doc/org.eclipse.ocl.doc/help/GettingStarted.html - ocl/org.eclipse.ocl - Git at Google

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 <h1 xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0">Getting Started</h1>
 <div class="section" title="Getting Started">
 <div class="titlepage">
 <div>
 <div>
 <h2 class="title" style="clear: both">
 <a name="GettingStarted"></a>Getting Started</h2>
 </div>
 </div>
 </div>
 <p>For a very quick demonstration of OCL, you may follow this very abbreviated version of the
 				<a class="link" href="Tutorials.html#OCLinEcoreTutorial" title="OCLinEcore tutorial">OCLinEcore tutorial</a>, where you can find
 				<a class="link" href="Installation.html" title="Installing the Eclipse OCL Examples and Editors">Installation</a> instructions. Once you have the OCL Examples and Editors feature installed you may follow these instructions to get an insight into the capabilities of OCL and the Eclipse OCL tooling.
 			</p>
 <p>Invoke
 				<span class="bold"><strong>File-&gt;New-&gt;Project...</strong></span> then select
 				<span class="bold"><strong>Examples</strong></span> then
 				<span class="bold"><strong>OCL (Object Constraint Language) Plugins</strong></span> then
 				<span class="bold"><strong>OCLinEcore Tutorial</strong></span> and
 				<span class="bold"><strong>Finish</strong></span> to create a small example project called
 				<span class="bold"><strong>org.eclipse.ocl.examples.project.oclinecoretutorial</strong></span>. It contains
 			</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="disc">
 <li class="listitem">
 <p>

 <span class="bold"><strong>model/Tutorial.ecore</strong></span> - a small Library meta-model
 					</p>
 </li>
 <li class="listitem">
 <p>

 <span class="bold"><strong>model/Tutorial.xmi</strong></span> - an even smaller Library model
 					</p>
 </li>
 <li class="listitem">
 <p>

 <span class="bold"><strong>model/Tutorial.genmodel</strong></span> - a gebnerator for Java code
 					</p>
 </li>
 </ul>
 </div>
 <p>Select
 				<span class="bold"><strong>model/Tutorial.ecore</strong></span> and use the right button to invoke
 				<span class="bold"><strong>Open With-&gt;OCLinEcore Editor</strong></span>. This gives you a textual view of the Ecore file with embedded OCL invariants such as the Book constraint
 			</p>
 <div class="literallayout">
 <p>
 <code class="code">invariant&nbsp;SufficientCopies:<br>
 &nbsp;&nbsp;library.loans-&gt;select((book&nbsp;=&nbsp;self))-&gt;size()&nbsp;&lt;=&nbsp;copies;<br>

