core/plugins/org.eclipse.dltk.debug.ui/src/org/eclipse/dltk/internal/debug/ui/interpreters/AbstractInterpreterLibraryBlock.java - dltk/org.eclipse.dltk.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2018 IBM Corporation and others.
  * 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
  *
  *******************************************************************************/
 package org.eclipse.dltk.internal.debug.ui.interpreters;

 import java.lang.reflect.InvocationTargetException;
 import java.util.Iterator;

 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.dltk.core.DLTKCore;
 import org.eclipse.dltk.core.environment.EnvironmentPathUtils;
 import org.eclipse.dltk.core.environment.IEnvironment;
 import org.eclipse.dltk.core.environment.IFileHandle;
 import org.eclipse.dltk.launching.EnvironmentVariable;
 import org.eclipse.dltk.launching.IInterpreterInstall;
 import org.eclipse.dltk.launching.IInterpreterInstallType;
 import org.eclipse.dltk.launching.LibraryLocation;
 import org.eclipse.dltk.launching.ScriptRuntime;
 import org.eclipse.dltk.ui.dialogs.TimeTriggeredProgressMonitorDialog;
 import org.eclipse.dltk.ui.environment.IEnvironmentUI;
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.dialogs.ProgressMonitorDialog;
 import org.eclipse.jface.viewers.IBaseLabelProvider;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;

 /**
  * Control used to edit the libraries associated with a Interpreter install
  */
 public abstract class AbstractInterpreterLibraryBlock
 		implements SelectionListener, ISelectionChangedListener {

 	/**
 	 * Attribute name for the last path used to open a file/directory chooser
 	 * dialog.
 	 */
 	protected static final String LAST_PATH_SETTING = "LAST_PATH_SETTING"; //$NON-NLS-1$

 	/**
 	 * the prefix for dialog setting pertaining to this block
 	 */
 	protected static final String DIALOG_SETTINGS_PREFIX = "AbstractInterpreterLibraryBlock"; //$NON-NLS-1$

 	protected boolean fInCallback = false;
 	protected IInterpreterInstall fInterpreterInstall;
 	protected IInterpreterInstallType fInterpreterInstallType;
 	protected IFileHandle fHome;

 	// widgets
 	protected LibraryContentProvider fLibraryContentProvider;
 	protected TreeViewer fLibraryViewer;
 	private Button fUpButton;
 	private Button fDownButton;
 	private Button fRemoveButton;
 	private Button fAddButton;
 	protected Button fDefaultButton;
 	protected Button fRediscoverButton;
 	private Button fEnabledButton;

 	protected AddScriptInterpreterDialog fDialog;

 	protected AbstractInterpreterLibraryBlock(
 			AddScriptInterpreterDialog dialog) {
 		this.fDialog = dialog;
 	}

 	/**
 	 * Creates and returns the source lookup control.
 	 *
 	 * @param parent
 	 *                   the parent widget of this control
 	 */
 	public Control createControl(Composite parent) {
 		Composite comp = new Composite(parent, SWT.NONE);
 		GridLayout topLayout = new GridLayout();
 		topLayout.numColumns = 2;
 		topLayout.marginHeight = 0;
 		topLayout.marginWidth = 0;
 		comp.setLayout(topLayout);
 		GridData gd = new GridData(GridData.FILL_BOTH);
 		comp.setLayoutData(gd);
 		createControlsIn(comp);
 		return comp;
 	}

 	/**
 	 * @since 2.0
 	 */
 	public void createControlsIn(Composite comp) {
 		Composite comp2 = new Composite(comp, SWT.NONE);
 		GridLayout topLayout = new GridLayout();
 		topLayout.numColumns = 1;
 		topLayout.marginHeight = 0;
 		topLayout.marginWidth = 0;
 		comp2.setLayout(topLayout);
 		GridData gd = new GridData(GridData.FILL_BOTH);
 		comp2.setLayoutData(gd);
 		fLibraryViewer = createViewer(comp2);
 		gd = new GridData(GridData.FILL_BOTH);
 		gd.heightHint = 6;
 		fLibraryViewer.getControl().setLayoutData(gd);
 		fLibraryContentProvider = createLibraryContentProvider();
 		fLibraryViewer.setContentProvider(fLibraryContentProvider);
 		fLibraryViewer.setLabelProvider(getLabelProvider());
 		fLibraryViewer.setInput(this);
 		fLibraryViewer.addSelectionChangedListener(this);

 		if (isEnableButtonSupported()) {
 			fEnabledButton = new Button(comp2, SWT.CHECK);
 			fEnabledButton.setText(
 					InterpretersMessages.AbstractInterpreterLibraryBlock_setPathVisibleToDltk);
 			fEnabledButton.addSelectionListener(this);
 			this.fLibraryViewer.addDoubleClickListener(event -> {
 				if (fLibraryContentProvider.canEnable(
 						(IStructuredSelection) fLibraryViewer.getSelection())) {
 					fLibraryContentProvider.changeEnabled();
 					updateButtons();
 				}
 			});
 		}

