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<td bgcolor="#0080c0" valign="top" align="left"> <b><font
face="Arial,Helvetica" color="#ffffff"> Eclipse 3.2 - Team Support for Logical
Model Integration</font></b></td>
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<h1>Team Support for Logical Model Integration</h1>
<p>Version 3.2 M4</p>
<p>The <a
href="http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-vcm-home/docs/online/team3.2/model-integration-proposals.html">Proposed
Support for Logical Model Integration</a> document outlines all the areas that
are targeted to be addressed in 3.2 related to logical model integration support
in Eclipse. The purpose of this document is to outline the proposed solutions
relating to Team. Feedback is strongly encouraged and may be provided on the
platform-team-dev mailing list or in the <a href="http://bugs.eclipse.org/bugs/show_bug.cgi?id=37723">bug
37723</a> for this plan item. The API described in this document is available
in builds but is not yet final and may undergo some revision before the end
of the Eclipse 3.2 development cycle. </p>
<p>This document is broken into the following sections:</p>
<ul>
<li><strong><a href="#ResourceMapping">Resource Mappings</a></strong>: API that
was introduced as provisional in 3.1</li>
<li><a href="#ModelProvider"><strong>Model Providers</strong></a>: This API
servers 2 purposes. It supports the grouping of resource mappings by model
for the purpose of performing batch operations and it supports the back-mapping
of file-system resources to resource mappings to ensure that team operations
include all relevant model elements in a team operation</li>
<li><strong><a href="#TeamInput">Team Operation Scope</a></strong>: API for
translating a set of selected model elements into the complete set of model
elements that should be included in a team operation.</li>
<li><a href="#AutoMerge"><strong>Model-based Merging</strong></a>: API for delegating
a merge operation (e.g. cvs update or merge) to a model so that model semantics
can be used to ensure model consistency and improve conflict resolution during
merge operations.</li>
<li><strong><a href="#FileHistory">File History</a></strong>: API for describing
the history of a file.</li>
</ul>
<p>It also contains a pointer to a download that contains a simple <a
href="#Example">Library example</a>.</p>
<h2>Overview of API</h2>
<p>The relationship between the APIs presented in this document can be described
in terms of a repository operation being performed on a logical model. Some
of the API relates to any repository operation while other parts are specific
to a merge operation (e.g. a CVS update). Here is a description of the steps
required to perform a CVS update on a logical model as it relates to the API
contained in this document.</p>
<ol>
<li>The user selects a set of model elements and chooses Team&gt;Update from
the context menu. </li>
<ul>
<li>The <em>ResourceMapping API</em> is what makes it possible for repository
tooling to recognize that the selected elements are related to file-system
resources in some way.</li>
</ul>
<li>The selected elements may be part of a higher level model or may only represent
part of the contents of a file. The team operation needs to know the complete
set of model elements and resources that need to be operated on. </li>
<ul>
<li>The <em>ModelProvider API</em> supports the mapping of file-system resources
to model elements</li>
<li>The <em>Team Operation Scope API</em> provides a set of reusable classes
that determine the complete input (which we refer to as the scope) of the
team operation.</li>
</ul>
<li>Once the complete scope of the operation is determined (i.e. the complete
set of resources to be operated on), the operation can be performed. For a
merge, the semantics of the model may dictate in what order files need to
be merged or may be able to reduce the chances of conflicts by using model
semantics to perform the merge.
<ol>
<li>The <em>Model-based Merging API</em> allows the team operation to delegate
the merge to the model.</li>
<li>To do so, the team operation must communicate the synchronization state
of all the files involved to the model and give the model access to the
remote contents of those files so that the model can perform the merge</li>
</ol>
</li>
</ol>
<p>The following sections describe each of these API pieces in more detail.</p>
<h2><a name="ResourceMapping"></a>Resource Mappings</h2>
<h3>The Basic Resource Mapping API</h3>
<p>This solution involves adding API to the Resources plugin that maps logical
models elements to workspace (i.e. file system) resources. The API is purposely
simple with logical model manipulations omitted. A client can't use this interface
to display logical models or gain any interesting additional knowledge about
it. It's purpose is simply to map one or more model elements to workspace resources.
</p>
<p>The API consists of the following classes: </p>
<ul>
<li><strong>ResourceMapping</strong>: The Class to which logical model elements
adapt to indicate that the model corresponds to a set of resources in the
workspace. The complete <code>ResourceMapping</code> class can be viewed <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/ResourceMapping.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">here</a>.
