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Parallel programming on the go
/*
* 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.gh.bmd.jrt.builder;
import com.gh.bmd.jrt.annotation.Pass;
import com.gh.bmd.jrt.annotation.Pass.PassMode;
import com.gh.bmd.jrt.annotation.ShareGroup;
import com.gh.bmd.jrt.channel.OutputChannel;
import com.gh.bmd.jrt.common.WeakIdentityHashMap;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import static com.gh.bmd.jrt.common.Reflection.boxingClass;
/**
* Utility class used to manage cached objects shared by routine builders.
*
* Created by davide on 3/23/15.
*/
public class RoutineBuilders {
private static final WeakIdentityHashMap> sMutexCache =
new WeakIdentityHashMap>();
/**
* Avoid direct instantiation.
*/
protected RoutineBuilders() {
}
/**
* Gets the async passing mode associated to the specified method parameter.
*
* @param method the target method.
* @param index the index of the parameter.
* @return the async passing mode.
*/
@Nullable
public static PassMode getParamMode(@Nonnull final Method method, final int index) {
Pass passAnnotation = null;
final Annotation[][] annotations = method.getParameterAnnotations();
for (final Annotation annotation : annotations[index]) {
if (annotation.annotationType() == Pass.class) {
passAnnotation = (Pass) annotation;
break;
}
}
if (passAnnotation == null) {
return null;
}
PassMode passMode = passAnnotation.mode();
final Class paramClass = passAnnotation.value();
final Class[] parameterTypes = method.getParameterTypes();
final Class parameterType = parameterTypes[index];
final int length = parameterTypes.length;
final boolean isArray = parameterType.isArray();
if (passMode == PassMode.AUTO) {
if (OutputChannel.class.isAssignableFrom(parameterType)) {
if ((length == 1) && (paramClass.isArray() || paramClass.isAssignableFrom(
List.class))) {
passMode = PassMode.COLLECTION;
} else {
passMode = PassMode.OBJECT;
}
} else if (isArray || Iterable.class.isAssignableFrom(parameterType)) {
if (isArray && !boxingClass(paramClass).isAssignableFrom(
boxingClass(parameterType.getComponentType()))) {
throw new IllegalArgumentException(
"[" + method + "] the async input array with passing mode "
+ PassMode.PARALLEL + " does not match the bound type: "
+ paramClass.getCanonicalName());
}
if (length > 1) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.PARALLEL
+ " cannot be applied to a method taking " + length +
" input parameters");
}
passMode = PassMode.PARALLEL;
} else {
throw new IllegalArgumentException("[" + method + "] cannot automatically choose a "
+ "passing mode for an output of type: "
+ parameterType.getCanonicalName());
}
} else if (passMode == PassMode.OBJECT) {
if (!OutputChannel.class.isAssignableFrom(parameterType)) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.OBJECT
+ " must extends an " + OutputChannel.class.getCanonicalName());
}
} else if (passMode == PassMode.COLLECTION) {
if (!OutputChannel.class.isAssignableFrom(parameterType)) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.COLLECTION
+ " must extends an " + OutputChannel.class.getCanonicalName());
}
if (!paramClass.isArray() && !paramClass.isAssignableFrom(List.class)) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.COLLECTION
+ " must be bound to an array or a superclass of "
+ List.class.getCanonicalName());
}
if (length > 1) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.COLLECTION +
" cannot be applied to a method taking " + length
+ " input parameters");
}
} else { // PassMode.PARALLEL
if (!isArray && !Iterable.class.isAssignableFrom(parameterType)) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.PARALLEL
+ " must be an array or implement an "
+ Iterable.class.getCanonicalName());
}
if (isArray && !boxingClass(paramClass).isAssignableFrom(
boxingClass(parameterType.getComponentType()))) {
throw new IllegalArgumentException(
"[" + method + "] the async input array with passing mode "
+ PassMode.PARALLEL + " does not match the bound type: "
+ paramClass.getCanonicalName());
}
if (length > 1) {
throw new IllegalArgumentException(
"[" + method + "] an async input with passing mode " + PassMode.PARALLEL
+ " cannot be applied to a method taking " + length
+ " input parameters");
}
}
return passMode;
}
/**
* Gets the async passing mode of the return type of the specified method.
