core/plugins/org.eclipse.dltk.debug.ui/src/org/eclipse/dltk/internal/debug/ui/interpreters/AbstractInterpreterComboBlock.java - dltk/org.eclipse.dltk.core - Gitiles

 /*******************************************************************************
  * 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.debug.ui.interpreters;

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

 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.ListenerList;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.dltk.core.DLTKCore;
 import org.eclipse.dltk.core.IBuildpathEntry;
 import org.eclipse.dltk.core.environment.IEnvironment;
 import org.eclipse.dltk.core.environment.IFileHandle;
 import org.eclipse.dltk.debug.ui.DLTKDebugUIPlugin;
 import org.eclipse.dltk.debug.ui.IDLTKDebugUIConstants;
 import org.eclipse.dltk.debug.ui.actions.ControlAccessibleListener;
 import org.eclipse.dltk.internal.launching.DLTKLaunchingPlugin;
 import org.eclipse.dltk.internal.ui.util.SWTUtil;
 import org.eclipse.dltk.launching.IInterpreterInstall;
 import org.eclipse.dltk.launching.IInterpreterInstallType;
 import org.eclipse.dltk.launching.InterpreterStandin;
 import org.eclipse.dltk.launching.ScriptLaunchConfigurationConstants;
 import org.eclipse.dltk.launching.ScriptRuntime;
 import org.eclipse.dltk.ui.DLTKUILanguageManager;
 import org.eclipse.dltk.ui.IDLTKUILanguageToolkit;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Combo;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Group;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.dialogs.PreferencesUtil;

 /**
  * A composite that displays installed InterpreterEnvironment's in a combo box,
  * with a 'manage...' button to modify installed InterpreterEnvironments.
  * <p>
  * This block implements ISelectionProvider - it sends selection change events
  * when the checked InterpreterEnvironment in the table changes, or when the
  * "use default" button check state changes.
  * </p>
  */
 public class AbstractInterpreterComboBlock {

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

 	/**
 	 * This block's control
 	 */
 	private Composite fControl;

 	/**
 	 * Interpreters being displayed
 	 */
 	private List<IInterpreterInstall> fInterpreters = new ArrayList<>();

 	/**
 	 * The main control
 	 */
 	private Combo fCombo;

 	// Action buttons
 	private Button fManageButton;

 	/**
 	 * InterpreterEnvironment change listeners
 	 */
 	private ListenerList<IPropertyChangeListener> fListeners = new ListenerList<>();

 	/**
 	 * Default InterpreterEnvironment descriptor or <code>null</code> if none.
 	 */
 	private InterpreterDescriptor fDefaultDescriptor = null;

 	/**
 	 * Specific InterpreterEnvironment descriptor or <code>null</code> if none.
 	 */
 	private InterpreterDescriptor fSpecificDescriptor = null;

 	/**
 	 * Default InterpreterEnvironment radio button or <code>null</code> if none
 	 */
 	private Button fDefaultButton = null;

 	/**
 	 * Selected InterpreterEnvironment radio button
 	 */
 	private Button fSpecificButton = null;

 	/**
 	 * The title used for the InterpreterEnvironment block
 	 */
 	private String fTitle = null;

 	private IStatus fStatus = OK_STATUS;

 	private static final IStatus OK_STATUS = new Status(IStatus.OK,
 			DLTKDebugUIPlugin.getUniqueIdentifier(), 0, "", null); //$NON-NLS-1$

 	private final IInterpreterComboBlockContext fContext;

 	/**
 	 * @since 2.0
 	 */
 	public AbstractInterpreterComboBlock(
 			IInterpreterComboBlockContext context) {
 		this.fContext = context;
 	}

 	/**
 	 * @since 2.0
 	 */
 	protected IInterpreterComboBlockContext getContext() {
 		return fContext;
 	}

 	public void addPropertyChangeListener(IPropertyChangeListener listener) {
 		fListeners.add(listener);
 	}

 	public void removePropertyChangeListener(IPropertyChangeListener listener) {
 		fListeners.remove(listener);
 	}

 	private void firePropertyChange() {
 		PropertyChangeEvent event = new PropertyChangeEvent(this,
 				PROPERTY_INTERPRETER, null, getInterpreterPath());
 		for (IPropertyChangeListener listener : fListeners) {
 			listener.propertyChange(event);
 		}
 	}

