org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/hover/JavaSourceHover.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2018 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jdt.internal.ui.text.java.hover;

 import java.io.IOException;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTException;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;

 import org.eclipse.core.runtime.CoreException;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.Document;
 import org.eclipse.jface.text.IDocument;
 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.ui.IEditorPart;
 import org.eclipse.ui.part.IWorkbenchPartOrientation;

 import org.eclipse.ui.editors.text.EditorsUI;

 import org.eclipse.jdt.core.IJavaElement;
 import org.eclipse.jdt.core.ILocalVariable;
 import org.eclipse.jdt.core.IMember;
 import org.eclipse.jdt.core.ISourceReference;
 import org.eclipse.jdt.core.ITypeParameter;
 import org.eclipse.jdt.core.ITypeRoot;
 import org.eclipse.jdt.core.JavaModelException;
 import org.eclipse.jdt.core.dom.ASTNode;
 import org.eclipse.jdt.core.dom.Block;
 import org.eclipse.jdt.core.dom.BodyDeclaration;
 import org.eclipse.jdt.core.dom.CompilationUnit;
 import org.eclipse.jdt.core.dom.IfStatement;
 import org.eclipse.jdt.core.dom.Javadoc;
 import org.eclipse.jdt.core.dom.NodeFinder;
 import org.eclipse.jdt.core.dom.Statement;
 import org.eclipse.jdt.core.dom.SwitchStatement;
 import org.eclipse.jdt.core.manipulation.SharedASTProviderCore;

 import org.eclipse.jdt.internal.core.manipulation.StubUtility;
 import org.eclipse.jdt.internal.core.manipulation.util.Strings;
 import org.eclipse.jdt.internal.corext.dom.ASTNodes;
 import org.eclipse.jdt.internal.corext.dom.TokenScanner;
 import org.eclipse.jdt.internal.corext.util.Messages;

 import org.eclipse.jdt.internal.ui.JavaPlugin;
 import org.eclipse.jdt.internal.ui.javaeditor.JavaEditor;
 import org.eclipse.jdt.internal.ui.javaeditor.JavaSourceViewer;
 import org.eclipse.jdt.internal.ui.text.JavaCodeReader;
 import org.eclipse.jdt.internal.ui.text.JavaPairMatcher;


 /**
  * Provides as hover info the source of the selected JavaElement, or the source near the matching
  * opening curly brace.
  */
 public class JavaSourceHover extends AbstractJavaEditorTextHover {

 	/**
 	 * The upward shift in location in lines for the bracket hover.
 	 *
 	 * @since 3.8
 	 */
 	private int fUpwardShiftInLines;

 	/**
 	 * The status text for the bracket hover.
 	 *
 	 * @since 3.8
 	 */
 	private String fBracketHoverStatus;

 	/**
 	 * The hovered Java element to get the source.
 	 *
 	 * @since 3.14
 	 */
 	private IJavaElement fJavaElement;

 	class JavaSourceInformationInput {
 		private IJavaElement fElement;

 		private String fHoverInfo;

 		public JavaSourceInformationInput(IJavaElement javaElement, String hoverInfo) {
 			fElement= javaElement;
 			fHoverInfo= hoverInfo;
 		}

 		public IJavaElement getJavaElement() {
 			return fElement;
 		}

 		public String getHoverInfo() {
 			return fHoverInfo;
 		}
 	}

 	@Override
 	public Object getHoverInfo2(ITextViewer textViewer, IRegion hoverRegion) {
 		String hoverInfoString= getHoverInfo(textViewer, hoverRegion);
 		if (hoverInfoString == null) {
 			return null;
 		}
 		if (fJavaElement == null) {
 			return hoverInfoString;
 		}
 		return new JavaSourceInformationInput(fJavaElement, hoverInfoString);
 	}

 	@Override
 	@Deprecated
 	public String getHoverInfo(ITextViewer textViewer, IRegion region) {
 		IJavaElement[] result= getJavaElementsAt(textViewer, region);
 		fJavaElement= null;

 		fUpwardShiftInLines= 0;
 		fBracketHoverStatus= null;

 		if (result == null || result.length == 0) {
 			return getBracketHoverInfo(textViewer, region);
 		}

 		if (result.length > 1)
 			return null;

 		fJavaElement= result[0];
 		if ((fJavaElement instanceof IMember || fJavaElement instanceof ILocalVariable || fJavaElement instanceof ITypeParameter) && fJavaElement instanceof ISourceReference) {
 			try {
 				String source= ((ISourceReference) fJavaElement).getSource();

 				String[] sourceLines= getTrimmedSource(source, fJavaElement);
 				if (sourceLines == null)
 					return null;

