179 lines
7.3 KiB
HTML
179 lines
7.3 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="en">
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<meta http-equiv="X-UA-Compatible" content="IE=edge">
|
|
<meta name="google-site-verification" content="CPhbjooaiTdROm7Vs4E7kuHZvBfkeLUtonGgcVUbTL8" />
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
<meta name="description" content="">
|
|
<meta name="author" content="">
|
|
<link rel="shortcut icon" href="ico/favicon.ico">
|
|
|
|
<title>Strolch: Policies</title>
|
|
|
|
<!-- Bootstrap core CSS -->
|
|
<link href="css/bootstrap.min.css" rel="stylesheet">
|
|
|
|
<!-- Custom styles for this template -->
|
|
<link href="css/custom.css" rel="stylesheet">
|
|
|
|
<!-- HTML5 shim and Respond.js IE8 support of HTML5 elements and media queries --><!--[if lt IE 9]>
|
|
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
|
|
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script><![endif]-->
|
|
</head>
|
|
<body>
|
|
<div class="navbar navbar-inverse navbar-fixed-top" role="navigation">
|
|
<div class="container">
|
|
<div class="navbar-header">
|
|
<a class="navbar-brand" href="index.html">Strolch</a>
|
|
</div>
|
|
<div class="collapse navbar-collapse">
|
|
<ul class="nav navbar-nav">
|
|
<li><a href="index.html">Overview</a></li>
|
|
<li><a href="api.html">API</a></li>
|
|
<li class="active"><a href="documentation.html">Documentation</a></li>
|
|
<li><a href="tutorial.html">Tutorial</a></li>
|
|
<li><a href="downloads.html">Downloads</a></li>
|
|
<li><a href="development.html">Development</a></li>
|
|
<li><a href="blog.html">Blog</a></li>
|
|
</ul>
|
|
</div>
|
|
<!--/.nav-collapse -->
|
|
</div>
|
|
</div>
|
|
|
|
<div class="container">
|
|
|
|
<div class="page-header">
|
|
<h1 class="page-title">Documentation: Policies</h1>
|
|
|
|
<p class="lead page-description">This page discusses the Strolch policies</p>
|
|
</div>
|
|
|
|
<div class="content">
|
|
|
|
<p>Policies are an integral part when writing business logic in Strolch. In many cases it would suffice to write
|
|
all such logic in <code>Services</code> and <code>Commands</code>, but as soon as behaviour can change,
|
|
depending on the element being accessed, then this would quickly lead to many if/else blocks.</p>
|
|
|
|
<p>Since writing large if/else blocks is not maintanable in the long run, Strolch offers a different approach.
|
|
All Strolch elements can store Policy definitions. This is a simple key/value store where the key defines the
|
|
type of policy, and the value references the policy to use.</p>
|
|
|
|
<p>Currently there are two ways to reference a policy in Strolch, either via a key which defines a further
|
|
lookup in the <code>PolicyHandler</code>, or directly as the name of the class to instantiate.</p>
|
|
|
|
<p>Using policies in Strolch gives the additional possibility of easily changing the behaviour at runtime, as a
|
|
Service and/or Command would delegate the behaviour to the currently configured policy on the releveant
|
|
element.</p>
|
|
|
|
<p>Policies are implemented by defining an abstract class and extends <code>StrolchPolicy</code>. This abstract
|
|
class then defines the API of the actual policy. A concrete class then extends this abstract class and
|
|
implements the concrete methods.</p>
|
|
|
|
<p>Policies are registered on Resources, Orders, Activities and Actions. The following shows defining two
|
|
policies on a Resource, a PlanningPolicy, an ExecutionPolicy in XML:</p>
|
|
<pre>
|
|
<Resource ...>
|
|
...
