platform-team/team3.1/logical-physical-public.html - www.eclipse.org/eclipse - Git at Google

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
 <head>
   <title>Support Logical Resources</title>
 </head>
 <body>
 <table border="0" cellspacing="5" cellpadding="2" width="100%">
   <tbody>
     <tr>
       <td align="left" valign="top" bgcolor="#0080c0"> <b><font
  color="#ffffff" face="Arial,Helvetica"> Eclipse 3.1 - Plan item</font></b>
       </td>
     </tr>
   </tbody>
 </table>
 <h1>Support Logical Resources</h1>
 This document outlines the state of the Eclipse Platform <strong>Support
 Logical Resources</strong> plan item. Interested parties should review
 this document and verify that their use cases are reflected in the
 requirements then later that the solution provided satisfies their
 needs. 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 report</a>
 for this plan item.
 <p class="MsoNormal">This is the plan item:</p>
 <blockquote>
   <p>"<em>The Eclipse Platform supports a strong physical view of
 projects, files, and folders in the workspace. However, there are many
 situations where a physical view is not the most salient or useful for
 many purposes. In some cases, multiple distinct objects happen to be
 stored in a single file, like an archive. Conversely, in other cases,
 something that is logically a single object is stored across multiple
 files. This discrepancy between logical and physical creates problems
 for common operations such as searching, comparing, and versioning,
 which need to work in the physical realm. Eclipse should support some
 way of mapping between a logical view and the physical organization of
 files on disk.</em>"</p>
   <p>Last Modified: July 2nd, 2003<br>
   </p>
 </blockquote>
 <h1>Motivation</h1>
 <p>By definition Eclipse supports logical resources. It's a "an open
 extensible IDE for anything and nothing in particular". The
 applications that are built with it can be tailored to a particular
 problem domain and the workbench extensions can be used to provide
 support for any logical model. What Eclipse really doesn't support is
 integrating tools at the logical model. In order to integrate two
 plugins into Eclipse either the two plugins have to know about each
 other, or both plugins have to depend on some common plugin. While the
 first option is satisfactory for a few cases, the second case is the
 most common and the most problematic. To illustrate, the Eclipse SDK
 contains several plugins that are based on the Resources plugin (e.g.
 Team, Search, Compare, JDT). When an application is packaged based on
 the SDK, because the plugins in the SDK are resource based that is the
 common integration point between plug-ins.<br>
 </p>
 <p>As you will see later, even the users of the SDK (JDT+CVS+Resources)
 can observe some of the problems associated with the lack of support
 for logical resources and the implicit mapping to physical resources.
 The lack of a logical integration point causes the co-existance of
 plugins in Eclipse to be error prone for the user. The next sections
 will examine the relationships between logical and physical resources
 and outline the visible problems with Eclipse 3.0.</p>
 <h2>Existing Bugs</h2>
 <p>Bug <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=32582">32582</a>
 logical to physical mapping problem , 1 model element = 2 Files problem<br>
 Bug <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=3979">3979</a>
 [CVS Decorator] show version info works incorrectly for sub packages
 (1GFDIEB)<br>
 </p>
 <h2>Logical Resources Defined<br>
 </h2>
 <p>Whereas logical resources are elements of the application that model
 the data/processes of a particular problem domain, the physical
 resources are the file system resources (e.g. files and folders) into
 which an application will eventually transform their application model
 for storage. Applications that don't use file system resources are not
 being considered as part of this plan item. For example, an application
