Connector User`s Manual
Contents
1. Connector Toolkit Components Connector API This is a collection of classes that provides developers with the necessary tools to manage I O and graphics Java like classes are provided such as FileInputStream FileOutputStream Frame and Graphics This API needs a configuration file to map all files with their remote locations To do this a file map must be declared in the directory of the application using this API File Map The file map uses a quadratic notation specifying the name of the file URL retrieving interval and type of read name URL interval extract The following explains these four fields 1 Name of the file used in the program This is also the name of the file at the remote location 2 URL of the remote location where the file is stored This field must also include the user s account name and password Also the path of the file must be declared 3 Interval is the amount in minutes a program will access a web site to retrieve data This field is only for data read from http servers 4 Extract tells the program that only text data should be retrieved from web sites If this field is missing form http server lines then the entire html code will be retrieved The file map also needs two other fields to allow programs know where a GUI or Web Server is and which port to use To do this the first two lines of the file map must include the IP address of the machine running the GUI Web server and the port to be used2. Constructor Summary Connector This constructor has not been fully implemented No tmp file defined Default Constructor Instantiates a ConnectorDaemon object using the local file tmp Connector config to set up the arguments required when booting ConnectorDaemon Connector String filename Filename Constructor Instantiates a ConnectorDaemon object using the file defined as a parameter in this constructor Connector String filename boolean needDaemonOnly int port Boolean Constructor Instantiates a ConnectorDaemon object using the file defined as a parameter Such file is used to set up the arguments required when booting a ConnectorDaemon A connection to a Connector GUI is dependent on the boolean argument If the boolean argument is true a Connector GUI connection is established this is just like using a filename constructor However ifthe boolean argument is false this Connector object will only instantiate a ConnectorDaemon and the out in and err funtions will be disabled This constructor is necessary for applications that do not require a Connector GUI in order to function Connector String filename int port Port Constructor Instantiates a ConnectorDaemon object using the file defined as a parameter in this constructor void close Closes all data streams used and terminates the ConnectorPanel and the O ComecorDaemonasouated withiheablede protected void Ensures that the close method o
3. error and graphics from a remote machine to a local user machine ConnectorPanel class can also interact with VikingX sensors through the FTP Sensor Server Connector Web Server This part of the project is still a prototype and very limited in terms of design and functionality Using the Netbeans IDE servlets have been implemented to be able to connect using TCP sockets to Connector Daemons Since http protocol does not keep permanent connections servlets are used to maintain Java sockets bound to Connector daemons in the background Whenever a user retrieves data by pushing a button in the web browser then the servlet grabs data from the TCP socket At this moment output input and error from the applications happens without trouble Redirecting graphics work by sending images and repacking them in the web server However X client capabilities are not possible Also functionality to manage Sensor Server has not been implemented Sensor Server Sensor Server was implemented in order to read information from VikingX sensors to remote applications This is an FTP server that allows applications to retrieve sensor information as if data was contained in files In order for this to work remote applications need to use Connector FileInputStream At the VikingX directory another two files must exist in order for Sensor Server to work properly Those files are files txt This file defines the IP and port of the GUI ConnectorPanel to which th
4. for the connection The first two lines should start with a sign followed by the i and p options The following is an example of how to construct a file map Notice that for Sensor server reads a port should be provided This is the default port used by Sensor server Interval is allowed for Sensor server reads i ip_address p port file1 txt sftp account password dante u washington edu SensorGrid sensor1 ftp account password hercules uwb edu 55555 master ftp account password hercules uwb edu 55555 1 file2 txt ftp account password ftp tripod com SensorGrid Temperatures file3 txt http www weather com today Bothell WA 98011 5 extract Something to keep in mind is the way a URL is written The URL should contain the path of the file location However the path should include only the file s directory but not the name of the file itself The file name is considered to be the first token of the line so is not needed to restate its name An error would occur if the file name were to be included in the URL Connector API s Classes This section is an overview of the classes and functions provided by the Connector API Connector Class Allows a remote local application to use standard input output and error using a Connector GUI The Connector object first connects to a Connector Daemon in order to transfer data from and to the Connector GUI Once a connection is established interaction may begin
