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| <td width="100%"><h1>Understanding the Architecture of a Client Application</h1></td> |
| <td align="right" valign="middle" nowrap><a href="index.html" title="Backward to Developing Client Applications"><img src="../../../images/backward.png" border="0"></a> <a href="Doc02_PreparingModels.html" title="Forward to Preparing EMF Models for CDO"><img src="../../../images/forward.png" border="0"></a></td> |
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| <p class="author">Author: Eike Stepper</p> |
| <p> |
| The architecture of a CDO application is characterized by its mandatory dependency on EMF, the Eclipse Modeling |
| Framework. Most of the time an application interacts with the object graph of the model through standard EMF APIs |
| because CDO model graph objects are <a href="http://download.eclipse.org/modeling/emf/emf/javadoc/2.11/org/eclipse/emf/ecore/EObject.html" target="_blank" title="Interface in org.eclipse.emf.ecore"><code>EObjects</code></a>. While CDO's basic functionality integrates nicely and |
| transparently with EMF's extension mechanisms some of the more advanced functions may require to add direct |
| dependencies on CDO to your application code. |
| <p> |
| The following diagram illustrates the major building blocks of a CDO application: <p align="center"><img src="application-architecture.png"> |
| |
| |
| <h2><a name="OSGi"></a>1 OSGi</h2> |
| <p> |
| All components of CDO are implemented as <a href="http://www.osgi.org">OSGi</a> bundles. The core components of |
| both clients and servers do not require OSGi to actually run to be functional, they can perfectly be operated |
| stand-alone. If OSGi is running the setup and configuration of some CDO facilities is a little simpler than in |
| stand-alone mode because the needed <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/factory/IFactory.html" title="Interface in org.eclipse.net4j.util.factory"><code>factories</code></a> get automatically registered with the central |
| <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/container/IPluginContainer.html" title="Interface in org.eclipse.net4j.util.container"><code>wiring container</code></a>. |
| <p> |
| CDO utilizes an <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/om/OMPlatform.html" title="Interface in org.eclipse.net4j.util.om"><code>operations and maintenance</code></a> framework to abstract common platform services such |
| as <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/om/log/OMLogger.html" title="Interface in org.eclipse.net4j.util.om.log"><code>logging</code></a>, <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/om/trace/OMTracer.html" title="Interface in org.eclipse.net4j.util.om.trace"><code>tracing</code></a>, <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/om/monitor/OMMonitor.html" title="Interface in org.eclipse.net4j.util.om.monitor"><code>monitoring</code></a> and <a href="../../../../org.eclipse.net4j.util.doc/javadoc/org/eclipse/net4j/util/om/pref/OMPreference.html" title="Interface in org.eclipse.net4j.util.om.pref"><code>configuration</code></a>. Without the need to depend on additional external libraries these services integrate seamlessly |
| with OSGi, if available at runtime, or emulate similar functionality if running stand-alone. |
| |
| <h2><a name="EMF"></a>2 EMF</h2> |
| <p> |
| The <a href="http://www.eclipse.org/modeling/emf">Eclipse Modeling Framework</a> is a modeling framework and code |
| generation facility for building tools and other applications based on a structured data model. From a model |
| specification described in XMI, EMF provides tools and runtime support to produce a set of Java classes for the model, |
| along with a set of adapter classes that enable viewing and command-based editing of the model, and a basic editor. |
| |
| <h2><a name="Client"></a>3 CDO Client</h2> |
| <p> |
| The CDO client enables an application to open one or more <a href="../../../javadoc/org/eclipse/emf/cdo/session/CDOSession.html" title="Interface in org.eclipse.emf.cdo.session"><code>sessions</code></a>. Each session represents |
| a connection to a <a href="../../../javadoc/org/eclipse/emf/cdo/server/IRepository.html" title="Interface in org.eclipse.emf.cdo.server"><code>repository</code></a> and provides a broad API to interact with it. A session does <b>not</b> |