 that stores it's application data directly into a database.</p>
 <p>The following table enumerates concrete examples of how logical and
 physical resources are used in current applications integrated into
 Eclipse.</p>
 <p><a name="#table1"></a>Table 1: Example logical to physical uses</p>
 <table width="100%" border="1">
   <tbody>
     <tr>
       <td width="23%">
       <div align="center"><strong>Relationships</strong></div>
       </td>
       <td width="77%">
       <div align="center"><strong>Examples</strong></div>
       </td>
     </tr>
     <tr>
       <td>
       <p>logical (1) &lt;-&gt; (*) physical</p>
       <p>one logical to many physical</p>
       </td>
       <td valign="top">
       <p><a name="#1a"></a>(<strong>1a</strong>) EJB maps to several
 physical files: (WSAD + XDE Tester). This is the most common case we
 have found. </p>
       <blockquote>
         <p>/src/org/app/bean.java<br>
 /src/org/app/beanr.java<br>
 /src/org/app/beanlocal.java</p>
       </blockquote>
       <p><em>Note: If one of the logical resource's files was deleted
 who would remember that the file used to exist and is an outgoing
 deletion or that there is an incoming addition to the logical resource?</em></p>
       <p><a name="#1b"></a>(<strong>1b</strong>) Composite Object
 (logical) maps to several changed physical resources. (Rational XDE)</p>
       <p><em>Note</em>: <em>With 1 to many relationship there is
 always the complication that arises if the logical element maps to
 files in an other project? This would cause many problems in the
 current Team plugin.</em></p>
       </td>
     </tr>
     <tr>
       <td>
       <p>logical (*) &lt;-&gt; (1) physical</p>
       <p>many logical to one physical</p>
       </td>
       <td valign="top">
       <p><a name="#2a"></a>(<strong>2a</strong>) Methods in a class map
 to their containing class file. (JDT)</p>
       <p><a name="#2b"></a>(<strong>2b</strong>) Archive files (zip,
 jar) can be seen as a logical and the contents of the archive all map
 to the same physical.(JTD + all)</p>
       </td>
     </tr>
     <tr>
       <td>
       <p>logical (1) &lt;-&gt; (1) physical</p>
       <p>one logical to one physical</p>
       </td>
       <td valign="top">
       <p><a name="#3a"></a>(<strong>3a</strong>) A Java Package maps to
 a folder but a package does not include sub folders (e.g. they are
 shallow). (JDT)</p>
       <p><a name="#3b"></a>(<strong>3b</strong>) A UML class maps to a
 file. For example, in a UML application a class could be stored in a
 single file called 'x435dsds.umlclass'. The reason it's a logical is
 that the user of the application will never be concerned about the
 actual file name or even the folder it's stored in. (XDE)</p>
       </td>
     </tr>
   </tbody>
 </table>
 <h1>Complaints<br>
 </h1>
 <p>The following complaints are representative of bug reports and
 requirements received from several Eclipse users and developers.<br>
 </p>
 <h2>Complaint 1: Not very adaptable</h2>
 <p>Object contributions and decorators are key mechanisms for providing
 rich integration between tools. Using object contributions and
 adaptable objects, any plugin can provide actions and decorators that
 will show in another plugin's view. </p>
 <p>Since IResource is the lowest common integration class and is
 strongly mapped to its physical storage as files and folders, the
 integration point for actions and decorators cannot be the logical
 types in the view. The actions will consequently use the adaptable type
 from the selection to perform the action or the decorator the resource
 from the getImage request.</p>
 <p>Here is an example to illustrate the problem with the CVS plugin.
 When running a CVS commit action in the packages view the action
 doesn't know that the IFolder is a Java package and is a shallow
 namespace. It will use the selection and traverse the selected
 IContainer using IContainer.members() and commit all child resources.
 This is the same when the CVS outgoing decorator is shown on a package.
