NextSequenceValueServlet.java

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 * Pentaho Data Integration
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 * Copyright (C) 2002-2013 by Pentaho : http://www.pentaho.com
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 * Licensed under the Apache License, Version 2.0 (the "License");
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package org.pentaho.di.www;

import java.io.IOException;
import java.io.PrintStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.pentaho.di.core.Const;
import org.pentaho.di.core.logging.LoggingObjectInterface;
import org.pentaho.di.core.logging.LoggingObjectType;
import org.pentaho.di.core.logging.SimpleLoggingObject;
import org.pentaho.di.core.xml.XMLHandler;

public class NextSequenceValueServlet extends BaseHttpServlet implements CartePluginInterface {
  private static final long serialVersionUID = 3634806745372015720L;

  public static final String CONTEXT_PATH = "/kettle/nextSequence";

  public static final String PARAM_NAME = "name";
  public static final String PARAM_INCREMENT = "increment";

  public static final String XML_TAG = "seq";
  public static final String XML_TAG_VALUE = "value";
  public static final String XML_TAG_INCREMENT = "increment";
  public static final String XML_TAG_ERROR = "error";

  public NextSequenceValueServlet() {
  }

  public NextSequenceValueServlet( TransformationMap transformationMap ) {
    super( transformationMap );
  }

  /**
<div id="mindtouch">
    <h1>/kettle/nextSequence</h1>
    <a name="GET"></a>
    <h2>GET</h2>
    <p>Increments specified pre-configured sequence.
  Method is used for reserving a number of IDs and incrementing a sequence pre-configured in Carte server configuration
  by specified amount. If no increment value provided 10000 is used by default.</p>

    <p><b>Example Request:</b><br />
    <pre function="syntax.xml">
    GET /kettle/nextSequence?name=test_seq
    </pre>

    </p>
    <h3>Parameters</h3>
    <table class="pentaho-table">
    <tbody>
    <tr>
      <th>name</th>
      <th>description</th>
      <th>type</th>
    </tr>
    <tr>
    <td>name</td>
    <td>name of the sequence specified in Carte configuration file.</td>
    <td>query</td>
    </tr>
    <tr>
    <td>increment</td>
    <td>(optional) parameter used for incrementing sequence. If no parameter specified
  10000 is used by default.</td>
    <td>integer, optional</td>
    </tr>
    </tbody>
    </table>

  <h3>Response Body</h3>

  <table class="pentaho-table">
    <tbody>
      <tr>
        <td align="right">text:</td>
        <td>HTML</td>
      </tr>
      <tr>
        <td align="right">media types:</td>
        <td>text/xml</td>
      </tr>
    </tbody>
  </table>
    <p>Response XML containing sequence value and the increment value used.</p>

    <p><b>Example Response:</b></p>
  <pre function="syntax.xml">
  <seq><value>570000</value><increment>10000</increment></seq>
  </pre>

    <h3>Status Codes</h3>
    <table class="pentaho-table">
  <tbody>
    <tr>
      <th>code</th>
      <th>description</th>
    </tr>
    <tr>
      <td>200</td>
      <td>Request was processed.</td>
    </tr>
    <tr>
      <td>404</td>
      <td>If the sequence was not found or error occurred during allocation</td>
    </tr>
    <tr>
      <td>500</td>
      <td>Internal server error occurs during request processing.</td>
    </tr>
  </tbody>
</table>
</div>
  */
  public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException,
    IOException {
    if ( isJettyMode() && !request.getContextPath().startsWith( CONTEXT_PATH ) ) {
      return;
    }

    if ( log.isDebug() ) {
      logDebug( toString() );
    }

    String name = request.getParameter( PARAM_NAME );
    long increment = Const.toLong( request.getParameter( PARAM_INCREMENT ), 10000 );

    response.setStatus( HttpServletResponse.SC_OK );
    response.setContentType( "text/xml" );
    response.setCharacterEncoding( Const.XML_ENCODING );

    PrintStream out = new PrintStream( response.getOutputStream() );
    out.println( XMLHandler.getXMLHeader( Const.XML_ENCODING ) );
    out.println( XMLHandler.openTag( XML_TAG ) );

    try {

      SlaveSequence slaveSequence = getTransformationMap().getSlaveSequence( name );
      if ( slaveSequence == null && getTransformationMap().isAutomaticSlaveSequenceCreationAllowed() ) {
        slaveSequence = getTransformationMap().createSlaveSequence( name );
      }
      if ( slaveSequence == null ) {
        response.setStatus( HttpServletResponse.SC_NOT_FOUND );
        out.println( XMLHandler.addTagValue( XML_TAG_ERROR, "Slave sequence '" + name + "' could not be found." ) );
      } else {
        LoggingObjectInterface loggingObject = new SimpleLoggingObject( "Carte", LoggingObjectType.CARTE, null );
        long nextValue = slaveSequence.getNextValue( loggingObject, increment );
        out.println( XMLHandler.addTagValue( XML_TAG_VALUE, nextValue ) );
        out.println( XMLHandler.addTagValue( XML_TAG_INCREMENT, increment ) );
      }

    } catch ( Exception e ) {
      response.setStatus( HttpServletResponse.SC_NOT_FOUND );
      out.println( XMLHandler.addTagValue( XML_TAG_ERROR, "Error retrieving next value from slave sequence: "
        + Const.getStackTracker( e ) ) );
    }

    out.println( XMLHandler.closeTag( XML_TAG ) );
  }

  public String toString() {
    return "Retrieve the next value of slave server sequence requested.";
  }

  public String getService() {
    return CONTEXT_PATH + " (" + toString() + ")";
  }

  public String getContextPath() {
    return CONTEXT_PATH;
  }

}