The methods of interest are:
<ul>
<li><code>Object getModelObject()</code>: The model object from which the
mapping was derived (or adapted).</li>
<li><code>ResourceTraversal[] getTraversals(ResourceMappingContext, IProgressMonitor)</code>:
The resource traversal that cover the resources that constitute the model
object.</li>
</ul>
</li>
<li><strong>ResourceTraversal</strong>: A <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/ResourceTraversal.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup"><code>ResourceTraversal</code></a>
contains a set of resources and a depth flag that indicates the depth to which
the resources in the traversal are associated with the originating model object.
Resource traversals are provided to a client by a resource mapping in order
to describe the contents of a model in such a way that the client (e.g. a
repository provider) can perform its operations in as efficient a means as
possible. Methods of interest are:
<ul>
<li><code>getResources()</code></li>
<li><code>getDepth()</code></li>
</ul>
</li>
<li><strong>ResourceMappingContext</strong>: a context that is provided to the
resource mapping by the client when obtaining traversals. This context allows
the logical model to determine what the remote state of the model is so that
the proper resources can be covered by the resource traversals returned by
the resource mapping. The use of the<code> <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/ResourceMappingContext.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">ResourceMappingContext</a></code>
and<code> <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/RemoteResourceMappingContext.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">RemoteResourceMappingContext</a></code>
is a bit more complicated and is described <a
href="#ResourceMappingContext">later</a>.</li>
</ul>
<p>There are two types of plugins that should be interested in resource mappings.
Those who provide a model that consists of, or is persisted in, resources in
the workspace and those that want to perform operations on resources. The following
two sections describe how to associate a resource mapping with a model object
and how to contribute menus to objects that adapt to resource mappings.</p>
<h4>Adapting a Model to a ResourceMapping</h4>
<p>Plugins that adapted their model objects to <code>IResource</code> in order
to get resource specific actions shown in the context menu can now adapt to
<code>ResourceMapping</code> if a richer description of how the object adapts
to resources is beneficial. However, they are not required to do so if there
is no benefit. For instance a Java compilation unit (i.e. *.java file shown
in a JDT view) that now currently adapts to <code>IFile</code> need not adapt
to <code>ResourceMapping</code> since nothing is gained. However, a Java package
should adapt to <code>ResourceMapping</code> in order to indicate that the package
consists of only the files in the corresponding folder and not the subfolders.</p>
<p>The preferred way to adapt model elements to a resource mapping is to use an
adapter factory. The following is the XML markup for contributing an adapter
factory in a plugin manifest. </p>
<pre style="background-color: rgb(204, 204, 255);"> &lt;extension<br> point="org.eclipse.core.runtime.adapters"&gt;<br> &lt;factory<br> class="org.eclipse.example.library.logical.AdapterFactory"<br> adaptableType="org.eclipse.example.library.Book"&gt;<br> &lt;adapter type="org.eclipse.core.resources.mapping.ResourceMapping"/&gt;<br> &lt;/factory&gt;<br> &lt;factory<br> class="org.eclipse.example.library.logical.AdapterFactory"<br> adaptableType="org.eclipse.example.library.Library"&gt;<br> &lt;adapter type="org.eclipse.core.resources.mapping.ResourceMapping"/&gt;<br> &lt;/factory&gt;<br> ...<br> &lt;/extension&gt;</pre>
<p>The adapter factory implementation would look something like this:</p>
<pre style="background-color: rgb(204, 204, 255);">public class AdapterFactory implements IAdapterFactory {<br> public Object getAdapter(Object adaptableObject, Class adapterType) {<br> if((adaptableObject instanceof EObject) &amp;&amp; adapterType == ResourceMapping.class) {<br> return new EObjectResourceMapping((EObject)adaptableObject);<br> }<br> return null;<br> }<br><br> public Class[] getAdapterList() {<br> return new Class[] {ResourceMapping.class};<br> }<br>}</pre>
<p>Model objects must implement the <code>IAdaptable</code> interface. When they
do so, they must ensure that the Platform adapter manager is consulted. This
can be done by either subclassing <code>PlatformObject</code> or by using the
following line of code:</p>
<blockquote>
<p><code>Platform.getAdapterManager().getAdapter(Object, Class)</code></p>
</blockquote>
<p>The above is the preferable approach. However, the model object can implement
the IAdaptable interface and provide a <code>getAdapter(Class)</code> implementation
that creates returns an instance of <code>ResourceMapping</code> explicitly
when asked for one. This is a more straightforward approach but the least desirable
as the model must have explicit knowledge of the adaptation to resources.</p>
<p>In some cases, the provider of a logical model may not want their model to
adapt to <code>IResource</code> in every context or may want the object to adapt
differently for object contributions than for other contexts. The workbench
UI provides a special intermediate adapter API, <code>IContributorResourceAdapter</code>,
for this purpose. When objects are being adapted to <code>IResource</code> in
the context of object contributions, the workbench first tries to adapt the
resource to <code>IContributorResourceAdapter</code> before trying to adapt
to <code>IResource</code> directly. A new sub-interface of this interface, <code>IContributorResourceAdapter2</code>,
has been added which provides the same capability for <code>ResourceMapping</code>.
