bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/registry/PerspectiveDescriptor.java

package org.eclipse.ui.internal.registry;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import java.io.*;

import org.eclipse.core.runtime.*;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.ui.*;
import org.eclipse.ui.internal.*;

/**
 * PerspectiveDescriptor.
 * <p>
 * A PerspectiveDesciptor has 3 states:
 * </p>
 * <ol>
 * <li>It <code>isPredefined()</code>, in which case it was defined from an
 * extension point.</li>
 * <li>It <code>isPredefined()</code> and <code>hasCustomFile</code>, in which 
 * case the user has customized a predefined perspective.</li>
 * <li>It <code>hasCustomFile</code>, in which case the user created a
 * new perspective.</li>
 * </ol>
 */
public class PerspectiveDescriptor implements IPerspectiveDescriptor {
	private String id;
	private String originalId;
	private String label;
	private String className;
	private boolean singleton;
	private ImageDescriptor image;
	private IConfigurationElement configElement;
	private File customFile;
	
	private static final String ATT_ID="id";//$NON-NLS-1$
	private static final String ATT_DEFAULT = "default";//$NON-NLS-1$
	private static final String ATT_NAME="name";//$NON-NLS-1$
	private static final String ATT_ICON="icon";//$NON-NLS-1$
	private static final String ATT_CLASS="class";//$NON-NLS-1$
	private static final String ATT_SINGLETON="singleton";//$NON-NLS-1$
	
/**
 * Create a descriptor from a file.
 */
public PerspectiveDescriptor(File file)
	throws IOException, WorkbenchException
{
	super();
	InputStream stream = null;
	try {
		stream = new FileInputStream(file);
		InputStreamReader reader = new InputStreamReader(stream, "utf-8"); //$NON-NLS-1$
		// Restore the layout state.
		IMemento memento = XMLMemento.createReadRoot(reader);
		IStatus status = restoreState(memento);
		reader.close();
		stream = null;
		customFile = file;
		if(status.getSeverity() == IStatus.ERROR)
			throw new WorkbenchException(status);
	} finally {
		if (stream != null)
			stream.close();
	}
}
/**
 * Create a new empty descriptor.
 */
public PerspectiveDescriptor(String id, String label,PerspectiveDescriptor originalDescriptor) {
	super();
	this.id = id;
	this.label = label;
	if(originalDescriptor != null) {
		this.originalId = originalDescriptor.getOriginalId();
		this.image = originalDescriptor.image;
	}
}
/**
 * Create a descriptor from a config element.
 */
public PerspectiveDescriptor(IConfigurationElement configElement)
	throws CoreException
{
	super();
	this.configElement = configElement;
	id = configElement.getAttribute(ATT_ID);
	label = configElement.getAttribute(ATT_NAME);
	className = configElement.getAttribute(ATT_CLASS);
	singleton = (configElement.getAttributeAsIs(ATT_SINGLETON) != null);

	// Sanity check.
	if ((label == null) || (className == null)) {
		throw new CoreException(new Status(IStatus.ERROR,
			WorkbenchPlugin.PI_WORKBENCH, 0,
			"Invalid extension (missing label or class name): " + id,//$NON-NLS-1$
			null));
	}

	// Load icon.
	String icon = configElement.getAttribute(ATT_ICON);
	if (icon != null) {
		image = WorkbenchImages.getImageDescriptorFromExtension(
			configElement.getDeclaringExtension(), icon);
	}
}
/**
 * Creates a factory for a predefined perspective.  If the perspective
 * is not predefined return null.
 *
 * @throws a CoreException if the object could not be instantiated.
 */
public IPerspectiveFactory createFactory() throws CoreException {
	if (className == null)
		return null;
	Object obj = WorkbenchPlugin.createExtension(configElement, ATT_CLASS);
	return (IPerspectiveFactory) obj;
}
/**
 * Deletes the custom file for a perspective..
 */
public boolean deleteCustomFile() {
	return customFile.delete();
}
/**
 * Returns the custom file.
 */
public File getCustomFile() {
	return customFile;
}
/**
 * Returns the ID.
 */
public String getId() {
	return id;
}
/**
 * Returns the descriptor of the image for this perspective.
 *
 * @return the descriptor of the image to display next to this perspective
 */
public ImageDescriptor getImageDescriptor() {
	return image;
}
/**
 * Returns the label.
 */
public String getLabel() {
	return label;
}
public String getOriginalId() {
	if(originalId == null)
		return id;
	return originalId;
}
/**
 * Returns true if this perspective has a custom file.
 */
public boolean hasCustomFile() {
	return customFile.exists();
}
/**
 * Returns true if this perspective wants to be default.
 */
public boolean hasDefaultFlag() {
	if (configElement == null)
		return false;
	String str = configElement.getAttribute(ATT_DEFAULT);
	if (str == null)
		return false;
	return str.equals("true");//$NON-NLS-1$
}
/**
 * Returns true if this perspective is predefined by an extension.
 */
public boolean isPredefined() {
	return (className != null);
}
/**
 * Returns true if this perspective is a singleton.
 */
public boolean isSingleton() {
	return singleton;
}
/**
 * @see IPersistable
 */
public IStatus restoreState(IMemento memento) {
	IMemento childMem = memento.getChild(IWorkbenchConstants.TAG_DESCRIPTOR);
	if(childMem != null) {
		id = childMem.getString(IWorkbenchConstants.TAG_ID);
		originalId = childMem.getString(IWorkbenchConstants.TAG_DESCRIPTOR);
		label = childMem.getString(IWorkbenchConstants.TAG_LABEL);
		className = childMem.getString(IWorkbenchConstants.TAG_CLASS);
		String customFileStr = childMem.getString(IWorkbenchConstants.TAG_FILE);
		if(customFileStr != null) {
			IPath path = WorkbenchPlugin.getDefault().getStateLocation();
			path = path.append(customFileStr);
			customFile = path.toFile();
		}
		singleton = (childMem.getInteger(IWorkbenchConstants.TAG_SINGLETON) != null);
	
		//Find a descriptor in the registry.
		PerspectiveDescriptor descriptor = (PerspectiveDescriptor)WorkbenchPlugin.getDefault().
			getPerspectiveRegistry().findPerspectiveWithId(getOriginalId());
	
		if(descriptor != null)
			//Copy the state from the registred descriptor.	
			image = descriptor.image;
	}
	return new Status(IStatus.OK,PlatformUI.PLUGIN_ID,0,"",null);		
}
/**
 * Revert to the predefined extension template.
 * Does nothing if this descriptor is user defined.
 */
public void revertToPredefined() {
	if (isPredefined())
		deleteCustomFile();
}
/**
 * @see IPersistable
 */
public IStatus saveState(IMemento memento) {
	IMemento childMem = memento.createChild(IWorkbenchConstants.TAG_DESCRIPTOR);
	childMem.putString(IWorkbenchConstants.TAG_ID,id);
	if(originalId != null)
		childMem.putString(IWorkbenchConstants.TAG_DESCRIPTOR,originalId);
	childMem.putString(IWorkbenchConstants.TAG_LABEL,label);
	childMem.putString(IWorkbenchConstants.TAG_CLASS,className);
	childMem.putString(IWorkbenchConstants.TAG_FILE,customFile.getName());
	if (singleton)
		childMem.putInteger(IWorkbenchConstants.TAG_SINGLETON, 1);
	return new Status(IStatus.OK,PlatformUI.PLUGIN_ID,0,"",null);
}
/**
 * Sets the custom file.
 */
public void setCustomFile(File file) {
	this.customFile = file;
}
}