 </code>
 </p>
 </div>
 <p></p>
 <p>This invariant is named SufficientCopies. It </p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="disc">
 <li class="listitem">
 <p>navigates from the implicit self (a Book)</p>
 </li>
 <li class="listitem">
 <p>via the library </p>
 </li>
 <li class="listitem">
 <p>to its loans which it searches</p>
 </li>
 <li class="listitem">
 <p>to select those loans that satisfy the predicate</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="circle">
 <li class="listitem">
 <p>loaned book is equal to the self Book</p>
 </li>
 </ul>
 </div>
 </li>
 <li class="listitem">
 <p>the size (number) of loans is computed</p>
 </li>
 <li class="listitem">
 <p>and compared to the number of copies of the self Book</p>
 </li>
 </ul>
 </div>
 <p>The invariant is satisfied if it evaluates true; i.e. if the number of loans is less than or equal to the number of copies.</p>
 <p>You can see this invariant at work, by selecting
 				<span class="bold"><strong>model/Tutorial.xmi</strong></span> and using the right button to invoke
 				<span class="bold"><strong>Open With-&gt;Sample Reflective Ecore Model Editor</strong></span>. This gives you a tree view of a small library model.
 			</p>
 <p>Expand the root element and then select the
 				<span class="bold"><strong>Library lib</strong></span> element and use the right button menu to invoke
 				<span class="bold"><strong>Validate</strong></span>. You should get a pop-up reporting problems during Validation. Click
 				<span class="bold"><strong>Details</strong></span> and you will see that one of the problems is with the
 				<span class="bold"><strong>SufficientCopies</strong></span> invariant we have just looked at. If you browse the Properties View for
 				<span class="bold"><strong>model/Tutorial.xmi</strong></span>, you can verify that there are three loans but only two copies for the offending Book.
 			</p>
 <p>You may evaluate custom OCL queries interactively. From the editor for
 				<span class="bold"><strong>Tutorial.xmi</strong></span>, invoke
 				<span class="bold"><strong>OCL-&gt;Show Xtext OCL Console</strong></span> from the context menu. Select
 				<span class="bold"><strong>Book b2</strong></span> in the editor, then in the bottom line of the console enter the OCL expression
 				<span class="bold"><strong>loans.member</strong></span> and then Enter. The results are shown in the panel and identify that all three loans are by
 				<span class="bold"><strong>Member m3</strong></span>.
 			</p>
 <p>The expression
 				<span class="bold"><strong>loans.member</strong></span> is an abbreviated form of
 				<span class="bold"><strong>self.loans-&gt;collect(aLoan : Loan | aLoan.member)</strong></span> and demonstrates OCL&rsquo;s ability to perform many useful navigations over multi-element properties. The expression
 			</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="disc">
 <li class="listitem">
 <p>navigates from self, the Book b2 selection</p>
 </li>
 <li class="listitem">
 <p>to its loans, using Book::loans which is a derived property defined in OCL</p>
 </li>
 <li class="listitem">
 <p>for each of the loans, the iterator variable, aLoan, is assigned to the loan and</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="circle">
 <li class="listitem">
 <p>the body, aLoan.member is evaluated to return the member making the loan</p>
 </li>
 </ul>
 </div>
 </li>
 <li class="listitem">
 <p>the resulting members are collected to return a collection result</p>
 </li>
 <li class="listitem">
 <p>the result is displayed on three lines in the results panel</p>
 </li>
 </ul>
 </div>