5. Connector User s Manual Jose Melchor Computing and Software Systems University of Washington Bothell Table of Contents ADOUE CONECTA ia Daba 2 Connector Toolkit Components amino 2 Connector A PL ds 2 HO MD osas 2 Connector APTS Cases tad 3 Connector AU A A A AAN NAERA 5 Connector Web Sere lia 6 Sensor OIE iia 6 Desish a o ATCMItecoure ii 7 HOWTO KUN rr aca 9 CONNECT eii 9 Connector API coria 10 Sensor y A A 10 PAP E A 10 KNOW ISSUES oana cai 11 About Connector Connector is a set of tools designed to help programs retrieve remote data The main objective of Connector is to help grid cloud applications obtain data residing outside of the grid cloud In order to achieve this Connector hides all channels of communication from the point of view of the developer Instead developers feel like data is local to the running application The current version of Connector is able to provide data from FTP SFTP and HTTP servers Connector also provides redirection of data to users local machines To achieve this a GUI and a Web Server is provided so that remote applications may redirect output input error and graphics to users Another key aspect of the Connector project is to provide data analysis applications running in the cloud with real time data Since sensor networks reside outside of the cloud a simple way to obtain data was necessary Sensor Server allows a sensor network to communicate with cloud running applications
6. an two The important thing is that no matter what the daemon expects two messages coming from API objects Figure 3 Communicating with daemon Application Inherited Socket A AA To remote program new Connector file_map Daemon To remote program Inherited Socket A A02 _y Support libraries are used to manage connections with FTP SFTP and HTTP servers The libraries used are e For FTP Apache Commons Net e For SFTP Jsch e For HTTP Htmlparser These libraries create independent connections to servers as necessary In other words connections are abstracted and transparent from the point of view of the connector daemon thread see figure 4 Figure 4 Connections using support libraries User s I O and Graphics display I O Channel Port 11112 FilelnputStream 6 thread Cluste Cronin FTP Server FilelnputStream Handled by supporting library Sensor Server is an FTP server However when replying to FTP clients the server reads from the VikingX sensor network at the DSLab The Hercules computing node at the DSLab contains the master sensor where all other sensors send information Using a program we retrieve data from sensors and then send the data to FTP clients as if it was a file At this moment the protocol of the sensor network is being reviewed and the Sensor Server will need to accommodate for any changes about the way data from sensors is obtained Sensors can be
7. e 1 b Writes len bytes from the specified byte array starting at offset off to this file output int off intlen stream Writes the specified byte to this file output stream and overwrites the remote file specified in the constructor DataPacket class This is a wrapper class intended to work mainly within FileInputStream and FileOutputStream classes This class provides the object required in the Connector Daemon to send either actual byte data or exceptions to the extended Connector s FileInputStream or FileOutputStream classes Frame class This class allows remote applications to draw graphics local and or where Connector GUI is running Constructor Summary Frame String title Construct a new instance of a Frame at the GUI s location With this constructor the application will work as aX client and the GUI as an X server Frame String format int seconds String fileLoc Constructs a new instance of a Frame at the location defined by the user With this constructor an image will be sent to the user as often as the user specifies The image is sent using a format provided by the user jpeg tiff or png Every time an image is sent to the GUI the GUI pops a frame to display it if necessary Method Summary void close Closes all connections to ConnectorDaemon Graphics getGraphics Creates a graphics context for this frame java awt Insets getInsets Determines the insets of this container which indicate the size
8. e Sensor Server will be connected if necessary and also defines the URL of the remote file containing sensor map users txt This file includes all the allowed user names and their passwords Each line must have one user name and a password only Example Jmelchor 54321 dslab 12345 Sensor map To manage sensors Sensor Server uses a Sensor map in order to keep a list of sensor names and sensor IP Mac addresses available Such list is not stored local to the Sensor Server but it is accessed from a remote FTP server The sensor map is retrieved using Connector FileInputStream and updated using Connector FileOutputStream For that reason files txt located in the VikingX directory must include the URL where the actual sensor map file is stored The sensor file map has the following format add IP Mac address sensor name Example add 192 168 15 3 sensorl add 0x082be4 sensor2 add all master Using master as a sensor name is a special case When master is used in an application or when setting up handlers it means that sensor information will come from all available sensors in the file map Design and Architecture Any application using the Connector API needs to always declare a Connector object before declaring any other Connector API objects or calling any functions from them The reason for this requirement is that a Connector object spawns a Connector Daemon that runs in the background This daemon thread se
