bundles/org.eclipse.wst.jsdt.ui/src/org/eclipse/wst/jsdt/internal/ui/text/java/hover/JavaInformationProvider.java

/*******************************************************************************
 * Copyright (c) 2000, 2020 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.jsdt.internal.ui.text.java.hover;


import org.eclipse.jface.internal.text.html.BrowserInformationControl;
import org.eclipse.jface.text.AbstractReusableInformationControlCreator;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.information.IInformationProvider;
import org.eclipse.jface.text.information.IInformationProviderExtension2;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IPartListener;
import org.eclipse.ui.IPerspectiveDescriptor;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.editors.text.EditorsUI;
import org.eclipse.wst.jsdt.internal.ui.text.JavaWordFinder;
import org.eclipse.wst.jsdt.internal.ui.text.html.HTMLTextPresenter;
import org.eclipse.wst.jsdt.ui.PreferenceConstants;
import org.eclipse.wst.jsdt.ui.text.java.hover.IJavaEditorTextHover;

public class JavaInformationProvider implements IInformationProvider, IInformationProviderExtension2 {

	/**
	 * Control creator.
	 */
	private static final class ControlCreator extends AbstractReusableInformationControlCreator {
		/*
		 * @see org.eclipse.wst.jsdt.internal.ui.text.java.hover.AbstractReusableInformationControlCreator#doCreateInformationControl(org.eclipse.swt.widgets.Shell)
		 */
		public IInformationControl doCreateInformationControl(Shell parent) {
			int shellStyle= SWT.RESIZE | SWT.TOOL;
			int style= SWT.V_SCROLL | SWT.H_SCROLL;
			if (BrowserInformationControl.isAvailable(parent)) {
				BrowserInformationControl browserInformationControl = new BrowserInformationControl(parent, PreferenceConstants.APPEARANCE_JAVADOC_FONT, true);
				browserInformationControl.setStatusText(EditorsUI.getTooltipAffordanceString());
				return browserInformationControl;
			}
			else
				return new DefaultInformationControl(parent, shellStyle, style, new HTMLTextPresenter(false));
		}
	}

	class EditorWatcher implements IPartListener {

		/**
		 * @see IPartListener#partOpened(IWorkbenchPart)
		 */
		public void partOpened(IWorkbenchPart part) {
		}

		/**
		 * @see IPartListener#partDeactivated(IWorkbenchPart)
		 */
		public void partDeactivated(IWorkbenchPart part) {
		}

		/**
		 * @see IPartListener#partClosed(IWorkbenchPart)
		 */
		public void partClosed(IWorkbenchPart part) {
			if (part == fEditor) {
				fEditor.getSite().getWorkbenchWindow().getPartService().removePartListener(fPartListener);
				fPartListener= null;
			}
		}

		/**
		 * @see IPartListener#partActivated(IWorkbenchPart)
		 */
		public void partActivated(IWorkbenchPart part) {
			update();
		}

		public void partBroughtToTop(IWorkbenchPart part) {
			update();
		}
	}

	protected IEditorPart fEditor;
	protected IPartListener fPartListener;

	protected String fCurrentPerspective;
	protected IJavaEditorTextHover fImplementation;

	/**
	 * The presentation control creator.
	 */
	private IInformationControlCreator fPresenterControlCreator;
	
	public JavaInformationProvider(IEditorPart editor) {

		fEditor= editor;

		if (fEditor != null) {

			fPartListener= new EditorWatcher();
			IWorkbenchWindow window= fEditor.getSite().getWorkbenchWindow();
			window.getPartService().addPartListener(fPartListener);

			update();
		}
	}

	protected void update() {
		IWorkbenchWindow window = fEditor.getSite().getWorkbenchWindow();
		IWorkbenchPage page = window != null ? window.getActivePage() : null;
		IPerspectiveDescriptor perspective = page != null ? page.getPerspective() : null;

		if (perspective != null)  {
			String perspectiveId= perspective.getId();

			if (fCurrentPerspective == null || fCurrentPerspective != perspectiveId) {
				fCurrentPerspective= perspectiveId;

				fImplementation= new JavaTypeHover();
				fImplementation.setEditor(fEditor);
			}
		}
	}

	/*
	 * @see IInformationProvider#getSubject(ITextViewer, int)
	 */
	public IRegion getSubject(ITextViewer textViewer, int offset) {

		if (textViewer != null)
			return JavaWordFinder.findWord(textViewer.getDocument(), offset);

		return null;
	}

	/*
	 * @see IInformationProvider#getInformation(ITextViewer, IRegion)
	 */
	public String getInformation(ITextViewer textViewer, IRegion subject) {
		if (fImplementation != null) {
			String s= fImplementation.getHoverInfo(textViewer, subject);
			if (s != null && s.trim().length() > 0) {
				return s;
			}
		}

		return null;
	}

	/*
	 * @see IInformationProviderExtension2#getInformationPresenterControlCreator()
	 * 
	 */
	public IInformationControlCreator getInformationPresenterControlCreator() {
		if (fPresenterControlCreator == null)
			fPresenterControlCreator= new ControlCreator();
		return fPresenterControlCreator;
	}
}