The only difference is that the model provider should register a factory for<code>
IContributorResourceAdapter</code> since the Workbench does an <em>instanceof</em>
check to see if the contributed adapter is also an instance of <code>IContributorResourceAdapter2</code>.</p>
<p>The implementation of the <code>ResourceMapping</code> subclass for a Java
package would look something like this.</p>
<pre style="background-color: rgb(204, 204, 255);">public class JavaPackageResourceMapping extends ResourceMapping {<br> IPackageFragment package;<br> ...<br> public getModelObject() {<br> return package;<br> }<br> public ResourceTraversals[] getTraversals(<br> ResourceMappingContext context, <br> IProgressMonitor monitor) {<br> return new ResourceTraversal[] { <br> new ResourceTraversal(<br> new IResource[] { package.getCorrespondingResource() },<br> IResource.DEPTH_ONE, IResource.NONE)<br> }<br> }<br>}</pre>
<p>This is a fairly straightforward mapping so the implementation is not complex.
The complexity of the resource mapping implementation will, of course, vary
from model to model. The <code>EObjectResourceMapping</code> example used above
is implemented in the example and has a more complicated implementation.</p>
<h4>Contributing Menus to Resource Mappings</h4>
<p>Plug-ins that contribute extensions to adaptable extension points will have
to make two changes to support the new <code>ResourceMapping</code> APIs:</p>
<ol>
<li>Update their plugin.xml files to change the objectClass of their adaptable
contributions to <code>ResourceMapping</code> (for those for which this is
appropriate).</li>
<li>Update their actions to work on <code>ResourceMapping</code> instead of
<code>IResource</code> and respect the depth constraints provided in the traversals.</li>
<li>(Optional) provide a <code>ResourceMappingContext</code> if they manage
remote resources (more on this <a href="#ResourceMappingContext">below</a>)</li>
</ol>
<p>First of all, plugins that add object contributions to <code>IResource</code>
(CVS, Search, Compare) can now add them to <code>ResourceMapping</code> instead,
if the action can apply to multiple resources. Here is an XML snippet that contributes
a menu action to objects that adapt to resource mappings:</p>
<pre style="background-color: rgb(204, 204, 255);"> &lt;extension<br> point="org.eclipse.ui.popupMenus"&gt;<br> &lt;objectContribution<br> adaptable="true"<br> objectClass="org.eclipse.core.resources.mapping.ResourceMapping"<br> id="org.eclipse.example.library.ResourceMappingContributions"&gt;<br> &lt;action<br> label="Show Resource Mappings"<br> class="org.eclipse.example.library.contributions.ShowResourceMappingsAction"<br> menubarPath="additions"<br> id="org.eclipse.example.library.showMappings"/&gt; <br> &lt;/objectContribution&gt;<br> &lt;/extension&gt;</pre>
<p>Contributions to <code>ResourceMapping</code> will automatically apply to objects
that adapt to <code>IResource</code>. This transitive association is handled
by the Workbench.</p>
<p>Filtering of the contributions to resource mappings can be done using action
filters or expressions. An expression for filtering by project persistent property
has been added to allow repository providers to have their menus appear on projects
that are mapped to their repositories.</p>
<pre style="background-color: rgb(204, 204, 255);"> &lt;extension<br> point="org.eclipse.ui.popupMenus"&gt;<br> &lt;objectContribution<br> objectClass="org.eclipse.core.resources.mapping.ResourceMapping"<br> adaptable="true"<br> id="org.eclipse.team.ccvs.ui.ResourceMapperContributions"&gt;<br> &lt;enablement&gt;<br> &lt;adapt type="org.eclipse.core.resources.mapping.ResourceMapping"&gt;<br> &lt;test <br> property="org.eclipse.core.resources.projectPersistentProperty" <br> args="org.eclipse.team.core.repository,org.eclipse.team.cvs.core.cvsnature" /&gt;<br> &lt;/adapt&gt;<br> &lt;/enablement&gt;<br> &lt;action<br> label="%UpdateAction.label"<br> definitionId="org.eclipse.team.cvs.ui.update"<br> class="org.eclipse.team.internal.ccvs.ui.actions.UpdateAction"<br> tooltip="%UpdateAction.tooltip"<br> menubarPath="team.main/group2"<br> id="org.eclipse.team.cvs.ui.update"&gt;<br> &lt;/action&gt;<br> ...<br> &lt;/objectContribution&gt;<br> &lt;/extension&gt;</pre>
<p>Actions that have been contributed to the <code>ResourceMapping</code> class
will be given a selection that contains one or more <code>ResourceMappings</code>.
