ExternalStorageSpaceContext.java

/*
 * Copyright (C) 2014 The Context Engine 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 uk.ac.tvu.mdse.contextengine.contexts;

import java.util.Timer;
import java.util.TimerTask;

import uk.ac.tvu.mdse.contextengine.Component;
import uk.ac.tvu.mdse.contextengine.reasoning.ContextValues;
import android.content.Context;
import android.os.Environment;
import android.os.StatFs;
import android.util.Log;

public class ExternalStorageSpaceContext extends Component {

	private static final long serialVersionUID = -4618383874590867306L;
	public static final String LOG_TAG = "ExternalStorageSpaceContext";
	public static final boolean D = true;
	private static final long interval = 1000; // in milliseconds
	private Timer intervalTimer;
	StatFs stat;

	public ExternalStorageSpaceContext(Context c) {
		super("ExternalStorageSpaceContext", c);
		if (D)
			Log.d(LOG_TAG, "constructor");
		intervalTimer = new Timer();
		intervalTimer.schedule(new TimerTask() {
			@Override
			public void run() {
				checkContext();
			}
		}, interval);
		this.contextInformation = obtainContextInformation();
	}

	protected void checkContext() {
		if (D)
			Log.d(LOG_TAG, "check context");
		if (stat == null)
			stat = new StatFs(Environment.getExternalStorageDirectory()
					.getPath());
		else
			stat.restat(Environment.getExternalStorageDirectory().getPath());
		long v = (long) stat.getAvailableBlocks() * (long) stat.getBlockSize();

		for (ContextValues cv : this.valuesSets) {
			if (cv.setNewContextValue(v))
				sendNotification(cv);
		}
	}

	protected String obtainContextInformation() {
		if (D)
			Log.d(LOG_TAG, "obtainContextInformation");
		checkContext();
		return this.valuesSets.get(1).contextInformation;
	}

}