 		Composite pathButtonComp = new Composite(comp, SWT.NONE);
 		GridLayout pathButtonLayout = new GridLayout();
 		pathButtonLayout.marginHeight = 0;
 		pathButtonLayout.marginWidth = 0;
 		pathButtonComp.setLayout(pathButtonLayout);
 		gd = new GridData(GridData.VERTICAL_ALIGN_BEGINNING
 				| GridData.HORIZONTAL_ALIGN_FILL);
 		pathButtonComp.setLayoutData(gd);

 		fAddButton = createPushButton(pathButtonComp,
 				InterpretersMessages.InterpreterLibraryBlock_7);
 		fAddButton.addSelectionListener(this);

 		fRemoveButton = createPushButton(pathButtonComp,
 				InterpretersMessages.InterpreterLibraryBlock_6);
 		fRemoveButton.addSelectionListener(this);

 		fUpButton = createPushButton(pathButtonComp,
 				InterpretersMessages.InterpreterLibraryBlock_4);
 		fUpButton.addSelectionListener(this);

 		fDownButton = createPushButton(pathButtonComp,
 				InterpretersMessages.InterpreterLibraryBlock_5);
 		fDownButton.addSelectionListener(this);

 		fDefaultButton = createPushButton(pathButtonComp,
 				InterpretersMessages.InterpreterLibraryBlock_9);
 		fDefaultButton.addSelectionListener(this);
 		if (this.fDialog.isRediscoverSupported()) {
 			fRediscoverButton = createPushButton(pathButtonComp,
 					InterpretersMessages.AbstractInterpreterLibraryBlock_rediscover);
 			fRediscoverButton.addSelectionListener(this);
 		}
 	}

 	protected boolean isEnableButtonSupported() {
 		return false;
 	}

 	protected LibraryContentProvider createLibraryContentProvider() {
 		return new LibraryContentProvider();
 	}

 	protected TreeViewer createViewer(Composite comp) {
 		return new TreeViewer(comp);
 	}

 	/**
 	 * The "default" button has been toggled
 	 */
 	public void restoreDefaultLibraries() {
 		LibraryLocation[] libs = getLibrariesWithEnvironment(
 				fDialog.getEnvironmentVariables());
 		if (libs != null) {
 			fLibraryContentProvider.setLibraries(libs);
 			fLibraryContentProvider.initialize(getHomeDirectory(),
 					fDialog.getEnvironmentVariables(), true);
 		}
 		update();
 	}

 	protected LibraryLocation[] getLibrariesWithEnvironment(
 			final EnvironmentVariable[] environmentVariables) {
 		final LibraryLocation[][] libs = new LibraryLocation[][] { null };
 		final IFileHandle installLocation = getHomeDirectory();
 		if (installLocation == null) {
 			libs[0] = new LibraryLocation[0];
 		} else {
 			ProgressMonitorDialog dialog = new TimeTriggeredProgressMonitorDialog(
 					null, 1000);
 			try {
 				dialog.run(true, true,
 						monitor -> libs[0] = getInterpreterInstallType()
 								.getDefaultLibraryLocations(installLocation,
 										environmentVariables, monitor));
 			} catch (InvocationTargetException e) {
 				e.printStackTrace();
 			} catch (InterruptedException e) {
 				e.printStackTrace();
 			}
 		}
 		return libs[0];
 	}

 	/**
 	 * Creates and returns a button
 	 *
 	 * @param parent
 	 *                   parent widget
 	 * @param label
 	 *                   label
 	 * @return Button
 	 */
 	protected Button createPushButton(Composite parent, String label) {
 		Button button = new Button(parent, SWT.PUSH);
 		button.setFont(parent.getFont());
 		button.setText(label);
 		setButtonLayoutData(button);
 		return button;
 	}

 	/**
 	 * Create some empty space
 	 */
 	protected void createVerticalSpacer(Composite comp, int colSpan) {
 		Label label = new Label(comp, SWT.NONE);
 		GridData gd = new GridData();
 		gd.horizontalSpan = colSpan;
 		label.setLayoutData(gd);
 	}

 	/**
 	 * Sets the home directory of the Interpreter Install the user has chosen
 	 */
 	public void setHomeDirectory(IFileHandle file) {
 		fHome = file;
 	}

 	/**
 	 * Returns the home directory
 	 */
 	protected IFileHandle getHomeDirectory() {
 		return fHome;
 	}

 	/**
 	 * Updates buttons and status based on current libraries
 	 */
 	public void update() {
 		updateButtons();
 		IStatus status = Status.OK_STATUS;
 		if (fLibraryContentProvider.getLibraries().length == 0) { // &&
 			// !isDefaultSystemLibrary())
 			// {
 			// status = new Status(
 			// IStatus.ERROR,
 			// DLTKDebugUIPlugin.getUniqueIdentifier(),
 			// IDLTKDebugUIConstants.INTERNAL_ERROR,
 			// InterpretersMessages.
 			// InterpreterLibraryBlock_Libraries_cannot_be_empty__1,
 			// null);
 		}
 		LibraryStandin[] standins = fLibraryContentProvider.getStandins();
 		for (int i = 0; i < standins.length; i++) {
 			IStatus st = standins[i].validate();
 			if (!st.isOK()) {
 				status = st;
 				break;
 			}
 		}
 		updateDialogStatus(status);
 	}