It is the actions responsibility to translate the resource mapping into a set
of resources to be operated on. This can be done by calling <code>getTraversals</code>
to get the traversals of the mapping. Traversals are used to allow the clients
of the traversal to optimize their operations based on the depth of the resources
being traversed. A client may traverse the resource manually or may use the
resource and the depth as input into an operation that the action delegates
to do the work. As an example, if the user performs a CVS update on a java package
and the java package resource mapping maps to a folder of depth one, CVS would
issue an appropriate command ("cvs update -l" for those who are curious) which
would perform a shallow update on the folder the package represents.</p>
<h3><a name="ResourceMappingContext"></a>Resource Mapping Context</h3>
<p>One of the advantages of a Resource Mapping API is that it allows plug-ins
to implement any operations they desire in terms of resource mappings (e.g.
CVS update, CVS commit, CVS tag, dirty decoration, etc.). However, the API that
has been introduced so far deals only with the local state of the model. When
working with a model that may be shared between developers, you end up in a
situation where the remote state of the model (i.e. the state of the model that
another user has checked-in to the repository) may differ from the state in
the workspace. If you performed a CVS update, you would want the local state
of the model to match the remote state even if it meant that additional files
needed to be included or some files needed to be removed.</p>
<p>This is not an issue for some logical models. For instance, a java package
is a container visited to a depth of one, regardless of the remote state of
the model. Given this, a repository provider can easily determine that outgoing
deletions should be included when committing or that incoming additions should
be included when updating. However, the resources that constitute some logical
models may change over time. For instance, the resources that constitute a model
element may depend of the contents of a manifest file (or some other similar
mechanism). In order for the resource mapping to return the proper traversal,
it must access the remote contents of the manifest file (if it differs from
the local contents) in order to see if there are additional resources that need
to be included. These additional resources may not exist in the workspace but
the repository provider would know how to make sure they did when the selected
action was performed.</p>
<p>In order to support these more complex models, a <code>RemoteResourceMappingContext</code>
can be passed to the <code>ResourceMapping#getTraversals</code> method. When
a context is provided, the mapping can use it to ensure that all the necessary
resources are included in the traversal. If a context is not provided, the mapping
can assume that only the local state is of interest. </p>
<h4>When does a ResourceMapping need to worry about the RemoteResourceMappingContext?</h4>
<p>A <code>ResourceMapping</code> need only worry about a context supplied to
the <code>getTraversals</code> method in cases were the resources that make
up a model change over time and the relationship between the model and resources
cannot be described by a simple traversal that is guaranteed to encompass those
resources (and only those resources) that constitute the model. For example,
although the resources of a Java package may change over time, the package can
be described as a folder of depth of one so a resource mapping for java packages
would not ned to make use of the resource mapping context. </p>
<p>As a more complicated example, consider an HTML file that contains several
images. Let's make the assumption that any images references from an HTML file
are part of the model of that file. When updating the local contents of the
HTML file from a repository, the user would expect that any new images would
be included. The <code>getTraversals</code> method for a <code>ResourceMapping</code>
for the HTML file model would look something like this:</p>
