edu.stanford.mobisocial.dungbeetle.ui.adapter.ObjectListCursorAdapter.java Source code

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Here is the source code for edu.stanford.mobisocial.dungbeetle.ui.adapter.ObjectListCursorAdapter.java

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/*
 * Copyright (C) 2011 The Stanford MobiSocial Laboratory
 *
 * This file is part of Musubi, a mobile social network.
 *
 *  This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package edu.stanford.mobisocial.dungbeetle.ui.adapter;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

import org.apache.commons.io.IOUtils;

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.support.v4.content.CursorLoader;
import android.support.v4.widget.CursorAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import edu.stanford.mobisocial.dungbeetle.R;
import edu.stanford.mobisocial.dungbeetle.feed.DbObjects;
import edu.stanford.mobisocial.dungbeetle.model.DbObject;

public class ObjectListCursorAdapter extends CursorAdapter {
    private Cursor originalCursor;
    private int mTotal = BATCH_SIZE;

    public ObjectListCursorAdapter(Context context, Cursor cursor) {
        super(context, cursor, FLAG_REGISTER_CONTENT_OBSERVER);
        // TODO: does contact cache handle images and attributes?
    }

    @Override
    public View newView(Context context, Cursor c, ViewGroup parent) {
        final LayoutInflater inflater = LayoutInflater.from(context);
        View v = inflater.inflate(R.layout.objects_item, parent, false);
        bindView(v, context, c);

        return v;
    }

    @Override
    public void bindView(View v, Context context, Cursor c) {
        DbObject.bindView(v, context, c, true);

    }

    static final int BATCH_SIZE = getBestBatchSize();

    public int getTotalQueried() {
        return mTotal;
    }

    public static CursorLoader queryObjects(Context context, Uri feedUri, String[] projection, String[] types) {
        return new CursorLoader(context, feedUri, projection, DbObjects.getFeedObjectClause(types), null,
                DbObject.LAST_MODIFIED_TIMESTAMP + " DESC LIMIT " + BATCH_SIZE);
    }

    private static int getBestBatchSize() {
        Runtime runtime = Runtime.getRuntime();
        if (runtime.availableProcessors() > 1)
            return 100;

        try {
            File max_cpu_freq = new File("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq");
            byte[] freq_bytes = IOUtils.toByteArray(new FileInputStream(max_cpu_freq));
            String freq_string = new String(freq_bytes);
            double freq = Double.valueOf(freq_string);
            if (freq > 950000) {
                return 50;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return 15;
    }

    public CursorLoader queryLaterObjects(Context context, Uri feedUri, int total, String[] types) {
        mTotal = total + BATCH_SIZE;
        CursorLoader cl = new CursorLoader(context, feedUri, null, DbObjects.getFeedObjectClause(types), null,
                DbObject._ID + " DESC LIMIT " + mTotal);
        Cursor newCursor = cl.loadInBackground();

        if (originalCursor == null) {
            originalCursor = this.swapCursor(newCursor);
        } else {
            this.changeCursor(newCursor);
        }
        return cl;
    }

    public void closeCursor() {
        if (originalCursor != null) {
            originalCursor.close();
        }
    }
}