Understanding the Architecture of a Client Application |
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Copyright (c) 2004 - 2011 Eike Stepper (Berlin, Germany) and others.
Understanding the Architecture of a Client Application |
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View Providers |
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+ A view provider allows clients to inject custom logic into the resource factory mechansim, capable of handling the whole session and view
+ instantiation process. This permits to obtain resources through the resource set
+ API transparently, without any prior CDO client API code. The view provider automatically kicks in the middle of the
+ ResourceSet.getResource() call, forgetting
+ about the whole openning session / openning transaction process, which happens behind the scenes.
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+ This is quite useful when integrating CDO with EMF-based frameworks and tools that are not prepared for a CDO + scenario themselves. +
+ Table of Contents
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| 1 | Implementing a View Provider | ||
| 2 | Contributing View Providers Programmatically | ||
| 3 | Contributing View Providers Using Extension Points | ||
+ Clients should implement the CDOViewProvider interface, or sub class the AbstractCDOViewProvider
+ class, which provides common functionality.
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+ The example below shows a simple implementation that opens a new session to a local
+ server and a new transaction on that session.
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+ ExampleViewProvider.java | + |
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The example provider catches all URIs with shape "cdo.local:
Register the provider with CDOViewProviderRegistry.
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+ A client's view provider implementation can be contributed programmatically to the CDOViewProviderRegistry,
+ as the following example suggests:
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+ ProviderContribution.java | + |
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+ // Instantiate your view provider
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Get the target CDOViewProvider implementation.
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+ Add the provider instance to CDOViewProviderRegistry.
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+ A specific CDOViewProvider implementation can also be contributed using the
+ org.eclipse.emf.cdo.viewProviders extension point. Clients specify:
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class implementing the CDOViewProvider interface.
+ URIs that should match with the contributed provider.
+ priority integer value, to indicate preference over other implementations
+ matching the same regular expression. A higher value indicates a higher priority, Integer#MAX_VALUE being
+ the maximum priority value and Integer#MIN_VALUE the minimum.
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