*
* @param method the target method.
* @return the async passing mode.
*/
@Nullable
public static PassMode getReturnMode(@Nonnull final Method method) {
final Pass annotation = method.getAnnotation(Pass.class);
if (annotation == null) {
return null;
}
final Class returnType = method.getReturnType();
PassMode passMode = annotation.mode();
if (passMode == PassMode.AUTO) {
if (returnType.isArray() || returnType.isAssignableFrom(List.class)) {
final Class returnClass = annotation.value();
if (returnType.isArray() && !boxingClass(
returnType.getComponentType()).isAssignableFrom(boxingClass(returnClass))) {
throw new IllegalArgumentException(
"[" + method + "] the async output array with passing mode "
+ PassMode.PARALLEL + " does not match the bound type: "
+ returnClass.getCanonicalName());
}
passMode = PassMode.PARALLEL;
} else if (returnType.isAssignableFrom(OutputChannel.class)) {
final Class returnClass = annotation.value();
if (returnClass.isArray() || Iterable.class.isAssignableFrom(returnClass)) {
passMode = PassMode.COLLECTION;
} else {
passMode = PassMode.OBJECT;
}
} else {
throw new IllegalArgumentException("[" + method + "] cannot automatically choose a "
+ "passing mode for an input of type: "
+ returnType.getCanonicalName());
}
} else if (passMode == PassMode.OBJECT) {
if (!returnType.isAssignableFrom(OutputChannel.class)) {
final String channelClassName = OutputChannel.class.getCanonicalName();
throw new IllegalArgumentException(
"[" + method + "] an async output with passing mode " + PassMode.OBJECT
+ " must be a superclass of " + channelClassName);
}
} else if (passMode == PassMode.COLLECTION) {
if (!returnType.isAssignableFrom(OutputChannel.class)) {
final String channelClassName = OutputChannel.class.getCanonicalName();
throw new IllegalArgumentException(
"[" + method + "] an async output with passing mode " + PassMode.OBJECT
+ " must be a superclass of " + channelClassName);
}
final Class returnClass = annotation.value();
if (!returnClass.isArray() && !Iterable.class.isAssignableFrom(returnClass)) {
throw new IllegalArgumentException(
"[" + method + "] an async output with passing mode " + PassMode.COLLECTION
+ " must be bound to an array or a type implementing an "
+ Iterable.class.getCanonicalName());
}
} else { // PassMode.PARALLEL
if (!returnType.isArray() && !returnType.isAssignableFrom(List.class)) {
throw new IllegalArgumentException(
"[" + method + "] an async output with passing mode " + PassMode.PARALLEL
+ " must be an array or a superclass " +
"of " + List.class.getCanonicalName());
}
final Class returnClass = annotation.value();
if (returnType.isArray() && !boxingClass(
returnType.getComponentType()).isAssignableFrom(boxingClass(returnClass))) {
throw new IllegalArgumentException(
"[" + method + "] the async output array with passing mode "
+ PassMode.PARALLEL + " does not match the bound type: "
+ returnClass.getCanonicalName());
}
}
return passMode;
}
/**
* Returns the cached mutex associated with the specified target and share group.
* If the cache was empty, it is filled with a new object automatically created.
*
* @param target the target object instance.
* @param shareGroup the share group name.
* @return the cached mutex.
* @throws java.lang.NullPointerException if the specified target or group name are null.
*/
@Nonnull
public static Object getSharedMutex(@Nonnull final Object target,
@Nullable final String shareGroup) {
synchronized (sMutexCache) {
final WeakIdentityHashMap> mutexCache = sMutexCache;
Map mutexMap = mutexCache.get(target);
if (mutexMap == null) {
mutexMap = new HashMap();
mutexCache.put(target, mutexMap);
}
final String groupName = (shareGroup != null) ? shareGroup : ShareGroup.ALL;
Object mutex = mutexMap.get(groupName);
if (mutex == null) {
mutex = new Object();
mutexMap.put(groupName, mutex);
}
return mutex;
}
}
}