBuilder(mi);
b.loadThis();
b.loadLocal(b.getParameter(0));
b.invokeSuperConstructor(new TypeDesc[] {masterSupportType});
b.returnVoid();
}
CodeBuilderUtil.definePrepareMethod(mClassFile, mStorableType, delegateSupportType);
// Implement abstract methods which all delegate to DelegateSupport instance.
generateDelegatedMethod
(MasterStorableGenerator.DO_TRY_LOAD_MASTER_METHOD_NAME, "doTryLoad");
generateDelegatedMethod
(MasterStorableGenerator.DO_TRY_INSERT_MASTER_METHOD_NAME, "doTryInsert");
generateDelegatedMethod
(MasterStorableGenerator.DO_TRY_UPDATE_MASTER_METHOD_NAME, "doTryUpdate");
generateDelegatedMethod
(MasterStorableGenerator.DO_TRY_DELETE_MASTER_METHOD_NAME, "doTryDelete");
Class<? extends S> generatedClass = mClassInjector.defineClass(mClassFile);
return generatedClass;
}
private void generateDelegatedMethod(String masterMethodName, String supportMethodName) {
TypeDesc triggerSupportType = TypeDesc.forClass(TriggerSupport.class);
TypeDesc delegateSupportType = TypeDesc.forClass(DelegateSupport.class);
TypeDesc[] storableParam = {TypeDesc.forClass(Storable.class)};
MethodInfo mi = mClassFile.addMethod
(Modifiers.PROTECTED, masterMethodName, TypeDesc.BOOLEAN, null);
CodeBuilder b = new CodeBuilder(mi);
b.loadThis();
b.loadField(StorableGenerator.SUPPORT_FIELD_NAME, triggerSupportType);
b.checkCast(delegateSupportType);
b.loadThis();
b.invokeInterface(delegateSupportType, supportMethodName, TypeDesc.BOOLEAN, storableParam);
b.returnValue(TypeDesc.BOOLEAN);
}
}
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