Android example source code file (DiskStatsService.java)

This example Android source code file (DiskStatsService.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, binder, content, context, data, diskstatsservice, error, file, fileoutputstream, illegalargumentexception, io, ioexception, k, os, override, printwriter, string, system

The DiskStatsService.java Android example source code

/*
 * Copyright (C) 2010 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 com.android.server;

import android.content.Context;
import android.os.Binder;
import android.os.Environment;
import android.os.FileUtils;
import android.os.StatFs;
import android.os.SystemClock;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * This service exists only as a "dumpsys" target which reports
 * statistics about the status of the disk.
 */
public class DiskStatsService extends Binder {
    private final Context mContext;

    public DiskStatsService(Context context) {
        mContext = context;
    }

    @Override
    protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
        // This data is accessible to any app -- no permission check needed.

        // Run a quick-and-dirty performance test: write 512 bytes
        byte[] junk = new byte[512];
        for (int i = 0; i < junk.length; i++) junk[i] = (byte) i;  // Write nonzero bytes

        File tmp = new File(Environment.getDataDirectory(), "system/perftest.tmp");
        FileOutputStream fos = null;
        IOException error = null;

        long before = SystemClock.uptimeMillis();
        try {
            fos = new FileOutputStream(tmp);
            fos.write(junk);
        } catch (IOException e) {
            error = e;
        } finally {
            try { if (fos != null) fos.close(); } catch (IOException e) {}
        }

        long after = SystemClock.uptimeMillis();
        if (tmp.exists()) tmp.delete();

        if (error != null) {
            pw.print("Test-Error: ");
            pw.println(error.toString());
        } else {
            pw.print("Latency: ");
            pw.print(after - before);
            pw.println("ms [512B Data Write]");
        }

        reportFreeSpace(Environment.getDataDirectory(), "Data", pw);
        reportFreeSpace(Environment.getDownloadCacheDirectory(), "Cache", pw);
        reportFreeSpace(new File("/system"), "System", pw);

        // TODO: Read /proc/yaffs and report interesting values;
        // add configurable (through args) performance test parameters.
    }

    private void reportFreeSpace(File path, String name, PrintWriter pw) {
        try {
            StatFs statfs = new StatFs(path.getPath());
            long bsize = statfs.getBlockSize();
            long avail = statfs.getAvailableBlocks();
            long total = statfs.getBlockCount();
            if (bsize <= 0 || total <= 0) {
                throw new IllegalArgumentException(
                        "Invalid stat: bsize=" + bsize + " avail=" + avail + " total=" + total);
            }

            pw.print(name);
            pw.print("-Free: ");
            pw.print(avail * bsize / 1024);
            pw.print("K / ");
            pw.print(total * bsize / 1024);
            pw.print("K total = ");
            pw.print(avail * 100 / total);
            pw.println("% free");
        } catch (IllegalArgumentException e) {
            pw.print(name);
            pw.print("-Error: ");
            pw.println(e.toString());
            return;
        }
    }
}