personalizationservice.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.services.personalization;

import java.security.Principal;

import javax.xml.rpc.ServiceException;
import javax.xml.rpc.server.ServletEndpointContext;

import org.springframework.remoting.jaxrpc.ServletEndpointSupport;

import com.esri.solutions.jitk.services.common.ServicesException;

/**
 * {@code PersonalizationService} is an abstract base class that provides functionality
 * common across all Personalization Web Services.
 * <p>
 * This functionality includes:
 * <ul>
 * 	<li>
 * 		Initializing parameters that are used by Personalization Web Services, including:
 * 		<ul>
 * 			<li>Checking for duplicate IDs on Insert (see checkForDuplicateIdOnInsert in web.xml)</li>
 * 		</ul>
 *  </li> 
 *  <li>Determining if a given ID exists in the datastore</li>
 *  <li>Retrieving the name of the logged-in user</li>
 * </ul> 
 */
public abstract class PersonalizationService extends ServletEndpointSupport {

	protected boolean checkForDuplicateIds = false;
	protected static final String CONTEXT_PARAM_CHECK_FOR_DUPLICATE_IDS = "checkForDuplicateIdOnInsert";
	protected static final String ERROR_ID_ALREADY_EXISTS = "A {0} with an ID of {1} already exists.";
	protected static final String ERROR_CANNOT_DETERMINE_LOGGED_IN_USER = "Cannot determine logged in user.";

	public PersonalizationService() {
		super();
	}

	/**
	 * {@inheritDoc}
	 * <p>
	 * This version of {@code onInit()} retrieves the value of the {@code checkForDuplicateIdOnInsert} parameter from the application's
	 * deployment descriptor and stores it locally.
	 * </p>
	 */
	protected void onInit() throws ServiceException {
		super.onInit();
		Object o = getServletContext().getInitParameter(
				CONTEXT_PARAM_CHECK_FOR_DUPLICATE_IDS);
		checkForDuplicateIds = Boolean.valueOf((String) o);
	}

	/**
	 * Given the ID of an item that is manipulated by the Personalization
	 * Service, this method will determine if an item with that ID already
	 * exists in the database
	 * 
	 * @param id
	 *            the id of the item to insert
	 * @return {@code boolean} {@code true} if the item exists; {@code false}
	 *         otherwise
	 * @throws ServicesException
	 *             If an exception occurs when checking the data in the database
	 */
	protected boolean okToInsert(String id) throws ServicesException {
		boolean okToInsert = true;
		if (checkForDuplicateIds) {
			okToInsert = !checkForId(id);
		}
		return okToInsert;
	}

	/**
	 * Abstract method that checks, in a service-specific manner, the datastore
	 * to see if an ID already exists.
	 * 
	 * @param id
	 *            {@link String} containing the ID whose existence shoudl be
	 *            determined
	 * @return {@code boolean} {@code true} if the id exists; {@code false}
	 *         otherwise
	 * @throws ServicesException
	 *             If an exception occurs when checking the data in the database
	 */
	protected abstract boolean checkForId(String id) throws ServicesException;

	/**
	 * Retrieves the name of the currently-logged-in user.
	 * <p>
	 * This is a convenience method that exists as a shortcut for the call:
	 * {@link #getServletEndpointContext()#getUserPrincipal()#getName()}.
	 * </p>
	 * 
	 * @return
	 * @throws ServicesException
	 *             If an exception occurs when trying to deterime the username.
	 */
	protected String getUsername() throws ServicesException {
		String name;
		try {
			ServletEndpointContext context = getServletEndpointContext();
			Principal principal = context.getUserPrincipal();
			name = principal.getName();
		} catch (Exception e) {
			throw new ServicesException(ERROR_CANNOT_DETERMINE_LOGGED_IN_USER,
					e);
		}
		return name;

	}

}