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| author | No Author <dev-null@apache.org> | 2000-06-30 22:39:45 +0000 |
|---|---|---|
| committer | No Author <dev-null@apache.org> | 2000-06-30 22:39:45 +0000 |
| commit | f0855dc2ad63dc096b1526c258ee77360a9f27ca (patch) | |
| tree | 9ce99ea8746d8a055a7920fa18db3126bdb0d8ad /spec/core.html | |
| parent | b21634835a8db02403c02bbae6f6c65218ae8754 (diff) | |
| download | ant-tomcat_32.tar.gz | |
This commit was manufactured by cvs2svn to create branch 'tomcat_32'.tomcat_32
git-svn-id: https://svn.apache.org/repos/asf/ant/core/branches/tomcat_32@267721 13f79535-47bb-0310-9956-ffa450edef68
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diff --git a/spec/core.html b/spec/core.html deleted file mode 100644 index 882659efc..000000000 --- a/spec/core.html +++ /dev/null @@ -1,278 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "strict.dtd"> -<HTML> - <HEAD> - <TITLE>Ant Specification, version 0.5</TITLE> - </HEAD> - <BODY> - <H1>Ant Specification</H1> - <P>Version 0.5 (2000/04/20)</P> - <P>This document specifies the behavior of Ant. At this time, this is a - working document with no implementation. It is hoped that this specification - will lead to a simplier and more consistent implementation of Ant.</P> - <P>This document is not intended to be used as an end user manual or user - guide to Ant. To adequatly explain the concepts herein in a way appropriate to - such a use would potentially complicate this document.</P> - <H2>Design Goals</H2> - <P>The following are the overall design goals of Ant:</P> - <UL> - <LI>Simplicity</LI> - <LI>Understandability</LI> - <LI>Extensibility</LI> - </UL> - <H3>Simplicity</H3> - <P>Ant must be simple to use. Of course, as the definition of simple varies - according to the audience of the program. For Ant, since it is a build tool - aimed at programmers, the goal is to be simple to use for a competent - programmer.</P> - <H3>Understandability</H3> - <P>Ant must be clearly understandible for a first time as well as a veteran - user. This means that a new user should be able to use Ant comfortably the - first time and understand how to modify a build file by looking at it. And it - should not require much experience with Ant to understand how it works and how - to configure it for particular situtations.</P> - <H3>Extensibility</H3> - <P>Ant must be easy to extend. The API used to extend Ant must be easy to - use and the way in which these extensions are located and used by the core - runtime should be clear.</P> - <H2>Conceptual Overview</H2> - <P>This is a conceptual overview of the components used by Ant. Full APIs - will be defined later.</P> - <H3>Project</H3> - <P>The base unit of work in Ant is the <STRONG>Project</STRONG>. A Project - is defined by an editable text file and is represented by an object of type - <CODE>org.apache.ant.Project</CODE> at runtime.</P> - <P>A Project is a collection of <STRONG>Properties</STRONG> and - <STRONG>Targets</STRONG>.</P> - <H3>Properties</H3> - <P>Properties are mutable name-value pairs that are scoped to the Project - and held in a table. Only one pair is allowed per name. It is anticipated that - this data structure would be of type <CODE>java.util.Properties</CODE> or a type that has approximatly - the same contract.</P> - <P>Properties can be defined in a hierarchical manner. The order of - precidence in this hiearchy is:</P> - <UL> - <LI>Properties defined on the command line or via a GUI tool</LI> - <LI>Properties defined in the text file which defines the project.</LI> - <LI>Properties defined in a file in the users <CODE>user.home</CODE> directory</LI> - <LI>Properties defined in the installation directory that can be shared - by multiple users.</LI> - </UL> - <P>Note: The current version of Ant allows the System property list to be - consulted for a return value if the property list doesn't satisfy the requested - property name. As all Java code has access to the system property list via the - <CODE>java.lang.System</CODE> class, this functionality is considered to be confusing and to be - removed.</P> - <P>Note: The current version of Ant allows property substitution to be - performed in the project file. This functionality is being removed.</P> - <H3>Targets</H3> - <P>Targets are ordered collections of <STRONG>Tasks</STRONG>, units of work - to be performed if a Target is executed. </P> - <P>Targets can define dependancies on other Targets within the Project. If - a Target is deemed to be executed, either directly on the command line, or via - a dependancy from some other Target, then all of its dependencies must first be - executed. Circular depenancies are resolved by examination of the dependancy - stack when a Target is evaluated. If a dependancy is already on the stack of - targets to be executed, then the dependancy is considered to have been - satisfied.</P> - <P>After all dependancies of a Target have been satisfied, all of the Tasks - contained by the target are configured and executed in sequential order. </P> - <H3>Tasks</H3> - <P>A Task is a unit of work. When a Task is to be executed, an instance of - the class that defines the behavior of the particular task specified is - instantiated and then configured. This class implements the <CODE>org.apache.ant.Task</CODE> interface. - It is then executed so that it may be able to perform its function. It is - important to note that this configuration occurs just before execution of the - task, and after execution of any previous tasks, so that configuration - information that was modified by any other Task can be properly set.