<pre style="background-color: rgb(204, 204, 255);">public class HTMLResourceMapping extends ResourceMapping {<br> private HTMLFile htmlFile;<br> public ResourceTraversal[] getTraversals(ResourceMappingContext context, <br> IProgressMonitor monitor)<br> IResource[] resources = htmlFile.getResources();<br> if (context instanceof RemoteResourceMappingContext) {<br> // Look for any additional resources on the server<br> RemoteResourceMappingContext remoteContext = (RemoteResourceMappingContext)context;<br> IFile file = htmlFile.getFile();<br> if (remoteContext.hasRemoteChange(file, monitor)) {<br> IStorage storage = remoteContext.fetchRemoteContents(file, monitor);<br> IResource[] additionalResources = getReferences(storage.getContents());<br> resources = combine(resources, additionalResources);<br> }<br> if (remoteContext.isThreeWay() &amp;&amp; remoteContext.hasLocalChange(file, monitor)) {<br> IStorage storage = remoteContext.fetchBaseContents(file, monitor);<br> IResource[] additionalResources = getReferences(storage.getContents());<br> resources = combine(resources, additionalResources);<br> }<br> }<br> return new ResourceTraversal[] { <br> new ResourceTraversal(resources, IResource.DEPTH_ZERO, IResource.NONE)};<br> }<br>}</pre>
<p>Notice that there are two sets of resources included in the model: those derived
from the local contents of the HTML file in the workspace and those obtained
from the contents of the remote file and base file. In either of these two sets,
there may be resources that do not exist in the workspace. For instance, the
local HTML file may contain a relative link to an image that does not exist
in the workspace. This resource should be included so that it will be fetched
if it exists remotely. As for the remote file, it may contain a new copy that
references additional images that should be fetched when the new remote contents
are downloaded.</p>
<h4>When does a repository need to provide a RemoteResourceMappingContext?</h4>
<p>Any tool that is providing the ability of sharing workspace resources through
a repository and is supporting ResourceMappings should provide an appropriate
context for determining the relevant remote state of the model resources. The
context provides three basic queries:</p>
<ul>
<li>What type of comparison is being performed: two-way or three-way
<ul>
<li>for two-way, does the local contents differ from the remote contents</li>
<li>for three-way, are there local changes and are there remote changes</li>
</ul>
</li>
<li>What are the contents of the remote (and base for three-way) counterparts
of the file</li>
<li>What are the remote members of a folder</li>
</ul>
<p>The answer to the first question above depends on the type of operation that
is being performed. Typically, updates and merges are three-way while comparisons
and replace operations are two-way.</p>
<p>The Eclipse Team API includes a <code>Subscriber</code> class that defines
an API for providing the synchronization state between the local workspace and
a remote server. A <code><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/internal/resources/mapping/ResourceTraversal.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">SubscriberResourceMappingContext</a></code>
has been created that uses a <code>Subscriber</code> to access the necessary
remote state. Clients that have a <code>Subscriber</code> do not need to do
any additional work to get a resource mapping context.</p>
<h2><a name="ModelProvider"></a>Model Providers</h2>
<p>Model providers are a means to group related resource mappings together. Here
is a link to the <code><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/ModelProvider.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">ModelProvider</a></code><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.core.resources/src/org/eclipse/core/resources/mapping/ModelProvider.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">
class</a>. This class serves two main purposes:</p>
<ol>
<li>From a model provider, clients can then obtain additional API pieces for
performing operations on a set of resource mappings.</li>
<li>Given a set of file-system resources, clients can query whether a model
provider has model elements persisted in those resources and, if it does,
obtain the set of resource mappings that describe the relationship.</li>
</ol>
<p>The following is an example of a modelProvider extension definition.</p>
<pre style="background-color: rgb(204, 204, 255);"> &lt;extension<br> id="modelProvider"<br> name="Library Example"<br> point="org.eclipse.core.resources.modelProviders"&gt;<br> &lt;modelProvider<br> class="org.eclipse.team.examples.library.adapt.LibraryModelProvider"<br> name="Library Example"/&gt;<br> &lt;extends-model id="org.eclipse.core.resources.modelProvider"/&gt;<br> &lt;enablement&gt;
&lt;test property=&quot;org.eclipse.core.resources.projectNature&quot;
value=&quot;org.eclipse.team.examples.library.view.nature&quot; /&gt;<br> &lt;/enablement&gt;<br> &lt;/extension&gt;<br></pre>
<p>The <code>LibraryModelProvider</code> is a subclass of <code>ModelProvider</code>.
