package extjtech;

import java.io.*;
import java.math.*;

import com.sssw.rt.util.*;

// The ExtData class shows how you can access a SilverStream
// server from an external Java client. It includes examples
// of retrieving and updating rows of data from a SilverStream 
// server object.
public class ExtData {

     // Instance variables for the SilverStream objects used 
     // by the ExtData class.
     AgrServerSession session;
     AgrData appdata;
   
  // Constructor for the ExtData class. It does the following:
  // * Connects to a SilverStream server
  // * Accesses the appropriate data
  // * Performs a requested operation on that data (including
  //   retrieval and/or update) 
  //
  // It takes 4 arguments:
  // 1 SilverStream server host
  //     myserver
  // 2 SilverStream db & data source object
  //     mydb:com.myorg.data.dsoMyPassthru
  // 3 Operation to perform
  //     costupdate
  // 4 Value to use in the operation
  //     2
  public ExtData(String s3serverhost,  
                 String s3dsolocation,
                 String operation,
                 String opvalue) {

    try  {
      // Initialize the SilverStream runtime environment. Do
      // this if you need to specify a login handler for the 
      // SilverStream server to call back when it requires user
      // authentication. (The login handler is a class that you
      // code and instantiate.)
      AgRuntime.init(new LoginHandler());

      // Connect to the appropriate SilverStream server. This
      // establishes a server session (represented by an instance
      // of AgrServerSession).
      //
      // The following example connects via HTTP. In this case, 
      // you wouldn't use RMI-IIOP (the connectRMI method),
      // because it doesn't support DSO access.
      session = AgRuntime.connect(s3serverhost);


      // Create an instance of AgrData (to represent the cache of
      // data you want to work with).
      appdata = new AgrData();

      // Initialize the AgrData by passing it the AgrServerSession.
      appdata.init(session);

      // Specify the data source for the AgrData. In this case, 
      // it is a pass-through DSO.
      appdata.setDataSource(s3dsolocation);

      // Invoke the DSO to get the data for the AgrData.
      appdata.invokeQuery(null);


      // Perform the requested operation (if supported).
      if (operation.equals("list")) {

        // Call the listRows() method of the ExtData class to 
        // display the rows that the DSO put in the AgrData. 
        listRows();
      }
      else if (operation.equals("costupdate")) {

        // Call the raiseCost() method of the ExtData class to
        // get the "Cost per lb" column value in each AgrData 
        // row and update it by a specified percentage. 
        raiseCost(opvalue);

        // For demonstration purposes (to prove that the update 
        // worked), execute a new query against the DSO to 
        // refresh the AgrData with the updated rows from the 
        // data source. (In your own applications, you may want 
        // to keep using the rows you already have cached locally
        // and avoid extra queries such as this.)
        appdata.query(null);

        // Call the listRows() method of the ExtData class to 
        // display the updated rows from the AgrData. 
        listRows();
      }
      else {
        // Notify user if the request can't be performed.
        System.out.println(
          "The requested operation:\n   " +
          operation + "\n" + 
          "is not supported. Please try again.");
      }
    }
    catch (Exception e) {
      System.out.println("Application error in ExtData");
      e.printStackTrace();
      System.exit(0);
    }
    finally {
      // When all done, close the SilverStream server session.
      session.close();
    }
  }


  // This method displays all of the rows and columns from
  // the current cache (AgrData).
  void listRows() {
    try {
      // Go to the first row of the AgrData.
      boolean found = appdata.gotoFirst();

      // Loop through the rows of the AgrData.
      while (found) {

        System.out.println(">>>Table row>>>");

        // Loop through the columns (properties) of the 
        // current row. For each column, display its name 
        // and value.
        for (int i = 0; i < appdata.getPropertyCount(); i++) {

          System.out.println(
            appdata.getPropertyName(i) + ": " +
            String.valueOf(appdata.getProperty(i)));
        }
        // Go to the next row of the AgrData.
        found = appdata.gotoNext();
      }
      System.out.println("<<<End of table rows<<<");
    }
    catch (AgoApiException e) {
      e.printStackTrace();
    }
  }


  // This method changes the value of a particular column
  // (Cost per lb) in every row of the current cache (AgrData).
  // Then it updates the data source with those changes.
  void raiseCost(String opvalue) {

    BigDecimal costprop; 
    double percent, oldcost, newcost;

    percent = (Double.parseDouble(opvalue)) / 100;

    try {
      // Loop through the rows of the AgrData.
      while (appdata.gotoNext()) {

        // Get the desired column value from the current row
        // and increase it by the specified percentage.
        costprop = (BigDecimal)appdata.getProperty("Cost per lb");
        oldcost = costprop.doubleValue();
        newcost = oldcost + (oldcost * percent);

        appdata.setProperty("Cost per lb",new BigDecimal(newcost));
      }
      // Send all of the row updates to the data source.
      appdata.updateRows();
    }
    catch (AgoApiException e) {
      e.printStackTrace();
    }
  }


  // Main method (used for application startup).
  public static void main(String[] args) {

    if (args.length < 4) {
      // Make sure all of the required command-line args
      // have been provided to the application. If not,
      // display an error message and terminate.
      System.out.println(
        "Missing Command-Line Arguments\n\n" +  
        "Required arguments:\n" +
          "1  SilverStream server host\n" +
          "2  SilverStream db & data source object\n" +
          "3  Operation to perform\n" +
          "4  Value to use in the operation\n\n" +
        "Example:\n" + "java extjtech.ExtData " +
          "myserver " +          
          "mydb:com.myorg.data.dsoMyPassthru " +
          "costupdate " + 
          "2");
      System.exit(0);
    }
    else {
      // Get the command-line args so the application can
      // pass them to the ExtData constructor.
      String s3serverhost = args[0];
      String s3dsolocation = args[1];
      String operation = args[2];
      String opvalue = args[3];

      // Create an instance of ExtData. This executes the 
      // constructor for the class, which then accesses the
      // SilverStream server and performs the requested
      // operation.
      ExtData extdata = new ExtData(s3serverhost,
                                    s3dsolocation,
                                    operation,
                                    opvalue);
    }
  }
}