ErrorHandler.java
/*
* Copyright (C) 2019 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.camera.core;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import androidx.annotation.GuardedBy;
import androidx.annotation.RestrictTo;
import androidx.annotation.RestrictTo.Scope;
import androidx.camera.core.CameraX.ErrorCode;
import androidx.camera.core.CameraX.ErrorListener;
/**
* Handler for sending and receiving error messages.
*
* @hide Only internal classes should post error messages
*/
@RestrictTo(Scope.LIBRARY_GROUP)
public final class ErrorHandler {
private static final String TAG = "ErrorHandler";
private final Object mErrorLock = new Object();
@GuardedBy("mErrorLock")
private ErrorListener mListener = new PrintingErrorListener();
@GuardedBy("mErrorLock")
private Handler mHandler = new Handler(Looper.getMainLooper());
/**
* Posts an error message.
*
* @param error the type of error that occurred
* @param message detailed message of the error condition
*/
void postError(final ErrorCode error, final String message) {
synchronized (mErrorLock) {
final ErrorListener listenerReference = mListener;
mHandler.post(new Runnable() {
@Override
public void run() {
listenerReference.onError(error, message);
}
});
}
}
/**
* Sets the listener for the error.
*
* @param listener the listener which should handle the error condition
* @param handler the handler on which to run the listener
*/
void setErrorListener(ErrorListener listener, Handler handler) {
synchronized (mErrorLock) {
if (handler == null) {
mHandler = new Handler(Looper.getMainLooper());
} else {
mHandler = handler;
}
if (listener == null) {
mListener = new PrintingErrorListener();
} else {
mListener = listener;
}
}
}
/** An error listener which logs the error message and returns. */
static final class PrintingErrorListener implements ErrorListener {
@Override
public void onError(ErrorCode error, String message) {
Log.e(TAG, "ErrorHandler occurred: " + error + " with message: " + message);
}
}
}