 It will reflect the deep outgoing state of the IContainer. This can
 lead to unexpected behavior because the user expected the action to run
 on the model that the action was displayed on.</p>
 <p>Example object contribution for the CVS commit action:</p>
 <pre>&lt;extension point="org.eclipse.ui.popupMenus"&gt;<br> &lt;objectContribution<br>  objectClass="org.eclipse.core.resources.IResource"<br>  adaptable="true"<br>  id="org.eclipse.team.ccvs.ui.IResourceContributions"&gt;<br> &lt;filter<br>  name="projectPersistentProperty"<br>  value="org.eclipse.team.core.repository=org.eclipse.team.cvs.core.cvsnature"&gt;<br> &lt;/filter&gt;<br> &lt;action<br>  label="Commit"<br>  tooltip="Commit resource to CVS repository"<br>  class="org.eclipse.team.internal.ccvs.ui.actions.CommitAction"<br>  menubarPath="team.main/group3"<br>  id="org.eclipse.team.ccvs.ui.commit"&gt;<br> &lt;/action&gt;<br> &lt;objectContribution&gt;<br>&lt;/extension&gt;<br></pre>
 <p>Example code run in the commit action to calculate the resources to
 commit:</p>
 <pre>public static Object[] getSelectedAdaptables(ISelection selection)    {<br>  ArrayList result = null;<br>  if (!selection.isEmpty()) {<br>    result = new ArrayList();<br>    Iterator elements = ((IStructuredSelection) selection).iterator();<br>    while (elements.hasNext()) {<br>      Object adapter = getAdapter(elements.next(), IResource.class);<br>      if (c.isInstance(adapter)) {<br>        result.add(adapter);<br>      }<br>    }<br>   }<br>   if (result != null &amp;&amp; !result.isEmpty()) {<br>   return (Object[])result.toArray((Object[])Array.newInstance(IResource.class, result.size()));<br>  }<br>  return (Object[])Array.newInstance(IResource.class, 0);<br>}</pre>
 <p>Example code for defining an IResource adaptable decorator:</p>
 <pre>&lt;extension<br>  point="org.eclipse.ui.decorators"&gt;<br>    &lt;decorator objectClass="org.eclipse.core.resources.IResource"<br>     adaptable="true"<br>     label="%DecoratorStandard.name"<br>     state="false"<br>     lightweight= "true"<br>     quadrant = "BOTTOM_RIGHT"<br>     class="org.eclipse.team.internal.ccvs.ui.CVSLightweightDecorator"<br>     id="org.eclipse.team.cvs.ui.decorator"&gt;<br>    &lt;description&gt;<br>      %DecoratorStandard.desc<br>    &lt;/description&gt;<br>  &lt;/decorator&gt;<br>&lt;/extension&gt;</pre>
 <h2>Complaint 2: Decorators</h2>
 <p>When the CVS decorator decorates a logical container in a view, the
 desire is to decorate parents with the dirty indicator if one or more
 of their logical children are dirty. To do this properly, the decorator
 would need to query the dirty status of each of the logical children of
 the container. This can be a costly operation as each child may itself
 be a logical container. We have optimized the dirty decoration by
 caching folder dirty states. This optimization becomes far more
 complicated with logical models where the caching must be based on this
 alternate model (i.e. the state must be cached for each model).</p>
 <p> In addition, often decorators rely on&nbsp;IResource change events
 to re-calculate some new state. In the case of a logical elements
 representing several physical resources there is no easy way of
 associated a IResource change event to its files and the actual logical
 element.</p>
 <h2>Complaint 3: Presentation of mixed logical models<br>
 </h2>
 <p>It would be nice to see the Java logical view in the Synchronize
 view, in the navigator, or in dialogs contributed by other plug-ins
 besides JDT. However, the entries in these views
 may not be IResources so an IResource independent mapping mechanism
 would be required. A workaround for this problem is demonstrated by the
 Search plug-in which allows for plug-ins to integrate with other tools
 by contributing domain specific pages. JDT contributes a JDT search
 page to the view and shows logical Java elements. This solution however
 doesn't allow showing mixed logical models in the same widget, which is
 required several presentations in the SDK such as the Synchronize View,
 Navigator, Refactoring Preview, and many others.<br>
 </p>
 Also, if an action prompts the user, for example to add resources to
 CVS, what icons and labels are used in the dialog? It would be nice to
 show those that are most familiar to the user. <br>
 <br>
 There are two levels of logical model presentation:<br>
 <ul>
   <li>Need for full access to a logical model that would allow building
 a dynamic UI. This would include mapping from an IResource to a logical
 element (Complex).<br>
   </li>
 </ul>
 <ul>
   <li>Need name and icon for a logical element to display in simple
 dialogs (Simple).<br>
   </li>
 </ul>
 <h2>Complaint 4: Change Sets</h2>
 <p>Consider a user's action as a logical change, for example, the user
 renames a class using the JDT refactoring action. In the user's mind he
 'renamed a class' and knows that there have been side effects to other
