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| 17 | <html>
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| 18 |
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| 19 | <head>
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| 20 | <meta http-equiv="Content-Language" content="en-us">
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| 21 | <link rel="stylesheet" type="text/css" href="stylesheets/style.css">
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| 22 | <title>Apache Ant User Manual - Introduction</title>
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| 23 | </head>
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| 24 |
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| 25 | <body>
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| 26 | <h1><a name="introduction">Introduction</a></h1>
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| 27 | <p>Apache Ant is a Java-based build tool. In theory, it is kind of like
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| 28 | <i>make</i>, without <i>make</i>'s wrinkles.</p>
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| 29 | <h3>Why?</h3>
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| 30 | <p>Why another build tool when there is already
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| 31 | <i>make</i>,
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| 32 | <i>gnumake</i>,
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| 33 | <i>nmake</i>,
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| 34 | <i>jam</i>,
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| 35 | and
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| 36 | others? Because all those tools have limitations that Ant's original author
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| 37 | couldn't live with when developing software across multiple platforms.
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| 38 | Make-like
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| 39 | tools are inherently shell-based: they evaluate a set of dependencies,
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| 40 | then execute commands not unlike what you would issue on a shell.
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| 41 | This means that you
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| 42 | can easily extend these tools by using or writing any program for the OS that
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| 43 | you are working on; however, this also means that you limit yourself to the OS,
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| 44 | or at least the OS type, such as Unix, that you are working on.</p>
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| 45 | <p>Makefiles are inherently evil as well. Anybody who has worked on them for any
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| 46 | time has run into the dreaded tab problem. "Is my command not executing
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| 47 | because I have a space in front of my tab?!!" said the original author of
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| 48 | Ant way too many times. Tools like Jam took care of this to a great degree, but
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| 49 | still have yet another format to use and remember.</p>
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| 50 | <p>Ant is different. Instead of a model where it is extended with shell-based
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| 51 | commands, Ant is extended using Java classes. Instead of writing shell commands,
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| 52 | the configuration files are XML-based, calling out a target tree where various
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| 53 | tasks get executed. Each task is run by an object that implements a particular
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| 54 | Task interface.</p>
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| 55 | <p>Granted, this removes some of the expressive power that is inherent in being
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| 56 | able to construct a shell command such as
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| 57 | <nobr><code>`find . -name foo -exec rm {}`</code></nobr>, but it
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| 58 | gives you the ability to be cross-platform--to work anywhere and
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| 59 | everywhere. And
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| 60 | hey, if you really need to execute a shell command, Ant has an
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| 61 | <code><exec></code> task that
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| 62 | allows different commands to be executed based on the OS it is executing
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| 63 | on.</p>
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| 64 |
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| 65 |
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| 66 |
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| 67 | </body>
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| 68 | </html>
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| 69 |
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