 	/**
 	 * Creates this block's control in the given control.
 	 *
 	 * @param anscestor
 	 *            containing control
 	 */
 	public void createControl(Composite ancestor) {
 		Font font = ancestor.getFont();
 		Composite comp = new Composite(ancestor, SWT.NONE);
 		comp.setLayout(new GridLayout());
 		comp.setLayoutData(new GridData(GridData.FILL_BOTH));
 		fControl = comp;
 		comp.setFont(font);

 		Group group = new Group(comp, SWT.NULL);
 		GridLayout layout = new GridLayout();
 		layout.numColumns = 3;
 		group.setLayout(layout);
 		group.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
 		group.setFont(font);

 		GridData data;

 		if (fTitle == null) {
 			fTitle = InterpretersMessages.InterpretersComboBlock_3;
 		}
 		group.setText(fTitle);

 		// display a' use default InterpreterEnvironment' check box
 		if (fDefaultDescriptor != null) {
 			fDefaultButton = new Button(group, SWT.RADIO);
 			fDefaultButton.setText(fDefaultDescriptor.getDescription());
 			fDefaultButton.addSelectionListener(new SelectionAdapter() {
 				@Override
 				public void widgetSelected(SelectionEvent e) {
 					if (fDefaultButton.getSelection()) {
 						setUseDefaultInterpreter();
 						if (fInterpreters.isEmpty()) {
 							setStatus(new Status(IStatus.ERROR,
 									DLTKLaunchingPlugin.getUniqueIdentifier(),
 									ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
 									InterpretersMessages.InterpretersComboBlock_0,
 									null));
 						} else {
 							setStatus(OK_STATUS);
 						}
 						firePropertyChange();
 					}
 				}
 			});
 			data = new GridData();
 			data.horizontalSpan = 3;
 			fDefaultButton.setLayoutData(data);
 			fDefaultButton.setFont(font);
 		}

 		fSpecificButton = new Button(group, SWT.RADIO);
 		if (fSpecificDescriptor != null) {
 			fSpecificButton.setText(fSpecificDescriptor.getDescription());
 		} else {
 			fSpecificButton
 					.setText(InterpretersMessages.InterpretersComboBlock_1);
 		}
 		fSpecificButton.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				if (fSpecificButton.getSelection()) {
 					fCombo.setEnabled(true);
 					if (fCombo.getText().length() == 0
 							&& !fInterpreters.isEmpty()) {
 						fCombo.select(0);
 					}
 					if (fInterpreters.isEmpty()) {
 						setStatus(new Status(IStatus.ERROR,
 								DLTKLaunchingPlugin.getUniqueIdentifier(),
 								ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
 								InterpretersMessages.InterpretersComboBlock_0,
 								null));
 					} else {
 						setStatus(OK_STATUS);
 					}
 					firePropertyChange();
 				}
 			}
 		});
 		fSpecificButton.setFont(font);
 		data = new GridData(GridData.BEGINNING);
 		fSpecificButton.setLayoutData(data);

 		fCombo = new Combo(group, SWT.DROP_DOWN | SWT.READ_ONLY);
 		fCombo.setFont(font);
 		data = new GridData(GridData.FILL_HORIZONTAL);
 		// data.minimumWidth = 100;
 		// data.widthHint = 100;
 		data.horizontalSpan = 1;
 		fCombo.setLayoutData(data);
 		ControlAccessibleListener.addListener(fCombo,
 				fSpecificButton.getText());

 		fCombo.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				firePropertyChange();
 			}
 		});

 		fManageButton = createPushButton(group,
 				InterpretersMessages.InterpretersComboBlock_2);
 		fManageButton.addListener(SWT.Selection,
 				event -> showInterpreterPreferencePage());

 		fillWithWorkspaceInterpreters();
 		if (fInterpreters.isEmpty()) {
 			setStatus(new Status(IStatus.ERROR,
 					DLTKLaunchingPlugin.getUniqueIdentifier(),
 					ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
 					InterpretersMessages.InterpretersComboBlock_0, null));
 		} else {
 			setStatus(OK_STATUS);
 		}

 	}

 	/**
 	 * Opens the given preference page, and updates when closed.
 	 *
 	 * @param id
 	 *            pref page id
 	 * @param page
 	 *            pref page
 	 */
 	protected void showPrefPage(String pageId) {
 		PreferencesUtil.createPreferenceDialogOn(getShell(), pageId,
 				new String[] { pageId }, null).open();

 		refreshInterpreters();
 	}

 	private void restoreCombo(List<?> elements, Object element, Combo combo) {
 		int index = -1;
 		if (element != null) {
 			index = elements.indexOf(element);
 		}
 		if (index >= 0) {
 			combo.select(index);
 		} else {
 			combo.select(0);
 		}
 	}

 	protected Button createPushButton(Composite parent, String label) {
 		return SWTUtil.createPushButton(parent, label, null);
 	}

