PROPOSAL.html - commons-daemon - Git at Google

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 <html>
 <head>
 <title>Proposal for Daemon Package</title>
 </head>
 <body bgcolor="white">

 <div align="center">
 <h1>Proposal for <em>Daemon</em> Package</h1>
 </div>

 <h3>(0) Rationale</h3>

     <P>
       Since 1994, the Java&trade; programming language evolved and became a
       valid tool to develop, other than applets and client applications,
       reliable and performant server applications. The major disadvantage of
       the Java&trade; platform is that still today the only portable way to
       start a Java&trade; applcation relies on a single point of entry: the
       <CODE><EM CLASS="key">public static void</EM> main(<EM CLASS="ref">String</EM>[])</CODE>
       method.
     </P>
     <P>
       Having a single-point of entry is a valid solution for client
       applications, where interactively a user can command to the application
       to quit (which can terminate the Virtual Machine process at calling the
       <CODE><EM CLASS="ref">System</EM>.exit(<EM CLASS="key">int</EM>)</CODE>
       method), but in those cases where the application is not interactive
       (server applications) there is currently no portable way to notify
       the Virtual Machine of its imminent shutdown.
     </P>
     <P>
       A server application written in Java might have to perform several tasks
       before being able to shutdown the Virtual Machine process. For example
       in the case of a Servlet container, before the VM process is shut down,
       sessions might need to be serialized to disk, and web applications need
       to be destroyed.
     </P>
     <P>
       One common solution to this problem is to create (for example) a
       <CODE><EM CLASS="ref">ServerSocket</EM></CODE> and wait for a particular
       message to be issued. When the message is received, all operations
       required to shut down the server applications are performed and at the
       end the <CODE><EM CLASS="ref">System</EM>.exit</CODE> method is called
       to terminate the Virtual Machine process. This method, however, implies
       several disadvantages and risks: for example in case of a system-wide
       shutdown, it might happen that the Virtual Machine process will be shut
       down directly by the operating system, without notifying the running
       server application. Or, for example, if an attacker finds out what is
       the required message to send to the server, and discovers a way to send
       this message to the running server application, he can easily interrupt
       the operation of a server, bypassing all the security restrictions
       implemented in the operating system.
     </P>
     <P>
       Most multi-user operating systems already have a way in which server
       applications are started and stopped, under Unix based operating systems
       non interactive server applications are called <em>daemons</em> and are
       controlled by the operating system with a set of specified
       <em>signals</em>. Under Windows such programs are called <em>services</em>
       and are controlled by appropriate calls to specific functions defined in
       the application binary, but although the ways of dealing with the problem
       are different, in both cases the operating system can notify a server
       application of its imminent shutdown, and the application has the
       ability to perform certain tasks before its process of execution is
       destroyed.
     </P>

 <h3>(1) Scope of the Package</h3>

     <P>
       The scope of this specification is to define an API in line with the
       current Java&trade; Platform APIs to support an alternative invocation
       mechanism which could be used instead of the above mentioned
       <CODE><EM CLASS="key">public static void</EM> main(<EM CLASS="ref">String</EM>[])</CODE>
       method. This specification cover the behavior and life cycle of what
       we define as &quot;Java &trade; daemons&quot;, or, in other words,
       non interactive Java&trade; applications.
     </P>
     <P>
       This specification does not cover how the container of a Java&trade;
       daemon must be implemented, or how to build a native liaison between
       the operating system and the <CODE><EM CLASS="ref">Daemon</EM></CODE>
       interface, but defines the relation between the an operating system
       process and the <CODE><EM CLASS="ref">Daemon</EM></CODE> implementation
       life cycle. It should be trivial for implementors to build a native
       liaison and container for Java&trade; daemons.
     </P>
     <P>
       This specification, together with the related API documentation, can be
       used by software deveopers to build portable non interactive applications
       based on the Java&trade; platform.
     </P>

 <h3>(1.5) Interaction With Other Packages</h3>

 <p><em>Daemon</em> relies only on standard JDK 1.2 (or later) APIs for
 production deployment.  It utilizes the JUnit unit testing framework for
 developing and executing unit tests, but this is of interest only to
 developers of the component.  Daemon will be a dependency for
 several existing components in the open source world.</p>

 <p>No external configuration files are utilized.</p>


 <h3>(2) Initial Source of the Package</h3>

 <p>The original Java classes come from the Jakarta Tomcat 4.0 project.</p>

 <p>The proposed package name for the new component is
 <code>org.apache.commons.daemon</code>.</p>


 <h3>(3)  Required Jakarta-Commons Resources</h3>

 <ul>
 <li>CVS Repository - New directory <code>daemon</code> in the
     <code>jakarta-commons</code> CVS repository.</li>
 <li>Mailing List - Discussions will take place on the general
     <em>dev@commons.apache.org</em> mailing list.  To help
     list subscribers identify messages of interest, it is suggested that
     the message subject of messages about this component be prefixed with
     [Daemon].</li>
 <li>Bugzilla - New component "Daemon" under the "Commons" product
     category, with appropriate version identifiers as needed.</li>
 <li>Jyve FAQ - New category "commons-daemon" (when available).</li>
 </ul>


 <h3>(4) Initial Committers</h3>

 <p>The initial committers on the Daemon component shall be:</p>
 <ul>
 <li>Jean-Frederic Clere</li>
 <li>Pier Fumagalli</li>
 <li>Remy Maucherat</li>