 <p>You can step through execution using the OCL debugger. In the Console View type PageUp to restore the earlier text entry, then with
 				<span class="bold"><strong>Book b2</strong></span> still selected in the editor, click the debug icon in the Console tool bar. The debugger should open automatically, but if it doesn&rsquo;t, use
 				<span class="bold"><strong>Window-&gt;Show View-&gt;Debug</strong></span> from the Eclipse menu bar. The Variables View shows model elemnt values. Click F5 or Step Into a few times to progress execution.
 			</p>
 <p>You have now seen</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="disc">
 <li class="listitem">
 <p>an Xtext editor that embeds OCL directly in Ecore models to provide programmed enrichment</p>
 </li>
 <li class="listitem">
 <p>execution of OCL while validating a model using conventional Ecore tooling</p>
 </li>
 <li class="listitem">
 <p>an interactive Console for custom OCL evaluations</p>
 </li>
 <li class="listitem">
 <p>execution of a derived property defined in OCL</p>
 </li>
 <li class="listitem">
 <p>the ability of OCL to express operations on multi-elements compactly</p>
 </li>
 <li class="listitem">
 <p>the ability to debug OCL execution and browse data</p>
 </li>
 </ul>
 </div>
 <p>You have not</p>
 <div class="itemizedlist">
 <ul class="itemizedlist" type="disc">
 <li class="listitem">
 <p>written any Java code</p>
 </li>
 <li class="listitem">
 <p>generated any plugins</p>
 </li>
 <li class="listitem">
 <p>needed to start an additional Eclipse session</p>
 </li>
 </ul>
 </div>
 <p>Please follow the tutorials, examples and reference material for further information.</p>
 </div>
 </body>
 </html>
	<html>
	<head>
	<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
	<title>Getting Started</title>
	<link href="book.css" rel="stylesheet" type="text/css">
	<meta content="DocBook XSL Stylesheets V1.75.1" name="generator">
	<link rel="home" href="index.html" title="OCL Documentation">
	<link rel="up" href="OverviewandGettingStarted.html" title="Overview and Getting Started">
	<link rel="prev" href="WhoisBehindEclipseOCL.html" title="Who is Behind Eclipse OCL?">
	<link rel="next" href="UsersGuide.html" title="Users Guide">
	</head>
	<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
	<h1 xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0">Getting Started</h1>
	<div class="section" title="Getting Started">
	<div class="titlepage">
	<div>
	<div>
	<h2 class="title" style="clear: both">
	<a name="GettingStarted"></a>Getting Started</h2>
	</div>
	</div>
	</div>
	<p>For a very quick demonstration of OCL, you may follow this very abbreviated version of the
	<a class="link" href="Tutorials.html#OCLinEcoreTutorial" title="OCLinEcore tutorial">OCLinEcore tutorial</a>, where you can find
	<a class="link" href="Installation.html" title="Installing the Eclipse OCL Examples and Editors">Installation</a> instructions. Once you have the OCL Examples and Editors feature installed you may follow these instructions to get an insight into the capabilities of OCL and the Eclipse OCL tooling.
	</p>
	<p>Invoke
	<span class="bold"><strong>File->New->Project...</strong></span> then select
	<span class="bold"><strong>Examples</strong></span> then
	<span class="bold"><strong>OCL (Object Constraint Language) Plugins</strong></span> then
	<span class="bold"><strong>OCLinEcore Tutorial</strong></span> and
	<span class="bold"><strong>Finish</strong></span> to create a small example project called
	<span class="bold"><strong>org.eclipse.ocl.examples.project.oclinecoretutorial</strong></span>. It contains
	</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="disc">
	<li class="listitem">
	<p>

