com.phonegap.Storage.java Source code

Introduction

Here is the source code for com.phonegap.Storage.java

Source

/*
 * PhoneGap is available under *either* the terms of the modified BSD license *or* the
 * MIT License (2008). See http://opensource.org/licenses/alphabetical for full text.
 * 
 * Copyright (c) 2005-2010, Nitobi Software Inc.
 * Copyright (c) 2010, IBM Corporation
 */
package com.phonegap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.phonegap.api.Plugin;
import com.phonegap.api.PluginResult;
import android.database.Cursor;
import android.database.sqlite.*;

/**
 * This class implements the HTML5 database support for Android 1.X devices.  
 * It is not used for Android 2.X, since HTML5 database is built in to the browser.
 */
public class Storage extends Plugin {

    SQLiteDatabase myDb = null; // Database object
    String path = null; // Database path
    String dbName = null; // Database name

    /**
     * Constructor.
     */
    public Storage() {
    }

    /**
     * Executes the request and returns PluginResult.
     * 
     * @param action       The action to execute.
     * @param args          JSONArry of arguments for the plugin.
     * @param callbackId   The callback id used when calling back into JavaScript.
     * @return             A PluginResult object with a status and message.
     */
    public PluginResult execute(String action, JSONArray args, String callbackId) {
        PluginResult.Status status = PluginResult.Status.OK;
        String result = "";

        try {
            // TODO: Do we want to allow a user to do this, since they could get to other app databases?
            if (action.equals("setStorage")) {
                this.setStorage(args.getString(0));
            } else if (action.equals("openDatabase")) {
                this.openDatabase(args.getString(0), args.getString(1), args.getString(2), args.getLong(3));
            } else if (action.equals("executeSql")) {
                JSONArray a = args.getJSONArray(1);
                int len = a.length();
                String[] s = new String[len];
                for (int i = 0; i < len; i++) {
                    s[i] = a.getString(i);
                }
                this.executeSql(args.getString(0), s, args.getString(2));
            }
            return new PluginResult(status, result);
        } catch (JSONException e) {
            return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
        }
    }

    /**
     * Identifies if action to be executed returns a value and should be run synchronously.
     * 
     * @param action   The action to execute
     * @return         T=returns value
     */
    public boolean isSynch(String action) {
        return false;
    }

    /**
     * Clean up and close database.
     */
    @Override
    public void onDestroy() {
        if (this.myDb != null) {
            this.myDb.close();
            this.myDb = null;
        }
    }

    //--------------------------------------------------------------------------
    // LOCAL METHODS
    //--------------------------------------------------------------------------

    /**
     * Set the application package for the database.  Each application saves its 
     * database files in a directory with the application package as part of the file name.
     * 
     * For example, application "com.phonegap.demo.Demo" would save its database
     * files in "/data/data/com.phonegap.demo/databases/" directory.
     * 
     * @param appPackage         The application package.
     */
    public void setStorage(String appPackage) {
        this.path = "/data/data/" + appPackage + "/databases/";
    }

    /**
     * Open database.
     * 
     * @param db               The name of the database
     * @param version            The version
     * @param display_name         The display name
     * @param size               The size in bytes
     */
    public void openDatabase(String db, String version, String display_name, long size) {

        // If database is open, then close it
        if (this.myDb != null) {
            this.myDb.close();
        }

        // If no database path, generate from application package
        if (this.path == null) {
            Package pack = this.ctx.getClass().getPackage();
            String appPackage = pack.getName();
            this.setStorage(appPackage);
        }

        this.dbName = this.path + db + ".db";
        this.myDb = SQLiteDatabase.openOrCreateDatabase(this.dbName, null);
    }

    /**
     * Execute SQL statement.
     * 
     * @param query            The SQL query
     * @param params         Parameters for the query
     * @param tx_id            Transaction id
     */
    public void executeSql(String query, String[] params, String tx_id) {
        try {
            Cursor myCursor = this.myDb.rawQuery(query, params);
            this.processResults(myCursor, tx_id);
            myCursor.close();
        } catch (SQLiteException ex) {
            ex.printStackTrace();
            System.out.println("Storage.executeSql(): Error=" + ex.getMessage());

            // Send error message back to JavaScript
            this.sendJavascript("droiddb.fail('" + ex.getMessage() + "','" + tx_id + "');");
        }
    }

    /**
     * Process query results.
     * 
     * @param cur            Cursor into query results
     * @param tx_id            Transaction id
     */
    public void processResults(Cursor cur, String tx_id) {

        String result = "[]";
        // If query result has rows

        if (cur.moveToFirst()) {
            JSONArray fullresult = new JSONArray();
            String key = "";
            String value = "";
            int colCount = cur.getColumnCount();

            // Build up JSON result object for each row
            do {
                JSONObject row = new JSONObject();
                try {
                    for (int i = 0; i < colCount; ++i) {
                        key = cur.getColumnName(i);
                        value = cur.getString(i);
                        row.put(key, value);
                    }
                    fullresult.put(row);

                } catch (JSONException e) {
                    e.printStackTrace();
                }

            } while (cur.moveToNext());

            result = fullresult.toString();
        }

        // Let JavaScript know that there are no more rows
        this.sendJavascript("droiddb.completeQuery('" + tx_id + "', " + result + ");");

    }

}