 	/**
 	 * Returns this block's control
 	 *
 	 * @return control
 	 */
 	public Control getControl() {
 		return fControl;
 	}

 	/**
 	 * Sets the InterpreterEnvironments to be displayed in this block
 	 *
 	 * @param Interpreters
 	 *            InterpreterEnvironments to be displayed
 	 */
 	protected void setInterpreters(List<IInterpreterInstall> interpreters) {
 		fInterpreters.clear();
 		fInterpreters.addAll(interpreters);
 		// sort by name
 		Collections.sort(fInterpreters,
 				(o1, o2) -> o1.getName().compareToIgnoreCase(o2.getName()));
 		// now make an array of names
 		String[] names = new String[fInterpreters.size()];
 		for (int i = 0, size = fInterpreters.size(); i < size; ++i) {
 			names[i] = fInterpreters.get(i).getName();
 		}
 		fCombo.setItems(names);
 		fCombo.setVisibleItemCount(Math.min(names.length, 20));
 		// if (names.length == 0) {
 		// fCombo.setEnabled(names.length > 0);
 		// fSpecificButton.setEnabled(names.length > 0);
 		// }
 	}

 	protected Shell getShell() {
 		return getControl().getShell();
 	}

 	/**
 	 * Selects a specific InterpreterEnvironment based on type/name.
 	 *
 	 * @param Interpreter
 	 *            InterpreterEnvironment
 	 */
 	private void selectInterpreter(IInterpreterInstall Interpreter) {
 		fSpecificButton.setSelection(true);
 		fDefaultButton.setSelection(false);
 		fCombo.setEnabled(true);
 		int index = fInterpreters.indexOf(Interpreter);
 		if (index >= 0) {
 			fCombo.select(index);
 		}
 		firePropertyChange();
 	}

 	/**
 	 * Returns the selected InterpreterEnvironment or <code>null</code> if none.
 	 *
 	 * @return the selected InterpreterEnvironment or <code>null</code> if none
 	 */
 	public IInterpreterInstall getInterpreter() {
 		if (this.isDefaultInterpreter()) {
 			return fDefaultDescriptor.getInterpreter();
 		}
 		int index = fCombo.getSelectionIndex();
 		if (index >= 0) {
 			return fInterpreters.get(index);
 		}
 		return null;
 	}

 	/**
 	 * Sets the Default InterpreterEnvironment Descriptor for this block.
 	 *
 	 * @param descriptor
 	 *            default InterpreterEnvironment descriptor
 	 */
 	public void setDefaultInterpreterDescriptor(
 			InterpreterDescriptor descriptor) {
 		fDefaultDescriptor = descriptor;
 		setButtonTextFromDescriptor(fDefaultButton, descriptor);
 	}

 	private void setButtonTextFromDescriptor(Button button,
 			InterpreterDescriptor descriptor) {
 		if (button != null) {
 			// update the description & InterpreterEnvironment in case it has
 			// changed
 			String currentText = button.getText();
 			String newText = descriptor.getDescription();
 			if (!newText.equals(currentText)) {
 				button.setText(newText);
 				fControl.layout();
 			}
 		}
 	}

 	/**
 	 * Sets the specific InterpreterEnvironment Descriptor for this block.
 	 *
 	 * @param descriptor
 	 *            specific InterpreterEnvironment descriptor
 	 */
 	public void setSpecificInterpreterDescriptor(
 			InterpreterDescriptor descriptor) {
 		fSpecificDescriptor = descriptor;
 		setButtonTextFromDescriptor(fSpecificButton, descriptor);
 	}

 	/**
 	 * Returns whether the 'use default InterpreterEnvironment' button is
 	 * checked.
 	 *
 	 * @return whether the 'use default InterpreterEnvironment' button is
 	 *         checked
 	 */
 	public boolean isDefaultInterpreter() {
 		if (fDefaultButton != null) {
 			return fDefaultButton.getSelection();
 		}
 		return false;
 	}

 	/**
 	 * Sets this control to use the 'default' InterpreterEnvironment.
 	 */
 	public void setUseDefaultInterpreter() {
 		if (fDefaultDescriptor != null) {
 			fDefaultButton.setSelection(true);
 			fSpecificButton.setSelection(false);
 			fCombo.setEnabled(false);
 			firePropertyChange();
 		}
 	}