 				String delim= StubUtility.getLineDelimiterUsed(fJavaElement);
 				source= Strings.concatenate(sourceLines, delim);

 				return source;
 			} catch (JavaModelException ex) {
 				//do nothing
 			}
 		}
 		return null;
 	}

 	private String getBracketHoverInfo(final ITextViewer textViewer, IRegion region) {
 		boolean isElsePart= false;
 		IEditorPart editor= getEditor();
 		ITypeRoot editorInput= getEditorInputJavaElement();
 		if (!(editor instanceof JavaEditor) || editorInput == null) {
 			return null;
 		}

 		int offset= region.getOffset();
 		IDocument document= textViewer.getDocument();
 		if (document == null)
 			return null;
 		try {
 			char c= document.getChar(offset);
 			if (c != '}')
 				return null;
 			JavaPairMatcher matcher= ((JavaEditor) editor).getBracketMatcher();
 			if (matcher == null)
 				return null;
 			IRegion match= matcher.match(document, offset);
 			if (match == null)
 				return null;

 			String delim= StubUtility.getLineDelimiterUsed(editorInput);

 			CompilationUnit ast= SharedASTProviderCore.getAST(editorInput, SharedASTProviderCore.WAIT_NO, null);
 			if (ast == null)
 				return null;
 			ASTNode bracketNode= NodeFinder.perform(ast, match.getOffset(),
 					match.getLength());
 			if (bracketNode == null)
 				return null;
 			ASTNode node;
 			ASTNode parent= bracketNode.getParent();
 			if (parent instanceof IfStatement) {
 				IfStatement parentIfStmt= (IfStatement) parent;
 				if ((parentIfStmt.getElseStatement() != null && ASTNodes.getInclusiveEnd(parentIfStmt.getElseStatement()) == offset) // if [else if]* else
 						|| (parentIfStmt.getLocationInParent() == IfStatement.ELSE_STATEMENT_PROPERTY && ASTNodes.getInclusiveEnd(parentIfStmt.getThenStatement()) == offset)) { // if [else if]+ else?
 					isElsePart= true;
 					while (parent.getLocationInParent() == IfStatement.ELSE_STATEMENT_PROPERTY) {
 						parent= parent.getParent();
 					}
 				}
 			}
 			if (bracketNode instanceof Block && !(parent instanceof Block) && !(parent instanceof SwitchStatement)) {
 				node= parent;
 			} else {
 				node= bracketNode;
 			}
 			int nodeStart;
 			int nodeLength;
 			if (node instanceof BodyDeclaration) {
 				BodyDeclaration declaration= (BodyDeclaration) node;
 				Javadoc javadoc= declaration.getJavadoc();
 				int lengthOfJavadoc= javadoc == null ? 0 : javadoc.getLength() +
 						delim.length();
 				nodeStart= node.getStartPosition() + lengthOfJavadoc;
 				nodeLength= node.getLength() - lengthOfJavadoc;
 			} else {
 				nodeStart= node.getStartPosition();
 				nodeLength= ASTNodes.getExclusiveEnd(bracketNode) - nodeStart;
 			}

 			int line1= document.getLineOfOffset(nodeStart);
 			int sourceOffset= document.getLineOffset(line1);
 			int line2= document.getLineOfOffset(nodeStart + nodeLength);
 			int hoveredLine= document.getLineOfOffset(offset);
 			if (line2 > hoveredLine)
 				line2= hoveredLine;

 			//check if line1 is visible
 			final int[] topIndex= new int[1];
 			StyledText textWidget= textViewer.getTextWidget();
 			if (textWidget == null)
 				return null;

 			Display display;
 			try {
 				display= textWidget.getDisplay();
 			} catch (SWTException ex) {
 				if (ex.code == SWT.ERROR_WIDGET_DISPOSED)
 					return null;
 				else
 					throw ex;
 			}

 			display.syncExec(new Runnable() {
 				@Override
 				public void run() {
 					topIndex[0]= textViewer.getTopIndex();
 				}
 			});

 			int topLine= topIndex[0];
 			if (topLine == -1)
 				return null;
 			int noOfSourceLines;
 			IRegion endLine;
 			int skippedLines= 0;
 			int wLine1= ((JavaSourceViewer) textViewer).modelLine2WidgetLine(line1);
 			int wLine2= ((JavaSourceViewer) textViewer).modelLine2WidgetLine(line2);
 			if ((line1 < topLine) || (wLine1 != -1 && (wLine2 - wLine1 != line2 - line1))) {
 				// match not visible or content is folded - see bug 399997
 				if (isElsePart) {
 					return getBracketHoverInfo((IfStatement) node, bracketNode, document, editorInput, delim); // see bug 377141, 201850
 				}
 				noOfSourceLines= 3;
 				if ((line2 - line1) < noOfSourceLines) {
 					noOfSourceLines= line2 - line1;
 				}
 				skippedLines= Math.abs(line2 - line1 - noOfSourceLines);
 				if (skippedLines == 1) {
 					noOfSourceLines++;
 					skippedLines= 0;
 				}
 				endLine= document.getLineInformation(line1 + noOfSourceLines);
 				fUpwardShiftInLines= noOfSourceLines;
 				if (skippedLines > 0) {
 					fBracketHoverStatus= Messages.format(JavaHoverMessages.JavaSourceHover_skippedLines, Integer.valueOf(skippedLines));
 				}
 			} else {
 				noOfSourceLines= line2 - line1;
 				endLine= document.getLineInformation(line2);
 				fUpwardShiftInLines= line2 - line1;
 			}
 			if (fUpwardShiftInLines == 0)
 				return null;