 resources. Currently there is not way of capturing these logical
 actions
 and associating the set of affected resources. This problem manifests
 itself more in tools where almost every change to the model has side
 effects.</p>
 <h2>Complaint 5: Participating in operations</h2>
 Some logical models may want to participate and even restrict the kinds
 of operations are
 allowed on theirs files. For example, if a logical element is composed
 of three files, the users should not be allowed to move, or delete them
 individually. In essence, a way of vetoing or participating in all
 resource refactorings for resources that are part of a logical model.<br>
 <br>
 The most obvious problem in the current Eclipse is that the resource
 navigator exposes resource refactorings (move, delete, copy) and the
 logical cannot easily override this behavior. <br>
 <h2>Complaint 6: IResource based views in the IDE</h2>
 There are several views in the workbench IDE that could be used by
 logical models but are currently too tied to resources. For example,
 the problems and tasks views have a resource column and works uniquely
 on IResource markers. This means that if a logical model provides
 problems and tasks the problems and tasks views cannot be used to show
 the logical element instead of the file.<br>
 <h2>Complaint 7: Merging can't consider all files related to a logical
 element</h2>
 When merging a logical element the repository may find a conflict in
 one of the files that is part of the logical element. The repository
 tool will typically fetch the revisions for the conflicting file so
 that a comparison can be shown to the user. But since the repository
 tool doesn't know that other files are part of the logical resource,
 the comparison shown to the user doesn't have access to the correct
 revisions of the other files. This is a problem because it then becomes
 impossible to implement a comparison that has access to all the
 revisions of the logical element's files.<br>
 <h2>Complaint 8: Creating non-IResource projects that appear in the
 navigator</h2>
 Currently the Navigator displays the Resources plugin workspace and
 thus only resource projects can be displayed. Many clients would like
 to create projects that are not file based. The current workaround is
 to provide access to the non-file based project via a custom view, but
 better integration would occur if the navigator actually showed all
 project types.<br>
 <h1>Discussion</h1>
 <p>Given the number of different complaints about logical resource
 support indicates that this is indeed a large problem space. If we plan
 on addressing any of the complaints for 3.1, we will have to scope the
 solution to address a subset of the complaints. I propose the following
 grouping of the complaints:<br>
 </p>
 <p><span style="font-weight: bold;">Adaptables: Related to providing a
 richer adaptable interface between plug-ins<br>
 </span>Complaint 1: Not very adaptable<br>
 Complaint 2: Decorators<br>
 Complaint 7: Merging can't consider files related to a logical element<br>
 </p>
 <p><span style="font-weight: bold;">Presentation of logical models:
 Related to exposing a non-resource based data modeling framework</span><br>
 Complaint 6: IResource based views in the IDE<br>
 Complaint 3: Presentation of mixed logical models<br>
 </p>
 <span style="font-weight: bold;">Others</span><br>
 Complaint 4: Change Sets<br>
 Complaint 5: Participating in operations<br>
 <p>A common discussion in the community is the idea
 that the resources plug-in should be generalized to become this generic
 model, but in reality it wasn't designed as such and although it
 contains common model services such as eventing and threading, it was
 explicitly designed to model the file system. Changes to the resources
 plug-in would be a major breaking API change and not acceptable to the
 community. <br>
 </p>
 <p>For 3.1 we will only address the Adaptables group of complaints. See
 <a href="logical-physical-adaptables.html">Solution 1: Support Logical
 Resources - Adaptables</a> for a discussion on a possible solution and
 investigate possible solutions for Complaint 3 and 5.<br>
 </p>
 </body>
 </html>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
	<html>
	<head>
	<title>Support Logical Resources</title>
	</head>
	<body>
	<table border="0" cellspacing="5" cellpadding="2" width="100%">
	<tbody>
	<tr>
	<td align="left" valign="top" bgcolor="#0080c0"> <b><font
	color="#ffffff" face="Arial,Helvetica"> Eclipse 3.1 - Plan item</font></b>
	</td>
	</tr>
	</tbody>
	</table>
	<h1>Support Logical Resources</h1>
	This document outlines the state of the Eclipse Platform <strong>Support
	Logical Resources</strong> plan item. Interested parties should review
	this document and verify that their use cases are reflected in the
	requirements then later that the solution provided satisfies their
	needs. 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 report</a>
	for this plan item.