 	/**
 	 * Saves settings in the given working copy
 	 */
 	public void performApply(IInterpreterInstall install) {
 		if (isDefaultLocations()) {
 			install.setLibraryLocations(null);
 		} else {
 			LibraryLocation[] libs = fLibraryContentProvider.getLibraries();
 			install.setLibraryLocations(libs);
 		}
 	}

 	/**
 	 * @since 2.0
 	 */
 	public LibraryLocation[] getLibraryLocations() {
 		if (isDefaultLocations()) {
 			return null;
 		} else {
 			LibraryLocation[] libs = fLibraryContentProvider.getLibraries();
 			return libs;
 		}
 	}

 	/**
 	 * Determines if the present setup is the default location s for this
 	 * InterpreterEnvironment
 	 *
 	 * @return true if the current set of locations are the defaults, false
 	 *         otherwise
 	 */
 	protected boolean isDefaultLocations() {
 		LibraryLocation[] libraryLocations = fLibraryContentProvider
 				.getLibraries();
 		IInterpreterInstall install = getInterpreterInstall();

 		if (install == null || libraryLocations == null) {
 			return true;
 		}
 		IFileHandle installLocation = install.getInstallLocation();
 		if (installLocation != null) {
 			LibraryLocation[] def = getInterpreterInstallType()
 					.getDefaultLibraryLocations(installLocation,
 							install.getEnvironmentVariables(), null);
 			if (def.length == libraryLocations.length) {
 				for (int i = 0; i < def.length; i++) {
 					if (!def[i].equals(libraryLocations[i])) {
 						return false;
 					}
 				}
 				return true;
 			}
 		}
 		return false;
 	}

 	/**
 	 * Returns the Interpreter install associated with this library block.
 	 *
 	 * @return Interpreter install
 	 */
 	protected IInterpreterInstall getInterpreterInstall() {
 		return fInterpreterInstall;
 	}

 	/**
 	 * Returns the Interpreter install type associated with this library block.
 	 *
 	 * @return Interpreter install
 	 */
 	protected IInterpreterInstallType getInterpreterInstallType() {
 		return fInterpreterInstallType;
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see
 	 * org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt
 	 * .events.SelectionEvent)
 	 */
 	@Override
 	public void widgetSelected(SelectionEvent e) {
 		Object source = e.getSource();
 		if (source == fUpButton) {
 			fLibraryContentProvider
 					.up((IStructuredSelection) fLibraryViewer.getSelection());
 		} else if (source == fDownButton) {
 			fLibraryContentProvider
 					.down((IStructuredSelection) fLibraryViewer.getSelection());
 		} else if (source == fRemoveButton) {
 			fLibraryContentProvider.remove(
 					(IStructuredSelection) fLibraryViewer.getSelection());
 			this.fDialog.updateValidateInterpreterLocation();
 		} else if (source == fAddButton) {
 			add((IStructuredSelection) fLibraryViewer.getSelection());
 		} else if (source == fDefaultButton) {
 			restoreDefaultLibraries();
 			this.fDialog.updateValidateInterpreterLocation();
 		} else if (source == fRediscoverButton) {
 			this.reDiscover(this.fDialog.getEnvironmentVariables(), null);
 		} else if (source == fEnabledButton) {
 			this.fLibraryContentProvider.changeEnabled();
 		}
 		update();
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.events.SelectionListener#widgetDefaultSelected(org.
 	 * eclipse .swt.events.SelectionEvent)
 	 */
 	@Override
 	public void widgetDefaultSelected(SelectionEvent e) {
 	}

 	private void add(IStructuredSelection selection) {
 		LibraryLocation libs = add();
 		if (libs == null)
 			return;
 		fLibraryContentProvider.add(new LibraryLocation[] { libs }, selection);
 		// We need to reinitialize.
 		fLibraryContentProvider.initialize(this.getHomeDirectory(),
 				fDialog.getEnvironmentVariables(), false);
 		update();
 		this.fDialog.updateValidateInterpreterLocation();
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see
 	 * org.eclipse.jface.viewers.ISelectionChangedListener#selectionChanged(
 	 * org.eclipse.jface.viewers.SelectionChangedEvent)
 	 */
 	@Override
 	public void selectionChanged(SelectionChangedEvent event) {
 		updateButtons();
 	}

 	/**
 	 * Refresh the enable/disable state for the buttons.
 	 */
 	private void updateButtons() {
 		IStructuredSelection selection = (IStructuredSelection) fLibraryViewer
 				.getSelection();
 		fRemoveButton.setEnabled(fLibraryContentProvider.canRemove(selection));
 		boolean enableUp = true, enableDown = true;
 		Object[] libraries = fLibraryContentProvider.getElements(null);
 		if (selection.isEmpty() || libraries.length == 0) {
 			enableUp = false;
 			enableDown = false;
 			if (isEnableButtonSupported()) {
 				fEnabledButton.setSelection(false);
 				fEnabledButton.setEnabled(false);
 			}
 		} else {
 			Object first = libraries[0];
 			Object last = libraries[libraries.length - 1];
 			if (isEnableButtonSupported()) {
 				fEnabledButton.setEnabled(
 						fLibraryContentProvider.canEnable(selection));
 			}
 			for (Iterator<?> iter = selection.iterator(); iter.hasNext();) {
 				Object element = iter.next();
 				Object lib;
 				lib = element;
 				if (isEnableButtonSupported() && selection.size() == 1) {
 					fEnabledButton.setSelection(
 							fLibraryContentProvider.isEnabled(lib));
 				}
 				if (lib == first) {
 					enableUp = false;
 				}
 				if (lib == last) {
 					enableDown = false;
 				}
 			}
 		}
 		fUpButton.setEnabled(
 				enableUp && fLibraryContentProvider.canUp(selection));
 		fDownButton.setEnabled(
 				enableDown && fLibraryContentProvider.canUp(selection));
 	}

