Eclipse Project Explorer filter for XML files

问题

I have many XML files in the workbench Project Explorer, each one an instance of one of ten different ecore models. For each ecore model I would like to contribute a commonFilter to the navigator's navigatorContent extension point to enable the user to show or hide the corresponding XML files. These are external tool files so there is not a way to identify the content merely by observing the file name or the xml extension, and renaming is not feasible. Using perhaps a class deriving from org.eclipse.jface.viewers.ViewerFilter, what is the best way to identify which of the ecore models the XML file contains? I presume there is a simple way to do this with EMF resources, or with EcoreUtil, or with adapters, but I haven't found a successful technique. Alternatively, a way to do this directly from the extension point's filterExpression or the viewer's viewerContentBinding would be fine. All of the genmodel-derived plugins are available for the various ecore models.

package com.my.navigator;
import org.eclipse.core.resources.IFile;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;


public class MyViewerFilter extends ViewerFilter {

public MyViewerFilter() {
}

@Override
public boolean select(Viewer viewer, Object parentElement, Object element) {
        if ( element instanceof IFile ) {
            IFile file = (IFile)element;
            // check whether file is one of our ecore models...
            // ...
        }

        return true;
    }

}

回答1:

You could use the org.eclipse.core.contenttype.contentTypes to define new content types for your file.

Use the describer argument of the content type definition to specify a 'content describer' class which can check that the XML file meets your requirements. There is already an XMLContentDescriber class that you can use as a basis for the describer.

For example this is the content type definition for Ant build.xml files:

<extension 
    point="org.eclipse.core.contenttype.contentTypes"> 
    <content-type  
        id="antBuildFile" 
        name="%antBuildFileContentType.name" 
        base-type="org.eclipse.core.runtime.xml"
        file-names="build.xml"
        file-extensions="macrodef,ent,xml,ant"
        priority="normal"> 
        <describer 
            class="org.eclipse.ant.internal.core.contentDescriber.AntBuildfileContentDescriber">
        </describer> 
    </content-type> 
</extension>

and this is the Ant content describer to give you a rough idea of what you can:

public final class AntBuildfileContentDescriber extends XMLContentDescriber implements IExecutableExtension {

    private int checkCriteria(InputSource contents) throws IOException {
        AntHandler antHandler = new AntHandler();
        try {
            if (!antHandler.parseContents(contents)) {
                return INDETERMINATE;
            }
        }
        catch (SAXException e) {
            // we may be handed any kind of contents... it is normal we fail to parse
            return INDETERMINATE;
        }
        catch (ParserConfigurationException e) {
            // some bad thing happened - force this describer to be disabled
            String message = "Internal Error: XML parser configuration error during content description for Ant buildfiles"; //$NON-NLS-1$
            throw new RuntimeException(message);
        }
        // Check to see if we matched our criteria.
        if (antHandler.hasRootProjectElement()) {
            if (antHandler.hasProjectDefaultAttribute() || antHandler.hasTargetElement() || antHandler.hasAntElement()) {
                // project and default attribute or project and target element(s)
                // or project and top level ant element(s) (classpath, import, macrodef, path, property, taskdef, typedef)
                return VALID;
            }
            // only a top level project element...maybe an Ant buildfile
            return INDETERMINATE;
        }

        return INDETERMINATE;
    }

    @Override
    public int describe(InputStream contents, IContentDescription description) throws IOException {
        // call the basic XML describer to do basic recognition
        if (super.describe(contents, description) == INVALID) {
            return INVALID;
        }
        // super.describe will have consumed some chars, need to rewind
        contents.reset();
        // Check to see if we matched our criteria.
        return checkCriteria(new InputSource(contents));
    }

    @Override
    public int describe(Reader contents, IContentDescription description) throws IOException {
        // call the basic XML describer to do basic recognition
        if (super.describe(contents, description) == INVALID) {
            return INVALID;
        }
        // super.describe will have consumed some chars, need to rewind
        contents.reset();
        // Check to see if we matched our criteria.
        return checkCriteria(new InputSource(contents));
    }

    @Override
    public void setInitializationData(IConfigurationElement config, String propertyName, Object data) throws CoreException {
        // do nothing
    }
}

来源：https://stackoverflow.com/questions/27971748/eclipse-project-explorer-filter-for-xml-files