 </body>
 </html>
	<!--
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file 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 "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.
	-->
	<html>
	<head>
	<title>Proposal for Daemon Package</title>
	</head>
	<body bgcolor="white">

	<div align="center">
	<h1>Proposal for <em>Daemon</em> Package</h1>
	</div>

	<h3>(0) Rationale</h3>

	<P>
	Since 1994, the Java™ programming language evolved and became a
	valid tool to develop, other than applets and client applications,
	reliable and performant server applications. The major disadvantage of
	the Java™ platform is that still today the only portable way to
	start a Java™ applcation relies on a single point of entry: the
	<CODE><EM CLASS="key">public static void</EM> main(<EM CLASS="ref">String</EM>[])</CODE>
	method.
	</P>
	<P>
	Having a single-point of entry is a valid solution for client
	applications, where interactively a user can command to the application
	to quit (which can terminate the Virtual Machine process at calling the
	<CODE><EM CLASS="ref">System</EM>.exit(<EM CLASS="key">int</EM>)</CODE>
	method), but in those cases where the application is not interactive
	(server applications) there is currently no portable way to notify
	the Virtual Machine of its imminent shutdown.
	</P>
	<P>
	A server application written in Java might have to perform several tasks
	before being able to shutdown the Virtual Machine process. For example
	in the case of a Servlet container, before the VM process is shut down,
	sessions might need to be serialized to disk, and web applications need
	to be destroyed.
	</P>
	<P>
	One common solution to this problem is to create (for example) a
	<CODE><EM CLASS="ref">ServerSocket</EM></CODE> and wait for a particular
	message to be issued. When the message is received, all operations
	required to shut down the server applications are performed and at the
	end the <CODE><EM CLASS="ref">System</EM>.exit</CODE> method is called
	to terminate the Virtual Machine process. This method, however, implies
	several disadvantages and risks: for example in case of a system-wide
	shutdown, it might happen that the Virtual Machine process will be shut
	down directly by the operating system, without notifying the running
	server application. Or, for example, if an attacker finds out what is
	the required message to send to the server, and discovers a way to send
	this message to the running server application, he can easily interrupt
	the operation of a server, bypassing all the security restrictions
	implemented in the operating system.
	</P>
	<P>
	Most multi-user operating systems already have a way in which server
	applications are started and stopped, under Unix based operating systems
	non interactive server applications are called <em>daemons</em> and are
	controlled by the operating system with a set of specified
	<em>signals</em>. Under Windows such programs are called <em>services</em>
	and are controlled by appropriate calls to specific functions defined in
	the application binary, but although the ways of dealing with the problem
	are different, in both cases the operating system can notify a server
	application of its imminent shutdown, and the application has the
	ability to perform certain tasks before its process of execution is
	destroyed.
	</P>

	<h3>(1) Scope of the Package</h3>

	<P>
	The scope of this specification is to define an API in line with the
	current Java™ Platform APIs to support an alternative invocation
	mechanism which could be used instead of the above mentioned
	<CODE><EM CLASS="key">public static void</EM> main(<EM CLASS="ref">String</EM>[])</CODE>
	method. This specification cover the behavior and life cycle of what
	we define as "Java ™ daemons", or, in other words,
	non interactive Java™ applications.
	</P>
	<P>
	This specification does not cover how the container of a Java™
	daemon must be implemented, or how to build a native liaison between
	the operating system and the <CODE><EM CLASS="ref">Daemon</EM></CODE>
	interface, but defines the relation between the an operating system
	process and the <CODE><EM CLASS="ref">Daemon</EM></CODE> implementation
	life cycle. It should be trivial for implementors to build a native
	liaison and container for Java™ daemons.
	</P>
	<P>
	This specification, together with the related API documentation, can be
	used by software deveopers to build portable non interactive applications
	based on the Java™ platform.
	</P>

	<h3>(1.5) Interaction With Other Packages</h3>

	<p><em>Daemon</em> relies only on standard JDK 1.2 (or later) APIs for
	production deployment. It utilizes the JUnit unit testing framework for
	developing and executing unit tests, but this is of interest only to
	developers of the component. Daemon will be a dependency for
	several existing components in the open source world.</p>

	<p>No external configuration files are utilized.</p>


	<h3>(2) Initial Source of the Package</h3>

	<p>The original Java classes come from the Jakarta Tomcat 4.0 project.</p>

	<p>The proposed package name for the new component is
	<code>org.apache.commons.daemon</code>.</p>


	<h3>(3) Required Jakarta-Commons Resources</h3>

	<ul>
	<li>CVS Repository - New directory <code>daemon</code> in the
	<code>jakarta-commons</code> CVS repository.</li>
	<li>Mailing List - Discussions will take place on the general
	<em>dev@commons.apache.org</em> mailing list. To help
	list subscribers identify messages of interest, it is suggested that
	the message subject of messages about this component be prefixed with
	[Daemon].</li>
	<li>Bugzilla - New component "Daemon" under the "Commons" product
	category, with appropriate version identifiers as needed.</li>
	<li>Jyve FAQ - New category "commons-daemon" (when available).</li>
	</ul>


	<h3>(4) Initial Committers</h3>

	<p>The initial committers on the Daemon component shall be:</p>
	<ul>
	<li>Jean-Frederic Clere</li>
	<li>Pier Fumagalli</li>
	<li>Remy Maucherat</li>



	</body>
	</html>