 	/**
 	 * Sets the title used for this InterpreterEnvironment block
 	 *
 	 * @param title
 	 *            title for this InterpreterEnvironment block
 	 */
 	public void setTitle(String title) {
 		fTitle = title;
 	}

 	/**
 	 * Refresh the default InterpreterEnvironment description.
 	 */
 	public void refresh() {
 		setDefaultInterpreterDescriptor(fDefaultDescriptor);
 	}

 	public void refreshInterpreters() {
 		IInterpreterInstall prevInterpreter = getInterpreter();
 		fillWithWorkspaceInterpreters();
 		if (fInterpreters.isEmpty()) {
 			setStatus(new Status(IStatus.ERROR,
 					DLTKLaunchingPlugin.getUniqueIdentifier(),
 					ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
 					InterpretersMessages.InterpretersComboBlock_0, null));
 		} else {
 			setStatus(OK_STATUS);
 		}
 		restoreCombo(fInterpreters, prevInterpreter, fCombo);

 		// update text
 		setDefaultInterpreterDescriptor(fDefaultDescriptor);
 		if (isDefaultInterpreter()) {
 			// reset in case default has changed
 			setUseDefaultInterpreter();
 		}
 		setPath(getInterpreterPath());
 		firePropertyChange();
 	}

 	/**
 	 * Returns a buildpath container path identifying the selected
 	 * InterpreterEnvironment.
 	 *
 	 * @return buildpath container path or <code>null</code>
 	 */
 	public IPath getInterpreterPath() {
 		if (fSpecificButton.getSelection()) {
 			int index = fCombo.getSelectionIndex();
 			if (index >= 0) {
 				IInterpreterInstall Interpreter = fInterpreters.get(index);
 				return ScriptRuntime.newInterpreterContainerPath(Interpreter);
 			}
 			return null;
 		}
 		return ScriptRuntime.newDefaultInterpreterContainerPath();
 	}

 	public IBuildpathEntry getEntry() {
 		return DLTKCore.newContainerEntry(getInterpreterPath());
 	}

 	/**
 	 * Sets the selection based on the given container path and returns a status
 	 * indicating if the selection was successful.
 	 *
 	 * @param containerPath
 	 * @return status
 	 */
 	public void setPath(IPath containerPath) {
 		if (fInterpreters.isEmpty()) {
 			setStatus(new Status(IStatus.ERROR,
 					DLTKLaunchingPlugin.getUniqueIdentifier(),
 					ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
 					InterpretersMessages.InterpretersComboBlock_0, null));
 		} else {
 			setStatus(OK_STATUS);
 		}
 		if (ScriptRuntime.newDefaultInterpreterContainerPath()
 				.equals(containerPath)) {
 			setUseDefaultInterpreter();
 		} else {
 			final IEnvironment environment = fContext.getEnvironment();
 			final IInterpreterInstall install = environment != null
 					? ScriptRuntime.getInterpreterInstall(
 							fContext.getNatureId(), environment.getId(),
 							containerPath)
 					: null;
 			if (install == null) {
 				setError(InterpretersMessages.InterpretersComboBlock_8);
 			} else {
 				selectInterpreter(install);
 				IFileHandle location = install.getInstallLocation();
 				if (location == null) {
 					setError(InterpretersMessages.InterpretersComboBlock_12);
 				} else if (!location.exists()) {
 					setError(InterpretersMessages.InterpretersComboBlock_13);
 				}
 			}
 		}
 	}

 	private void setError(String message) {
 		setStatus(new Status(IStatus.ERROR,
 				DLTKDebugUIPlugin.getUniqueIdentifier(),
 				IDLTKDebugUIConstants.INTERNAL_ERROR, message, null));
 	}

 	/**
 	 * Returns the status of the interpreter selection.
 	 *
 	 * @return status
 	 */
 	public IStatus getStatus() {
 		return fStatus;
 	}

 	private void setStatus(IStatus status) {
 		fStatus = status;
 	}

 	/**
 	 * Shows window with appropriate language preference page.
 	 */
 	protected void showInterpreterPreferencePage() {
 		IDLTKUILanguageToolkit toolkit = DLTKUILanguageManager
 				.getLanguageToolkit(getCurrentLanguageNature());
 		if (toolkit != null) {
 			final String pageId = toolkit.getInterpreterPreferencePage();
 			if (pageId != null) {
 				showPrefPage(pageId);
 			}
 		}
 	}