	<p class="MsoNormal">This is the plan item:</p>
	<blockquote>
	<p>"<em>The Eclipse Platform supports a strong physical view of
	projects, files, and folders in the workspace. However, there are many
	situations where a physical view is not the most salient or useful for
	many purposes. In some cases, multiple distinct objects happen to be
	stored in a single file, like an archive. Conversely, in other cases,
	something that is logically a single object is stored across multiple
	files. This discrepancy between logical and physical creates problems
	for common operations such as searching, comparing, and versioning,
	which need to work in the physical realm. Eclipse should support some
	way of mapping between a logical view and the physical organization of
	files on disk.</em>"</p>
	<p>Last Modified: July 2nd, 2003<br>
	</p>
	</blockquote>
	<h1>Motivation</h1>
	<p>By definition Eclipse supports logical resources. It's a "an open
	extensible IDE for anything and nothing in particular". The
	applications that are built with it can be tailored to a particular
	problem domain and the workbench extensions can be used to provide
	support for any logical model. What Eclipse really doesn't support is
	integrating tools at the logical model. In order to integrate two
	plugins into Eclipse either the two plugins have to know about each
	other, or both plugins have to depend on some common plugin. While the
	first option is satisfactory for a few cases, the second case is the
	most common and the most problematic. To illustrate, the Eclipse SDK
	contains several plugins that are based on the Resources plugin (e.g.
	Team, Search, Compare, JDT). When an application is packaged based on
	the SDK, because the plugins in the SDK are resource based that is the
	common integration point between plug-ins.<br>
	</p>
	<p>As you will see later, even the users of the SDK (JDT+CVS+Resources)
	can observe some of the problems associated with the lack of support
	for logical resources and the implicit mapping to physical resources.
