android/WALT/app/src/main/java/org/chromium/latency/walt/SimpleLogger.java

/*
 * Copyright (C) 2015 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 org.chromium.latency.walt;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;

/**
 * A very simple logger that keeps its data in a StringBuilder. We need on screen log because the
 * USB port is often taken and we don't have easy access to adb log.
 */
public class SimpleLogger {
    private static final String LOG_INTENT = "log-message";
    public static final String TAG = "WaltLogger";

    private static final Object LOCK = new Object();
    private static SimpleLogger instance;

    private StringBuilder sb = new StringBuilder();
    private LocalBroadcastManager broadcastManager;

    public static SimpleLogger getInstance(Context context) {
        synchronized (LOCK) {
            if (instance == null) {
                instance = new SimpleLogger(context.getApplicationContext());
            }
            return instance;
        }
    }

    private SimpleLogger(Context context) {
        broadcastManager = LocalBroadcastManager.getInstance(context);
    }

    public synchronized void log(String msg) {
        Log.i(TAG, msg);
        sb.append(msg);
        sb.append('\n');
        if (broadcastManager != null) {
            Intent intent = new Intent(LOG_INTENT);
            intent.putExtra("message", msg);
            broadcastManager.sendBroadcast(intent);
        }
    }

    public void registerReceiver(BroadcastReceiver broadcastReceiver) {
        broadcastManager.registerReceiver(broadcastReceiver, new IntentFilter(LOG_INTENT));
    }

    public void unregisterReceiver(BroadcastReceiver broadcastReceiver) {
        broadcastManager.unregisterReceiver(broadcastReceiver);
    }

    public String getLogText() {
        return sb.toString();
    }

    public void clear() {
        sb = new StringBuilder();
    }

}