AuthenticationTokenBin.java

/*******************************************************************************
 * Copyright 2013 Open mHealth
 * 
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 * 
 * 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.openmhealth.reference.data;

import org.openmhealth.reference.domain.AuthenticationToken;
import org.openmhealth.reference.exception.OmhException;

/**
 * <p>
 * The interface to the database-backed authentication token repository.
 * </p>
 *
 * @author John Jenkins
 */
public abstract class AuthenticationTokenBin {
	/**
	 * The name of the DB document/table/whatever that contains the
	 * authentication tokens.
	 */
	public static final String DB_NAME = "authentication_token_bin";
	
	/**
	 * The instance of this AuthenticationTokenBin to use. 
	 */
	protected static AuthenticationTokenBin instance;
	
	/**
	 * Default constructor.
	 */
	protected AuthenticationTokenBin() {
		instance = this;
	}
	
	/**
	 * Returns the singular instance of this class.
	 * 
	 * @return The singular instance of this class.
	 */
	public static AuthenticationTokenBin getInstance() {
		return instance;
	}

	/**
	 * Stores an existing authentication token.
	 * 
	 * @param token
	 *        The token to be saved.
	 * 
	 * @throws OmhException
	 *         The token is null.
	 */
	public abstract void storeToken(
		final AuthenticationToken token)
		throws OmhException;
	
	/**
	 * Retrieves the {@link AuthenticationToken} object based on the given
	 * token string.
	 * 
	 * @param token
	 *        The authentication token.
	 * 
	 * @return The {@link AuthenticationToken} or null if the authentication 
	 * 		   token string does not exist or is expired.
	 * 
	 * @throws OmhException
	 *         Multiple copies of the same authentication token exist.
	 */
	public abstract AuthenticationToken getToken(
		final String token)
		throws OmhException;
}