 			int sourceLength= (endLine.getOffset() + endLine.getLength()) - sourceOffset;
 			String source= document.get(sourceOffset, sourceLength);
 			String[] sourceLines= getTrimmedSource(source, editorInput);
 			if (sourceLines == null)
 				return null;
 			String[] str= new String[noOfSourceLines];
 			System.arraycopy(sourceLines, 0, str, 0, noOfSourceLines);
 			source= Strings.concatenate(str, delim);
 			if (skippedLines > 0) {
 				source= source.concat(delim).concat(JavaHoverMessages.JavaSourceHover_skippedLinesSymbol);
 				fUpwardShiftInLines++;
 			}
 			return source;
 		} catch (BadLocationException e) {
 			JavaPlugin.log(e);
 			return null;
 		}
 	}

 	/**
 	 * Creates the hover text for 'else if' or 'else' closing bracket in 'if [else if]+ else?' or
 	 * 'if [else if]* else' cases by stitching together all the headers when the beginning of the
 	 * first 'if' is not visible in the text editor.
 	 *
 	 * @param ifNode the first 'if' node in the structure
 	 * @param bracketNode the node at whose closing bracket the hover text is required
 	 * @param document the input document of the text viewer on which the hover popup should be
 	 *            shown
 	 * @param editorInput the editor's input as {@link ITypeRoot}
 	 * @param delim the line delimiter used for the editorInput
 	 * @return the hover text for 'else if' or 'else' closing bracket in 'if [else if]+ else?' or
 	 *         'if [else if]* else' cases respectively
 	 * @throws BadLocationException if an attempt has been performed to access a non-existing
 	 *             position in the document
 	 * @since 3.9
 	 */
 	private String getBracketHoverInfo(IfStatement ifNode, ASTNode bracketNode, final IDocument document, final ITypeRoot editorInput, final String delim) throws BadLocationException {
 		int totalSkippedLines= 0;
 		String hoverText= null;

 		Statement currentStatement= ifNode.getThenStatement();
 		int nodeStart= ifNode.getStartPosition();
 		while (currentStatement != null) {
 			int nodeLength= ASTNodes.getExclusiveEnd(currentStatement) - nodeStart;
 			int line1= document.getLineOfOffset(nodeStart);
 			int sourceOffset= document.getLineOffset(line1);
 			int line2= document.getLineOfOffset(nodeStart + nodeLength);
 			int line3= line2;
 			if (currentStatement != bracketNode && ifNode != null && ifNode.getElseStatement() != null) {
 				int elseStartOffset= getNextElseOffset(ifNode.getThenStatement(), editorInput);
 				if (elseStartOffset != -1) {
 					line3= document.getLineOfOffset(elseStartOffset); // next 'else'
 				}
 			}
 			int noOfTotalLines= (line2 == line3) ? (line2 - line1) : (line2 - line1 + 1);
 			int noOfSourceLines= 3;

 			if (noOfTotalLines < noOfSourceLines) {
 				noOfSourceLines= noOfTotalLines;
 			}
 			int noOfSkippedLines= noOfTotalLines - noOfSourceLines;
 			if (noOfSkippedLines == 1) {
 				noOfSourceLines++;
 				noOfSkippedLines= 0;
 			}

 			if (noOfSourceLines > 0) {
 				IRegion endLine= document.getLineInformation(line1 + noOfSourceLines - 1);
 				int sourceLength= (endLine.getOffset() + endLine.getLength()) - sourceOffset;
 				String source= document.get(sourceOffset, sourceLength);
 				String[] sourceLines= getTrimmedSource(source, editorInput);
 				if (sourceLines == null)
 					return null;
 				source= Strings.concatenate(sourceLines, delim);
 				if (noOfSkippedLines > 0) {
 					source= source.concat(delim).concat(JavaHoverMessages.JavaSourceHover_skippedLinesSymbol);
 					fUpwardShiftInLines++;
 				}

 				fUpwardShiftInLines+= noOfSourceLines;
 				totalSkippedLines+= noOfSkippedLines;
 				if (hoverText == null) {
 					hoverText= source;
 				} else {
 					hoverText= hoverText.concat(delim).concat(source);
 				}
 			}
 			// advance currentStatement to the next 'else if' or 'else' statement; set it to null when no further processing is required
 			// advance ifNode to the 'if' in next 'else if'; set it to null if 'else' is reached
 			if (currentStatement != bracketNode) {
 				Statement thenStatement= ifNode.getThenStatement();
 				Statement nextStatement= ifNode.getElseStatement();
 				if (nextStatement instanceof IfStatement) {
 					currentStatement= ((IfStatement) nextStatement).getThenStatement();
 					ifNode= (IfStatement) nextStatement;
 				} else {
 					currentStatement= nextStatement;
 					ifNode= null;
 				}
 				// update nodeStart to next 'else' start offset
 				int nextStartOffset= getNextElseOffset(thenStatement, editorInput);
 				if (nextStartOffset != -1) {
 					nodeStart= nextStartOffset;
 				} else {
 					nodeStart= nextStatement.getStartPosition();
 				}
 			} else {
 				currentStatement= null;
 			}
 		}