 	/**
 	 * Initializes this control based on the settings in the given Interpreter
 	 * install and type.
 	 *
 	 * @param Interpreter
 	 *                        Interpreter or <code>null</code> if none
 	 * @param type
 	 *                        type of Interpreter install
 	 */

 	public void initializeFrom(IInterpreterInstall Interpreter,
 			IInterpreterInstallType type) {
 		fInterpreterInstall = Interpreter;
 		fInterpreterInstallType = type;
 		if (Interpreter != null) {
 			setHomeDirectory(Interpreter.getInstallLocation());
 			// fLibraryContentProvider.setLibraries(ScriptRuntime
 			// .getLibraryLocations(getInterpreterInstall(), null));
 			final LibraryLocation[][] libs = new LibraryLocation[][] { null };
 			ProgressMonitorDialog dialog = new TimeTriggeredProgressMonitorDialog(
 					null, 3000);
 			try {
 				dialog.run(true, true, monitor -> libs[0] = ScriptRuntime
 						.getLibraryLocations(getInterpreterInstall(), monitor));
 			} catch (InvocationTargetException e) {
 				if (DLTKCore.DEBUG) {
 					e.printStackTrace();
 				}
 			} catch (InterruptedException e) {
 				if (DLTKCore.DEBUG) {
 					e.printStackTrace();
 				}
 			}
 			fLibraryContentProvider.setLibraries(libs[0]);

 			// Set All possibly libraries here
 			fLibraryContentProvider.initialize(getHomeDirectory(),
 					fDialog.getEnvironmentVariables(), false);
 		}
 		update();
 	}

 	protected abstract IBaseLabelProvider getLabelProvider();

 	protected void updateDialogStatus(IStatus status) {
 		fDialog.setSystemLibraryStatus(status);
 		fDialog.updateStatusLine();
 	}

 	protected void setButtonLayoutData(Button button) {
 		fDialog.setButtonLayoutData(button);
 	}

 	/**
 	 * @deprecated
 	 */
 	@Deprecated
 	protected IDialogSettings getDialogSettions() {
 		return null;
 	}

 	protected LibraryLocation add() {
 		IEnvironment environment = fDialog.getEnvironment();
 		IEnvironmentUI ui = environment.getAdapter(IEnvironmentUI.class);
 		String res = ui.selectFolder(fLibraryViewer.getControl().getShell());
 		if (res == null) {
 			return null;
 		}

 		IPath path = EnvironmentPathUtils.getFullPath(environment,
 				new Path(res));
 		LibraryLocation lib = new LibraryLocation(path.makeAbsolute());
 		return lib;
 	}

 	/**
 	 * Rediscover using following technicue:
 	 *
 	 * 1) Keep all user added entries.
 	 *
 	 * 2) Remove all default entries.
 	 *
 	 * 3) Rediscover
 	 *
 	 * 4) Add all new entries to list.
 	 *
 	 * @param environmentVariables
 	 * @param oldVars
 	 */
 	public void reDiscover(EnvironmentVariable[] environmentVariables,
 			EnvironmentVariable[] oldVars) {
 		// if (oldVars == null) {
 		// if (this.fInterpreterInstall != null) {
 		// oldVars = this.fInterpreterInstall.getEnvironmentVariables();
 		// }
 		// // if( oldVars != null && oldVars.length == 0 ) {
 		// // restoreDefaultLibraries();
 		// // return;
 		// // }
 		// }
 		// if (oldVars == null) {
 		// if (this.fInterpreterInstall == null) {
 		// restoreDefaultLibraries();
 		// }
 		// return;
 		// }
 		// // Skip re discover if variables are same.
 		// if (equals(environmentVariables, oldVars)) {
 		// return;
 		// }
 		// LibraryLocation[] currentLibraries = this.fLibraryContentProvider
 		// .getLibraries();
 		//
 		// LibraryLocation[] oldLibs = getLibrariesWithEnvironment(oldVars);
 		// LibraryLocation[] newLibs =
 		// getLibrariesWithEnvironment(environmentVariables);
 		// // If current are equal to old, we could easy set new libs.
 		// if (equals(currentLibraries, oldLibs)) {
 		// if (newLibs != null)
 		// fLibraryContentProvider.setLibraries(newLibs);
 		// } else { // We need to build delta.
 		// Set delta = new HashSet();
 		// delta.addAll(Arrays.asList(currentLibraries));
 		// delta.removeAll(Arrays.asList(oldLibs));
 		//
 		// List newList = new ArrayList();
 		// newList.addAll(Arrays.asList(newLibs));
 		// for (Iterator iterator = delta.iterator(); iterator.hasNext();) {
 		// LibraryLocation lib = (LibraryLocation) iterator.next();
 		// if (!newList.contains(lib)) {
 		// newList.add(lib);
 		// }
 		// }
 		//
 		// LibraryLocation[] aNew = (LibraryLocation[]) newList
 		// .toArray(new LibraryLocation[delta.size()]);
 		// fLibraryContentProvider.setLibraries(aNew);
 		// }
 		fLibraryContentProvider.initialize(getHomeDirectory(),
 				fDialog.getEnvironmentVariables(), false);
 		update();
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2018 IBM Corporation and others.
	* 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
	*
	*******************************************************************************/
	package org.eclipse.dltk.internal.debug.ui.interpreters;

