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Retrieving IPackageFragmentRoot from a JAR [message #254045]

Wed, 18 June 2008 08:49

Eclipse User

Hi Folks,

I'm having trouble constructing a valid IType reference to a class file
located in a JAR. I'm using the SearchEngine of Eclipse 3.2 (sorry I'm
stuck with this version) which hands me results via my implementation of
TypeNameRequestor. In some cases, the path attribute is of the form

"<path to JAR>|<classname>.jar"

I extract the <path to JAR> part and resolve it to an IFile reference I
called "file" in the snippet below. This JAR file is located in a
Simple Eclipse project without a Java nature. I "opened" the project
out of desperation in line 2, but that didn't seem to have an effect.

In the debugger, line 3 returns null. The Javadoc says this happens
with the archive is not of an appropriate format. But the JDT
SearchEngine had no trouble finding the class file inside it. The
"packageName" and "typeName" variables below were populated by the
SearchEngine.

Ultimately, I'm simply trying to find a list of methods of a type
returned to me via the SearchEngine. I'd appreciate any pointers.

1 if (file.exists()) {
2 file.getProject().open(null);
3 IPackageFragmentRoot jarRoot =
JavaCore.createJarPackageFragmentRootFrom(file);
4 IPackageFragment packageFragment =
jarRoot.getPackageFragment(packageName);
5 IClassFile classFile =
packageFragment.getClassFile(typeName + ".class");
6 if (classFile.getType().isStructureKnown()) {
7 result = classFile.getType();
8 } else {
9 System.out.println("JDT could not determine the structure of "
+ classFile.getElementName());
10 }

- Paul Glezen

Re: Retrieving IPackageFragmentRoot from a JAR [message #254049 is a reply to message #254045]

Wed, 18 June 2008 09:05

Eclipse User

Paul Glezen wrote:
> Hi Folks,
>
> I'm having trouble constructing a valid IType reference to a class file
> located in a JAR. I'm using the SearchEngine of Eclipse 3.2 (sorry I'm
> stuck with this version) which hands me results via my implementation of
> TypeNameRequestor. In some cases, the path attribute is of the form
>
> "<path to JAR>|<classname>.jar"
>
> I extract the <path to JAR> part and resolve it to an IFile reference I
> called "file" in the snippet below. This JAR file is located in a
> Simple Eclipse project without a Java nature. I "opened" the project
> out of desperation in line 2, but that didn't seem to have an effect.
>
> In the debugger, line 3 returns null. The Javadoc says this happens
> with the archive is not of an appropriate format. But the JDT
> SearchEngine had no trouble finding the class file inside it. The
> "packageName" and "typeName" variables below were populated by the
> SearchEngine.
>
> Ultimately, I'm simply trying to find a list of methods of a type
> returned to me via the SearchEngine. I'd appreciate any pointers.
>
> 1 if (file.exists()) {
> 2 file.getProject().open(null);
> 3 IPackageFragmentRoot jarRoot =
> JavaCore.createJarPackageFragmentRootFrom(file);
> 4 IPackageFragment packageFragment =
> jarRoot.getPackageFragment(packageName);
> 5 IClassFile classFile =
> packageFragment.getClassFile(typeName + ".class");
> 6 if (classFile.getType().isStructureKnown()) {
> 7 result = classFile.getType();
> 8 } else {
> 9 System.out.println("JDT could not determine the structure of "
> + classFile.getElementName());
> 10 }
>
>
> - Paul Glezen
>
Is the jar on the classpath of file.getProject() or is it on the classpath of another project?
If it is on the classpath of another project, you should use JavaCore.create(IFile,IJavaProject).

Jerome

Re: Retrieving IPackageFragmentRoot from a JAR [message #254056 is a reply to message #254049]

Wed, 18 June 2008 10:46

Eclipse User

Thanks for the tip, Jerome. Unfortunately, that method was added in
Eclipse 3.3. I'm on a project using RSA 7.0 which is based on Eclipse
3.2.

To answer your question, the JAR is located in a simple project. It is
in the classpath of the Java file that references it.

Is there a way achieve the effect of the API you referenced before
Eclipse 3.3?

Thanks,
- Paul

Jerome Lanneluc wrote:
> Paul Glezen wrote:
>>
>> 1 if (file.exists()) {
>> 2 file.getProject().open(null);
>> 3 IPackageFragmentRoot jarRoot =
>> JavaCore.createJarPackageFragmentRootFrom(file);
>> 4 IPackageFragment packageFragment =
>> jarRoot.getPackageFragment(packageName);
>> 5 IClassFile classFile =
>> packageFragment.getClassFile(typeName + ".class");
>> 6 if (classFile.getType().isStructureKnown()) {
>> 7 result = classFile.getType();
>> 8 } else {
>> 9 System.out.println("JDT could not determine the structure of "
>> + classFile.getElementName());
>> 10 }
>>
>>
>> - Paul Glezen
>>
> Is the jar on the classpath of file.getProject() or is it on the
> classpath of another project?
> If it is on the classpath of another project, you should use
> JavaCore.create(IFile,IJavaProject).
>
> Jerome

Re: Retrieving IPackageFragmentRoot from a JAR [message #254075 is a reply to message #254056]

Wed, 18 June 2008 12:39

Eclipse User

Paul Glezen wrote:
> Thanks for the tip, Jerome. Unfortunately, that method was added in
> Eclipse 3.3. I'm on a project using RSA 7.0 which is based on Eclipse 3.2.
>
> To answer your question, the JAR is located in a simple project. It is
> in the classpath of the Java file that references it.
>
> Is there a way achieve the effect of the API you referenced before
> Eclipse 3.3?
>
If you know the referring project, the following should do the trick:
IProject referringProject = ...;
IJavaProject javaProject = JavaCore.create(referringProject);
return javaProject.getPackageFragmentRoot(file);

If you don't know the referring project, then you would need to walk
all Java projects in the workspace:

IJavaProject[] projects = JavaCore.create(ResourcesPlugin.getWorkspace().getRoot()).ge tJavaProjects();
for (int i = 0; i < projects.length; i++) {
IPackageFragmentRoot root = projects[i].getPackageFragmentRoot(file);
if (root.exists())
return root;
}
return null;

Re: Retrieving IPackageFragmentRoot from a JAR [message #254078 is a reply to message #254075]

Wed, 18 June 2008 13:33

Eclipse User

This works! After meditating on your first reply, I figured that I need
to somehow supply a Java project that does have the JAR in its
classpath. Fortunately, I will know this project in advance. So I was
able to use the IJavaProject in a manner similar to your suggestion below.

Thanks a lot. This was really driving me nuts.

-Paul

Jerome Lanneluc wrote:
>>
> If you know the referring project, the following should do the trick:
> IProject referringProject = ...;
> IJavaProject javaProject = JavaCore.create(referringProject);
> return javaProject.getPackageFragmentRoot(file);
>
> If you don't know the referring project, then you would need to walk
> all Java projects in the workspace:
>
> IJavaProject[] projects =
> JavaCore.create(ResourcesPlugin.getWorkspace().getRoot()).ge tJavaProjects();
>
> for (int i = 0; i < projects.length; i++) {
> IPackageFragmentRoot root = projects[i].getPackageFragmentRoot(file);
> if (root.exists())
> return root;
> }
> return null;

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