 		if (fUpwardShiftInLines == 0)
 			return null;
 		if ((totalSkippedLines) > 0) {
 			fBracketHoverStatus= Messages.format(JavaHoverMessages.JavaSourceHover_skippedLines, Integer.valueOf(totalSkippedLines));
 		}
 		return hoverText;
 	}

 	private int getNextElseOffset(Statement then, ITypeRoot editorInput) {
 		int thenEnd= ASTNodes.getExclusiveEnd(then);
 		try {
 			TokenScanner scanner= new TokenScanner(editorInput);
 			return scanner.getNextStartOffset(thenEnd, true);
 		} catch (CoreException e) {
 			// ignore
 		}
 		return -1;
 	}

 	/**
 	 * Returns the trimmed source lines.
 	 *
 	 * @param source the source string, could be <code>null</code>
 	 * @param javaElement the java element
 	 * @return the trimmed source lines or <code>null</code>
 	 */
 	private String[] getTrimmedSource(String source, IJavaElement javaElement) {
 		if (source == null)
 			return null;
 		source= removeLeadingComments(source);
 		String[] sourceLines= Strings.convertIntoLines(source);
 		Strings.trimIndentation(sourceLines, javaElement.getJavaProject());
 		return sourceLines;
 	}

 	private String removeLeadingComments(String source) {
 		final JavaCodeReader reader= new JavaCodeReader();
 		IDocument document= new Document(source);
 		int i;
 		try {
 			reader.configureForwardReader(document, 0, document.getLength(), true, false);
 			int c= reader.read();
 			while (c != -1 && (c == '\r' || c == '\n')) {
 				c= reader.read();
 			}
 			i= reader.getOffset();
 			reader.close();
 		} catch (IOException ex) {
 			i= 0;
 		} finally {
 			try {
 				reader.close();
 			} catch (IOException ex) {
 				JavaPlugin.log(ex);
 			}
 		}

 		if (i < 0)
 			return source;
 		return source.substring(i);
 	}

 	/*
 	 * @see org.eclipse.jface.text.ITextHoverExtension#getHoverControlCreator()
 	 * @since 3.0
 	 */
 	@Override
 	public IInformationControlCreator getHoverControlCreator() {
 		if (fUpwardShiftInLines > 0)
 			return createInformationControlCreator(false, fBracketHoverStatus, true);
 		else
 			return createInformationControlCreator(false, EditorsUI.getTooltipAffordanceString(), true);
 	}

 	/*
 	 * @see org.eclipse.jdt.internal.ui.text.java.hover.AbstractJavaEditorTextHover#getInformationPresenterControlCreator()
 	 * @since 3.0
 	 */
 	@Override
 	public IInformationControlCreator getInformationPresenterControlCreator() {
 		if (fUpwardShiftInLines > 0)
 			return createInformationControlCreator(false, fBracketHoverStatus, true);
 		else
 			return createInformationControlCreator(true, EditorsUI.getTooltipAffordanceString(), true);
 	}

 	/**
 	 * Returns the information control creator.
 	 *
 	 * @param isResizable <code>true</code> if resizable
 	 * @param statusFieldText the text to be used in the optional status field or <code>null</code>
 	 *            if the status field should be hidden
 	 * @param doShiftUp <code>true</code> iff {@link #fUpwardShiftInLines} should be considered
 	 * @return the information control creator
 	 * @since 3.8
 	 */
 	private IInformationControlCreator createInformationControlCreator(final boolean isResizable, final String statusFieldText, final boolean doShiftUp) {
 		return new IInformationControlCreator() {
 			@Override
 			public IInformationControl createInformationControl(final Shell parent) {
 				final IEditorPart editor= getEditor();
 				int orientation= SWT.NONE;
 				if (editor instanceof IWorkbenchPartOrientation)
 					orientation= ((IWorkbenchPartOrientation) editor).getOrientation();

 				return new SourceViewerInformationControl(parent, isResizable, orientation, statusFieldText) {
 					@Override
 					public void setLocation(Point location) {
 						Point loc= location;
 						if (doShiftUp && fUpwardShiftInLines > 0) {
 							Point size= super.computeSizeConstraints(0, fUpwardShiftInLines + 1);
 							//bracket hover is rendered above '}'
 							int y= location.y - size.y - 5; //AbstractInformationControlManager.fMarginY = 5
 							Rectangle trim= computeTrim();
 							loc= new Point(location.x + trim.x - getViewer().getTextWidget().getLeftMargin(), y - trim.height - trim.y);
 						}
 						super.setLocation(loc);
 					}

 					@Override
 					public Point computeSizeConstraints(int widthInChars, int heightInChars) {
 						if (doShiftUp && fUpwardShiftInLines > 0) {
 							Point sizeConstraints= super.computeSizeConstraints(widthInChars, heightInChars);
 							return new Point(sizeConstraints.x, 0); //set height as 0 to ensure selection of bottom anchor in AbstractInformationControlManager.computeInformationControlLocation(...)
 						} else {
 							return super.computeSizeConstraints(widthInChars, heightInChars);
 						}
 					}