	import java.lang.reflect.InvocationTargetException;
	import java.util.Iterator;

	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.dltk.core.DLTKCore;
	import org.eclipse.dltk.core.environment.EnvironmentPathUtils;
	import org.eclipse.dltk.core.environment.IEnvironment;
	import org.eclipse.dltk.core.environment.IFileHandle;
	import org.eclipse.dltk.launching.EnvironmentVariable;
	import org.eclipse.dltk.launching.IInterpreterInstall;
	import org.eclipse.dltk.launching.IInterpreterInstallType;
	import org.eclipse.dltk.launching.LibraryLocation;
	import org.eclipse.dltk.launching.ScriptRuntime;
	import org.eclipse.dltk.ui.dialogs.TimeTriggeredProgressMonitorDialog;
	import org.eclipse.dltk.ui.environment.IEnvironmentUI;
	import org.eclipse.jface.dialogs.IDialogSettings;
	import org.eclipse.jface.dialogs.ProgressMonitorDialog;
	import org.eclipse.jface.viewers.IBaseLabelProvider;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.TreeViewer;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Label;

	/**
	* Control used to edit the libraries associated with a Interpreter install
	*/
	public abstract class AbstractInterpreterLibraryBlock
	implements SelectionListener, ISelectionChangedListener {

	/**
	* Attribute name for the last path used to open a file/directory chooser
	* dialog.
	*/
	protected static final String LAST_PATH_SETTING = "LAST_PATH_SETTING"; //$NON-NLS-1$

	/**
	* the prefix for dialog setting pertaining to this block
	*/
	protected static final String DIALOG_SETTINGS_PREFIX = "AbstractInterpreterLibraryBlock"; //$NON-NLS-1$

	protected boolean fInCallback = false;
	protected IInterpreterInstall fInterpreterInstall;
	protected IInterpreterInstallType fInterpreterInstallType;
	protected IFileHandle fHome;

	// widgets
	protected LibraryContentProvider fLibraryContentProvider;
	protected TreeViewer fLibraryViewer;
	private Button fUpButton;
	private Button fDownButton;
	private Button fRemoveButton;
	private Button fAddButton;
	protected Button fDefaultButton;
	protected Button fRediscoverButton;
	private Button fEnabledButton;

	protected AddScriptInterpreterDialog fDialog;

	protected AbstractInterpreterLibraryBlock(
	AddScriptInterpreterDialog dialog) {
	this.fDialog = dialog;
	}

	/**
	* Creates and returns the source lookup control.
	*
	* @param parent
	* the parent widget of this control
	*/
	public Control createControl(Composite parent) {
	Composite comp = new Composite(parent, SWT.NONE);
	GridLayout topLayout = new GridLayout();
	topLayout.numColumns = 2;
	topLayout.marginHeight = 0;
	topLayout.marginWidth = 0;
	comp.setLayout(topLayout);
	GridData gd = new GridData(GridData.FILL_BOTH);
	comp.setLayoutData(gd);
	createControlsIn(comp);
	return comp;
	}

	/**
	* @since 2.0
	*/
	public void createControlsIn(Composite comp) {
	Composite comp2 = new Composite(comp, SWT.NONE);
	GridLayout topLayout = new GridLayout();
	topLayout.numColumns = 1;
	topLayout.marginHeight = 0;
	topLayout.marginWidth = 0;
	comp2.setLayout(topLayout);
	GridData gd = new GridData(GridData.FILL_BOTH);
	comp2.setLayoutData(gd);
	fLibraryViewer = createViewer(comp2);
	gd = new GridData(GridData.FILL_BOTH);
	gd.heightHint = 6;
	fLibraryViewer.getControl().setLayoutData(gd);
	fLibraryContentProvider = createLibraryContentProvider();
	fLibraryViewer.setContentProvider(fLibraryContentProvider);
	fLibraryViewer.setLabelProvider(getLabelProvider());
	fLibraryViewer.setInput(this);
	fLibraryViewer.addSelectionChangedListener(this);

	if (isEnableButtonSupported()) {
	fEnabledButton = new Button(comp2, SWT.CHECK);
	fEnabledButton.setText(
	InterpretersMessages.AbstractInterpreterLibraryBlock_setPathVisibleToDltk);
	fEnabledButton.addSelectionListener(this);
	this.fLibraryViewer.addDoubleClickListener(event -> {
	if (fLibraryContentProvider.canEnable(
	(IStructuredSelection) fLibraryViewer.getSelection())) {
	fLibraryContentProvider.changeEnabled();
	updateButtons();
	}
	});
	}