 	protected void fillWithWorkspaceInterpreters() {
 		// fill with interpreters
 		final List<IInterpreterInstall> standins = new ArrayList<>();
 		final IInterpreterInstallType[] types = ScriptRuntime
 				.getInterpreterInstallTypes(getCurrentLanguageNature());
 		final IEnvironment environment = fContext.getEnvironment();

 		for (int i = 0; i < types.length; i++) {
 			IInterpreterInstallType type = types[i];
 			IInterpreterInstall[] installs = type.getInterpreterInstalls();
 			for (int j = 0; j < installs.length; j++) {
 				final IInterpreterInstall install = installs[j];
 				if (environment != null && environment.getId()
 						.equals(install.getEnvironmentId())) {
 					standins.add(new InterpreterStandin(install));
 				}
 			}
 		}
 		setInterpreters(standins);
 	}

 	protected final String getCurrentLanguageNature() {
 		return fContext.getNatureId();
 	}
 }
	/*******************************************************************************
	* 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.debug.ui.interpreters;

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

	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.ListenerList;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.dltk.core.DLTKCore;
	import org.eclipse.dltk.core.IBuildpathEntry;
	import org.eclipse.dltk.core.environment.IEnvironment;
	import org.eclipse.dltk.core.environment.IFileHandle;
	import org.eclipse.dltk.debug.ui.DLTKDebugUIPlugin;
	import org.eclipse.dltk.debug.ui.IDLTKDebugUIConstants;
	import org.eclipse.dltk.debug.ui.actions.ControlAccessibleListener;
	import org.eclipse.dltk.internal.launching.DLTKLaunchingPlugin;
	import org.eclipse.dltk.internal.ui.util.SWTUtil;
	import org.eclipse.dltk.launching.IInterpreterInstall;
	import org.eclipse.dltk.launching.IInterpreterInstallType;
	import org.eclipse.dltk.launching.InterpreterStandin;
	import org.eclipse.dltk.launching.ScriptLaunchConfigurationConstants;
	import org.eclipse.dltk.launching.ScriptRuntime;
	import org.eclipse.dltk.ui.DLTKUILanguageManager;
	import org.eclipse.dltk.ui.IDLTKUILanguageToolkit;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Combo;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Group;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.ui.dialogs.PreferencesUtil;

	/**
	* A composite that displays installed InterpreterEnvironment's in a combo box,
	* with a 'manage...' button to modify installed InterpreterEnvironments.
	* <p>
	* This block implements ISelectionProvider - it sends selection change events
	* when the checked InterpreterEnvironment in the table changes, or when the
	* "use default" button check state changes.
	* </p>
	*/
	public class AbstractInterpreterComboBlock {

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

	/**
	* This block's control
	*/
	private Composite fControl;

	/**
	* Interpreters being displayed
	*/
	private List<IInterpreterInstall> fInterpreters = new ArrayList<>();

	/**
	* The main control
	*/
	private Combo fCombo;

	// Action buttons
	private Button fManageButton;

	/**
	* InterpreterEnvironment change listeners
	*/
	private ListenerList<IPropertyChangeListener> fListeners = new ListenerList<>();

	/**
	* Default InterpreterEnvironment descriptor or <code>null</code> if none.
	*/
	private InterpreterDescriptor fDefaultDescriptor = null;

	/**
	* Specific InterpreterEnvironment descriptor or <code>null</code> if none.
	*/
	private InterpreterDescriptor fSpecificDescriptor = null;

	/**
	* Default InterpreterEnvironment radio button or <code>null</code> if none
	*/
	private Button fDefaultButton = null;

	/**
	* Selected InterpreterEnvironment radio button
	*/
	private Button fSpecificButton = null;

	/**
	* The title used for the InterpreterEnvironment block
	*/
	private String fTitle = null;

	private IStatus fStatus = OK_STATUS;

	private static final IStatus OK_STATUS = new Status(IStatus.OK,
	DLTKDebugUIPlugin.getUniqueIdentifier(), 0, "", null); //$NON-NLS-1$

	private final IInterpreterComboBlockContext fContext;

	/**
	* @since 2.0
	*/
	public AbstractInterpreterComboBlock(
	IInterpreterComboBlockContext context) {
	this.fContext = context;
	}

	/**
	* @since 2.0
	*/
	protected IInterpreterComboBlockContext getContext() {
	return fContext;
	}

	public void addPropertyChangeListener(IPropertyChangeListener listener) {
	fListeners.add(listener);
	}

	public void removePropertyChangeListener(IPropertyChangeListener listener) {
	fListeners.remove(listener);
	}

	private void firePropertyChange() {
	PropertyChangeEvent event = new PropertyChangeEvent(this,
	PROPERTY_INTERPRETER, null, getInterpreterPath());
	for (IPropertyChangeListener listener : fListeners) {
	listener.propertyChange(event);
	}
	}