</P> - <P>When a Task is executed, it is provided access to the object - representing the Project it is running in allowing it to examine the Property - list of the project and access to various methods needed to operate.</P> - <H2>Task Jar Layout</H2> - <P>Tasks are defined within Java Archive files. The name of the JAR - determines the name under which the task is known by in the system. For - example, if a Task JAR is named mvdir.jar, the task is known to the system as - <CODE>"mvdir"</CODE>.</P> - <P><EM>Question: Should we say that tasks belong in a JAR file with the - .tsk extension?</EM></P> - <P>The class within the Jar file that implements the <CODE>org.apache.ant.Task</CODE> interface is - specified by a manifest attribute named <CODE>Ant-Task-Class</CODE> in the Jar manifest. An example - manifest would look like:</P> - <PRE> Manifest-Version: 1.0 - Ant-Task-Class: org.apache.ant.task.javac.JavacTask</PRE> - <P>When the task is used by Ant, a class loader is created that reads - classes from the JAR file. This ensures that there is no chance of namespace - collision in the classes of various task JAR files.</P> - <H2>Installation</H2> - <P>When Ant is installed on a user system, it installs a directory - structure with the following form:</P> - <PRE><installdir>/ant (unix shell script) - /ant.bat - /ant.jar - /ant.properties - /tasks/[task jar files] - /docs/[documentation] - /README</PRE> - <P>Note: Current Jakarta practice is to name the Unix shell script with a - .sh extension. This goes against Unix conventions and is unecessary. Testing - has shown that the leaving the extension off on Unix will not interfere with - the working of the Windows batch file.</P> - <P>Note: The ant.jar file has been moved from the lib/ directory and placed - alongside the shell startup scripts (which have also been moved out of the bin/ - directory). This is because on windows platforms, the .jar file is an - executable file of sorts.</P> - <H3>Ant Properties</H3> - <P>The <CODE>ant.properties</CODE> file contains a list of all the properties that should be - set by default when ant is run. In addition there are a few special properties - that are used directly by ant. An example of these properties in use is:</P> - <PRE> system.taskdir=tasks/ - user.taskdir=anttasks/</PRE> - <P>The <CODE>system.taskdir</CODE> property sets where the system looks for Java ARchive files - containing tasks. If this property defines a relative path, then the path is - taken as relative from the installation directory.</P> - <P>The <CODE>user.taskdir</CODE> property defines where users can locate Java Archive files - containing tasks. If this property defines a realtive path, then the path is - taken as relative from the users home directory (as defined by the <CODE>user.home</CODE> - system property). Task JAR files in this directory take precendence of those in - the system directory.</P> - <P>Note: <EM>It has been suggested to add a properties file hook to the - command line to roll in props. Pending investigation.</EM></P> - <H3>User Preferences</H3> - <P>In addition to the Ant installation directory, an <CODE>ant.properties</CODE> file can be - located in the user's home directory (as found by the system property <CODE>user.home</CODE>) - which can define user preferences such as the location of a user tasks - directory. Properties defined in this file take precidence over those set in - the installation's <CODE>ant.properties</CODE> file. Such a file could look like:</P> - <PRE> user.taskdir=anttasks/ - javac.debug=off</PRE> - <P>Properties starting with <CODE>"system."</CODE> in the user's <CODE>ant.properties</CODE> file are not - allowed and must cause a warning to be thrown.</P> - <H2>Project Configuration</H2> - <P>Ant's Project text file is structured using XML and reflects the - structure of the various components described in the Conceptual Overview.</P> - <P>A sample Project file:</P> - <PRE><project name="projectname" defaulttarget="main" taskdir="tasks/"> - <property name="javac.debug" value="on"/> - <target name="main"> - <taskimpl ...> - ... - </taskimpl> - </target> -</project></PRE> - <H3>The Project Element</H3> - <P>The <CODE>project</CODE> element has the following required attributes:</P> - <UL> - <LI><CODE><STRONG>defaulttarget</STRONG></CODE> defining the default target to be executed if no other target - is specified when Ant is run</LI> - </UL> - <P>It also has the following optional allowed attributes:</P> - <UL> - <LI><CODE><CODE><STRONG>name</STRONG></CODE></CODE> defining a name for this project</LI> - <LI><CODE><STRONG>taskdir</STRONG></CODE> defining a directory in which project specific tasks can be - located. Tasks in this directory take precedence over those in the either the - user taskdir or the installation taskdir.