bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/dialogs/ElementTreeSelectionDialog.java

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
package org.eclipse.ui.dialogs;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;

import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.jface.viewers.ViewerSorter;

import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.WorkbenchMessages;

/**
 * A class to select elements out of a tree structure.
 * 
 * @since 2.0
 */
public class ElementTreeSelectionDialog extends SelectionStatusDialog {
	
	private TreeViewer fViewer;
	private ILabelProvider fLabelProvider;
	private ITreeContentProvider fContentProvider;
	
	private ISelectionStatusValidator fValidator= null;
	private ViewerSorter fSorter;
	private boolean fAllowMultiple= true;
	private boolean fDoubleClickSelects= true;
	private String fEmptyListMessage= WorkbenchMessages.getString("ElementTreeSelectionDialog.nothing_available"); //$NON-NLS-1$	
	
	private IStatus fCurrStatus= new Status(IStatus.OK, PlatformUI.PLUGIN_ID, IStatus.OK, "", null);
	private List fFilters;
	private Object fInput;		
	private boolean fIsEmpty;
	
	private int fWidth= 60;
	private int fHeight= 18;

	/**
	 * Constructs an instance of <code>ElementTreeSelectionDialog</code>.
	 * @param labelProvider   the label provider to render the entries
	 * @param contentProvider the content provider to evaluate the tree structure
	 */	
	public ElementTreeSelectionDialog(Shell parent, ILabelProvider labelProvider,
		ITreeContentProvider contentProvider)
	{
		super(parent);
		
		fLabelProvider= labelProvider;
		fContentProvider= contentProvider;

		setResult(new ArrayList(0));
		setStatusLineAboveButtons(true);
		
		int shellStyle= getShellStyle();
		setShellStyle(shellStyle | SWT.MAX | SWT.RESIZE);		
	}	

	/**
	 * Sets the initial selection.
	 * Convenience method.
	 * @param selection the initial selection.
	 */
	public void setInitialSelection(Object selection) {
		setInitialSelections(new Object[] {selection});
	}

	/**
	 * Sets the message to be displayed if the list is empty.
	 * @param message the message to be displayed.
	 */	
	public void setEmptyListMessage(String message) {
		fEmptyListMessage= message;
	}	

	/**
	 * Specifies if multiple selection is allowed.
	 */
	public void setAllowMultiple(boolean allowMultiple) {
		fAllowMultiple= allowMultiple;
	}
	
	/**
	 * Specifies if default selected events (double click) are created.
	 */
	public void setDoubleClickSelects(boolean doubleClickSelects) {
		fDoubleClickSelects= doubleClickSelects;
	}
	
	/**
	 * Sets the sorter used by the tree viewer.
	 */
	public void setSorter(ViewerSorter sorter) {
		fSorter= sorter;
	}		
	
	/**
	 * Adds a filter to the tree viewer.
	 * @param filter a filter.
	 */
	public void addFilter(ViewerFilter filter) {
		if (fFilters == null)
			fFilters= new ArrayList(4);
			
		fFilters.add(filter);
	}
	
	/**
	 * Sets an optional validator to check if the selection is valid.
	 * The validator is invoked whenever the selection changes.
	 * @param validator the validator to validate the selection.
	 */
	public void setValidator(ISelectionStatusValidator validator) {
		fValidator= validator;
	}			
	
	/**
	 * Sets the tree input.
	 * @param input the tree input.
	 */
	public void setInput(Object input) {
		fInput= input;
	} 

	/**
	 * Sets the size of the tree in unit of characters.
	 * @param width  the width of the tree.
	 * @param height the height of the tree.
	 */
	public void setSize(int width, int height) {
		fWidth= width;
		fHeight= height;
	}

	protected void updateOKStatus() {
		if (!fIsEmpty) {
			if (fValidator != null) {
				fCurrStatus= fValidator.validate(getResult());
				updateStatus(fCurrStatus);
			} else {
				fCurrStatus= new Status(IStatus.OK, PlatformUI.PLUGIN_ID, IStatus.OK, "", null);
			}
		} else {
			fCurrStatus= new Status(IStatus.ERROR, PlatformUI.PLUGIN_ID, IStatus.ERROR, fEmptyListMessage, null);
		}
		updateStatus(fCurrStatus);
	}
	
