UnboundID Server SDK

Ping Identity
UnboundID Server SDK Documentation

ExampleScriptedHTTPServletExtension.groovy

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package com.unboundid.directory.sdk.examples.groovy;



import java.util.Arrays;
import java.util.List;

import com.unboundid.directory.sdk.examples.ExampleHelloServlet;
import com.unboundid.directory.sdk.http.config.HTTPServletExtensionConfig;
import com.unboundid.directory.sdk.http.scripting.ScriptedHTTPServletExtension;
import com.unboundid.directory.sdk.http.types.HTTPServerContext;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.ResultCode;
import com.unboundid.util.args.ArgumentException;
import com.unboundid.util.args.ArgumentParser;
import com.unboundid.util.args.StringArgument;



/**
 * This class provides a simple example of a scripted HTTP servlet extension
 * which will create a simple "Hello, World!" servlet.  It has two configuration
 * arguments:
 * <UL>
 *   <LI>name -- The name to display in the servlet's hello message.  If this is
 *       not provided, then a default value of "World" will be used.</LI>
 *   <LI>path -- The path that should be used to invoke the servlet.  If this is
 *       not provided, then a default value of "/hello" will be used.</LI>
 * </UL>
 */
public final class ExampleScriptedHTTPServletExtension
       extends ScriptedHTTPServletExtension
{
  /**
   * The name of the argument that will be used to specify the name that should
   * be used in the greeting.
   */
  private static final String ARG_NAME_NAME = "name";



  /**
   * The name of the argument that will be used to specify the path that will be
   * used to access the servlet.
   */
  private static final String ARG_NAME_PATH = "path";



  // The servlet that has been created.
  private volatile ExampleHelloServlet servlet;

  // The path that will be used for the servlet.
  private volatile String path;



  /**
   * Creates a new instance of this HTTP servlet extension.  All HTTP servlet
   * extension implementations must include a default constructor, but any
   * initialization should generally be done in the {@code createServlet}
   * method.
   */
  public ExampleScriptedHTTPServletExtension()
  {
    servlet = null;
    path    = null;
  }



  /**
   * Updates the provided argument parser to define any configuration arguments
   * which may be used by this HTTP servlet extension.  The argument parser
   * may also be updated to define relationships between arguments (e.g., to
   * specify required, exclusive, or dependent argument sets).
   *
   * @param  parser  The argument parser to be updated with the configuration
   *                 arguments which may be used by this HTTP servlet
   *                 extension.
   *
   * @throws  ArgumentException  If a problem is encountered while updating the
   *                             provided argument parser.
   */
  @Override()
  public void defineConfigArguments(final ArgumentParser parser)
         throws ArgumentException
  {
    // Add an argument that allows you to specify the name to use in the
    // greeting.
    Character shortIdentifier = null;
    String    longIdentifier  = ARG_NAME_NAME;
    boolean   required        = false;
    int       maxOccurrences  = 1;
    String    placeholder     = "{name}";
    String    description     = "The name to use in the greeting.";
    String    defaultValue    = "World";
    parser.addArgument(new StringArgument(shortIdentifier, longIdentifier,
         required, maxOccurrences, placeholder, description, defaultValue));


    // Add an argument that allows you to specify the request path.
    shortIdentifier = null;
    longIdentifier  = ARG_NAME_PATH;
    required        = false;
    maxOccurrences  = 1;
    placeholder     = "{path}";
    description     = "The path to use to access the servlet.  Note that " +
         "changes to this argument will only take effect if the associated " +
         "HTTP connection handler (or the entire server) is stopped and " +
         "re-started.";
    defaultValue    = "/hello";
    parser.addArgument(new StringArgument(shortIdentifier, longIdentifier,
         required, maxOccurrences, placeholder, description, defaultValue));
  }



  /**
   * Creates an HTTP servlet extension using the provided information.
   *
   * @param  serverContext  A handle to the server context for the server in
   *                        which this extension is running.
   * @param  config         The general configuration for this HTTP servlet
   *                        extension.
   * @param  parser         The argument parser which has been initialized from
   *                        the configuration for this HTTP servlet extension.
   *
   * @return  The HTTP servlet that has been created.
   *
   * @throws  LDAPException  If a problem is encountered while attempting to
   *                         create the HTTP servlet.
   */
  @Override()
  public ExampleHelloServlet createServlet(
              final HTTPServerContext serverContext,
              final HTTPServletExtensionConfig config,
              final ArgumentParser parser)
         throws LDAPException
  {
    // Get the new greeting name.
    final StringArgument nameArg =
         (StringArgument) parser.getNamedArgument(ARG_NAME_NAME);

    // Get the servlet path.
    final StringArgument pathArg =
         (StringArgument) parser.getNamedArgument(ARG_NAME_PATH);
    path = pathArg.getValue();

    servlet = new ExampleHelloServlet(nameArg.getValue());
    return servlet;
  }



  /**
   * Retrieves a list of the request paths for which the associated servlet
   * should be invoked.  This method will be called after the
   * {@link #createServlet} method has been used to create the servlet instance.
   *
   * @return  A list of the request paths for which the associated servlet
   *          should be invoked.
   */
  @Override()
  public List<String> getServletPaths()
  {
    return Arrays.asList(path);
  }



  /**
   * Indicates whether the configuration contained in the provided argument
   * parser represents a valid configuration for this extension.
   *
   * @param  config               The general configuration for this HTTP
   *                              servlet extension.
   * @param  parser               The argument parser which has been initialized
   *                              with the proposed configuration.
   * @param  unacceptableReasons  A list that can be updated with reasons that
   *                              the proposed configuration is not acceptable.
   *
   * @return  {@code true} if the proposed configuration is acceptable, or
   *          {@code false} if not.
   */
  @Override()
  public boolean isConfigurationAcceptable(
                      final HTTPServletExtensionConfig config,
                      final ArgumentParser parser,
                      final List<String> unacceptableReasons)
  {
    // No special validation is required.
    return true;
  }



  /**
   * Attempts to apply the configuration contained in the provided argument
   * parser.
   *
   * @param  config                The general configuration for this HTTP
   *                               servlet extension.
   * @param  parser                The argument parser which has been
   *                               initialized with the new configuration.
   * @param  adminActionsRequired  A list that can be updated with information
   *                               about any administrative actions that may be
   *                               required before one or more of the
   *                               configuration changes will be applied.
   * @param  messages              A list that can be updated with information
   *                               about the result of applying the new
   *                               configuration.
   *
   * @return  A result code that provides information about the result of
   *          attempting to apply the configuration change.
   */
  @Override()
  public ResultCode applyConfiguration(final HTTPServletExtensionConfig config,
                                       final ArgumentParser parser,
                                       final List<String> adminActionsRequired,
                                       final List<String> messages)
  {
    // We only need to validate changes made after the servlet has been created.
    // If the servlet hasn't yet been created, then we don't need to do
    // anything.
    if (servlet == null)
    {
      return ResultCode.SUCCESS;
    }

    // Get the new greeting name.
    final StringArgument nameArg =
         (StringArgument) parser.getNamedArgument(ARG_NAME_NAME);
    servlet.setName(nameArg.getValue());

    // The path will not change dynamically.  If a different path was given,
    // then report that as a required administrative action.
    final StringArgument pathArg =
         (StringArgument) parser.getNamedArgument(ARG_NAME_PATH);
    if (! path.equals(pathArg.getValue()))
    {
      adminActionsRequired.add("Changes to the servlet path will not take " +
           "effect until the HTTP connection handler (or entire server) is " +
           "restarted.");
    }

    return ResultCode.SUCCESS;
  }
}