</LI> - </UL> - <P>The following elements are allowed as children of the project - element:</P> - <UL> - <LI><CODE><STRONG>property</STRONG></CODE> defining a property scoped to the project</LI> - <LI><CODE><STRONG>target</STRONG></CODE> defining a target</LI> - </UL> - <H3>The Property Element</H3> - <P>asdf</P> - <H3>The Target Element</H3> - <P>asfd</P> - <H2>Configuration of Tasks</H2> - <P>The Task section of the configuration file is structured as such:</P> - <PRE> <[taskname] [attname=value] [attname=value]...]> - [<[elementname] [attname=value] ...> ... </[elementname]>] - </[taskname]></PRE> - <P>The taskname is used to find the class of the Task. Once the class has - been located and an instance of it created, all of the attributes of the Task - are reflected into the task instance using bean patterns. For example, if a - Task contains an attribute named "directory", the method named - setDirectory would be called with the attribute value cast to the appropriate - type desired by the method. <EM>(What to do if the type isn't a file or a - simple type, look for the class and see if it has a setString method?)</EM></P> - - <P>Text blocks contained by the element are added to task using an addText - method. <EM>Place an example...</EM></P> - <P>For each element contained in the Task definition, an addElementname - method is found on the task. The parameter type of the method defines an object - that will be loaded and instantiated. The attributes of the element are - reflected into the object using bean methods. Any text is set using the addText - method. Any elements are recursed in the same fashion.</P> - <P>Search order of tasks.... project/user/system</P> - <H2>Command Line</H2> - <P>The command line utility provided with Ant must support the following - allowable syntax:</P> - <P><CODE>ant projectfile [prop=value [prop=value...]] [target]</CODE></P> - <P>Internally, the command line shell scripts should call the <CODE>org.apache.ant.Main</CODE> class - with the following arguments:</P> - <PRE>java -Dant.home=installdir org.apache.ant.Main $*</PRE> - <P>or its equivalent on the host platform. Note that the ant installation - directory is a System property. The above syntax results in ant.home being - placed in the System property list.</P> - <P>Note: <EM>On unix, finding the directory of the script that was launched - is relatively easy. However on Windows, I'm not sure the best way of handling - this.</EM></P> - <H2>File Naming Conventions</H2> - <P>File naming in a cross platform tool is tricky. For maximum portability - and understandiblity it is recommended that project files use the following - conventions:</P> - <UL> - <LI>The '/' character is used as a directory seperator</LI> - <LI>The ':' character is used as a path seperator</LI> - <LI>Only relative paths are used</LI> - </UL> - <P>However, to allow for maximum flexibility and to allow project authors - to use conventions that make sense on their native platform, Ant allows for a - representation of file names which has the following rules:</P> - <UL> - <LI>Directories are seperated by the forward slash ('/') or backwards - slash ('\') character.</LI> - <LI>File names starting with either of the above directory seperators are - considered to be absolute paths.</LI> - <LI>On systems that support multiple file roots (e.g. Windows), a file - name that starts with a single alphabetical character followed by a colon (':') - followed by a directory seperator defines an absolute path where the letter - corresponds with a directory root.</LI> - <LI>File names starting with any other character are considered to be - relative paths. In project files, all relative paths are resolved relative to - the directory in which the project file is located.</LI> - </UL> - <P>Absolute paths are not recommended for build files as they reduce the - ability to share a project between u sers or machines.</P> - <P>In situtations where a set of filenames need to be specified, such as - defining a classpath, both the colon (':') andsemicolon (';') are allowable - characters to seperate each filename. The only case that has to be - disambiguated is if a user specifies paths that contain windows style absolute - paths. In this case, the colon is not treated as a path seperator if the - following rules are met:</P> - <UL> - <LI>The character two places before the colon is either of the allowable - path seperators (':' or ';') or if the colon is the second character of the - string.</LI> - <LI>The character immediately before the colon is a alphabetic character - in the range a-z or A-Z.</LI> - <LI>The character immediately after the colon is either of the allowable - directory seperators ('/' or '\').</LI> - </UL> - <H2>Scripting Model</H2> - <P>Sam, I'm leaving this to you. </P> - <H2>Runtime Requirements</H2> - <P>The following requirements are system requirements that Ant should have - in order to run correctly. We should not bundle in any of these into the - distribution of ant.</P> - <UL> - <LI>JDK 1.1 or greater</LI> - <LI>A JAXP compliant parser on the classpath</LI> - </UL> - <P>Note: <EM>When running on JDK 1.2 or greater, the tools.jar isn't on the - classpath by default. There's a few different ways we can take care of this. - One is to put it on the classpath in the execute script (I don't like this - one). Another is to find the location of tools.jar at runtime and put it on the - classpath of class loaders that load in task.jars so that, at least in the - scope of the Tasks, the relevant classes are there. </EM></P> - <P></P> - <P></P> </BODY> -</HTML> |