001: /****************************************************************
002: * Licensed to the Apache Software Foundation (ASF) under one *
003: * or more contributor license agreements. See the NOTICE file *
004: * distributed with this work for additional information *
005: * regarding copyright ownership. The ASF licenses this file *
006: * to you under the Apache License, Version 2.0 (the *
007: * "License"); you may not use this file except in compliance *
008: * with the License. You may obtain a copy of the License at *
009: * *
010: * http://www.apache.org/licenses/LICENSE-2.0 *
011: * *
012: * Unless required by applicable law or agreed to in writing, *
013: * software distributed under the License is distributed on an *
014: * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
015: * KIND, either express or implied. See the License for the *
016: * specific language governing permissions and limitations *
017: * under the License. *
018: ****************************************************************/package org.apache.mailet;
019:
020: /**
021: * Draft of a Mailet inteface. The <code>service</code> perform all needed work
022: * on the Mail object. Whatever remains at the end of the service is considered
023: * to need futher processing and will go to the next Mailet if there is one
024: * configured or will go to the error processor if not.
025: * Setting a Mail state (setState(String)) to Mail.GHOST or cleaning its recipient
026: * list has the same meaning that s no more processing is needed.
027: * Instead of creating new messages, the mailet can put a message with new recipients
028: * at the top of the mail queue, or insert them immediately after it's execution
029: * through the API are provided by the MailetContext interface.
030: * <p>
031: * This interface defines methods to initialize a mailet, to service messages, and to
032: * remove a mailet from the server. These are known as life-cycle methods and are called
033: * in the following sequence:
034: * <ol>
035: * <li>The mailet is constructed, then initialized with the init method. </li>
036: * <li>Any messages for the service method are handled.</li>
037: * <li>The mailet is taken out of service, then destroyed with the destroy method,
038: * then garbage collected and finalized.</li>
039: * </ol>
040: * In addition to the life-cycle methods, this interface provides the getMailetConfig
041: * method, which the mailet can use to get any startup information, and the
042: * getMailetInfo method, which allows the mailet to return basic information about itself,
043: * such as author, version, and copyright.
044: *
045: * @version 1.0.0, 24/04/1999
046: */
047: public interface Mailet {
048:
049: /**
050: * Called by the mailet container to indicate to a mailet that the
051: * mailet is being taken out of service. This method is only called once
052: * all threads within the mailet's service method have exited or after a
053: * timeout period has passed. After the mailet container calls this method,
054: * it will not call the service method again on this mailet.
055: * <p>
056: * This method gives the mailet an opportunity to clean up any resources that
057: * are being held (for example, memory, file handles, threads) and make sure
058: * that any persistent state is synchronized with the mailet's current state in memory.
059: */
060: void destroy();
061:
062: /**
063: * Returns information about the mailet, such as author, version, and
064: * copyright.
065: * <p>
066: * The string that this method returns should be plain text and not markup
067: * of any kind (such as HTML, XML, etc.).
068: *
069: * @return a String containing servlet information
070: */
071: String getMailetInfo();
072:
073: /**
074: * Returns a MailetConfig object, which contains initialization and
075: * startup parameters for this mailet.
076: * <p>
077: * Implementations of this interface are responsible for storing the MailetConfig
078: * object so that this method can return it. The GenericMailet class, which implements
079: * this interface, already does this.
080: *
081: * @return the MailetConfig object that initializes this mailet
082: */
083: MailetConfig getMailetConfig();
084:
085: /**
086: * Called by the mailet container to indicate to a mailet that the
087: * mailet is being placed into service.
088: * <p>
089: * The mailet container calls the init method exactly once after
090: * instantiating the mailet. The init method must complete successfully
091: * before the mailet can receive any requests.
092: *
093: * @param config - a MailetConfig object containing the mailet's configuration
094: * and initialization parameters
095: * @throws javax.mail.MessagingException - if an exception has occurred that interferes with
096: * the mailet's normal operation
097: */
098: void init(MailetConfig config) throws javax.mail.MessagingException;
099:
100: /**
101: * Called by the mailet container to allow the mailet to process to
102: * a message.
103: * <p>
104: * This method is only called after the mailet's init() method has completed
105: * successfully.
106: * <p>
107: * Mailets typically run inside multithreaded mailet containers that can handle
108: * multiple requests concurrently. Developers must be aware to synchronize access
109: * to any shared resources such as files, network connections, as well as the
110: * mailet's class and instance variables. More information on multithreaded
111: * programming in Java is available in <a href="http://java.sun.com/Series/Tutorial/java/threads/multithreaded.html">the
112: * Java tutorial on multi-threaded programming</a>.
113: *
114: * @param mail - the Mail object that contains the message and routing information
115: * @throws javax.mail.MessagingException - if a message or address parsing exception occurs or
116: * an exception that interferes with the mailet's normal operation
117: */
118: void service(Mail mail) throws javax.mail.MessagingException;
119: }
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