The enablement rule is used to match resources that the Library model persists
its model in. In the above example, the model provider will match any resource
in a project that has the library nature. </p>
<p>Once the model provider is defined, the <code>ResourceMapping#getModelProviderId()</code>
method should be overridden to return the id of the model provider.</p>
<pre style="background-color: rgb(204, 204, 255);"> public String getModelProviderId() {<br> return "org.eclipse.team.examples.library.adapt.modelProvider";<br> }<br></pre>
<p>To get the proper inverse mapping of resources to resource mapping for those
resources that match your provider's enablement rule, you should also override
one or both of the <code>getMapping</code> methods. The method that you need
to override depends on whether your model has elements that contain multiple
resources or not. If your model elements map to a single resource, you can override
the method that accepts a single<code>IResource</code> argument. Otherwise,
you will need to override the method that accepts an array of resources. Here's
an example using the single resource case.</p>
<p>The following example method wraps a library model file in an appropriate resource
mapping. It also wraps folders that contain files that are of interest to the
model provider.<br>
</p>
<pre style="background-color: rgb(204, 204, 255);">public class LibraryModelProvider extends ModelProvider {<br> public ResourceMapping[] getMappings(IResource resource, <br> ResourceMappingContext context, IProgressMonitor monitor) {<br> if (isModelFile(resource)) {<br> // Return a resource mapping on the file<br> return new LibraryResourceMapping(resource);<br> } if (containsModelFiles(resource)) {<br> // Create a deep resource mapping on the container<br> return new LibraryContainerResourceMapping(resource);<br> }<br> // The resource is not of interest to this model provider<br> return null;<br> }<br>}</pre>
<p>Clients can then access the model provider to determine whether the model providers
cares about the resources that are about to be operated on. The next section
describes API that will be provided to team operations that use the model provider
API to determine the complete set of resource mappings to be operated on when
a team operation is performed on a set of selected resources or model elements.</p>
<h2><a name="TeamInput"></a>Team Operation Scope</h2>
<p>For team operations, the selected mappings need to be translated into the set
of mappings to be operated on. This process involves consulting all model providers
to ensure that they get included in operations on resources that match their
enablement rules. The term we use to describe the complete set of resource mappings
to be operated on is the operation <em>scope</em>. The following API has been
provided for this:</p>
<ul>
<li><code><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/IResourceMappingScope.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IResourceMappingScope</a></code>:
Interface that defines the API for accessing the scope of the operation. It
provides access to all the resource mappings being operated on and the traversals
for those mappings as they were calculated during the scope building process.</li>
<li><code><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/ScopeGenerator.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">ScopeGenerator</a></code>:
Class that is used to build a scope given a set of input mappings and a resource
mapping context.</li>
</ul>
<p>The code for creating an initializing an input would look something like this:</p>
<pre style="background-color: rgb(204, 204, 255);">ResourceMapping[] selectedMappings = getSelectedMappings();<br>ResourceMappingContext context = getResourceMappingContext();<br>ScopeGenerator builder = new ScopeGenerator();<br>IResourceMappingScope scope = builder.prepareScope(selectedMappings, context, monitor);<br>if (scope.hasAdditionalMappings()) {<br> // inform user of additional mappings<br>}<br>// Now get the set of mappings to be operated on<br>ResourceMapping[] operationMappings = scope.getMappings();<br>// Get the traversals that were cached during the input determination process<br>ResourceTraversal[] allTraversals = scope.getTraversals();</pre>
<p>Team operations will provide the set of selected resource mappings and a resource
mapping context. They will then call <code>buildScope</code> which calculates
all the resource mappings that need to be included in the operation. The scope
also caches the results so they do not need to be recalculated during the operation.
You can get all the traversals or only those for a particular mapping.</p>
<h2><a name="AutoMerge"></a>Model-based Merging</h2>
<p>This section offers a brief explanation of what model based merging involves
and provides pointers to example implementations in the SDK.</p>
<ul>
<li>The team provider needs to calculate the synchronization state of all the
resources involved in the merge. This is done by subclassing <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.ui/src/org/eclipse/team/ui/operations/ResourceMappingMergeOperation.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">ResourceMappingMergeOperation</a>
and overriding the <code>buildContext</code> method to return an <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/IMergeContext.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IMergeContext</a>.
The merge context provides the model access to the synchronization state of
the files involved (see the <code>getSyncInfoTree()</code> method) along with
access to the contents of the files (see <code>SyncInfo#getRemote()</code>
and <code>SyncInfo#getBase()</code>). The CVS UI plugin contains an a merge
operation subclass named <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.cvs.ui/src/org/eclipse/team/internal/ccvs/ui/mappings/CVSMappingMergeOperation.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">CVSMappingMergeOperation</a>.</li>
<li>The model needs to adapt it's model provider to an instance of <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/IResourceMappingMerger.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IResourceMappingMerger</a>.