 					@Override
 					public void setSize(int width, int height) {
 						if (doShiftUp && fUpwardShiftInLines != 0) {
 							//compute the correct height of hover, this was set to 0 in computeSizeConstraints(..)
 							Point size= super.computeSizeConstraints(0, fUpwardShiftInLines);
 							Rectangle trim= computeTrim();
 							super.setSize(width, size.y + trim.height - trim.y);
 						} else {
 							super.setSize(width, height);
 						}
 					}

 					@Override
 					public IInformationControlCreator getInformationPresenterControlCreator() {
 						if (doShiftUp && fUpwardShiftInLines > 0) {
 							// Hack: We don't wan't to have auto-enrichment when the mouse moves into the hover,
 							// but we do want F2 to persist the hover. The framework has no way to distinguish the
 							// two requests, so we have to implement this aspect.
 							for (StackTraceElement element : Thread.currentThread().getStackTrace()) {
 								if ("canMoveIntoInformationControl".equals(element.getMethodName()) //$NON-NLS-1$
 										&& "org.eclipse.jface.text.AbstractHoverInformationControlManager".equals(element.getClassName())) //$NON-NLS-1$
 									return null; //do not enrich bracket hover
 							}
 							return JavaSourceHover.this.createInformationControlCreator(isResizable && !isResizable, statusFieldText, false);
 						} else {
 							return super.getInformationPresenterControlCreator();
 						}
 					}
 				};
 			}
 		};
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2018 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jdt.internal.ui.text.java.hover;

	import java.io.IOException;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTException;
	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Shell;

	import org.eclipse.core.runtime.CoreException;

	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.Document;
	import org.eclipse.jface.text.IDocument;
	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.ui.IEditorPart;
	import org.eclipse.ui.part.IWorkbenchPartOrientation;

	import org.eclipse.ui.editors.text.EditorsUI;

	import org.eclipse.jdt.core.IJavaElement;
	import org.eclipse.jdt.core.ILocalVariable;
	import org.eclipse.jdt.core.IMember;
	import org.eclipse.jdt.core.ISourceReference;
	import org.eclipse.jdt.core.ITypeParameter;
	import org.eclipse.jdt.core.ITypeRoot;
	import org.eclipse.jdt.core.JavaModelException;
	import org.eclipse.jdt.core.dom.ASTNode;
	import org.eclipse.jdt.core.dom.Block;
	import org.eclipse.jdt.core.dom.BodyDeclaration;
	import org.eclipse.jdt.core.dom.CompilationUnit;
	import org.eclipse.jdt.core.dom.IfStatement;
	import org.eclipse.jdt.core.dom.Javadoc;
	import org.eclipse.jdt.core.dom.NodeFinder;
	import org.eclipse.jdt.core.dom.Statement;
	import org.eclipse.jdt.core.dom.SwitchStatement;
	import org.eclipse.jdt.core.manipulation.SharedASTProviderCore;

	import org.eclipse.jdt.internal.core.manipulation.StubUtility;
	import org.eclipse.jdt.internal.core.manipulation.util.Strings;
	import org.eclipse.jdt.internal.corext.dom.ASTNodes;
	import org.eclipse.jdt.internal.corext.dom.TokenScanner;
	import org.eclipse.jdt.internal.corext.util.Messages;

	import org.eclipse.jdt.internal.ui.JavaPlugin;
	import org.eclipse.jdt.internal.ui.javaeditor.JavaEditor;
	import org.eclipse.jdt.internal.ui.javaeditor.JavaSourceViewer;
	import org.eclipse.jdt.internal.ui.text.JavaCodeReader;
	import org.eclipse.jdt.internal.ui.text.JavaPairMatcher;


	/**
	* Provides as hover info the source of the selected JavaElement, or the source near the matching
	* opening curly brace.
	*/
	public class JavaSourceHover extends AbstractJavaEditorTextHover {

	/**
	* The upward shift in location in lines for the bracket hover.
	*
	* @since 3.8
	*/
	private int fUpwardShiftInLines;

	/**
	* The status text for the bracket hover.
	*
	* @since 3.8
	*/
	private String fBracketHoverStatus;

	/**
	* The hovered Java element to get the source.
	*
	* @since 3.14
	*/
	private IJavaElement fJavaElement;

	class JavaSourceInformationInput {
	private IJavaElement fElement;

	private String fHoverInfo;

	public JavaSourceInformationInput(IJavaElement javaElement, String hoverInfo) {
	fElement= javaElement;
	fHoverInfo= hoverInfo;
	}

	public IJavaElement getJavaElement() {
	return fElement;
	}

	public String getHoverInfo() {
	return fHoverInfo;
	}
	}

	@Override
	public Object getHoverInfo2(ITextViewer textViewer, IRegion hoverRegion) {
	String hoverInfoString= getHoverInfo(textViewer, hoverRegion);
	if (hoverInfoString == null) {
	return null;
	}
	if (fJavaElement == null) {
	return hoverInfoString;
	}
	return new JavaSourceInformationInput(fJavaElement, hoverInfoString);
	}