	Composite pathButtonComp = new Composite(comp, SWT.NONE);
	GridLayout pathButtonLayout = new GridLayout();
	pathButtonLayout.marginHeight = 0;
	pathButtonLayout.marginWidth = 0;
	pathButtonComp.setLayout(pathButtonLayout);
	gd = new GridData(GridData.VERTICAL_ALIGN_BEGINNING
	\| GridData.HORIZONTAL_ALIGN_FILL);
	pathButtonComp.setLayoutData(gd);

	fAddButton = createPushButton(pathButtonComp,
	InterpretersMessages.InterpreterLibraryBlock_7);
	fAddButton.addSelectionListener(this);

	fRemoveButton = createPushButton(pathButtonComp,
	InterpretersMessages.InterpreterLibraryBlock_6);
	fRemoveButton.addSelectionListener(this);

	fUpButton = createPushButton(pathButtonComp,
	InterpretersMessages.InterpreterLibraryBlock_4);
	fUpButton.addSelectionListener(this);

	fDownButton = createPushButton(pathButtonComp,
	InterpretersMessages.InterpreterLibraryBlock_5);
	fDownButton.addSelectionListener(this);

	fDefaultButton = createPushButton(pathButtonComp,
	InterpretersMessages.InterpreterLibraryBlock_9);
	fDefaultButton.addSelectionListener(this);
	if (this.fDialog.isRediscoverSupported()) {
	fRediscoverButton = createPushButton(pathButtonComp,
	InterpretersMessages.AbstractInterpreterLibraryBlock_rediscover);
	fRediscoverButton.addSelectionListener(this);
	}
	}

	protected boolean isEnableButtonSupported() {
	return false;
	}

	protected LibraryContentProvider createLibraryContentProvider() {
	return new LibraryContentProvider();
	}

	protected TreeViewer createViewer(Composite comp) {
	return new TreeViewer(comp);
	}

	/**
	* The "default" button has been toggled
	*/
	public void restoreDefaultLibraries() {
	LibraryLocation[] libs = getLibrariesWithEnvironment(
	fDialog.getEnvironmentVariables());
	if (libs != null) {
	fLibraryContentProvider.setLibraries(libs);
	fLibraryContentProvider.initialize(getHomeDirectory(),
	fDialog.getEnvironmentVariables(), true);
	}
	update();
	}

	protected LibraryLocation[] getLibrariesWithEnvironment(
	final EnvironmentVariable[] environmentVariables) {
	final LibraryLocation[][] libs = new LibraryLocation[][] { null };
	final IFileHandle installLocation = getHomeDirectory();
	if (installLocation == null) {
	libs[0] = new LibraryLocation[0];
	} else {
	ProgressMonitorDialog dialog = new TimeTriggeredProgressMonitorDialog(
	null, 1000);
	try {
	dialog.run(true, true,
	monitor -> libs[0] = getInterpreterInstallType()
	.getDefaultLibraryLocations(installLocation,
	environmentVariables, monitor));
	} catch (InvocationTargetException e) {
	e.printStackTrace();
	} catch (InterruptedException e) {
	e.printStackTrace();
	}
	}
	return libs[0];
	}

	/**
	* Creates and returns a button
	*
	* @param parent
	* parent widget
	* @param label
	* label
	* @return Button
	*/
	protected Button createPushButton(Composite parent, String label) {
	Button button = new Button(parent, SWT.PUSH);
	button.setFont(parent.getFont());
	button.setText(label);
	setButtonLayoutData(button);
	return button;
	}

	/**
	* Create some empty space
	*/
	protected void createVerticalSpacer(Composite comp, int colSpan) {
	Label label = new Label(comp, SWT.NONE);
	GridData gd = new GridData();
	gd.horizontalSpan = colSpan;
	label.setLayoutData(gd);
	}

	/**
	* Sets the home directory of the Interpreter Install the user has chosen
	*/
	public void setHomeDirectory(IFileHandle file) {
	fHome = file;
	}

	/**
	* Returns the home directory
	*/
	protected IFileHandle getHomeDirectory() {
	return fHome;
	}

	/**
	* Updates buttons and status based on current libraries
	*/
	public void update() {
	updateButtons();
	IStatus status = Status.OK_STATUS;
	if (fLibraryContentProvider.getLibraries().length == 0) { // &&
	// !isDefaultSystemLibrary())
	// {
	// status = new Status(
	// IStatus.ERROR,
	// DLTKDebugUIPlugin.getUniqueIdentifier(),
	// IDLTKDebugUIConstants.INTERNAL_ERROR,
	// InterpretersMessages.
	// InterpreterLibraryBlock_Libraries_cannot_be_empty__1,
	// null);
	}
	LibraryStandin[] standins = fLibraryContentProvider.getStandins();
	for (int i = 0; i < standins.length; i++) {
	IStatus st = standins[i].validate();
	if (!st.isOK()) {
	status = st;
	break;
	}
	}
	updateDialogStatus(status);
	}

