core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/internal/ui/wizards/buildpath/BuildpathContainerDescriptor.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *******************************************************************************/
package org.eclipse.dltk.internal.ui.wizards.buildpath;

import java.util.ArrayList;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.dltk.core.IBuildpathEntry;
import org.eclipse.dltk.core.IScriptProject;
import org.eclipse.dltk.internal.ui.util.CoreUtility;
import org.eclipse.dltk.internal.ui.wizards.IBuildpathContainerPage;
import org.eclipse.dltk.ui.DLTKUIPlugin;

public class BuildpathContainerDescriptor {

	private IConfigurationElement fConfigElement;
	private IBuildpathContainerPage fPage;

	private static final String ATT_EXTENSION = "buildpathContainerPage"; //$NON-NLS-1$

	private static final String ATT_ID = "id"; //$NON-NLS-1$
	private static final String ATT_NAME = "name"; //$NON-NLS-1$
	private static final String ATT_PAGE_CLASS = "class"; //$NON-NLS-1$
	private static final String ATT_NATURE = "nature"; //$NON-NLS-1$

	public BuildpathContainerDescriptor(IConfigurationElement configElement)
			throws CoreException {
		super();
		fConfigElement = configElement;
		fPage = null;

		String id = fConfigElement.getAttribute(ATT_ID);
		String name = configElement.getAttribute(ATT_NAME);
		String pageClassName = configElement.getAttribute(ATT_PAGE_CLASS);
		String nature = configElement.getAttribute(ATT_NATURE);

		if (name == null) {
			throw new CoreException(
					new Status(IStatus.ERROR, DLTKUIPlugin.PLUGIN_ID, 0,
							"Invalid extension (missing name): " + id, null)); //$NON-NLS-1$
		}
		if (nature == null) {
			throw new CoreException(new Status(IStatus.ERROR,
					DLTKUIPlugin.PLUGIN_ID, 0,
					"Invalid extension (missing nature): " + nature, null)); //$NON-NLS-1$
		}
		if (pageClassName == null) {
			throw new CoreException(
					new Status(IStatus.ERROR, DLTKUIPlugin.PLUGIN_ID, 0,
							"Invalid extension (missing page class name): " //$NON-NLS-1$
									+ id, null));
		}
	}

	public IBuildpathContainerPage createPage() throws CoreException {
		if (fPage == null) {
			Object elem = CoreUtility.createExtension(fConfigElement,
					ATT_PAGE_CLASS);
			if (elem instanceof IBuildpathContainerPage) {
				fPage = (IBuildpathContainerPage) elem;
			} else {
				String id = fConfigElement.getAttribute(ATT_ID);
				throw new CoreException(new Status(IStatus.ERROR,
						DLTKUIPlugin.PLUGIN_ID, 0,
						"Invalid extension (page not of type IBuildpathContainerPage): " //$NON-NLS-1$
								+ id,
						null));
			}
		}
		return fPage;
	}

	public IBuildpathContainerPage getPage() {
		return fPage;
	}

	public void setPage(IBuildpathContainerPage page) {
		fPage = page;
	}

	public void dispose() {
		if (fPage != null) {
			fPage.dispose();
			fPage = null;
		}
	}

	public String getName() {
		return fConfigElement.getAttribute(ATT_NAME);
	}

	public String getPageClass() {
		return fConfigElement.getAttribute(ATT_PAGE_CLASS);
	}

	public String getNature() {
		return fConfigElement.getAttribute(ATT_NATURE);
	}

	public boolean canEdit(IBuildpathEntry entry, String defid) {
		String id = fConfigElement.getAttribute(ATT_ID);
		return id.equals(defid);
	}

	public boolean canEdit(IBuildpathEntry entry) {
		String id = fConfigElement.getAttribute(ATT_ID);
		if (entry.getEntryKind() == IBuildpathEntry.BPE_CONTAINER) {
			String type = entry.getPath().segment(0);
			return id.equals(type);
		}
		return false;
	}

	public static BuildpathContainerDescriptor[] getDescriptors() {
		return getDescriptors(null);
	}

	public static BuildpathContainerDescriptor[] getDescriptors(
			IScriptProject proj) {
		ArrayList<BuildpathContainerDescriptor> containers = new ArrayList<>();

		IExtensionPoint extensionPoint = Platform.getExtensionRegistry()
				.getExtensionPoint(DLTKUIPlugin.PLUGIN_ID, ATT_EXTENSION);
		if (extensionPoint != null) {
			BuildpathContainerDescriptor defaultPage = null;
			String defaultPageName = BuildpathContainerDefaultPage.class
					.getName();

			IConfigurationElement[] elements = extensionPoint
					.getConfigurationElements();
			for (int i = 0; i < elements.length; i++) {
				try {
					BuildpathContainerDescriptor curr = new BuildpathContainerDescriptor(
							elements[i]);
					if (defaultPageName.equals(curr.getPageClass())) {
						defaultPage = curr;
					} else {
						if (proj == null || proj.getProject()
								.hasNature(curr.getNature()))
							containers.add(curr);
					}
				} catch (CoreException e) {
					DLTKUIPlugin.log(e);
				}
			}
			if (defaultPageName != null && containers.isEmpty()
					&& defaultPage != null) {
				// default page only added of no other extensions found
				containers.add(defaultPage);
			}
		}
		return containers
				.toArray(new BuildpathContainerDescriptor[containers.size()]);
	}
}