The merge operation delegates the merge to the registered merger. The platform
has a default implementation, <a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.ui/src/org/eclipse/team/internal/ui/mapping/DefaultResourceMappingMerger.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">DefaultResourceMappingMerger</a>,
that performs a text-based merge on the files using the IStreamMerger registered
for that file type.</li>
</ul>
<h3>Synchronization and Merge Context</h3>
<p>An important aspect of model-based merging is the API used to communicate the
synchronization state of the resources involved to the model provider. There
are two interfaces of interest:</p>
<ul>
<li><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/ISynchronizationContext.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">ISynchronzationContext</a>:
provides access to the synchronization stat of all resources within the scope
of the operation. The following API pieces are used to describe the synchronization
state of resources.
<ul>
<li><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/IDiffTree.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IDiffTree</a>/<a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/IResourceDiffTree.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IResourceDiffTree</a>:
data structure that contains the synchronization state for all resources
in the operation scope that are out-of-sync.</li>
<li><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/IDiffNode.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IDiffNode</a>/<a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/ITwoWayDiff.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">ITwoWayDiff</a>//<a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/IResourceDiff.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IResourceDiff</a>/<a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/diff/IThreeWayDiff.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IThreeWayDiff</a>:
describes the synchronization of a single resource</li>
<li><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/variants/IResourceVariant.java?rev=HEAD&amp;content-type=text/vnd.viewcvs-markup">IResourceVariant</a>:
provides access to the base or remote file stat and contents that were
used to determine the synchronization state for a local resource. </li>
</ul>
</li>
<li><a
href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/mapping/IMergeContext.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IMergeContext</a>:
a synchronization context with additional methods that support merging.</li>
</ul>
<h3>Model Content in Team Operation Views</h3>
<p>API has been added in M4 that allows models to provide a team-aware content
provider that can be used by Team providers to display the effetcs of team operation
in termes of model elements and hierarchies. The CVS Team&gt;Update context
menu action in Eclipse 3.2 Milestone 4 (M4) can be configured to display logical
model elements and hierarchies when previewing the effects of an update. You
must turn on the &quot;Perform client side merges on update&quot; preference
on the <strong>Team&gt;CVS&gt;Work In Progress</strong> preference page.</p>
<p><img src="updatePrefs.png" width="419" height="150"></p>
<p>In M4, Java implements a team-aware content provider which allows the effects
of an update to be shown with respect to the Java model.</p>
<p><img src="update.png" width="410" height="281"></p>
<p>There are three steps required to create a team-aware content provider</p>
<ol>
<li>Create a extension to the <em>org.eclipse.ui.navigator.navigatorContent</em>
extension point. Minimally, you will need to provide a content provider and
label provider and an enablement rule that matches the appropriate model elements.
The enablement sule should also match both <code>IResourceMappingScope</code>
and <code>ISynchronizationContext</code> as either of these could be used
as the input object to a Team viewer.</li>
<li>Associate your <em>navigatorContent</em> extension with the Team viewer
using the <em>org.eclipse.ui.navigator.viewer</em> extension point. The Team
viewer id is <em>org.eclipse.team.ui.navigatorViewer</em>.</li>
<li>Bind your content extension to your model provider using the <em>org.eclipse.team.ui.teamContentProviders</em>
extenson point.</li>
</ol>
<p>The following xml shows how the Java content provider is made team-aware.</p>
<pre style="background-color: rgb(204, 204, 255);"> &lt;extension point=&quot;org.eclipse.ui.navigator.navigatorContent&quot;&gt;<br> &lt;navigatorContent<br> contentProvider=&quot;org.eclipse.jdt.internal.ui.model.JavaSynchronizationContentProvider&quot;<br> id=&quot;org.eclipse.jdt.ui.resourceContent&quot;<br> labelProvider=&quot;org.eclipse.jdt.internal.ui.model.JavaSynchronizationLabelProvider&quot;<br> name=&quot;%JavaModelContent.name&quot;&gt;<br> &lt;enablement&gt;<br> &lt;or&gt;<br> &lt;instanceof value=&quot;org.eclipse.jdt.internal.ui.model.JavaModelProvider&quot;/&gt;<br> &lt;instanceof value=&quot;org.eclipse.jdt.core.IJavaElement&quot;/&gt;<br> &lt;instanceof value=&quot;org.eclipse.team.core.mapping.IResourceMappingScope&quot;/&gt;<br> &lt;instanceof value=&quot;org.eclipse.team.core.mapping.ISynchronizationContext&quot;/&gt;<br> &lt;/or&gt;<br> &lt;/enablement&gt;<br> &lt;/navigatorContent&gt;<br> &lt;/extension&gt;