	@Override
	@Deprecated
	public String getHoverInfo(ITextViewer textViewer, IRegion region) {
	IJavaElement[] result= getJavaElementsAt(textViewer, region);
	fJavaElement= null;

	fUpwardShiftInLines= 0;
	fBracketHoverStatus= null;

	if (result == null \|\| result.length == 0) {
	return getBracketHoverInfo(textViewer, region);
	}

	if (result.length > 1)
	return null;

	fJavaElement= result[0];
	if ((fJavaElement instanceof IMember \|\| fJavaElement instanceof ILocalVariable \|\| fJavaElement instanceof ITypeParameter) && fJavaElement instanceof ISourceReference) {
	try {
	String source= ((ISourceReference) fJavaElement).getSource();

	String[] sourceLines= getTrimmedSource(source, fJavaElement);
	if (sourceLines == null)
	return null;

	String delim= StubUtility.getLineDelimiterUsed(fJavaElement);
	source= Strings.concatenate(sourceLines, delim);

	return source;
	} catch (JavaModelException ex) {
	//do nothing
	}
	}
	return null;
	}

	private String getBracketHoverInfo(final ITextViewer textViewer, IRegion region) {
	boolean isElsePart= false;
	IEditorPart editor= getEditor();
	ITypeRoot editorInput= getEditorInputJavaElement();
	if (!(editor instanceof JavaEditor) \|\| editorInput == null) {
	return null;
	}

	int offset= region.getOffset();
	IDocument document= textViewer.getDocument();
	if (document == null)
	return null;
	try {
	char c= document.getChar(offset);
	if (c != '}')
	return null;
	JavaPairMatcher matcher= ((JavaEditor) editor).getBracketMatcher();
	if (matcher == null)
	return null;
	IRegion match= matcher.match(document, offset);
	if (match == null)
	return null;

	String delim= StubUtility.getLineDelimiterUsed(editorInput);

	CompilationUnit ast= SharedASTProviderCore.getAST(editorInput, SharedASTProviderCore.WAIT_NO, null);
	if (ast == null)
	return null;
	ASTNode bracketNode= NodeFinder.perform(ast, match.getOffset(),
	match.getLength());
	if (bracketNode == null)
	return null;
	ASTNode node;
	ASTNode parent= bracketNode.getParent();
	if (parent instanceof IfStatement) {
	IfStatement parentIfStmt= (IfStatement) parent;
	if ((parentIfStmt.getElseStatement() != null && ASTNodes.getInclusiveEnd(parentIfStmt.getElseStatement()) == offset) // if [else if]* else
	\|\| (parentIfStmt.getLocationInParent() == IfStatement.ELSE_STATEMENT_PROPERTY && ASTNodes.getInclusiveEnd(parentIfStmt.getThenStatement()) == offset)) { // if [else if]+ else?
	isElsePart= true;
	while (parent.getLocationInParent() == IfStatement.ELSE_STATEMENT_PROPERTY) {
	parent= parent.getParent();
	}
	}
	}
	if (bracketNode instanceof Block && !(parent instanceof Block) && !(parent instanceof SwitchStatement)) {
	node= parent;
	} else {
	node= bracketNode;
	}
	int nodeStart;
	int nodeLength;
	if (node instanceof BodyDeclaration) {
	BodyDeclaration declaration= (BodyDeclaration) node;
	Javadoc javadoc= declaration.getJavadoc();
	int lengthOfJavadoc= javadoc == null ? 0 : javadoc.getLength() +
	delim.length();
	nodeStart= node.getStartPosition() + lengthOfJavadoc;
	nodeLength= node.getLength() - lengthOfJavadoc;
	} else {
	nodeStart= node.getStartPosition();
	nodeLength= ASTNodes.getExclusiveEnd(bracketNode) - nodeStart;
	}

	int line1= document.getLineOfOffset(nodeStart);
	int sourceOffset= document.getLineOffset(line1);
	int line2= document.getLineOfOffset(nodeStart + nodeLength);
	int hoveredLine= document.getLineOfOffset(offset);
	if (line2 > hoveredLine)
	line2= hoveredLine;

	//check if line1 is visible
	final int[] topIndex= new int[1];
	StyledText textWidget= textViewer.getTextWidget();
	if (textWidget == null)
	return null;

