/**********************************************************************************
 * $URL: https://source.sakaiproject.org/svn/email/tags/sakai_2-3-1/email-api/api/src/java/org/sakaiproject/email/api/DigestService.java $
 * $Id: DigestService.java 7287 2006-03-30 21:21:55Z ggolden@umich.edu $
 ***********************************************************************************
 *
 * Copyright (c) 2003, 2004, 2005, 2006 The Sakai Foundation.
 * 
 * Licensed under the Educational Community License, Version 1.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at
 * 
 *      http://www.opensource.org/licenses/ecl1.php
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 *
 **********************************************************************************/

package org.sakaiproject.email.api;

import java.util.List;

import org.sakaiproject.exception.IdUnusedException;
import org.sakaiproject.exception.IdUsedException;
import org.sakaiproject.exception.InUseException;

/**
 * <p>
 * The DigestService collects sets of messages for different users, and sends them out periodically.
 * </p>
 */
public interface DigestService
{
	/** This string can be used to find the service in the service manager. */
	static final String SERVICE_NAME = DigestService.class.getName();

	/** This string starts the references to resources in this service. */
	static final String REFERENCE_ROOT = "/digest";

	/** Securiy / Event for adding a digest. */
	static final String SECURE_ADD_DIGEST = "digest.add";

	/** Securiy / Event for updating a digest. */
	static final String SECURE_EDIT_DIGEST = "digest.upd";

	/** Securiy / Event for removing a digest. */
	static final String SECURE_REMOVE_DIGEST = "digest.del";

	/**
	 * Access a digest associated with this id.
	 * 
	 * @param id
	 *        The digest id.
	 * @return The Digest object.
	 * @exception IdUnusedException
	 *            if there is not digest object with this id.
	 */
	Digest getDigest(String id) throws IdUnusedException;

	/**
	 * Access all digest objects.
	 * 
	 * @return A List (Digest) of all defined digests.
	 */
	List getDigests();

	/**
	 * Add a new message to a digest, creating one if needed. This returns right away; the digest will be added as soon as possible.
	 * 
	 * @param message
	 *        The message to digest.
	 * @param subject
	 *        The to (user id) of the message.
	 * @param subject
	 *        The subject of the message.
	 * @param body
	 *        The subject of the message.
	 */
	void digest(String to, String Subject, String body);

	/**
	 * Add a new digest with this id. Must commit(), remove() or cancel() when done.
	 * 
	 * @param id
	 *        The digest id.
	 * @return A new DigestEdit object for editing.
	 * @exception IdUsedException
	 *            if these digest already exist.
	 */
	DigestEdit add(String id) throws IdUsedException;

	/**
	 * Get a locked Digest object for editing. May be new. Must commit(), cancel() or remove() when done.
	 * 
	 * @param id
	 *        The digest id.
	 * @return A DigestEdit object for editing.
	 * @exception InUseException
	 *            if the digest object is locked by someone else.
	 */
	DigestEdit edit(String id) throws InUseException;

	/**
	 * Commit the changes made to a DigestEdit object, and release the lock. The DigestEdit is disabled, and not to be used after this call.
	 * 
	 * @param user
	 *        The DigestEdit object to commit.
	 */
	void commit(DigestEdit edit);

	/**
	 * Cancel the changes made to a DigestEdit object, and release the lock. The DigestEdit is disabled, and not to be used after this call.
	 * 
	 * @param user
	 *        The DigestEdit object to commit.
	 */
	void cancel(DigestEdit edit);

	/**
	 * Remove this DigestEdit - it must be locked from edit(). The DigestEdit is disabled, and not to be used after this call.
	 * 
	 * @param user
	 *        The DigestEdit object to remove.
	 */
	void remove(DigestEdit edit);
}
