package com.ibm.mil.smartringer;

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;

public final class NoiseMeter {
    public static final int METER_LIMIT = 32768;

    private static final int SAMPLE_RATE = 8000;
    private static final int MIN_BUFFER_SIZE = AudioRecord.getMinBufferSize(SAMPLE_RATE,
            AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);

    private AudioRecord mAudioRecord;

    public void start() {
        mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, SAMPLE_RATE,
                AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, MIN_BUFFER_SIZE);
        mAudioRecord.startRecording();
    }

    public void stop() {
        if (mAudioRecord != null) {
            mAudioRecord.stop();
            mAudioRecord.release();
        }
    }

    public int getMaxAmplitude() {
        short[] buffer = new short[MIN_BUFFER_SIZE];

        if (mAudioRecord != null) {
            mAudioRecord.read(buffer, 0, MIN_BUFFER_SIZE);
        }

        int max = 0;
        for (short s : buffer) {
            int abs = Math.abs(s);
            if (abs > max) {
                max = abs;
            }
        }

        return max;
    }
}

package com.ibm.mil.smartringer;

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;

public final class NoiseMeter {
    public static final int METER_LIMIT = 32768;

    private static final int SAMPLE_RATE = 8000;
    private static final int MIN_BUFFER_SIZE = AudioRecord.getMinBufferSize(SAMPLE_RATE,
            AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);

    private AudioRecord mAudioRecord;

    public void start() {
        mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, SAMPLE_RATE,
                AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, MIN_BUFFER_SIZE);
        mAudioRecord.startRecording();
    }

    public void stop() {
        if (mAudioRecord != null) {
            mAudioRecord.stop();
            mAudioRecord.release();
        }
    }

    public int getMaxAmplitude() {
        short[] buffer = new short[MIN_BUFFER_SIZE];

        if (mAudioRecord != null) {
            mAudioRecord.read(buffer, 0, MIN_BUFFER_SIZE);
        }

        int max = 0;
        for (short s : buffer) {
            int abs = Math.abs(s);
            if (abs > max) {
                max = abs;
            }
        }

        return max;
    }

    public static class Sampler {
        private NoiseMeter mNoiseMeter;
        private int mPollingRate;
        private Receiver mReceiver;

        public Sampler(NoiseMeter noiseMeter, int pollingRate, Receiver receiver) {
            mNoiseMeter = noiseMeter;
            mPollingRate = pollingRate;
            mReceiver = receiver;
        }

        public void startSampling() {
            // sample from noise meter and notify receiver of result
            mReceiver.receiveSample(1000);
        }

        public void stopSampling() {
            // stop sampling from noise meter
        }
    }

    public interface Receiver {
        void receiveSample(int amplitude);
    }

}

Create a nested Sampler class and Receiver interface inside NoiseMeter