	Display display;
	try {
	display= textWidget.getDisplay();
	} catch (SWTException ex) {
	if (ex.code == SWT.ERROR_WIDGET_DISPOSED)
	return null;
	else
	throw ex;
	}

	display.syncExec(new Runnable() {
	@Override
	public void run() {
	topIndex[0]= textViewer.getTopIndex();
	}
	});

	int topLine= topIndex[0];
	if (topLine == -1)
	return null;
	int noOfSourceLines;
	IRegion endLine;
	int skippedLines= 0;
	int wLine1= ((JavaSourceViewer) textViewer).modelLine2WidgetLine(line1);
	int wLine2= ((JavaSourceViewer) textViewer).modelLine2WidgetLine(line2);
	if ((line1 < topLine) \|\| (wLine1 != -1 && (wLine2 - wLine1 != line2 - line1))) {
	// match not visible or content is folded - see bug 399997
	if (isElsePart) {
	return getBracketHoverInfo((IfStatement) node, bracketNode, document, editorInput, delim); // see bug 377141, 201850
	}
	noOfSourceLines= 3;
	if ((line2 - line1) < noOfSourceLines) {
	noOfSourceLines= line2 - line1;
	}
	skippedLines= Math.abs(line2 - line1 - noOfSourceLines);
	if (skippedLines == 1) {
	noOfSourceLines++;
	skippedLines= 0;
	}
	endLine= document.getLineInformation(line1 + noOfSourceLines);
	fUpwardShiftInLines= noOfSourceLines;
	if (skippedLines > 0) {
	fBracketHoverStatus= Messages.format(JavaHoverMessages.JavaSourceHover_skippedLines, Integer.valueOf(skippedLines));
	}
	} else {
	noOfSourceLines= line2 - line1;
	endLine= document.getLineInformation(line2);
	fUpwardShiftInLines= line2 - line1;
	}
	if (fUpwardShiftInLines == 0)
	return null;

	int sourceLength= (endLine.getOffset() + endLine.getLength()) - sourceOffset;
	String source= document.get(sourceOffset, sourceLength);
	String[] sourceLines= getTrimmedSource(source, editorInput);
	if (sourceLines == null)
	return null;
	String[] str= new String[noOfSourceLines];
	System.arraycopy(sourceLines, 0, str, 0, noOfSourceLines);
	source= Strings.concatenate(str, delim);
	if (skippedLines > 0) {
	source= source.concat(delim).concat(JavaHoverMessages.JavaSourceHover_skippedLinesSymbol);
	fUpwardShiftInLines++;
	}
	return source;
	} catch (BadLocationException e) {
	JavaPlugin.log(e);
	return null;
	}
	}

	/**
	* Creates the hover text for 'else if' or 'else' closing bracket in 'if [else if]+ else?' or
	* 'if [else if]* else' cases by stitching together all the headers when the beginning of the
	* first 'if' is not visible in the text editor.
	*
	* @param ifNode the first 'if' node in the structure
	* @param bracketNode the node at whose closing bracket the hover text is required
	* @param document the input document of the text viewer on which the hover popup should be
	* shown
	* @param editorInput the editor's input as {@link ITypeRoot}
	* @param delim the line delimiter used for the editorInput
	* @return the hover text for 'else if' or 'else' closing bracket in 'if [else if]+ else?' or
	* 'if [else if]* else' cases respectively
	* @throws BadLocationException if an attempt has been performed to access a non-existing
	* position in the document
	* @since 3.9
	*/
	private String getBracketHoverInfo(IfStatement ifNode, ASTNode bracketNode, final IDocument document, final ITypeRoot editorInput, final String delim) throws BadLocationException {
	int totalSkippedLines= 0;
	String hoverText= null;

	Statement currentStatement= ifNode.getThenStatement();
	int nodeStart= ifNode.getStartPosition();
	while (currentStatement != null) {
	int nodeLength= ASTNodes.getExclusiveEnd(currentStatement) - nodeStart;
	int line1= document.getLineOfOffset(nodeStart);
	int sourceOffset= document.getLineOffset(line1);
	int line2= document.getLineOfOffset(nodeStart + nodeLength);
	int line3= line2;
	if (currentStatement != bracketNode && ifNode != null && ifNode.getElseStatement() != null) {
	int elseStartOffset= getNextElseOffset(ifNode.getThenStatement(), editorInput);
	if (elseStartOffset != -1) {
	line3= document.getLineOfOffset(elseStartOffset); // next 'else'
	}
	}
	int noOfTotalLines= (line2 == line3) ? (line2 - line1) : (line2 - line1 + 1);
	int noOfSourceLines= 3;

	if (noOfTotalLines < noOfSourceLines) {
	noOfSourceLines= noOfTotalLines;
	}
	int noOfSkippedLines= noOfTotalLines - noOfSourceLines;
	if (noOfSkippedLines == 1) {
	noOfSourceLines++;
	noOfSkippedLines= 0;
	}

	if (noOfSourceLines > 0) {
	IRegion endLine= document.getLineInformation(line1 + noOfSourceLines - 1);
	int sourceLength= (endLine.getOffset() + endLine.getLength()) - sourceOffset;
	String source= document.get(sourceOffset, sourceLength);
	String[] sourceLines= getTrimmedSource(source, editorInput);
	if (sourceLines == null)
	return null;
	source= Strings.concatenate(sourceLines, delim);
	if (noOfSkippedLines > 0) {
	source= source.concat(delim).concat(JavaHoverMessages.JavaSourceHover_skippedLinesSymbol);
	fUpwardShiftInLines++;
	}

