TargetPlatform.java

/*****************************************************************************
 * Copyright (c) 2006-2013, Cloudsmith Inc.
 * The code, documentation and other materials contained herein have been
 * licensed under the Eclipse Public License - v 1.0 by the copyright holder
 * listed above, as the Initial Contributor under such license. The text of
 * such license is available at www.eclipse.org.
 *****************************************************************************/
package org.eclipse.buckminster.core;

import java.io.File;
import java.net.URL;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import org.eclipse.buckminster.core.cspec.model.ComponentIdentifier;
import org.eclipse.buckminster.core.helpers.AbstractExtension;
import org.eclipse.buckminster.core.helpers.FileUtils;
import org.eclipse.buckminster.runtime.BuckminsterException;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.osgi.service.datalocation.Location;

/**
 * @author Thomas Hallgren
 */
public class TargetPlatform extends AbstractExtension implements ITargetPlatform {
	private static ITargetPlatform instance = null;

	public static final String TARGET_PLATFORM_PROVIDERS_POINT = CorePlugin.CORE_NAMESPACE + ".targetPlatformProviders"; //$NON-NLS-1$

	public static final String TARGET_PREFIX = "target"; //$NON-NLS-1$

	public static final String TARGET_OS = TARGET_PREFIX + ".os"; //$NON-NLS-1$

	public static final String TARGET_WS = TARGET_PREFIX + ".ws"; //$NON-NLS-1$

	public static final String TARGET_ARCH = TARGET_PREFIX + ".arch"; //$NON-NLS-1$

	public static final String TARGET_NL = TARGET_PREFIX + ".nl"; //$NON-NLS-1$

	public static final String TARGET_LOCATION = TARGET_PREFIX + ".location"; //$NON-NLS-1$

	public static synchronized ITargetPlatform getInstance() throws CoreException {
		if (instance == null) {
			IExtensionRegistry exReg = Platform.getExtensionRegistry();
			IConfigurationElement[] elems = exReg.getConfigurationElementsFor(TARGET_PLATFORM_PROVIDERS_POINT);

			IConfigurationElement candidate = null;
			int maxPrio = -1;
			for (IConfigurationElement elem : elems) {
				String prioStr = elem.getAttribute("priority"); //$NON-NLS-1$
				if (prioStr == null)
					//
					// Bogus entry. The priority attribute is mandatory
					//
					continue;

				try {
					int prio = Integer.parseInt(prioStr);
					if (prio > maxPrio) {
						maxPrio = prio;
						candidate = elem;
					}
				} catch (NumberFormatException e) {
					continue;
				}
			}

			if (candidate == null)
				throw BuckminsterException.fromMessage(Messages.No_targetPlatformProvider_registered_with_targetPlatformProviders_extension_point);
			instance = (ITargetPlatform) candidate.createExecutableExtension("class"); //$NON-NLS-1$
			CorePlugin.getLogger().debug("Target platform provided by %s", instance.getClass()); //$NON-NLS-1$
		}
		return instance;
	}

	public static File getPlatformInstallLocation() {
		Location location = Platform.getInstallLocation();
		if (location == null)
			return null;

		URL eclipseHome = location.getURL();
		if (eclipseHome == null)
			return null;

		assert ("file".equals(eclipseHome.getProtocol())); //$NON-NLS-1$
		return FileUtils.getFile(eclipseHome);
	}

	@Override
	public String getArch() {
		return Platform.getOSArch();
	}

	@Override
	public final List<ComponentIdentifier> getComponents() throws CoreException {
		return Collections.emptyList();
	}

	@Override
	public File getDefaultPlatformLocation(boolean asActive) throws CoreException {
		return null;
	}

	@Override
	public File getLocation() {
		return getPlatformInstallLocation();
	}

	@Override
	public String getNL() {
		return Platform.getNL();
	}

	@Override
	public String getOS() {
		return Platform.getOS();
	}

	@Override
	public String getWS() {
		return Platform.getWS();
	}

	@Override
	public void locationsChanged(Set<File> locations) {
		// Nothing to do here.
	}

	@Override
	public void refresh() {
		// Nothing to do here.
	}
}