	The lack of a logical integration point causes the co-existance of
	plugins in Eclipse to be error prone for the user. The next sections
	will examine the relationships between logical and physical resources
	and outline the visible problems with Eclipse 3.0.</p>
	<h2>Existing Bugs</h2>
	<p>Bug <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=32582">32582</a>
	logical to physical mapping problem , 1 model element = 2 Files problem<br>
	Bug <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=3979">3979</a>
	[CVS Decorator] show version info works incorrectly for sub packages
	(1GFDIEB)<br>
	</p>
	<h2>Logical Resources Defined<br>
	</h2>
	<p>Whereas logical resources are elements of the application that model
	the data/processes of a particular problem domain, the physical
	resources are the file system resources (e.g. files and folders) into
	which an application will eventually transform their application model
	for storage. Applications that don't use file system resources are not
	being considered as part of this plan item. For example, an application
	that stores it's application data directly into a database.</p>
	<p>The following table enumerates concrete examples of how logical and
	physical resources are used in current applications integrated into
	Eclipse.</p>
	<p><a name="#table1"></a>Table 1: Example logical to physical uses</p>
	<table width="100%" border="1">
	<tbody>
	<tr>
	<td width="23%">
	<div align="center"><strong>Relationships</strong></div>
	</td>
	<td width="77%">
	<div align="center"><strong>Examples</strong></div>
	</td>
	</tr>
	<tr>
	<td>
	<p>logical (1) <-> (*) physical</p>
	<p>one logical to many physical</p>
	</td>
	<td valign="top">
	<p><a name="#1a"></a>(<strong>1a</strong>) EJB maps to several
	physical files: (WSAD + XDE Tester). This is the most common case we
	have found. </p>
	<blockquote>
	<p>/src/org/app/bean.java<br>
	/src/org/app/beanr.java<br>
	/src/org/app/beanlocal.java</p>
	</blockquote>
	<p><em>Note: If one of the logical resource's files was deleted
	who would remember that the file used to exist and is an outgoing
	deletion or that there is an incoming addition to the logical resource?</em></p>
	<p><a name="#1b"></a>(<strong>1b</strong>) Composite Object
	(logical) maps to several changed physical resources. (Rational XDE)</p>
	<p><em>Note</em>: <em>With 1 to many relationship there is
	always the complication that arises if the logical element maps to
	files in an other project? This would cause many problems in the
	current Team plugin.</em></p>
	</td>
	</tr>
	<tr>
	<td>
	<p>logical (*) <-> (1) physical</p>
	<p>many logical to one physical</p>
	</td>
	<td valign="top">
	<p><a name="#2a"></a>(<strong>2a</strong>) Methods in a class map
	to their containing class file. (JDT)</p>
	<p><a name="#2b"></a>(<strong>2b</strong>) Archive files (zip,
	jar) can be seen as a logical and the contents of the archive all map
	to the same physical.(JTD + all)</p>
	</td>
	</tr>
	<tr>
	<td>
	<p>logical (1) <-> (1) physical</p>
	<p>one logical to one physical</p>
	</td>
	<td valign="top">
	<p><a name="#3a"></a>(<strong>3a</strong>) A Java Package maps to
	a folder but a package does not include sub folders (e.g. they are
	shallow). (JDT)</p>
	<p><a name="#3b"></a>(<strong>3b</strong>) A UML class maps to a
	file. For example, in a UML application a class could be stored in a
	single file called 'x435dsds.umlclass'. The reason it's a logical is
	that the user of the application will never be concerned about the
	actual file name or even the folder it's stored in. (XDE)</p>
	</td>
	</tr>
	</tbody>
	</table>
	<h1>Complaints<br>
	</h1>
	<p>The following complaints are representative of bug reports and
	requirements received from several Eclipse users and developers.<br>
	</p>
	<h2>Complaint 1: Not very adaptable</h2>
	<p>Object contributions and decorators are key mechanisms for providing
	rich integration between tools. Using object contributions and
	adaptable objects, any plugin can provide actions and decorators that
	will show in another plugin's view. </p>
	<p>Since IResource is the lowest common integration class and is
	strongly mapped to its physical storage as files and folders, the
	integration point for actions and decorators cannot be the logical
	types in the view. The actions will consequently use the adaptable type
	from the selection to perform the action or the decorator the resource
	from the getImage request.</p>
	<p>Here is an example to illustrate the problem with the CVS plugin.
	When running a CVS commit action in the packages view the action
	doesn't know that the IFolder is a Java package and is a shallow
	namespace. It will use the selection and traverse the selected
	IContainer using IContainer.members() and commit all child resources.
	This is the same when the CVS outgoing decorator is shown on a package.
