/****************************************************************************
* ADOBE SYSTEMS INCORPORATED
* Copyright 2012 Adobe Systems Incorporated and it’s licensors
* All Rights Reserved.
*
* NOTICE: Adobe permits you to use, modify, and distribute this file
* in accordance with the terms of the license agreement accompanying it.
* ****************************************************************************/
package databaseUtils
{
import flash.data.SQLConnection;
import flash.data.SQLStatement;
import flash.errors.SQLError;
import flash.events.SQLErrorEvent;
import flash.events.SQLEvent;
import mx.controls.Alert;
/**
* The fileHistory class manages the database calls for retrieving the file History for the file pull down menu.
*/
public class FileHistory
{
/**
* @private
* The XML representing the file history
*/
private var fileXML:XML;
/**
* An Array representing the results of the SQL database information
*/
public var fHistory:Array;
/**
* @private
* A pointer to the database connection
*/
private var dbConn:SQLConnection;
/**
* @private
* The default length for the file history
*/
private var maxFileHistory:int = 4;
/**
* @private
* Global to keep track of current position when shifting data
*/
private var positionTracker:int;
/**
* Constructor
*
* @param dbParenConn A pointer to the SQLConnection object for the database.
*/
public function FileHistory(dbParentConn:SQLConnection)
{
this.dbConn = dbParentConn;
}
/**
* Returns the XML representation of the file history for the pull down menu
*
* @return An XML representation of the file history
*/
public function returnFileHistoryXML():XML {
this.getFileHistory();
if (this.fHistory == null || this.fHistory.length == 0) {
this.fileXML = <menuitem label="Open Recent" enabled="false"></menuitem>;
} else {
this.fileXML = <menuitem label="Open Recent" enabled="true"></menuitem>;
for (var i:int = this.fHistory.length - 1; i > -1; i--) {
var tempXML:XML = new XML("<menuitem label=\"" + this.fHistory[i].name + "\" data=\"" + this.fHistory[i].type + "|" + this.fHistory[i].location + "\"/>");
fileXML.appendChild(tempXML);
}
}
return (this.fileXML);
}
/**
* Creates the file history table if it did not previously exist.
*
* @param eventObj The SQLEvent from the event listener
*/
public function create_table(eventObj:SQLEvent):void {
var createStatement:SQLStatement = new SQLStatement();
createStatement.sqlConnection = this.dbConn;
createStatement.text = "CREATE TABLE IF NOT EXISTS fileHistory (id INTEGER PRIMARY KEY AUTOINCREMENT, position INTEGER ASC, name TEXT, type TEXT, location TEXT)";
createStatement.addEventListener(SQLErrorEvent.ERROR, errorHandler);
createStatement.execute();
}
/**
* Resets the default file history length to the new value
*
* @param len An int representing the new default history length.
*/
public function reset_length(len:int):void {
this.maxFileHistory = len;
this.clearFileHistory(len);
}
/**
* @private
* A default error handler which only dumps trace information.
*
* @param errorObj The SQLErrorEvent from the failed query.
*/
private function errorHandler(errorObj:SQLErrorEvent):void {
trace("Error ID: " + errorObj.errorID);
trace("Message: " + errorObj.error.message);
}
/**
* @private
* Performs the db call to retrieve the file history and populates the fHistory array using displayFileResults.
*
* @param eventObj An optional SQLEvent if this was fired from an event listener.
*/
private function getFileHistory(eventObj:SQLEvent = null):void {
var getFHistory:SQLStatement = new SQLStatement();
getFHistory.sqlConnection = this.dbConn;
getFHistory.addEventListener(SQLEvent.RESULT, displayFileResults);
getFHistory.text = "SELECT * FROM fileHistory;";
try {
getFHistory.execute();
} catch (err:SQLError) {
mx.controls.Alert.show(err.details,err.message);
}
}
/**
* @private
* The event listener for getFileHistory which populates the fHistory Array
*
* @param eventObj The SQLEvent from the event listener call
*/
private function displayFileResults(eventObj:SQLEvent):void {
this.fHistory = eventObj.target.getResult().data;
}
/**
* @private
* Checks to see if the file already exists within the file history.
*
* @param name The name of the file to search for
* @param type The type of file location (a string).
