/*
 * Copyright 2005-2010 the original author or authors.
 *
 * 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.springframework.ws.transport.mail.monitor;

import javax.mail.Folder;
import javax.mail.MessagingException;

/**
 * Implementation of the {@link MonitoringStrategy} interface that uses a simple polling mechanism. Defines a {@link
 * #setPollingInterval(long) polling interval} property which defines the interval in between message polls.
 *
 * <p><b>Note</b> that this implementation is not suitable for use with POP3 servers. Use the {@link
 * Pop3PollingMonitoringStrategy} instead.
 *
 * @author Arjen Poutsma
 * @since 1.5.0
 */
public class PollingMonitoringStrategy extends AbstractMonitoringStrategy {

	/** Defines the default polling frequency. Set to 1000 * 60 milliseconds (i.e. 1 minute). */
	public static final long DEFAULT_POLLING_FREQUENCY = 1000 * 60;

	private long pollingInterval = DEFAULT_POLLING_FREQUENCY;

	/**
	 * Sets the interval used in between message polls, <strong>in milliseconds</strong>. The default is 1000 * 60 ms,
	 * that is 1 minute.
	 */
	public void setPollingInterval(long pollingInterval) {
		this.pollingInterval = pollingInterval;
	}

	@Override
	protected void waitForNewMessages(Folder folder) throws MessagingException, InterruptedException {
		Thread.sleep(pollingInterval);
		afterSleep(folder);
	}

	/**
	 * Invoked after the {@link Thread#sleep(long)} method has been invoked. This implementation calls {@link
	 * Folder#getMessageCount()}, to force new messages to be seen.
	 *
	 * @param folder the folder to check for new messages
	 * @throws MessagingException in case of JavaMail errors
	 */
	protected void afterSleep(Folder folder) throws MessagingException {
		folder.getMessageCount();
	}

}