	/**
	* Creates this block's control in the given control.
	*
	* @param anscestor
	* containing control
	*/
	public void createControl(Composite ancestor) {
	Font font = ancestor.getFont();
	Composite comp = new Composite(ancestor, SWT.NONE);
	comp.setLayout(new GridLayout());
	comp.setLayoutData(new GridData(GridData.FILL_BOTH));
	fControl = comp;
	comp.setFont(font);

	Group group = new Group(comp, SWT.NULL);
	GridLayout layout = new GridLayout();
	layout.numColumns = 3;
	group.setLayout(layout);
	group.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
	group.setFont(font);

	GridData data;

	if (fTitle == null) {
	fTitle = InterpretersMessages.InterpretersComboBlock_3;
	}
	group.setText(fTitle);

	// display a' use default InterpreterEnvironment' check box
	if (fDefaultDescriptor != null) {
	fDefaultButton = new Button(group, SWT.RADIO);
	fDefaultButton.setText(fDefaultDescriptor.getDescription());
	fDefaultButton.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	if (fDefaultButton.getSelection()) {
	setUseDefaultInterpreter();
	if (fInterpreters.isEmpty()) {
	setStatus(new Status(IStatus.ERROR,
	DLTKLaunchingPlugin.getUniqueIdentifier(),
	ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
	InterpretersMessages.InterpretersComboBlock_0,
	null));
	} else {
	setStatus(OK_STATUS);
	}
	firePropertyChange();
	}
	}
	});
	data = new GridData();
	data.horizontalSpan = 3;
	fDefaultButton.setLayoutData(data);
	fDefaultButton.setFont(font);
	}

	fSpecificButton = new Button(group, SWT.RADIO);
	if (fSpecificDescriptor != null) {
	fSpecificButton.setText(fSpecificDescriptor.getDescription());
	} else {
	fSpecificButton
	.setText(InterpretersMessages.InterpretersComboBlock_1);
	}
	fSpecificButton.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	if (fSpecificButton.getSelection()) {
	fCombo.setEnabled(true);
	if (fCombo.getText().length() == 0
	&& !fInterpreters.isEmpty()) {
	fCombo.select(0);
	}
	if (fInterpreters.isEmpty()) {
	setStatus(new Status(IStatus.ERROR,
	DLTKLaunchingPlugin.getUniqueIdentifier(),
	ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
	InterpretersMessages.InterpretersComboBlock_0,
	null));
	} else {
	setStatus(OK_STATUS);
	}
	firePropertyChange();
	}
	}
	});
	fSpecificButton.setFont(font);
	data = new GridData(GridData.BEGINNING);
	fSpecificButton.setLayoutData(data);

	fCombo = new Combo(group, SWT.DROP_DOWN \| SWT.READ_ONLY);
	fCombo.setFont(font);
	data = new GridData(GridData.FILL_HORIZONTAL);
	// data.minimumWidth = 100;
	// data.widthHint = 100;
	data.horizontalSpan = 1;
	fCombo.setLayoutData(data);
	ControlAccessibleListener.addListener(fCombo,
	fSpecificButton.getText());

	fCombo.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	firePropertyChange();
	}
	});

	fManageButton = createPushButton(group,
	InterpretersMessages.InterpretersComboBlock_2);
	fManageButton.addListener(SWT.Selection,
	event -> showInterpreterPreferencePage());

	fillWithWorkspaceInterpreters();
	if (fInterpreters.isEmpty()) {
	setStatus(new Status(IStatus.ERROR,
	DLTKLaunchingPlugin.getUniqueIdentifier(),
	ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
	InterpretersMessages.InterpretersComboBlock_0, null));
	} else {
	setStatus(OK_STATUS);
	}

	}

	/**
	* Opens the given preference page, and updates when closed.
	*
	* @param id
	* pref page id
	* @param page
	* pref page
	*/
	protected void showPrefPage(String pageId) {
	PreferencesUtil.createPreferenceDialogOn(getShell(), pageId,
	new String[] { pageId }, null).open();

	refreshInterpreters();
	}

	private void restoreCombo(List<?> elements, Object element, Combo combo) {
	int index = -1;
	if (element != null) {
	index = elements.indexOf(element);
	}
	if (index >= 0) {
	combo.select(index);
	} else {
	combo.select(0);
	}
	}

	protected Button createPushButton(Composite parent, String label) {
	return SWTUtil.createPushButton(parent, label, null);
	}