	It will reflect the deep outgoing state of the IContainer. This can
	lead to unexpected behavior because the user expected the action to run
	on the model that the action was displayed on.</p>
	<p>Example object contribution for the CVS commit action:</p>
	<pre><extension point="org.eclipse.ui.popupMenus"><br> <objectContribution<br> objectClass="org.eclipse.core.resources.IResource"<br> adaptable="true"<br> id="org.eclipse.team.ccvs.ui.IResourceContributions"><br> <filter<br> name="projectPersistentProperty"<br> value="org.eclipse.team.core.repository=org.eclipse.team.cvs.core.cvsnature"><br> </filter><br> <action<br> label="Commit"<br> tooltip="Commit resource to CVS repository"<br> class="org.eclipse.team.internal.ccvs.ui.actions.CommitAction"<br> menubarPath="team.main/group3"<br> id="org.eclipse.team.ccvs.ui.commit"><br> </action><br> <objectContribution><br></extension><br></pre>
	<p>Example code run in the commit action to calculate the resources to
	commit:</p>
	<pre>public static Object[] getSelectedAdaptables(ISelection selection) {<br> ArrayList result = null;<br> if (!selection.isEmpty()) {<br> result = new ArrayList();<br> Iterator elements = ((IStructuredSelection) selection).iterator();<br> while (elements.hasNext()) {<br> Object adapter = getAdapter(elements.next(), IResource.class);<br> if (c.isInstance(adapter)) {<br> result.add(adapter);<br> }<br> }<br> }<br> if (result != null && !result.isEmpty()) {<br> return (Object[])result.toArray((Object[])Array.newInstance(IResource.class, result.size()));<br> }<br> return (Object[])Array.newInstance(IResource.class, 0);<br>}</pre>
	<p>Example code for defining an IResource adaptable decorator:</p>
	<pre><extension<br> point="org.eclipse.ui.decorators"><br> <decorator objectClass="org.eclipse.core.resources.IResource"<br> adaptable="true"<br> label="%DecoratorStandard.name"<br> state="false"<br> lightweight= "true"<br> quadrant = "BOTTOM_RIGHT"<br> class="org.eclipse.team.internal.ccvs.ui.CVSLightweightDecorator"<br> id="org.eclipse.team.cvs.ui.decorator"><br> <description><br> %DecoratorStandard.desc<br> </description><br> </decorator><br></extension></pre>
	<h2>Complaint 2: Decorators</h2>
	<p>When the CVS decorator decorates a logical container in a view, the
	desire is to decorate parents with the dirty indicator if one or more
	of their logical children are dirty. To do this properly, the decorator
	would need to query the dirty status of each of the logical children of
	the container. This can be a costly operation as each child may itself
	be a logical container. We have optimized the dirty decoration by
	caching folder dirty states. This optimization becomes far more
	complicated with logical models where the caching must be based on this
	alternate model (i.e. the state must be cached for each model).</p>
	<p> In addition, often decorators rely on IResource change events
	to re-calculate some new state. In the case of a logical elements
	representing several physical resources there is no easy way of
	associated a IResource change event to its files and the actual logical
	element.</p>
	<h2>Complaint 3: Presentation of mixed logical models<br>
	</h2>
	<p>It would be nice to see the Java logical view in the Synchronize
	view, in the navigator, or in dialogs contributed by other plug-ins
	besides JDT. However, the entries in these views
	may not be IResources so an IResource independent mapping mechanism
	would be required. A workaround for this problem is demonstrated by the
	Search plug-in which allows for plug-ins to integrate with other tools
	by contributing domain specific pages. JDT contributes a JDT search
	page to the view and shows logical Java elements. This solution however
	doesn't allow showing mixed logical models in the same widget, which is
	required several presentations in the SDK such as the Synchronize View,
	Navigator, Refactoring Preview, and many others.<br>
	</p>
	Also, if an action prompts the user, for example to add resources to
	CVS, what icons and labels are used in the dialog? It would be nice to
	show those that are most familiar to the user. <br>
	<br>
	There are two levels of logical model presentation:<br>
	<ul>
	<li>Need for full access to a logical model that would allow building
	a dynamic UI. This would include mapping from an IResource to a logical
	element (Complex).<br>
	</li>
	</ul>
	<ul>
	<li>Need name and icon for a logical element to display in simple
	dialogs (Simple).<br>