&lt;extension point=&quot;org.eclipse.ui.navigator.viewer&quot;&gt;<br> &lt;viewerContentBinding viewerId=&quot;org.eclipse.team.ui.navigatorViewer&quot;&gt;<br> &lt;includes&gt;<br> &lt;contentExtension isRoot=&quot;true&quot;<br> pattern=&quot;org.eclipse.jdt.ui.resourceContent&quot;/&gt;<br> &lt;/includes&gt;<br> &lt;/viewerContentBinding&gt;
&lt;/extension&gt;
&lt;extension&gt;
id=&quot;jdtContentProvider&quot;<br> point=&quot;org.eclipse.team.ui.teamContentProviders&quot;&gt;<br> &lt;teamContentProvider<br> contentExtensionId=&quot;org.eclipse.jdt.ui.resourceContent&quot;<br> modelProviderId=&quot;org.eclipse.jdt.ui.modelProvider&quot;/&gt;<br> &lt;/extension&gt;
</pre>
<p>The <code><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/model/JavaSynchronizationContentProvider.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">JavaSynchronizationContentProvider</a></code>
and <code><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/model/JavaSynchronizationLabelProvider.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">JavaSynchronizationLabelProvider</a></code>
classes in the above example are subclasses of <code><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.ui/src/org/eclipse/team/ui/mapping/SynchronizationContentProvider.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">SynchronizationContentProvider</a></code>
and <code><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.ui/src/org/eclipse/team/ui/mapping/SynchronizationLabelProvider.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">SynchronizationLabelProvider</a></code>
and make use of the synchronization context to provide filtering and label decoration.</p>
<h2><a name="FileHistory"></a>File History</h2>
<p>The proposed file history API consists of the following interfaces:</p>
<ul>
<li><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/filehistory/IFileHistoryProvider.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IFileHistoryProvider</a>:
Obtained from a RepositoryProvider, the file history provider allows clients
to obtain the file history of a particular file.</li>
<li><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/filehistory/IFileHistory.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IFileHistory</a>:
A data structure that allows access to the history of a file</li>
<li><a href="http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.team.core/src/org/eclipse/team/core/filehistory/IFileRevision.java?rev=HEAD&content-type=text/vnd.viewcvs-markup">IFileRevision</a>:
The description of a single revision or state of a file at a particular poin
tin time in its history.</li>
</ul>
<p>Along with this API, a generic file history view is being proposed. A preview
version is available in M4.</p>
<p><img src="history.png" width="456" height="216"></p>
<h2><a name="Example"></a>EMF Library Example</h2>
<p>This example, available <a
href="libraryExample.html">here</a>, is built on a model that consists of libraries,
books and writers.</p>
<h2>What's Next</h2>
<p>See the <a href="plan.html">Eclipse Team/CVS 3.2 plan</a> for what is happening
in M5 and beyond.</p>
<h2>Conclusion</h2>
<p>This document contains a description of the API available so far in 3.2. This
is only a portion of the feature set described in the <a
href="http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-vcm-home/docs/online/team3.2/model-integration-proposals.html">Proposed
Support for Logical Model Integration</a> document. Additional API for Team
support of logical model integration will be added to the document as it becomes
available. Also, the API described in this document may still undergo change
in the 3.2 release cycle. The document will be updated with any changes as well.</p>
<h2>Change History</h2>
<p>Changes in version 3.2 M4</p>
<ul>
<li>Updated to contain a brief description of the new API added in M4. This
includes
<ul>
<li>IDiffTree/IDiffNode API for describing changes</li>
<li>Use of Common Navigator framework to support the display of model elements
in views and dialogs associated with a Team operation</li>
<li>File history API</li>
</ul>
</li>
</ul>
<p>Changes in version 3.2 M3</p>
<ul>
<li>Updated 3.1 <a
href="http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-vcm-home/docs/online/team3.1/logical-physical-mappings.html">Resource
Mapping</a> document to reflect new support available in 3.2 M3.<br>
</li>
</ul>
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