	/**
	* Returns this block's control
	*
	* @return control
	*/
	public Control getControl() {
	return fControl;
	}

	/**
	* Sets the InterpreterEnvironments to be displayed in this block
	*
	* @param Interpreters
	* InterpreterEnvironments to be displayed
	*/
	protected void setInterpreters(List<IInterpreterInstall> interpreters) {
	fInterpreters.clear();
	fInterpreters.addAll(interpreters);
	// sort by name
	Collections.sort(fInterpreters,
	(o1, o2) -> o1.getName().compareToIgnoreCase(o2.getName()));
	// now make an array of names
	String[] names = new String[fInterpreters.size()];
	for (int i = 0, size = fInterpreters.size(); i < size; ++i) {
	names[i] = fInterpreters.get(i).getName();
	}
	fCombo.setItems(names);
	fCombo.setVisibleItemCount(Math.min(names.length, 20));
	// if (names.length == 0) {
	// fCombo.setEnabled(names.length > 0);
	// fSpecificButton.setEnabled(names.length > 0);
	// }
	}

	protected Shell getShell() {
	return getControl().getShell();
	}

	/**
	* Selects a specific InterpreterEnvironment based on type/name.
	*
	* @param Interpreter
	* InterpreterEnvironment
	*/
	private void selectInterpreter(IInterpreterInstall Interpreter) {
	fSpecificButton.setSelection(true);
	fDefaultButton.setSelection(false);
	fCombo.setEnabled(true);
	int index = fInterpreters.indexOf(Interpreter);
	if (index >= 0) {
	fCombo.select(index);
	}
	firePropertyChange();
	}

	/**
	* Returns the selected InterpreterEnvironment or <code>null</code> if none.
	*
	* @return the selected InterpreterEnvironment or <code>null</code> if none
	*/
	public IInterpreterInstall getInterpreter() {
	if (this.isDefaultInterpreter()) {
	return fDefaultDescriptor.getInterpreter();
	}
	int index = fCombo.getSelectionIndex();
	if (index >= 0) {
	return fInterpreters.get(index);
	}
	return null;
	}

	/**
	* Sets the Default InterpreterEnvironment Descriptor for this block.
	*
	* @param descriptor
	* default InterpreterEnvironment descriptor
	*/
	public void setDefaultInterpreterDescriptor(
	InterpreterDescriptor descriptor) {
	fDefaultDescriptor = descriptor;
	setButtonTextFromDescriptor(fDefaultButton, descriptor);
	}

	private void setButtonTextFromDescriptor(Button button,
	InterpreterDescriptor descriptor) {
	if (button != null) {
	// update the description & InterpreterEnvironment in case it has
	// changed
	String currentText = button.getText();
	String newText = descriptor.getDescription();
	if (!newText.equals(currentText)) {
	button.setText(newText);
	fControl.layout();
	}
	}
	}

	/**
	* Sets the specific InterpreterEnvironment Descriptor for this block.
	*
	* @param descriptor
	* specific InterpreterEnvironment descriptor
	*/
	public void setSpecificInterpreterDescriptor(
	InterpreterDescriptor descriptor) {
	fSpecificDescriptor = descriptor;
	setButtonTextFromDescriptor(fSpecificButton, descriptor);
	}

	/**
	* Returns whether the 'use default InterpreterEnvironment' button is
	* checked.
	*
	* @return whether the 'use default InterpreterEnvironment' button is
	* checked
	*/
	public boolean isDefaultInterpreter() {
	if (fDefaultButton != null) {
	return fDefaultButton.getSelection();
	}
	return false;
	}

	/**
	* Sets this control to use the 'default' InterpreterEnvironment.
	*/
	public void setUseDefaultInterpreter() {
	if (fDefaultDescriptor != null) {
	fDefaultButton.setSelection(true);
	fSpecificButton.setSelection(false);
	fCombo.setEnabled(false);
	firePropertyChange();
	}
	}

	/**
	* Sets the title used for this InterpreterEnvironment block
	*
	* @param title
	* title for this InterpreterEnvironment block
	*/
	public void setTitle(String title) {
	fTitle = title;
	}

