/
Lifecycling.java
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/
Lifecycling.java
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/*
* Copyright (C) 2017 The Android Open Source Project
*
* 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 androidx.lifecycle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Internal class to handle lifecycle conversion etc.
*
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP_PREFIX)
public class Lifecycling {
private static final int REFLECTIVE_CALLBACK = 1;
private static final int GENERATED_CALLBACK = 2;
private static Map<Class<?>, Integer> sCallbackCache = new HashMap<>();
private static Map<Class<?>, List<Constructor<? extends GeneratedAdapter>>> sClassToAdapters =
new HashMap<>();
// Left for binary compatibility when lifecycle-common goes up 2.1 as transitive dep
// but lifecycle-runtime stays 2.0
/**
* @deprecated Left for compatibility with lifecycle-runtime:2.0
*/
@SuppressWarnings("deprecation")
@Deprecated
@NonNull
static GenericLifecycleObserver getCallback(final Object object) {
final LifecycleEventObserver observer = lifecycleEventObserver(object);
return new GenericLifecycleObserver() {
@Override
public void onStateChanged(@NonNull LifecycleOwner source,
@NonNull Lifecycle.Event event) {
observer.onStateChanged(source, event);
}
};
}
@NonNull
static LifecycleEventObserver lifecycleEventObserver(Object object) {
boolean isLifecycleEventObserver = object instanceof LifecycleEventObserver;
boolean isFullLifecycleObserver = object instanceof FullLifecycleObserver;
if (isLifecycleEventObserver && isFullLifecycleObserver) {
return new FullLifecycleObserverAdapter((FullLifecycleObserver) object,
(LifecycleEventObserver) object);
}
if (isFullLifecycleObserver) {
return new FullLifecycleObserverAdapter((FullLifecycleObserver) object, null);
}
if (isLifecycleEventObserver) {
return (LifecycleEventObserver) object;
}
final Class<?> klass = object.getClass();
int type = getObserverConstructorType(klass);
if (type == GENERATED_CALLBACK) {
List<Constructor<? extends GeneratedAdapter>> constructors =
sClassToAdapters.get(klass);
if (constructors.size() == 1) {
GeneratedAdapter generatedAdapter = createGeneratedAdapter(
constructors.get(0), object);
return new SingleGeneratedAdapterObserver(generatedAdapter);
}
GeneratedAdapter[] adapters = new GeneratedAdapter[constructors.size()];
for (int i = 0; i < constructors.size(); i++) {
adapters[i] = createGeneratedAdapter(constructors.get(i), object);
}
return new CompositeGeneratedAdaptersObserver(adapters);
}
return new ReflectiveGenericLifecycleObserver(object);
}
private static GeneratedAdapter createGeneratedAdapter(
Constructor<? extends GeneratedAdapter> constructor, Object object) {
//noinspection TryWithIdenticalCatches
try {
return constructor.newInstance(object);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e);
}
}
@Nullable
private static Constructor<? extends GeneratedAdapter> generatedConstructor(Class<?> klass) {
try {
Package aPackage = klass.getPackage();
String name = klass.getCanonicalName();
final String fullPackage = aPackage != null ? aPackage.getName() : "";
final String adapterName = getAdapterName(fullPackage.isEmpty() ? name :
name.substring(fullPackage.length() + 1));
@SuppressWarnings("unchecked") final Class<? extends GeneratedAdapter> aClass =
(Class<? extends GeneratedAdapter>) Class.forName(
fullPackage.isEmpty() ? adapterName : fullPackage + "." + adapterName);
Constructor<? extends GeneratedAdapter> constructor =
aClass.getDeclaredConstructor(klass);
if (!constructor.isAccessible()) {
constructor.setAccessible(true);
}
return constructor;
} catch (ClassNotFoundException e) {
return null;
} catch (NoSuchMethodException e) {
// this should not happen
throw new RuntimeException(e);
}
}
private static int getObserverConstructorType(Class<?> klass) {
Integer callbackCache = sCallbackCache.get(klass);
if (callbackCache != null) {
return callbackCache;
}
int type = resolveObserverCallbackType(klass);
sCallbackCache.put(klass, type);
return type;
}
private static int resolveObserverCallbackType(Class<?> klass) {
// anonymous class bug:35073837
if (klass.getCanonicalName() == null) {
return REFLECTIVE_CALLBACK;
}
Constructor<? extends GeneratedAdapter> constructor = generatedConstructor(klass);
if (constructor != null) {
sClassToAdapters.put(klass, Collections
.<Constructor<? extends GeneratedAdapter>>singletonList(constructor));
return GENERATED_CALLBACK;
}
boolean hasLifecycleMethods = ClassesInfoCache.sInstance.hasLifecycleMethods(klass);
if (hasLifecycleMethods) {
return REFLECTIVE_CALLBACK;
}
Class<?> superclass = klass.getSuperclass();
List<Constructor<? extends GeneratedAdapter>> adapterConstructors = null;
if (isLifecycleParent(superclass)) {
if (getObserverConstructorType(superclass) == REFLECTIVE_CALLBACK) {
return REFLECTIVE_CALLBACK;
}
adapterConstructors = new ArrayList<>(sClassToAdapters.get(superclass));
}
for (Class<?> intrface : klass.getInterfaces()) {
if (!isLifecycleParent(intrface)) {
continue;
}
if (getObserverConstructorType(intrface) == REFLECTIVE_CALLBACK) {
return REFLECTIVE_CALLBACK;
}
if (adapterConstructors == null) {
adapterConstructors = new ArrayList<>();
}
adapterConstructors.addAll(sClassToAdapters.get(intrface));
}
if (adapterConstructors != null) {
sClassToAdapters.put(klass, adapterConstructors);
return GENERATED_CALLBACK;
}
return REFLECTIVE_CALLBACK;
}
private static boolean isLifecycleParent(Class<?> klass) {
return klass != null && LifecycleObserver.class.isAssignableFrom(klass);
}
/**
* Create a name for an adapter class.
*/
public static String getAdapterName(String className) {
return className.replace(".", "_") + "_LifecycleAdapter";
}
private Lifecycling() {
}
}