	/*
	 * @see Window#open()
	 */	 
	public int open() {
		fIsEmpty= evaluateIfTreeEmpty(fInput);
		BusyIndicator.showWhile(null, new Runnable() {
			public void run() {
				access$superOpen();
			}
		});
		
		return getReturnCode();
	}

	private void access$superOpen() {
		super.open();
	}	
	 		
	/**
	 * Handles cancel button pressed event.
	 */	 
	protected void cancelPressed() {
		setResult(null);
		super.cancelPressed();
	} 

	/*
	 * @see SelectionStatusDialog#computeResult()
	 */	 
	protected void computeResult() {
		setResult(((IStructuredSelection) fViewer.getSelection()).toList());
	} 
	 
	/*
	 * @see Window#create()
	 */	 
	public void create() {
		super.create();

		fViewer.setSelection(new StructuredSelection(getInitialElementSelections()), true);

		updateOKStatus();
	}		
	
	/*
	 * @see Dialog#createDialogArea(Composite)
	 */	 
	protected Control createDialogArea(Composite parent) {
		Composite composite= (Composite)super.createDialogArea(parent);
		
		Label messageLabel= createMessageArea(composite);
		TreeViewer treeViewer= createTreeViewer(composite);

		GridData data= new GridData(GridData.FILL_BOTH);
		data.widthHint= convertWidthInCharsToPixels(fWidth);
		data.heightHint= convertHeightInCharsToPixels(fHeight);
		
		Tree treeWidget= treeViewer.getTree();
		treeWidget.setLayoutData(data);
		
		if (fIsEmpty) {
			messageLabel.setEnabled(false);
			treeWidget.setEnabled(false);
		}
		
		return composite;
	}
	
	/**
	 * Creates the tree viewer.
	 * 
	 * @param parent the parent composite
	 * @return the tree viewer
	 */
	protected TreeViewer createTreeViewer(Composite parent) {
		int style= SWT.BORDER | (fAllowMultiple ? SWT.MULTI : SWT.SINGLE);

		fViewer= new TreeViewer(new Tree(parent, style));
		fViewer.setContentProvider(fContentProvider);
		fViewer.setLabelProvider(fLabelProvider);
		fViewer.addSelectionChangedListener(new ISelectionChangedListener() {
			public void selectionChanged(SelectionChangedEvent event) {
				access$setResult(((IStructuredSelection) event.getSelection()).toList());
				updateOKStatus();
			}	
		});
		
		fViewer.setSorter(fSorter);
		if (fFilters != null) {
			for (int i= 0; i != fFilters.size(); i++)
				fViewer.addFilter((ViewerFilter)fFilters.get(i));
		}
		
		if (fDoubleClickSelects) {
			Tree tree= fViewer.getTree();
			tree.addSelectionListener(new SelectionAdapter() {
				public void widgetDefaultSelected(SelectionEvent e) {
					updateOKStatus();
					if (fCurrStatus.isOK())
						access$superButtonPressed(IDialogConstants.OK_ID);
				}
			});
		}
		
		fViewer.setInput(fInput);
		
		return fViewer;
	}

	/**
	 * Returns the tree viewer.
	 * 
	 * @return the tree viewer
	 */
	protected TreeViewer getTreeViewer() {
		return fViewer;
	}
	
	private boolean evaluateIfTreeEmpty(Object input) {
		Object[] elements= fContentProvider.getElements(input);
		if (elements.length > 0) {
			if (fFilters != null) {
				for (int i= 0; i < fFilters.size(); i++) {
					ViewerFilter curr= (ViewerFilter)fFilters.get(i);
					elements= curr.filter(fViewer, input, elements);
				}
			}
		}
		return elements.length == 0;
	}
	
	protected void access$superButtonPressed(int id) {
		super.buttonPressed(id);
	}
	
	protected void access$setResult(List result) {
		super.setResult(result);
	}
	
   /**
	* @see org.eclipse.jface.window.Window#handleShellCloseEvent()
	*/
	protected void handleShellCloseEvent() {
		super.handleShellCloseEvent();

		//Handle the closing of the shell by selecting the close icon
		if (getReturnCode() == CANCEL)
			setResult(null);
	}
	
}