	/**
	* Saves settings in the given working copy
	*/
	public void performApply(IInterpreterInstall install) {
	if (isDefaultLocations()) {
	install.setLibraryLocations(null);
	} else {
	LibraryLocation[] libs = fLibraryContentProvider.getLibraries();
	install.setLibraryLocations(libs);
	}
	}

	/**
	* @since 2.0
	*/
	public LibraryLocation[] getLibraryLocations() {
	if (isDefaultLocations()) {
	return null;
	} else {
	LibraryLocation[] libs = fLibraryContentProvider.getLibraries();
	return libs;
	}
	}

	/**
	* Determines if the present setup is the default location s for this
	* InterpreterEnvironment
	*
	* @return true if the current set of locations are the defaults, false
	* otherwise
	*/
	protected boolean isDefaultLocations() {
	LibraryLocation[] libraryLocations = fLibraryContentProvider
	.getLibraries();
	IInterpreterInstall install = getInterpreterInstall();

	if (install == null \|\| libraryLocations == null) {
	return true;
	}
	IFileHandle installLocation = install.getInstallLocation();
	if (installLocation != null) {
	LibraryLocation[] def = getInterpreterInstallType()
	.getDefaultLibraryLocations(installLocation,
	install.getEnvironmentVariables(), null);
	if (def.length == libraryLocations.length) {
	for (int i = 0; i < def.length; i++) {
	if (!def[i].equals(libraryLocations[i])) {
	return false;
	}
	}
	return true;
	}
	}
	return false;
	}

	/**
	* Returns the Interpreter install associated with this library block.
	*
	* @return Interpreter install
	*/
	protected IInterpreterInstall getInterpreterInstall() {
	return fInterpreterInstall;
	}

	/**
	* Returns the Interpreter install type associated with this library block.
	*
	* @return Interpreter install
	*/
	protected IInterpreterInstallType getInterpreterInstallType() {
	return fInterpreterInstallType;
	}

	/*
	* (non-Javadoc)
	*
	* @see
	* org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt
	* .events.SelectionEvent)
	*/
	@Override
	public void widgetSelected(SelectionEvent e) {
	Object source = e.getSource();
	if (source == fUpButton) {
	fLibraryContentProvider
	.up((IStructuredSelection) fLibraryViewer.getSelection());
	} else if (source == fDownButton) {
	fLibraryContentProvider
	.down((IStructuredSelection) fLibraryViewer.getSelection());
	} else if (source == fRemoveButton) {
	fLibraryContentProvider.remove(
	(IStructuredSelection) fLibraryViewer.getSelection());
	this.fDialog.updateValidateInterpreterLocation();
	} else if (source == fAddButton) {
	add((IStructuredSelection) fLibraryViewer.getSelection());
	} else if (source == fDefaultButton) {
	restoreDefaultLibraries();
	this.fDialog.updateValidateInterpreterLocation();
	} else if (source == fRediscoverButton) {
	this.reDiscover(this.fDialog.getEnvironmentVariables(), null);
	} else if (source == fEnabledButton) {
	this.fLibraryContentProvider.changeEnabled();
	}
	update();
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.events.SelectionListener#widgetDefaultSelected(org.
	* eclipse .swt.events.SelectionEvent)
	*/
	@Override
	public void widgetDefaultSelected(SelectionEvent e) {
	}

	private void add(IStructuredSelection selection) {
	LibraryLocation libs = add();
	if (libs == null)
	return;
	fLibraryContentProvider.add(new LibraryLocation[] { libs }, selection);
	// We need to reinitialize.
	fLibraryContentProvider.initialize(this.getHomeDirectory(),
	fDialog.getEnvironmentVariables(), false);
	update();
	this.fDialog.updateValidateInterpreterLocation();
	}

	/*
	* (non-Javadoc)
	*
	* @see
	* org.eclipse.jface.viewers.ISelectionChangedListener#selectionChanged(
	* org.eclipse.jface.viewers.SelectionChangedEvent)
	*/
	@Override
	public void selectionChanged(SelectionChangedEvent event) {
	updateButtons();
	}

	/**
	* Refresh the enable/disable state for the buttons.
	*/
	private void updateButtons() {
	IStructuredSelection selection = (IStructuredSelection) fLibraryViewer
	.getSelection();
	fRemoveButton.setEnabled(fLibraryContentProvider.canRemove(selection));
	boolean enableUp = true, enableDown = true;
	Object[] libraries = fLibraryContentProvider.getElements(null);
	if (selection.isEmpty() \|\| libraries.length == 0) {
	enableUp = false;
	enableDown = false;
	if (isEnableButtonSupported()) {
	fEnabledButton.setSelection(false);
	fEnabledButton.setEnabled(false);
	}
	} else {
	Object first = libraries[0];
	Object last = libraries[libraries.length - 1];
	if (isEnableButtonSupported()) {
	fEnabledButton.setEnabled(
	fLibraryContentProvider.canEnable(selection));
	}
	for (Iterator<?> iter = selection.iterator(); iter.hasNext();) {
	Object element = iter.next();
	Object lib;
	lib = element;
	if (isEnableButtonSupported() && selection.size() == 1) {
	fEnabledButton.setSelection(
	fLibraryContentProvider.isEnabled(lib));
	}
	if (lib == first) {
	enableUp = false;
	}
	if (lib == last) {
	enableDown = false;
	}
	}
	}
	fUpButton.setEnabled(
	enableUp && fLibraryContentProvider.canUp(selection));
	fDownButton.setEnabled(
	enableDown && fLibraryContentProvider.canUp(selection));
	}

