org.eclipse.n4js.ui.preferences.external.ExternalLibraryTreeContentProvider.java Source code

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Here is the source code for org.eclipse.n4js.ui.preferences.external.ExternalLibraryTreeContentProvider.java

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/**
 * Copyright (c) 2016 NumberFour AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   NumberFour AG - Initial API and implementation
 */
package org.eclipse.n4js.ui.preferences.external;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.eclipse.jface.viewers.ILazyTreeContentProvider;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.n4js.external.N4JSExternalProject;
import org.eclipse.n4js.preferences.ExternalLibraryPreferenceStore;
import org.eclipse.n4js.projectDescription.ProjectDescription;
import org.eclipse.n4js.projectModel.IN4JSProject;
import org.eclipse.n4js.projectModel.locations.FileURI;
import org.eclipse.n4js.ui.external.EclipseExternalLibraryWorkspace;
import org.eclipse.xtext.util.Pair;

import com.google.common.base.Optional;
import com.google.common.collect.Iterables;
import com.google.inject.Inject;

/**
 * Lazy tree content provider implementation for the external libraries preference page's viewer.
 */
public class ExternalLibraryTreeContentProvider implements ILazyTreeContentProvider {

    private Optional<TreeViewer> treeViewerRef;
    // cache list of projects per location (invalidated on #inputChanged)
    private final Map<FileURI, List<IN4JSProject>> locationProjectsCache = new HashMap<>();

    @Inject
    private EclipseExternalLibraryWorkspace externalLibraryWorkspace;

    @Inject
    private ExternalLibraryPreferenceStore externalLibraryPreferenceStore;

    @Override
    public void dispose() {
        // Nothing to dispose.
    }

    @Override
    public void inputChanged(final Viewer viewer, final Object oldInput, final Object newInput) {
        if (viewer instanceof TreeViewer) {
            this.treeViewerRef = Optional.of((TreeViewer) viewer);
        } else {
            this.treeViewerRef = Optional.absent();
        }
        // clear projects cache when input changes
        this.locationProjectsCache.clear();
    }

    @Override
    public void updateElement(final Object parent, final int index) {
        if (treeViewerRef.isPresent()) {
            final TreeViewer treeViewer = treeViewerRef.get();
            if (parent instanceof Iterable) {
                final Object child = Iterables.get((Iterable<?>) parent, index);
                treeViewer.replace(parent, index, child);
                if (child instanceof FileURI) {
                    treeViewer.setChildCount(child, getProjects((FileURI) child).size());
                }
            } else if (parent instanceof FileURI) {
                final IN4JSProject child = getProjects((FileURI) parent).get(index);
                treeViewer.replace(parent, index, child);
            }
        }
    }

    @Override
    public void updateChildCount(final Object element, final int currentChildCount) {
        if (treeViewerRef.isPresent()) {
            final TreeViewer treeViewer = treeViewerRef.get();
            if (element instanceof Iterable) {
                treeViewer.setChildCount(element, Iterables.size((Iterable<?>) element));
            } else if (element instanceof FileURI) {
                treeViewer.setChildCount(element, getProjects((FileURI) element).size());
            } else {
                treeViewer.setChildCount(element, 0);
            }
        }
    }

    @Override
    public Object getParent(final Object element) {
        return null;
    }

    /** Returns the list of {@link IN4JSProject} to be found in the given external location. */
    private List<IN4JSProject> getProjects(FileURI location) {
        if (locationProjectsCache.isEmpty()) {
            initCache();
        }

        return locationProjectsCache.get(location);
    }

    private void initCache() {
        locationProjectsCache.clear();
        for (FileURI extLoc : externalLibraryPreferenceStore.getLocations()) {
            locationProjectsCache.putIfAbsent(extLoc, new LinkedList<>());
        }

        for (Pair<FileURI, ProjectDescription> pair : externalLibraryWorkspace.getProjectsIncludingUnnecessary()) {

            FileURI prjLocation = pair.getFirst();
            FileURI rootLocation = externalLibraryWorkspace.getRootLocationForResource(prjLocation);
            N4JSExternalProject project = externalLibraryWorkspace.getProject(prjLocation);
            locationProjectsCache.putIfAbsent(rootLocation, new LinkedList<>());
            List<IN4JSProject> list = locationProjectsCache.get(rootLocation);
            IN4JSProject iProject = project.getIProject();
            list.add(iProject);
        }
    }

}