Android Open Source - tum-campus Link Manager

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License

The source code is released under:

GNU General Public License

Java Source Code

?package de.tum.in.tumcampus.models;
//from w w w.  j a v a 2 s  .  c  om
import java.io.File;

import de.tum.in.tumcampus.common.Utils;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
 * Link Manager, handles database stuff, internal imports, external downloads (icons)
 */
public class LinkManager {

  /**
   * Database connection
   */
  private SQLiteDatabase db;

  /**
   * Last insert counter
   */
  public static int lastInserted = 0;

  /**
   * Additional information for exception messages
   */
  public String lastInfo = "";

  /**
   * Constructor, open/create database, create table if necessary
   * 
   * <pre>
   * @param context Context
   * </pre>
   */
  public LinkManager(Context context) {
    db = DatabaseManager.getDb(context);

    // create table if needed
    db.execSQL("CREATE TABLE IF NOT EXISTS links (id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR, "
        + "url VARCHAR, icon VARCHAR)");
  }

  /**
   * Import links from internal sd-card directory
   * 
   * @throws Exception
   */
  public void importFromInternal() throws Exception {
    File[] files = new File(Utils.getCacheDir("links")).listFiles();

    int count = Utils.dbGetTableCount(db, "links");

    db.beginTransaction();
    try {
      for (File file : files) {
        String filename = file.getName();
        if (filename.toLowerCase().endsWith(".url")) {
          lastInfo = filename;
          String name = filename.substring(0, filename.length() - 4);
          String url = Utils.getLinkFromUrlFile(file);

          insertUpdateIntoDb(new Link(name, url));
        }
      }
      db.setTransactionSuccessful();
    } finally {
      db.endTransaction();
    }
    // update last insert counter
    lastInserted += Utils.dbGetTableCount(db, "links") - count;
  }

  /**
   * Check if all icons are available in the cache directory
   */
  public void checkExistingIcons() {
    Cursor c = db.rawQuery("SELECT DISTINCT icon FROM links WHERE icon!=''", null);

    while (c.moveToNext()) {
      String icon = c.getString(0);

      File f = new File(icon);
      if (!f.exists()) {
        db.execSQL("UPDATE links SET icon='' WHERE icon=?", new String[] { icon });
      }
    }
    c.close();
  }

  /**
   * Download missing link icons
   * 
   * @throws Exception
   */
  public void downloadMissingIcons() throws Exception {
    checkExistingIcons();

    Cursor c = db.rawQuery("SELECT DISTINCT url FROM links WHERE icon=''", null);

    while (c.moveToNext()) {
      String url = c.getString(0);

      String target = Utils.getCacheDir("links/cache") + Utils.md5(url) + ".ico";
      Utils.downloadIconFileThread(url, target);

      db.execSQL("UPDATE links SET icon=? WHERE url=?", new String[] { target, url });
    }
    c.close();
  }

  /**
   * Get all links from the database
   * 
   * @return Database cursor (icon, name, url, _id)
   */
  public Cursor getAllFromDb() {
    return db.rawQuery("SELECT icon, name, url, id as _id FROM links ORDER BY name", null);
  }

  /**
   * Checks if the links table is empty
   * 
   * @return true if no links are available, else false
   */
  public boolean empty() {
    boolean result = true;
    Cursor c = db.rawQuery("SELECT id FROM links LIMIT 1", null);
    if (c.moveToNext()) {
      result = false;
    }
    c.close();
    return result;
  }

  /**
   * Insert or Update a link in the database
   * 
   * <pre>
   * @param l Link object
   * @throws Exception
   * </pre>
   */
  public void insertUpdateIntoDb(Link l) throws Exception {
    Utils.log(l.toString());

    l.name = l.name.trim();
    l.url = l.url.trim();

    if (l.name.length() == 0) {
      throw new Exception("Invalid name.");
    }
    if (l.url.length() == 0) {
      throw new Exception("Invalid url.");
    }

    Cursor c = db.rawQuery("SELECT id FROM links WHERE name = ?", new String[] { l.name });

    if (c.moveToNext()) {
      db.execSQL("UPDATE links SET url=?, icon='' WHERE id=?", new String[] { l.url, c.getString(0) });

    } else {
      db.execSQL("INSERT INTO links (name, url, icon) VALUES (?, ?, '')", new String[] { l.name, l.url });
    }
  }

  /**
   * Removes all cache items
   */
  public void removeCache() {
    db.execSQL("UPDATE links SET icon = ''");
    Utils.emptyCacheDir("links/cache");
  }

  /**
   * Delete Link from database
   * 
   * <pre>
   * @param id Link id
   * </pre>
   */
  public void deleteFromDb(int id) {
    db.execSQL("DELETE FROM links WHERE id = ?", new String[] { String.valueOf(id) });
  }
}

Java Source Code List

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