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authorcoreyg <coreyg@13f79535-47bb-0310-9956-ffa450edef68>2014-11-21 09:30:19 +0000
committercoreyg <coreyg@13f79535-47bb-0310-9956-ffa450edef68>2014-11-21 09:30:19 +0000
commit200a40b332420f94992eb39a6d0ea1cf1490ffc4 (patch)
tree1c76ef1d254c7bfc91128a313d319bd60da9d01e /site/trunk/site-publish/workingwithpaging.html
parent85f53ab6ab4f664d63774c94b672a875c9e52b8a (diff)
Adding tuscany's website to their svn repo for svnpubsub
git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1640879 13f79535-47bb-0310-9956-ffa450edef68
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+
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE- 2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<HTML>
+ <HEAD>
+ <!-- generateKeywords macro -->
+ <META name="description" content="Apache Tuscany">
+ <META name="keywords" content="apache, apache tuscany, tuscany, service, services, fabric, soa, service oriented architecture, sca, service component architecture, das, sdo, csa, ruby, opensource">
+ <!-- generateKeywords macro end -->
+
+ <LINK type="text/css" rel="stylesheet" href="http://tuscany.apache.org/stylesheets/default.css">
+ <LINK rel="SHORTCUT ICON" href="https://cwiki.apache.org/confluence/display/TUSCANY/$images/favicon.ico">
+ <TITLE>Apache Tuscany : WorkingWithPaging</TITLE>
+ <META http-equiv="Content-Type" content="text/html;charset=UTF-8"></HEAD>
+
+ <BODY onload="init()">
+ <!-- topNav macro -->
+ <TABLE valign="top" border="0" cellspacing="0" cellpadding="0" width="100%" background="http://tuscany.apache.org/images/TuscanyLogoNEW_Text_120px_bg.jpg">
+ <TR>
+ <TD valing="top" align="left">
+ <A href="https://cwiki.apache.org/confluence/pages/viewpage.action?spaceKey=TUSCANY&title=$siteroot"><IMG src="http://tuscany.apache.org/images/TuscanyLogoNEW_Text_120px_bg.jpg" height="91" width="25" border="0"></A>
+ </TD>
+ <TD>
+ <A href="http://tuscany.apache.org/"><IMG src="http://tuscany.apache.org/images/TuscanyLogo.jpg" border="0"></A>
+ </TD>
+
+ <TD width="100%">
+ &nbsp;
+ </TD>
+
+ <!-- Adds the edit page link to the top banner-->
+ <TD valign="bottom">
+ <DIV style="padding: 2px 10px; margin: 0px;">
+ <A href="https://cwiki.apache.org/confluence/pages/editpage.action?pageId=52837">
+ <IMG src="http://tuscany.apache.org/images/notep_16.gif" height="16" width="16" border="0" align="absmiddle" title="Edit Page"></A>
+ </DIV>
+ </TD>
+
+ </TR>
+ </TABLE>
+ <!-- topNav macro end -->
+
+ <!-- breadCrumbs macro -->
+ <TABLE border="0" cellpadding="2" cellspacing="0" width="100%">
+ <TR class="topBar">
+ <TD align="left" valign="middle" class="topBarDiv" nowrap="true" width="100%">
+ &nbsp;<A href="home.html" title="Apache Tuscany">Apache Tuscany</A>&nbsp;&gt;&nbsp;<A href="home.html" title="Home">Home</A>&nbsp;&gt;&nbsp;<A href="das-overview.html" title="DAS Overview">DAS Overview</A>&nbsp;&gt;&nbsp;<A href="das-java.html" title="DAS Java">DAS Java</A>&nbsp;&gt;&nbsp;<A href="das-java-documentation-menu.html" title="DAS Java Documentation Menu">DAS Java Documentation Menu</A>&nbsp;&gt;&nbsp;<A href="das-java-developer-guide.html" title="DAS Java Developer Guide">DAS Java Developer Guide</A>&nbsp;&gt;&nbsp;<A href="rdb-das-java.html" title="RDB DAS Java">RDB DAS Java</A>&nbsp;&gt;&nbsp;<A href="rdb-das-user-guide.html" title="RDB DAS - User Guide">RDB DAS - User Guide</A>&nbsp;&gt;&nbsp;<A href="" title="WorkingWithPaging">WorkingWithPaging</A>
+ </TD>
+
+ <TD align="right" valign="middle" class="topBarDiv" align="left" nowrap="true">
+ <A href="http://mail-archives.apache.org/mod_mbox/tuscany-user">User List</A> | <A href="http://mail-archives.apache.org/mod_mbox/tuscany-dev">Dev List</A> | <A href="http://issues.apache.org/jira/browse/Tuscany">Issue Tracker</A>&nbsp;&nbsp;
+ </TD>
+ </TR>
+ </TABLE>
+ <!-- breadCrumbs macro end -->
+
+
+ <TABLE border="0" cellpadding="0" width="100%" bgcolor="#FFFFFF">
+ <TR>
+ <TD align="left" valign="top">
+
+ <!-- pageContent macro -->
+ <DIV id="PageContent">
+
+ <DIV class="pagecontent">
+ <DIV class="wiki-content">