9. f this Connector object is called when there are no more finalize references to it String in Retrieves a string from a ConnectorPanel void out String Sends a string to a ConnetorPanel Reads the filename defined in the constructor and boots a connectorDaemon ConnectorDaemon Class Daemon process that manages I O operations from applications A ConnectorDaemon starts automatically once a Connector object is instantiated Every I O request made is handled in a separate thread ConnectorDaemon accepts requests from Connector FileInputStream FileOutputStream Frame and Graphics classes So in a sense this class is a helper class in charge of setting up all data channel connections and data retrievals FileInputStream Class With this class a user application can open read and close remote files FileInputStream establishes a socket connection to the local Connector daemon process within its constructor sends FilelnputStream and the remote file name from which to read reads data through the socket from Connector and forward the data to its application Irae Main constructor The filename is the remote file needed to retrieve a Initializes communication with the Connector daemon through a specified port number Method Summary int available Returns an estimate of the number of remaining bytes that can be read or skipped over from this input stream without blocking by the next invocation of a meth
10. managed using a Connector GUI To achieve this Sensor Server uses a Connector object to use input and output Instructions are exchanged between the GUI and the server Sensor Server recognizes instructions so that changes on sensors can be performed more information on how to manage sensors can be found in the How to Run section Figure 5 provides a view of how Sensor Server interacts with other components of the Connector system Figure 5 Visualization of Sensor Server Sensor Server Create daemon FTP Update file map Server Retrieve file map Managing Sensor Server through GUI twork Read Sensor Data Data Analysis Application GUI connected J Gano to Application E Daemon S C Send Receive I O Cluster How to Run Connector GUI To start the GUI run the following command java ConnectorPanel Below is a snapshot of GUI s components D f Connector Panel ERE A PITER A Output Field bounding to remote application ort 11112 Connect Disconnect Input Field Status of the Panel Ready and Listening through selected Port Connector APl Programs using the Connector API need to use the following commands while at the same directory as the application java cp Connector jar program name arguments The directory of the application needs to contain the file map for the connector object Sensor Server Sensor Server allows a Connector GUI to interac
11. od for this input stream the stream no more references to it Reads a byte of data from this input stream int read byte b Reads up to b length bytes of data from this input stream into an array of bytes int read byte b int off int len long skip long n Skips over and discards n bytes of data from the input stream Reads up to len bytes of data from this input stream into an array of bytes FileOutputStream Class With this class a user application can open write and close a remote file FileOutputStream establishes a socket connection to the local ConnectorDaemon process within its constructor sends FileOutputStream and the remote file name from which to write and writes data through the socket from Connector No acknowledgment is received if data was successfully stored at the remote server Constructor Summary FileOutputStream String name Main constructor The name of the remote file is passed as the parameter FileOutputStream String name int port Initializes communication with Connector Daemon through an specified port number Method Summary void close Closes this file output stream and releases any system resources associated with this protected void Cleans up the connection to the file and ensures that the close method of this file output stream is called when there are no more references to this stream Writes b length bytes from the specified byte array to this file output stream writ
12. of the container s border void setLocation int x int y Moves frame to a new location vane a ae Sets whether this frame is resizable by the user resizable vna Sale Dn nes Resizes this component so that it has width width and height height void setVisible boolean b Shows or hides this Window depending on the value of parameter b Graphics Class This class allows to draw inside a Connector s Frame Constructor Summary Graphics Bufferedlmage image Constructor allowing Graphics to display on request by the user Graphics Constructor allowing Graphics as an X client Method Summary void fill3DRect int x me nt width m Paints a 3 D highlighted rectangle filled with the current color height boolean raised void fillRect int x int y int width int height Fills the specified rectangle void setColor Color c Sets this graphics context s current color to the specified color Connector GUI Connector GUT s functionality resides in the ConnectorPanel java This is the front end application required to reroute standard input output and error to a machine local to the user This ConnectorPanel connects to ta ConnectorDaemon to manage I O operations launched by Connector FileInputStream and FileOutputStream objects Also ConnectorPanel recognizes messages from the Frame and Graphics classes so that it can render graphics local remote in relation to the user In addition to rerouting standard input output