| provide direct access to model <i>instances</i>; <a href="../../../javadoc/org/eclipse/emf/cdo/view/CDOView.html" title="Interface in org.eclipse.emf.cdo.view"><code>views</code></a> or <a href="../../../javadoc/org/eclipse/emf/cdo/transaction/CDOTransaction.html" title="Interface in org.eclipse.emf.cdo.transaction"><code>transactions</code></a> are needed |
| to navigate or modify the model instance graph. |
| <p> |
| A session consists of several generic (network and storage independent) <b>components</b>, such as: |
| <p> |
| <ul> |
| <li>a <a href="../../../javadoc/org/eclipse/emf/cdo/common/revision/CDORevision.html" title="Interface in org.eclipse.emf.cdo.common.revision"><code>revision</code></a> <a href="../../../javadoc/org/eclipse/emf/cdo/common/revision/CDORevisionManager.html" title="Interface in org.eclipse.emf.cdo.common.revision"><code>manager</code></a> and <a href="../../../javadoc/org/eclipse/emf/cdo/common/revision/CDORevisionCache.html" title="Interface in org.eclipse.emf.cdo.common.revision"><code>cache</code></a>, |
| <li>a <a href="../../../javadoc/org/eclipse/emf/cdo/common/branch/CDOBranch.html" title="Interface in org.eclipse.emf.cdo.common.branch"><code>branch</code></a> <a href="../../../javadoc/org/eclipse/emf/cdo/common/branch/CDOBranchManager.html" title="Interface in org.eclipse.emf.cdo.common.branch"><code>manager</code></a>, |
| <li>a <a href="http://download.eclipse.org/modeling/emf/emf/javadoc/2.11/org/eclipse/emf/ecore/EPackage.html" target="_blank" title="Interface in org.eclipse.emf.ecore"><code>package</code></a> <a href="../../../javadoc/org/eclipse/emf/cdo/common/model/CDOPackageRegistry.html" title="Interface in org.eclipse.emf.cdo.common.model"><code>registry</code></a>, |
| <li>a <a href="../../../javadoc/org/eclipse/emf/cdo/common/commit/CDOCommitInfo.html" title="Interface in org.eclipse.emf.cdo.common.commit"><code>commit info</code></a> <a href="../../../javadoc/org/eclipse/emf/cdo/common/commit/CDOCommitInfoManager.html" title="Interface in org.eclipse.emf.cdo.common.commit"><code>manager</code></a>, |
| </ul> |
| <p> |
| All <b>communication aspects</b> (the sending/receiving of signals to/from a network system) are fully abstracted |
| through the service provider interface (SPI) <a href="../../../javadoc/org/eclipse/emf/spi/cdo/CDOSessionProtocol.html" title="Interface in org.eclipse.emf.spi.cdo"><code>CDOSessionProtocol</code></a>. Concrete implementations are fully separated |
| and can be plugged into the core as described in <a href="Doc01_Architecture.html#Protocol" title="Chapter in CDO Model Repository Documentation">Protocol</a>.<p><b>See Also:</b></p> |
| <ul> |
| <li><a href="Doc01_Architecture.html#EMF" title="Chapter in CDO Model Repository Documentation">EMF</a></li> |
| <li><a href="Doc01_Architecture.html#Models" title="Chapter in CDO Model Repository Documentation">Models</a></li> |
| </ul> |
| |
| |
| <h2><a name="Net4j"></a>4 Net4j Core</h2> |
| <p> |
| The <i>Net4j Signalling Platform</i> is an extensible client/server communications framework. Net4j eases the |
| development of fast and maintainable application <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/signal/ISignalProtocol.html" title="Interface in org.eclipse.net4j.signal"><code>protocols</code></a> that are independent of the |
| physical <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/connector/IConnector.html" title="Interface in org.eclipse.net4j.connector"><code>transport</code></a> medium. Transport protocols are pluggable and Net4j ships with support for |
| <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/tcp/ITCPConnector.html" title="Interface in org.eclipse.net4j.tcp"><code>TCP</code></a>, <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/tcp/ssl/SSLUtil.html" title="Class in org.eclipse.net4j.tcp.ssl"><code>SSL</code></a>, <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/http/common/IHTTPConnector.html" title="Interface in org.eclipse.net4j.http.common"><code>HTTP</code></a> and <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/jvm/IJVMConnector.html" title="Interface in org.eclipse.net4j.jvm"><code>JVM</code></a> |
| (in-process) transport. The core of Net4j is a fast, asynchronous and non-blocking <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/buffer/IBuffer.html" title="Interface in org.eclipse.net4j.buffer"><code>buffer</code></a> |
| multiplexing kernel, based on <a href="Doc01_Architecture.html#OSGi" title="Chapter in CDO Model Repository Documentation">OSGi</a> but also executable stand-alone.<p><b>See Also:</b></p> |