|
|
<Policies>
|
|
<Policy Type="PlanningPolicy" Value="key:SimplePlanning" />
|
|
<Policy Type="ExecutionPolicy" Value="java:li.strolch.policytest.TestSimulatedExecutionPolicy" />
|
|
</Policies>
|
|
</Resource></pre>
|
|
|
|
<p><b>Note</b> how the PlanningPolicy has a value of <code>key:SimplePlanning</code> and the ExecutionPolicy
|
|
defines a reference to an actual class.</p>
|
|
|
|
<br />
|
|
<p>To use the PolicyHandler, it must be configured in the StrolchConfiguration.xml as follows:</p>
|
|
<pre>
|
|
<Component>
|
|
<name>PolicyHandler</name>
|
|
<api>li.strolch.policy.PolicyHandler</api>
|
|
<impl>li.strolch.policy.DefaultPolicyHandler</impl>
|
|
<Properties>
|
|
<readPolicyFile>true</readPolicyFile>
|
|
<policyConfigFile>StrolchPolicies.xml</policyConfigFile>
|
|
</Properties>
|
|
</Component></pre>
|
|
|
|
<br />
|
|
<p>And this policy handler implementation requires a file where the lookups for the policies is defined,
|
|
e.g.:</p>
|
|
<pre>
|
|
<StrolchPolicies>
|
|
|
|
<PolicyType Type="PlanningPolicy" Api="li.strolch.policytest.TestPlanningPolicy">
|
|
<Policy Key="SimplePlanning" Class="li.strolch.policytest.TestSimplePlanningPolicy" />
|
|
</PolicyType>
|
|
|
|
<PolicyType Type="ConfirmationPolicy" Api="li.strolch.policytest.TestConfirmationPolicy">
|
|
<Policy Key="NoConfirmation" Class="li.strolch.policytest.TestNoConfirmationPolicy" />
|
|
</PolicyType>
|
|
|
|
</StrolchPolicies></pre>
|
|
|
|
<br />
|
|
<p>Now at runtime we can access the policies:</p>
|
|
<pre>
|
|
PolicyHandler policyHandler = getComponent(PolicyHandler.class);
|
|
|
|
try (StrolchTransaction tx = openTx()) {
|
|
|
|
Resource res = tx.getResourceBy("TestType", "MyTestResource");
|
|
PolicyDefs policyDefs = res.getPolicyDefs();
|
|
|
|
PolicyDef planningPolicyDef = policyDefs.getPolicyDef("PlanningPolicy");
|
|
PlanningPolicy planningPolicy = policyHandler.getPolicy(planningPolicyDef, tx);
|
|
planningPolicy.plan(...);
|
|
|
|
PolicyDef executionPolicyDef = res.getPolicyDefs().getPolicyDef("ExecutionPolicy");
|
|
ExecutionPolicy executionPolicy = policyHandler.getPolicy(executionPolicyDef, tx);
|
|
executionPolicy.execute(...);
|
|
}</pre>
|
|
|
|
|
|
<!-- content here -->
|
|
|
|
</div>
|
|
<!-- /.content -->
|
|
|
|
<div id="footer">
|
|
<div class="container">
|
|
<p class="text-muted">© Strolch / <a href="mailto:eitch@eitchnet.ch">Robert von Burg</a> / Hosting by
|
|
<a href="http://www.eitchnet.ch">eitchnet.ch</a></p>
|
|
</div>
|
|
</div>
|
|
|
|
</div>
|
|
<!-- /.container -->
|
|
|
|
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
|
|
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
|
|
<!-- Include all compiled plugins (below), or include individual xsd as needed -->
|
|
<script src="js/bootstrap.min.js"></script>
|
|
|
|
<!-- Piwik -->
|
|
<script type="text/javascript">
|
|
var _paq = _paq || [];
|
|
_paq.push(['trackPageView']);
|
|
_paq.push(['enableLinkTracking']);
|
|
(function () {
|
|
var u = (("https:" == document.location.protocol) ? "https" : "http") + "://piwik.eitchnet.ch/";
|
|
_paq.push(['setTrackerUrl', u + 'piwik.php']);
|
|
_paq.push(['setSiteId', 2]);
|
|
var d = document, g = d.createElement('script'), s = d.getElementsByTagName('script')[0];
|
|
g.type = 'text/javascript';
|
|
g.defer = true;
|
|
g.async = true;
|
|
g.src = u + 'piwik.js';
|
|
s.parentNode.insertBefore(g, s);
|
|
})();
|
|
</script>
|
|
<noscript><p><img src="http://piwik.eitchnet.ch/piwik.php?idsite=2" style="border:0;" alt="" /></p></noscript>
|
|
<!-- End Piwik Code -->
|
|
|
|
</body>
|
|
</html>
|