13. pod com output writeUFT input nextLine System close Terminate the Connector Daemon y 3 Close the connector After the daemon thread and connections to GUI are established then the user application can start the interaction with remote files Figure 2 shows how threads would communicate with a GUI Notice that the graphics thread is only to illustrate that such thread would have its own channel once created however no graphics thread is instantiated with the Connector object Figure 2 Connector bound to GUI Remote Analyzing Job User s I O and Graphics display daemon Daemon F Cluster Create Port 11112 sConnecto Alive AmlAlive 4 As mentioned before Connector API objects use daemon threads to perform their jobs In order to communicate with the daemon thread Connector API objects use inner process communication through sockets Each object communicates using port 11111 as default to send instructions to the running Connector daemon The daemon thread needs two messages to be able to spawn an independent thread to handle the request of any API object For example FileInputStream first establishes a socket connection with the daemon thread and then sends two strings messages One message is FilelnputStream and the other is the name of the file see figure 3 Some API objects only require one message for the daemon to spawn a new thread while others require more th
14. rves all Connector API objects by spawning thread for each operation performed When a Connector object is instantiated first a Connector Daemon thread is spawned Once a daemon thread is up and running the connector object signals the daemon to start a thread that handles communications with a Connector GUI This thread is alive until the Connector object calls the close function The daemon thread also starts a thread that keeps listening for heartbeat messages from the Connector GUI This thread ensures that GUI is able to figure out if an application moved failed see figure 1 to see the format of a program using the Connector API Figure 1 Simple application using Connector API import Connector Il Import Connector Package import java util Scanner 1 Start a daemon public class TemperatureRecording with the file map public static void main String args Il Initialize a Connector daemon thread Connector System new Connector file map Il forward the message to a remote thread System out Recording Il Connect to an orchard sensor FilelnputStream in new FilelnputStream sensor1 Scanner input new Scanner in 2 Start using Connector API to dl dido de HIROT ld I O with GUI or perform File I O FileOutputStream out new FileOutputStream file2 P DataOutputStream output new DataOutputStream out for data analysis while input hasNextLine llTransfer data from the orchard sensor to ftp tri
15. t directly with it Such interaction makes possible the modification addition of sensor names and sensor IPs Also Sensor Server can set conditions to monitor sensors based on commands defined from the GUI These tasks can be achieved by following these steps 1 Start a GUI using this command e java ConnectorPanel 2 Sensor Server connects to Connector GUI using port number 11113 so set the port field to 11113 Then press the Connect button 3 Run Sensor Server located in the VikingX directory with a GUI option like this e java cp Connector jar SensorServer g 4 Onceaconnection is established then commands from the GUI can be sent to Sensor Server Remember that the GUI s IP need to be set in the file map located at the VikingX directory in order for the connection to be successful The following is the structure of commands that can be used to alter sensors and place event handlers to monitor sensors To add a sensor type add ip sensorName To delete a sensor type delete ip sensorName Event handler commands detect sensorName logical operator temperature absolute relative Remove handler conditions detect sensorName Examples add 192 168 15 3 sensorl delete 192 168 15 3 delete sensor2 detect master lt 32 0 absolute detect sensorl gt 0 2 relative detect sensorl detect master Examples Examples can be found at folder dslab s folder of Test programs dslab SensorGrid Connector Tes
16. tPrograms Most programs are very simple and follow the format stated in the How to Run section The programs have been modified throughout development to test different cases However there are programs to test each Connector API object 10 Known Issues By far the main issue with Connector is the Web Server As mentioned before the web server functionality is at minimal stage not to mention design of the web site However the framework is set up and the construction should not be too complicated Also the skeleton of the web server should follow the format of the GUI to ease construction and connectivity with Connector daemon There are a few issues that need to be fully tested One of those issues is the handling of exceptions at the daemon application side At this point connector wraps exceptions within a DataPacket object and sends it to the GUI for display but I have not tested this Another issue is that sometimes when an application is killed the GUI goes back to listening state as it is suppose to do but then when another application starts the GUI is not able awake and display the application s requests unless the GUI is disconnected and reconnected again Surely more bugs will pop up as the Connector system keeps growing However the author is willing provide support whenever more information is desired 11
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