| <ul> |
| <li><a href="Doc01_Architecture.html#Transport" title="Chapter in CDO Model Repository Documentation">Transport</a></li> |
| <li><a href="Doc01_Architecture.html#Protocol" title="Chapter in CDO Model Repository Documentation">Protocol</a></li> |
| </ul> |
| |
| |
| <h2><a name="Models"></a>5 Models</h2> |
| <p> |
| The models, usually in the form of interfaces that are generated by <a href="Doc01_Architecture.html#EMF" title="Chapter in CDO Model Repository Documentation">EMF</a>, represent the business knowledge |
| in an application. They define the structure (and, mostly irrelevant for CDO, the behavior) of the business entities |
| and they're used by the generic <a href="Doc01_Architecture.html#Client" title="Chapter in CDO Model Repository Documentation">CDO client</a> to manage, e.g., load, commit, query, the business data. |
| <p> |
| CDO can transparently support <i>scalable</i> models such that arbitrary, single <a href="../../../javadoc/org/eclipse/emf/cdo/CDOObject.html" title="Interface in org.eclipse.emf.cdo"><code>objects</code></a> are loaded |
| on demand and automatically unloaded (garbage collected) when they're no longer needed. For these sophisticated |
| features to work properly and efficiently the models have to be re-generated with slightly modified GenModel properties. |
| The CDO SDK comes with a convenient migrator tool for existing GenModels and an importer tool for new GenModels.<p><b>See Also:</b></p> |
| <ul> |
| <li><a href="Doc01_Architecture.html#EMF" title="Chapter in CDO Model Repository Documentation">EMF</a></li> |
| </ul> |
| |
| |
| <h2><a name="Protocol"></a>6 Protocol</h2> |
| <p> |
| A concrete communications adapter, a <a href="../../../javadoc/org/eclipse/emf/spi/cdo/CDOSessionProtocol.html" title="Interface in org.eclipse.emf.spi.cdo"><code>CDOSessionProtocol</code></a> implementation that operates inside the |
| <a href="Doc01_Architecture.html#Client" title="Chapter in CDO Model Repository Documentation">CDO client</a>. The only session protocol implementation that currently ships with CDO is based on |
| <a href="Doc01_Architecture.html#Net4j" title="Chapter in CDO Model Repository Documentation">Net4j Core</a>. |
| |
| <h2><a name="Transport"></a>7 Transport</h2> |
| <p> |
| A concrete transport adapter, an <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/connector/IConnector.html" title="Interface in org.eclipse.net4j.connector"><code>IConnector</code></a> implementation that operates on top of the |
| <a href="Doc01_Architecture.html#Net4j" title="Chapter in CDO Model Repository Documentation">Net4j core</a>. Net4j currently ships with <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/jvm/IJVMConnector.html" title="Interface in org.eclipse.net4j.jvm"><code>IJVMConnector</code></a>, <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/tcp/ITCPConnector.html" title="Interface in org.eclipse.net4j.tcp"><code>ITCPConnector</code></a> |
| (optionally with SSL support) and <a href="../../../../org.eclipse.net4j.doc/javadoc/org/eclipse/net4j/http/common/IHTTPConnector.html" title="Interface in org.eclipse.net4j.http.common"><code>IHTTPConnector</code></a>. |
| <p> |
| The <a href="../server/Architecture.html" title="Article in CDO Model Repository Documentation">server</a> must be deployed and configured with |
| the matching <a href="../server/Architecture.html#Transport" title="Chapter in CDO Model Repository Documentation">transport</a>. |
| |
| <p align="right"> |
| <a href="index.html" title="Backward to Developing Client Applications"><img src="../../../images/backward.png" border="0"></a> <a href="Doc02_PreparingModels.html" title="Forward to Preparing EMF Models for CDO"><img src="../../../images/forward.png" border="0"></a></p> |
| <!-- <div class="help_breadcrumbs breadcrumbs_bottom"><a href="../../Overview.html" title="CDO Model Repository Documentation">CDO Model Repository Documentation</a> > <a href="../index.html" title="Category in CDO Model Repository Documentation">Programmer's Guide</a> > <a href="index.html" title="Category in CDO Model Repository Documentation">Developing Client Applications</a></div> --> |
| |
| <div class="copyright">Copyright (c) 2014 Eike Stepper (Berlin, Germany) and others.<br>All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html</div> |
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