+ <H1><A name="WorkingWithPaging-WorkingWithPaging"></A>WorkingWithPaging</H1>
+<P>The RDB DAS provides a mechanism for working with the result of large queries one chunk (page) at a time. This capability is modeled after the behavior of web search engines. For example, if I Google &quot;RDB DAS&quot; I am presented with a page representing the first ten references. I am also told that there were close to 500,000 matches and I am given the opportunity to go to the next page or directly to pages two through ten. After moving from the first page I am also provided the opportunity to move back to some previous page.</P>
+
+<P>The DAS &quot;Pager&quot; is a wrapper around a provided read command and provides the APIs for paging. Here is the Pager interface:</P>
+<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent">
+<PRE class="code-java">
+<SPAN class="code-keyword">public</SPAN> <SPAN class="code-keyword">interface</SPAN> Pager {
+
+ /**
+ * Get the next page of data
+ */
+ DataObject next();
+
+ /**
+ * Get the page prior to the last page returned
+ */
+ DataObject previous();
+
+ /**
+ * Return a specific identified page.
+ */
+ DataObject getPage(<SPAN class="code-object">int</SPAN> page);
+
+}
+</PRE>
+</DIV></DIV>
+<P>A Pager is instantiated on a given read Command and the constructor is used to specify the desired page size (number of database rows per page). The following example illustrates construction and use of a pager: </P>
+<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent">
+<PRE class="code-java">
+DAS das = DAS.FACTORY.createDAS(getConnection());
+ <SPAN class="code-comment">// Build command to read all customers
+</SPAN> Command custCommand = das.createCommand(<SPAN class="code-quote">&quot;select * from CUSTOMER order by ID&quot;</SPAN>);
+
+ <SPAN class="code-comment">// Create a pager with the command
+</SPAN> Pager pager = <SPAN class="code-keyword">new</SPAN> PagerImpl(custCommand, 2);
+
+ <SPAN class="code-comment">// Get and work with first page
+</SPAN> DataObject root = pager.next();
+ DataObject customer1 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[1]&quot;</SPAN>);
+ DataObject customer2 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[2]&quot;</SPAN>);
+
+ <SPAN class="code-comment">// Get and work with the second page
+</SPAN> root = pager.next();
+ customer1 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[1]&quot;</SPAN>);
+ customer2 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[2]&quot;</SPAN>);
+
+ <SPAN class="code-comment">// First page again
+</SPAN> root = pager.previous();
+ customer1 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[1]&quot;</SPAN>);
+ customer2 = root.getDataObject(<SPAN class="code-quote">&quot;CUSTOMER[2]&quot;</SPAN>);
+</PRE>
+</DIV></DIV>
+<P>The current Pager specification and implementation are very preliminary and will likely change in significant ways&#33; For instance, the pager is intended to work in completely disconnected scenarios so there should be no connection context maintained between invocations of the pager. Currently the Pager references a Command that, in turn, references a connection (oops&#33;). Some work must be done to make the pager lightweight as it will likely be stored in session.</P>
+
+<P>We probably should also create a Factory rather than using the impl constructor. </P>
+ </DIV>
+ </DIV>
+ </DIV>
+ <!-- pageContent macro end -->
+
+ </TD>
+ </TR>
+ </TABLE>
+
+ <!-- footer macro -->
+ <SCRIPT src="http://www.google-analytics.com/urchin.js" type="text/javascript">
+ </SCRIPT>
+ <SCRIPT type="text/javascript">
+ _uacct = "UA-1174707-5";
+ urchinTracker();
+ </SCRIPT>
+
+ <A href="http://www.statcounter.com/" target="_blank"><IMG src="http://c26.statcounter.com/counter.php?sc_project=2619156&java=0&security=94bd7e7d&invisible=0" alt="website stats" border="0"></A>
+
+ <DIV class="footer">
+ Copyright � 2003-2012, The Apache Software Foundation&nbsp;&nbsp;</BR>
+ Apache Tuscany and the Apache Tuscany project logo are trademarks of The Apache Software Foundation.
+ </DIV>
+ <!-- footer macro end -->
+
+ </BODY>
+</HTML>