	/**
	* Refresh the default InterpreterEnvironment description.
	*/
	public void refresh() {
	setDefaultInterpreterDescriptor(fDefaultDescriptor);
	}

	public void refreshInterpreters() {
	IInterpreterInstall prevInterpreter = getInterpreter();
	fillWithWorkspaceInterpreters();
	if (fInterpreters.isEmpty()) {
	setStatus(new Status(IStatus.ERROR,
	DLTKLaunchingPlugin.getUniqueIdentifier(),
	ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
	InterpretersMessages.InterpretersComboBlock_0, null));
	} else {
	setStatus(OK_STATUS);
	}
	restoreCombo(fInterpreters, prevInterpreter, fCombo);

	// update text
	setDefaultInterpreterDescriptor(fDefaultDescriptor);
	if (isDefaultInterpreter()) {
	// reset in case default has changed
	setUseDefaultInterpreter();
	}
	setPath(getInterpreterPath());
	firePropertyChange();
	}

	/**
	* Returns a buildpath container path identifying the selected
	* InterpreterEnvironment.
	*
	* @return buildpath container path or <code>null</code>
	*/
	public IPath getInterpreterPath() {
	if (fSpecificButton.getSelection()) {
	int index = fCombo.getSelectionIndex();
	if (index >= 0) {
	IInterpreterInstall Interpreter = fInterpreters.get(index);
	return ScriptRuntime.newInterpreterContainerPath(Interpreter);
	}
	return null;
	}
	return ScriptRuntime.newDefaultInterpreterContainerPath();
	}

	public IBuildpathEntry getEntry() {
	return DLTKCore.newContainerEntry(getInterpreterPath());
	}

	/**
	* Sets the selection based on the given container path and returns a status
	* indicating if the selection was successful.
	*
	* @param containerPath
	* @return status
	*/
	public void setPath(IPath containerPath) {
	if (fInterpreters.isEmpty()) {
	setStatus(new Status(IStatus.ERROR,
	DLTKLaunchingPlugin.getUniqueIdentifier(),
	ScriptLaunchConfigurationConstants.ERR_NO_DEFAULT_INTERPRETER_INSTALL,
	InterpretersMessages.InterpretersComboBlock_0, null));
	} else {
	setStatus(OK_STATUS);
	}
	if (ScriptRuntime.newDefaultInterpreterContainerPath()
	.equals(containerPath)) {
	setUseDefaultInterpreter();
	} else {
	final IEnvironment environment = fContext.getEnvironment();
	final IInterpreterInstall install = environment != null
	? ScriptRuntime.getInterpreterInstall(
	fContext.getNatureId(), environment.getId(),
	containerPath)
	: null;
	if (install == null) {
	setError(InterpretersMessages.InterpretersComboBlock_8);
	} else {
	selectInterpreter(install);
	IFileHandle location = install.getInstallLocation();
	if (location == null) {
	setError(InterpretersMessages.InterpretersComboBlock_12);
	} else if (!location.exists()) {
	setError(InterpretersMessages.InterpretersComboBlock_13);
	}
	}
	}
	}

	private void setError(String message) {
	setStatus(new Status(IStatus.ERROR,
	DLTKDebugUIPlugin.getUniqueIdentifier(),
	IDLTKDebugUIConstants.INTERNAL_ERROR, message, null));
	}

	/**
	* Returns the status of the interpreter selection.
	*
	* @return status
	*/
	public IStatus getStatus() {
	return fStatus;
	}

	private void setStatus(IStatus status) {
	fStatus = status;
	}

	/**
	* Shows window with appropriate language preference page.
	*/
	protected void showInterpreterPreferencePage() {
	IDLTKUILanguageToolkit toolkit = DLTKUILanguageManager
	.getLanguageToolkit(getCurrentLanguageNature());
	if (toolkit != null) {
	final String pageId = toolkit.getInterpreterPreferencePage();
	if (pageId != null) {
	showPrefPage(pageId);
	}
	}
	}

	protected void fillWithWorkspaceInterpreters() {
	// fill with interpreters
	final List<IInterpreterInstall> standins = new ArrayList<>();
	final IInterpreterInstallType[] types = ScriptRuntime
	.getInterpreterInstallTypes(getCurrentLanguageNature());
	final IEnvironment environment = fContext.getEnvironment();

	for (int i = 0; i < types.length; i++) {
	IInterpreterInstallType type = types[i];
	IInterpreterInstall[] installs = type.getInterpreterInstalls();
	for (int j = 0; j < installs.length; j++) {
	final IInterpreterInstall install = installs[j];
	if (environment != null && environment.getId()
	.equals(install.getEnvironmentId())) {
	standins.add(new InterpreterStandin(install));
	}
	}
	}
	setInterpreters(standins);
	}

	protected final String getCurrentLanguageNature() {
	return fContext.getNatureId();
	}
	}