| /* |
| * Copyright (C) 2014 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 android.hardware.camera2.dispatch; |
| |
| import android.hardware.camera2.utils.UncheckedThrow; |
| import android.os.Handler; |
| import android.util.Log; |
| |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| |
| import static com.android.internal.util.Preconditions.*; |
| |
| /** |
| * Forward all interface calls into a handler by posting it as a {@code Runnable}. |
| * |
| * <p>All calls will return immediately; functions with return values will return a default |
| * value of {@code null}, {@code 0}, or {@code false} where that value is legal.</p> |
| * |
| * <p>Any exceptions thrown on the handler while trying to invoke a method |
| * will be re-thrown. Throwing checked exceptions on a handler which doesn't expect any |
| * checked exceptions to be thrown will result in "undefined" behavior |
| * (although in practice it is usually thrown as normal).</p> |
| */ |
| public class HandlerDispatcher<T> implements Dispatchable<T> { |
| |
| private static final String TAG = "HandlerDispatcher"; |
| |
| private final Dispatchable<T> mDispatchTarget; |
| private final Handler mHandler; |
| |
| /** |
| * Create a dispatcher that forwards it's dispatch calls by posting |
| * them onto the {@code handler} as a {@code Runnable}. |
| * |
| * @param dispatchTarget the destination whose method calls will be redirected into the handler |
| * @param handler all calls into {@code dispatchTarget} will be posted onto this handler |
| * @param <T> the type of the element you want to wrap. |
| * @return a dispatcher that will forward it's dispatch calls to a handler |
| */ |
| public HandlerDispatcher(Dispatchable<T> dispatchTarget, Handler handler) { |
| mDispatchTarget = checkNotNull(dispatchTarget, "dispatchTarget must not be null"); |
| mHandler = checkNotNull(handler, "handler must not be null"); |
| } |
| |
| @Override |
| public Object dispatch(final Method method, final Object[] args) throws Throwable { |
| mHandler.post(new Runnable() { |
| @Override |
| public void run() { |
| try { |
| mDispatchTarget.dispatch(method, args); |
| } catch (InvocationTargetException e) { |
| Throwable t = e.getTargetException(); |
| // Potential UB. Hopefully 't' is a runtime exception. |
| UncheckedThrow.throwAnyException(t); |
| } catch (IllegalAccessException e) { |
| // Impossible |
| Log.wtf(TAG, "IllegalAccessException while invoking " + method, e); |
| } catch (IllegalArgumentException e) { |
| // Impossible |
| Log.wtf(TAG, "IllegalArgumentException while invoking " + method, e); |
| } catch (Throwable e) { |
| UncheckedThrow.throwAnyException(e); |
| } |
| } |
| }); |
| |
| // TODO handle primitive return values that would avoid NPE if unboxed |
| return null; |
| } |
| } |