	<span class="bold"><strong>model/Tutorial.ecore</strong></span> - a small Library meta-model
	</p>
	</li>
	<li class="listitem">
	<p>

	<span class="bold"><strong>model/Tutorial.xmi</strong></span> - an even smaller Library model
	</p>
	</li>
	<li class="listitem">
	<p>

	<span class="bold"><strong>model/Tutorial.genmodel</strong></span> - a gebnerator for Java code
	</p>
	</li>
	</ul>
	</div>
	<p>Select
	<span class="bold"><strong>model/Tutorial.ecore</strong></span> and use the right button to invoke
	<span class="bold"><strong>Open With->OCLinEcore Editor</strong></span>. This gives you a textual view of the Ecore file with embedded OCL invariants such as the Book constraint
	</p>
	<div class="literallayout">
	<p>
	<code class="code">invariant SufficientCopies:<br>
	library.loans->select((book = self))->size() <= copies;<br>

	</code>
	</p>
	</div>
	<p></p>
	<p>This invariant is named SufficientCopies. It </p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="disc">
	<li class="listitem">
	<p>navigates from the implicit self (a Book)</p>
	</li>
	<li class="listitem">
	<p>via the library </p>
	</li>
	<li class="listitem">
	<p>to its loans which it searches</p>
	</li>
	<li class="listitem">
	<p>to select those loans that satisfy the predicate</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="circle">
	<li class="listitem">
	<p>loaned book is equal to the self Book</p>
	</li>
	</ul>
	</div>
	</li>
	<li class="listitem">
	<p>the size (number) of loans is computed</p>
	</li>
	<li class="listitem">
	<p>and compared to the number of copies of the self Book</p>
	</li>
	</ul>
	</div>
	<p>The invariant is satisfied if it evaluates true; i.e. if the number of loans is less than or equal to the number of copies.</p>
	<p>You can see this invariant at work, by selecting
	<span class="bold"><strong>model/Tutorial.xmi</strong></span> and using the right button to invoke
	<span class="bold"><strong>Open With->Sample Reflective Ecore Model Editor</strong></span>. This gives you a tree view of a small library model.
	</p>
	<p>Expand the root element and then select the
	<span class="bold"><strong>Library lib</strong></span> element and use the right button menu to invoke
	<span class="bold"><strong>Validate</strong></span>. You should get a pop-up reporting problems during Validation. Click
	<span class="bold"><strong>Details</strong></span> and you will see that one of the problems is with the
	<span class="bold"><strong>SufficientCopies</strong></span> invariant we have just looked at. If you browse the Properties View for
	<span class="bold"><strong>model/Tutorial.xmi</strong></span>, you can verify that there are three loans but only two copies for the offending Book.
	</p>
	<p>You may evaluate custom OCL queries interactively. From the editor for
	<span class="bold"><strong>Tutorial.xmi</strong></span>, invoke
	<span class="bold"><strong>OCL->Show Xtext OCL Console</strong></span> from the context menu. Select
	<span class="bold"><strong>Book b2</strong></span> in the editor, then in the bottom line of the console enter the OCL expression
	<span class="bold"><strong>loans.member</strong></span> and then Enter. The results are shown in the panel and identify that all three loans are by
	<span class="bold"><strong>Member m3</strong></span>.
	</p>
	<p>The expression
	<span class="bold"><strong>loans.member</strong></span> is an abbreviated form of
	<span class="bold"><strong>self.loans->collect(aLoan : Loan \| aLoan.member)</strong></span> and demonstrates OCL’s ability to perform many useful navigations over multi-element properties. The expression
	</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="disc">
	<li class="listitem">
	<p>navigates from self, the Book b2 selection</p>
	</li>
	<li class="listitem">
	<p>to its loans, using Book::loans which is a derived property defined in OCL</p>
	</li>
	<li class="listitem">
	<p>for each of the loans, the iterator variable, aLoan, is assigned to the loan and</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="circle">
	<li class="listitem">
	<p>the body, aLoan.member is evaluated to return the member making the loan</p>
	</li>
	</ul>
	</div>
	</li>
	<li class="listitem">
	<p>the resulting members are collected to return a collection result</p>
	</li>
	<li class="listitem">
	<p>the result is displayed on three lines in the results panel</p>
	</li>
	</ul>
	</div>
	<p>You can step through execution using the OCL debugger. In the Console View type PageUp to restore the earlier text entry, then with
	<span class="bold"><strong>Book b2</strong></span> still selected in the editor, click the debug icon in the Console tool bar. The debugger should open automatically, but if it doesn’t, use
	<span class="bold"><strong>Window->Show View->Debug</strong></span> from the Eclipse menu bar. The Variables View shows model elemnt values. Click F5 or Step Into a few times to progress execution.
	</p>
	<p>You have now seen</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="disc">
	<li class="listitem">
	<p>an Xtext editor that embeds OCL directly in Ecore models to provide programmed enrichment</p>
	</li>
	<li class="listitem">
	<p>execution of OCL while validating a model using conventional Ecore tooling</p>
	</li>
	<li class="listitem">
	<p>an interactive Console for custom OCL evaluations</p>
	</li>
	<li class="listitem">
	<p>execution of a derived property defined in OCL</p>
	</li>
	<li class="listitem">
	<p>the ability of OCL to express operations on multi-elements compactly</p>
	</li>
	<li class="listitem">
	<p>the ability to debug OCL execution and browse data</p>
	</li>
	</ul>
	</div>
	<p>You have not</p>
	<div class="itemizedlist">
	<ul class="itemizedlist" type="disc">
	<li class="listitem">
	<p>written any Java code</p>
	</li>
	<li class="listitem">
	<p>generated any plugins</p>
	</li>
	<li class="listitem">
	<p>needed to start an additional Eclipse session</p>
	</li>
	</ul>
	</div>
	<p>Please follow the tutorials, examples and reference material for further information.</p>
	</div>
	</body>
	</html>