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Annotated docs/resource-creation.html

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2005-11-15 paulb file changeset files shortlog [project @ 2005-11-15 15:46:01 by paulb] Added has_key method.
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type" />
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  <title>How Resources are Created</title>
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  <meta name="generator"
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 content="amaya 8.1a, see http://www.w3.org/Amaya/" />
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  <link href="styles.css" rel="stylesheet" type="text/css" />
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</head>
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<body>
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<h1>How Resources are Created
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</h1>
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<p>In the&nbsp;<code>MyApplication</code>
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<a href="resources.html">example</a> (and in many applications),
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the only
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thing we need to
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consider is
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what our code does, not how&nbsp;objects are created from the <code>MyResource</code>
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class and how the <code>respond</code>
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method is invoked. However, the mechanisms behind all these things are
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not magic - the&nbsp;<a href="deploying.html">adapter
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code</a> is responsible for all of
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this. Let us
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turn the diagram of components on its side and investigate what happens
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when a request is sent to the application from a user:</p>
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<table class="layers"
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 style="width: 80%; text-align: left; margin-left: auto; margin-right: auto;"
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 border="0" cellpadding="5" cellspacing="0">
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  <tbody>
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    <tr>
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      <th
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 style="border-width: 1px 1px 0px; text-align: center; vertical-align: middle; background-color: rgb(192, 192, 192); width: 30%; border-top-style: solid; border-left-style: solid;">Server
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environment</th>
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      <th
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 style="border-width: 1px; text-align: center; vertical-align: middle; border-left-style: solid; border-top-style: solid; width: 30%; background-color: rgb(102, 203, 255);">Adapter
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      </th>
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      <th
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 style="text-align: center; vertical-align: middle; border-top-style: solid; border-left-style: solid; border-right-style: solid; border-top-width: 1px; border-left-width: 1px; border-right-width: 1px; background-color: rgb(193, 255, 102); width: 40%;">Application
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      </th>
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    </tr>
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    <tr>
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      <td
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 style="background-color: rgb(192, 192, 192); border-left-style: solid; border-left-width: 1px;"
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 align="undefined" valign="undefined"><span class="method">The request
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is received and sent to
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the adapter... </span></td>
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      <td
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 style="background-color: rgb(102, 203, 255); border-left-style: solid; border-left-width: 1px;"
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 align="undefined" valign="undefined"><span class="method">The adapter
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creates a resource object
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in the application... </span></td>
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      <td
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 style="background-color: rgb(193, 255, 102); border-left-style: solid; border-right-style: solid; border-left-width: 1px; border-right-width: 1px;"
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 align="undefined" valign="undefined"><span class="method">A&nbsp;resource
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object is
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created and initialised. </span></td>
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    </tr>
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    <tr>
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      <td
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 style="background-color: rgb(192, 192, 192); border-left-style: solid; border-bottom-style: solid; border-left-width: 1px; border-right-width: 1px; border-bottom-width: 1px;"><br />
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      </td>
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      <td
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 style="background-color: rgb(102, 203, 255); border-left-style: solid; border-bottom-style: solid; border-left-width: 1px; border-bottom-width: 1px;"
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 align="undefined" valign="undefined"><span class="method">The adapter
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calls the <code>respond</code> method on the new resource...</span></td>
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      <td
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 style="background-color: rgb(193, 255, 102); border-left-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-width: 1px; border-right-width: 1px; border-bottom-width: 1px;"
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 align="undefined" valign="undefined"><span class="method">The code
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within the resource's <code>respond</code> method is executed. </span></td>
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    </tr>
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  </tbody>
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</table>
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<h2>The Role of the Adapter</h2>
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<p>So it is the responsibility of the adapter to create at least one
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resource object so that the application code may be executed when a
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request is received from a user. This is described in the <a
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 href="deploying.html">deployment documentation</a>.</p>
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<h2>Creating Many Resources</h2>
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<p>In more
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complicated applications, there may
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be a
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need to create a number of&nbsp;resource objects and possibly to do so
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dynamically within an application itself, but this is not usually
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interesting or relevant to think about when writing your first
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application - see <a href="paths-filesystem.html">"Treating the Path
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Like
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a Filesystem"</a> for a
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discussion of creating new resource objects both in the adapter code
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and dynamically within applications.</p>
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</body>
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</html>