	/**
	* Initializes this control based on the settings in the given Interpreter
	* install and type.
	*
	* @param Interpreter
	* Interpreter or <code>null</code> if none
	* @param type
	* type of Interpreter install
	*/

	public void initializeFrom(IInterpreterInstall Interpreter,
	IInterpreterInstallType type) {
	fInterpreterInstall = Interpreter;
	fInterpreterInstallType = type;
	if (Interpreter != null) {
	setHomeDirectory(Interpreter.getInstallLocation());
	// fLibraryContentProvider.setLibraries(ScriptRuntime
	// .getLibraryLocations(getInterpreterInstall(), null));
	final LibraryLocation[][] libs = new LibraryLocation[][] { null };
	ProgressMonitorDialog dialog = new TimeTriggeredProgressMonitorDialog(
	null, 3000);
	try {
	dialog.run(true, true, monitor -> libs[0] = ScriptRuntime
	.getLibraryLocations(getInterpreterInstall(), monitor));
	} catch (InvocationTargetException e) {
	if (DLTKCore.DEBUG) {
	e.printStackTrace();
	}
	} catch (InterruptedException e) {
	if (DLTKCore.DEBUG) {
	e.printStackTrace();
	}
	}
	fLibraryContentProvider.setLibraries(libs[0]);

	// Set All possibly libraries here
	fLibraryContentProvider.initialize(getHomeDirectory(),
	fDialog.getEnvironmentVariables(), false);
	}
	update();
	}

	protected abstract IBaseLabelProvider getLabelProvider();

	protected void updateDialogStatus(IStatus status) {
	fDialog.setSystemLibraryStatus(status);
	fDialog.updateStatusLine();
	}

	protected void setButtonLayoutData(Button button) {
	fDialog.setButtonLayoutData(button);
	}

	/**
	* @deprecated
	*/
	@Deprecated
	protected IDialogSettings getDialogSettions() {
	return null;
	}

	protected LibraryLocation add() {
	IEnvironment environment = fDialog.getEnvironment();
	IEnvironmentUI ui = environment.getAdapter(IEnvironmentUI.class);
	String res = ui.selectFolder(fLibraryViewer.getControl().getShell());
	if (res == null) {
	return null;
	}

	IPath path = EnvironmentPathUtils.getFullPath(environment,
	new Path(res));
	LibraryLocation lib = new LibraryLocation(path.makeAbsolute());
	return lib;
	}

	/**
	* Rediscover using following technicue:
	*
	* 1) Keep all user added entries.
	*
	* 2) Remove all default entries.
	*
	* 3) Rediscover
	*
	* 4) Add all new entries to list.
	*
	* @param environmentVariables
	* @param oldVars
	*/
	public void reDiscover(EnvironmentVariable[] environmentVariables,
	EnvironmentVariable[] oldVars) {
	// if (oldVars == null) {
	// if (this.fInterpreterInstall != null) {
	// oldVars = this.fInterpreterInstall.getEnvironmentVariables();
	// }
	// // if( oldVars != null && oldVars.length == 0 ) {
	// // restoreDefaultLibraries();
	// // return;
	// // }
	// }
	// if (oldVars == null) {
	// if (this.fInterpreterInstall == null) {
	// restoreDefaultLibraries();
	// }
	// return;
	// }
	// // Skip re discover if variables are same.
	// if (equals(environmentVariables, oldVars)) {
	// return;
	// }
	// LibraryLocation[] currentLibraries = this.fLibraryContentProvider
	// .getLibraries();
	//
	// LibraryLocation[] oldLibs = getLibrariesWithEnvironment(oldVars);
	// LibraryLocation[] newLibs =
	// getLibrariesWithEnvironment(environmentVariables);
	// // If current are equal to old, we could easy set new libs.
	// if (equals(currentLibraries, oldLibs)) {
	// if (newLibs != null)
	// fLibraryContentProvider.setLibraries(newLibs);
	// } else { // We need to build delta.
	// Set delta = new HashSet();
	// delta.addAll(Arrays.asList(currentLibraries));
	// delta.removeAll(Arrays.asList(oldLibs));
	//
	// List newList = new ArrayList();
	// newList.addAll(Arrays.asList(newLibs));
	// for (Iterator iterator = delta.iterator(); iterator.hasNext();) {
	// LibraryLocation lib = (LibraryLocation) iterator.next();
	// if (!newList.contains(lib)) {
	// newList.add(lib);
	// }
	// }
	//
	// LibraryLocation[] aNew = (LibraryLocation[]) newList
	// .toArray(new LibraryLocation[delta.size()]);
	// fLibraryContentProvider.setLibraries(aNew);
	// }
	fLibraryContentProvider.initialize(getHomeDirectory(),
	fDialog.getEnvironmentVariables(), false);
	update();
	}
	}