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* Licensed to the Apache Software Foundation (ASF) under one *
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* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
* to you 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 *
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* KIND, either express or implied. See the License for the *
* specific language governing permissions and limitations *
* under the License. *
****************************************************************/
package org.apache.mailet;
import javax.mail.MessagingException;
import java.util.Iterator;
/**
* GenericMailet makes writing mailets easier. It provides simple
* versions of the lifecycle methods init and destroy and of the methods
* in the MailetConfig interface. GenericMailet also implements the log
* method, declared in the MailetContext interface.
* <p>
* To write a generic mailet, you need only override the abstract service
* method.
*
* @version 1.0.0, 24/04/1999
*/
public abstract class GenericMailet implements Mailet, MailetConfig {
private MailetConfig config = null;
/**
* Called by the mailer container to indicate to a mailet that the
* mailet is being taken out of service.
*/
public void destroy() {
//Do nothing
}
/**
* Returns a String containing the value of the named initialization
* parameter, or null if the parameter does not exist.
* <p>
* This method is supplied for convenience. It gets the value of the
* named parameter from the mailet's MailetConfig object.
*
* @param name - a String specifying the name of the initialization parameter
* @return a String containing the value of the initalization parameter
*/
public String getInitParameter(String name) {
return config.getInitParameter(name);
}
/**
* Returns a String containing the value of the named initialization
* parameter, or defValue if the parameter does not exist.
* <p>
* This method is supplied for convenience. It gets the value of the
* named parameter from the mailet's MailetConfig object.
*
* @param name - a String specifying the name of the initialization parameter
* @param defValue - a String specifying the default value when the parameter
* is not present
* @return a String containing the value of the initalization parameter
*/
public String getInitParameter(String name, String defValue) {
String res = config.getInitParameter(name);
if (res == null) {
return defValue;
} else {
return res;
}
}
/**
* Returns the names of the mailet's initialization parameters as an
* Iterator of String objects, or an empty Iterator if the mailet has no
* initialization parameters.
* <p>
* This method is supplied for convenience. It gets the parameter names from
* the mailet's MailetConfig object.
*
* @return an Iterator of String objects containing the names of
* the mailet's initialization parameters
*/
public Iterator getInitParameterNames() {
return config.getInitParameterNames();
}
/**
* Returns this Mailet's MailetConfig object.
*
* @return the MailetConfig object that initialized this mailet
*/
public MailetConfig getMailetConfig() {
return config;
}
/**
* Returns a reference to the MailetContext in which this mailet is
* running.
*
* @return the MailetContext object passed to this mailet by the init method
*/
public MailetContext getMailetContext() {
return getMailetConfig().getMailetContext();
}
/**
* Returns information about the mailet, such as author, version, and
* copyright. By default, this method returns an empty string. Override
* this method to have it return a meaningful value.
*
* @return information about this mailet, by default an empty string
*/
public String getMailetInfo() {
return "";
}
/**
* Returns the name of this mailet instance.
*
* @return the name of this mailet instance
*/
public String getMailetName() {
return config.getMailetName();
}
/**
* <p>Called by the mailet container to indicate to a mailet that the
* mailet is being placed into service.</p>
*
* <p>This implementation stores the MailetConfig object it receives from
* the mailet container for later use. When overriding this form of the
* method, call super.init(config).</p>
*
* @param MailetConfig newconfig - the MailetConfig object that contains
* configutation information for this mailet
* @throws MessagingException
* if an exception occurs that interrupts the mailet's normal operation
*/
public void init(MailetConfig newConfig) throws MessagingException {
config = newConfig;
init();
}
/**
* <p>A convenience method which can be overridden so that there's no
* need to call super.init(config).</p>
*
* Instead of overriding init(MailetConfig), simply override this
* method and it will be called by GenericMailet.init(MailetConfig config).
* The MailetConfig object can still be retrieved via getMailetConfig().
*
* @throws MessagingException
* if an exception occurs that interrupts the mailet's normal operation
*/
public void init() throws MessagingException {
//Do nothing... can be overriden
}
/**
* Writes the specified message to a mailet log file, prepended by
* the mailet's name.
*
* @param message - a String specifying the message to be written to the log file
*/
public void log(String message) {
StringBuffer logBuffer =
new StringBuffer(256)
.append(getMailetName())
.append(": ")
.append(message);
getMailetContext().log(logBuffer.toString());
}
/**
* Writes an explanatory message and a stack trace for a given Throwable
* exception to the mailet log file, prepended by the mailet's name.
*
* @param message - a String that describes the error or exception
* @param t - the java.lang.Throwable to be logged
*/
public void log(String message, Throwable t) {
StringBuffer logBuffer =
new StringBuffer(256)
.append(config.getMailetName())
.append(": ")
.append(message);
getMailetContext().log(logBuffer.toString(), t);
}
/**
* <p>Called by the mailet container to allow the mailet to process a
* message.</p>
*
* <p>This method is declared abstract so subclasses must override it.</p>
*
* @param mail - the Mail object that contains the MimeMessage and
* routing information
* @throws javax.mail.MessagingException - if an exception occurs that interferes with the mailet's normal operation
*/
public abstract void service(Mail mail) throws javax.mail.MessagingException;
}
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