	</li>
	</ul>
	<h2>Complaint 4: Change Sets</h2>
	<p>Consider a user's action as a logical change, for example, the user
	renames a class using the JDT refactoring action. In the user's mind he
	'renamed a class' and knows that there have been side effects to other
	resources. Currently there is not way of capturing these logical
	actions
	and associating the set of affected resources. This problem manifests
	itself more in tools where almost every change to the model has side
	effects.</p>
	<h2>Complaint 5: Participating in operations</h2>
	Some logical models may want to participate and even restrict the kinds
	of operations are
	allowed on theirs files. For example, if a logical element is composed
	of three files, the users should not be allowed to move, or delete them
	individually. In essence, a way of vetoing or participating in all
	resource refactorings for resources that are part of a logical model.<br>
	<br>
	The most obvious problem in the current Eclipse is that the resource
	navigator exposes resource refactorings (move, delete, copy) and the
	logical cannot easily override this behavior. <br>
	<h2>Complaint 6: IResource based views in the IDE</h2>
	There are several views in the workbench IDE that could be used by
	logical models but are currently too tied to resources. For example,
	the problems and tasks views have a resource column and works uniquely
	on IResource markers. This means that if a logical model provides
	problems and tasks the problems and tasks views cannot be used to show
	the logical element instead of the file.<br>
	<h2>Complaint 7: Merging can't consider all files related to a logical
	element</h2>
	When merging a logical element the repository may find a conflict in
	one of the files that is part of the logical element. The repository
	tool will typically fetch the revisions for the conflicting file so
	that a comparison can be shown to the user. But since the repository
	tool doesn't know that other files are part of the logical resource,
	the comparison shown to the user doesn't have access to the correct
	revisions of the other files. This is a problem because it then becomes
	impossible to implement a comparison that has access to all the
	revisions of the logical element's files.<br>
	<h2>Complaint 8: Creating non-IResource projects that appear in the
	navigator</h2>
	Currently the Navigator displays the Resources plugin workspace and
	thus only resource projects can be displayed. Many clients would like
	to create projects that are not file based. The current workaround is
	to provide access to the non-file based project via a custom view, but
	better integration would occur if the navigator actually showed all
	project types.<br>
	<h1>Discussion</h1>
	<p>Given the number of different complaints about logical resource
	support indicates that this is indeed a large problem space. If we plan
	on addressing any of the complaints for 3.1, we will have to scope the
	solution to address a subset of the complaints. I propose the following
	grouping of the complaints:<br>
	</p>
	<p><span style="font-weight: bold;">Adaptables: Related to providing a
	richer adaptable interface between plug-ins<br>
	</span>Complaint 1: Not very adaptable<br>
	Complaint 2: Decorators<br>
	Complaint 7: Merging can't consider files related to a logical element<br>
	</p>
	<p><span style="font-weight: bold;">Presentation of logical models:
	Related to exposing a non-resource based data modeling framework</span><br>
	Complaint 6: IResource based views in the IDE<br>
	Complaint 3: Presentation of mixed logical models<br>
	</p>
	<span style="font-weight: bold;">Others</span><br>
	Complaint 4: Change Sets<br>
	Complaint 5: Participating in operations<br>
	<p>A common discussion in the community is the idea
	that the resources plug-in should be generalized to become this generic
	model, but in reality it wasn't designed as such and although it
	contains common model services such as eventing and threading, it was
	explicitly designed to model the file system. Changes to the resources
	plug-in would be a major breaking API change and not acceptable to the
	community. <br>
	</p>
	<p>For 3.1 we will only address the Adaptables group of complaints. See
	<a href="logical-physical-adaptables.html">Solution 1: Support Logical
	Resources - Adaptables</a> for a discussion on a possible solution and
	investigate possible solutions for Complaint 3 and 5.<br>
	</p>
	</body>
	</html>