* @param location The location where the file exists (as a string)
* @return An integer representing where in the array the file exists
*/
private function checkFHExists(name:String,type:String,location:String):int {
if (this.fHistory == null || this.fHistory.length == 0) {
return (-1);
}
for (var i:int = 0; i < this.fHistory.length; i++) {
if (this.fHistory[i].name == name && this.fHistory[i].location == location && this.fHistory[i].type == type) {
return(this.fHistory[i].position);
}
}
return (-1);
}
/**
* @private
* Inserts a new value into the file history
*
* @param position An int represnting where in the history to insert the information
* @param name The string containing the name of the file
* @param type The string representing the type of location
* @param location The string representing the location of the file
*/
private function insertHistoryLocation(position:int, name:String, type:String, location:String):void {
var dbStatement:SQLStatement = new SQLStatement();
dbStatement.sqlConnection = this.dbConn;
dbStatement.addEventListener(SQLEvent.RESULT, this.getFileHistory);
dbStatement.addEventListener(SQLErrorEvent.ERROR, errorHandler);
dbStatement.text = "INSERT INTO fileHistory (position, name, type, location) values (:position, :name, :type, :location)";
dbStatement.parameters[":position"] = position;
dbStatement.parameters[":name"] = name;
dbStatement.parameters[":type"] = type;
dbStatement.parameters[":location"] = location;
dbStatement.execute();
}
/**
* @private
* Deletes an entry from the file history at the specified position
*
* @param position An int representing the position in the array to delete
*/
private function deleteFileHistory(position:int):void {
var dbStatement:SQLStatement = new SQLStatement();
this.positionTracker = position;
dbStatement.sqlConnection = this.dbConn;
dbStatement.addEventListener(SQLEvent.RESULT, this.shiftFileHistoryDown);
dbStatement.addEventListener(SQLErrorEvent.ERROR, errorHandler);
dbStatement.text = "DELETE from fileHistory where position = :position";
dbStatement.parameters[":position"] = position;
dbStatement.execute();
}
/**
* @private
* Shifts the entries in the file history down to accomadate for a new entry.
*
* @param eventObjt The SQLEvent from the event listener
*/
private function shiftFileHistoryDown (eventObj:SQLEvent):void {
var dbStatement:SQLStatement = new SQLStatement();
dbStatement.sqlConnection = this.dbConn;
if (this.positionTracker > 0) {
this.positionTracker -= 1;
dbStatement.addEventListener(SQLEvent.RESULT, this.shiftFileHistoryDown);
}
dbStatement.addEventListener(SQLErrorEvent.ERROR, errorHandler);
dbStatement.text = "UPDATE fileHistory set position = :new where position = :old";
dbStatement.parameters[":new"] = this.positionTracker + 1;
dbStatement.parameters[":old"] = this.positionTracker;
dbStatement.execute();
}
/**
* Updates the file history with the newly specified values
*
* @param name The string representing the name of the file
* @param type The string represneting the type of location (url || file)
* @param location The string representing the file's location
*/
public function updateFileHistory(name:String, type:String, location:String):void {
var itemExists:int = this.checkFHExists(name,type,location);
if (itemExists == 0) {
//already the first item
return;
}
if (this.fHistory != null && this.fHistory.length == this.maxFileHistory && itemExists == -1) {
this.deleteFileHistory(this.maxFileHistory - 1);
} else if (this.fHistory != null && this.fHistory.length > 0) {
if (itemExists == -1) {
this.positionTracker = this.fHistory.length;
this.shiftFileHistoryDown(null);
} else {
this.deleteFileHistory(itemExists);
}
}
this.insertHistoryLocation(0,name,type,location);
}
/**
* Deletes all entries from the file history from the specified value and greater
*
* @param pos The minimum position to start deleting entries from (default 0);
*/
public function clearFileHistory(pos:int = 0):void {
var dbStatement:SQLStatement = new SQLStatement();
dbStatement.sqlConnection = this.dbConn;
dbStatement.addEventListener(SQLErrorEvent.ERROR, errorHandler);
dbStatement.text = "DELETE FROM fileHistory WHERE position >= :pos";
dbStatement.parameters[":pos"] = pos;
dbStatement.execute();
}
}
}