	fUpwardShiftInLines+= noOfSourceLines;
	totalSkippedLines+= noOfSkippedLines;
	if (hoverText == null) {
	hoverText= source;
	} else {
	hoverText= hoverText.concat(delim).concat(source);
	}
	}
	// advance currentStatement to the next 'else if' or 'else' statement; set it to null when no further processing is required
	// advance ifNode to the 'if' in next 'else if'; set it to null if 'else' is reached
	if (currentStatement != bracketNode) {
	Statement thenStatement= ifNode.getThenStatement();
	Statement nextStatement= ifNode.getElseStatement();
	if (nextStatement instanceof IfStatement) {
	currentStatement= ((IfStatement) nextStatement).getThenStatement();
	ifNode= (IfStatement) nextStatement;
	} else {
	currentStatement= nextStatement;
	ifNode= null;
	}
	// update nodeStart to next 'else' start offset
	int nextStartOffset= getNextElseOffset(thenStatement, editorInput);
	if (nextStartOffset != -1) {
	nodeStart= nextStartOffset;
	} else {
	nodeStart= nextStatement.getStartPosition();
	}
	} else {
	currentStatement= null;
	}
	}

	if (fUpwardShiftInLines == 0)
	return null;
	if ((totalSkippedLines) > 0) {
	fBracketHoverStatus= Messages.format(JavaHoverMessages.JavaSourceHover_skippedLines, Integer.valueOf(totalSkippedLines));
	}
	return hoverText;
	}

	private int getNextElseOffset(Statement then, ITypeRoot editorInput) {
	int thenEnd= ASTNodes.getExclusiveEnd(then);
	try {
	TokenScanner scanner= new TokenScanner(editorInput);
	return scanner.getNextStartOffset(thenEnd, true);
	} catch (CoreException e) {
	// ignore
	}
	return -1;
	}

	/**
	* Returns the trimmed source lines.
	*
	* @param source the source string, could be <code>null</code>
	* @param javaElement the java element
	* @return the trimmed source lines or <code>null</code>
	*/
	private String[] getTrimmedSource(String source, IJavaElement javaElement) {
	if (source == null)
	return null;
	source= removeLeadingComments(source);
	String[] sourceLines= Strings.convertIntoLines(source);
	Strings.trimIndentation(sourceLines, javaElement.getJavaProject());
	return sourceLines;
	}

	private String removeLeadingComments(String source) {
	final JavaCodeReader reader= new JavaCodeReader();
	IDocument document= new Document(source);
	int i;
	try {
	reader.configureForwardReader(document, 0, document.getLength(), true, false);
	int c= reader.read();
	while (c != -1 && (c == '\r' \|\| c == '\n')) {
	c= reader.read();
	}
	i= reader.getOffset();
	reader.close();
	} catch (IOException ex) {
	i= 0;
	} finally {
	try {
	reader.close();
	} catch (IOException ex) {
	JavaPlugin.log(ex);
	}
	}

	if (i < 0)
	return source;
	return source.substring(i);
	}

	/*
	* @see org.eclipse.jface.text.ITextHoverExtension#getHoverControlCreator()
	* @since 3.0
	*/
	@Override
	public IInformationControlCreator getHoverControlCreator() {
	if (fUpwardShiftInLines > 0)
	return createInformationControlCreator(false, fBracketHoverStatus, true);
	else
	return createInformationControlCreator(false, EditorsUI.getTooltipAffordanceString(), true);
	}

	/*
	* @see org.eclipse.jdt.internal.ui.text.java.hover.AbstractJavaEditorTextHover#getInformationPresenterControlCreator()
	* @since 3.0
	*/
	@Override
	public IInformationControlCreator getInformationPresenterControlCreator() {
	if (fUpwardShiftInLines > 0)
	return createInformationControlCreator(false, fBracketHoverStatus, true);
	else
	return createInformationControlCreator(true, EditorsUI.getTooltipAffordanceString(), true);
	}

	/**
	* Returns the information control creator.
	*
	* @param isResizable <code>true</code> if resizable
	* @param statusFieldText the text to be used in the optional status field or <code>null</code>
	* if the status field should be hidden
	* @param doShiftUp <code>true</code> iff {@link #fUpwardShiftInLines} should be considered
	* @return the information control creator
	* @since 3.8
	*/
	private IInformationControlCreator createInformationControlCreator(final boolean isResizable, final String statusFieldText, final boolean doShiftUp) {
	return new IInformationControlCreator() {
	@Override
	public IInformationControl createInformationControl(final Shell parent) {
	final IEditorPart editor= getEditor();
	int orientation= SWT.NONE;
	if (editor instanceof IWorkbenchPartOrientation)
	orientation= ((IWorkbenchPartOrientation) editor).getOrientation();

	return new SourceViewerInformationControl(parent, isResizable, orientation, statusFieldText) {
	@Override
	public void setLocation(Point location) {
	Point loc= location;
	if (doShiftUp && fUpwardShiftInLines > 0) {
	Point size= super.computeSizeConstraints(0, fUpwardShiftInLines + 1);
	//bracket hover is rendered above '}'
	int y= location.y - size.y - 5; //AbstractInformationControlManager.fMarginY = 5
	Rectangle trim= computeTrim();
	loc= new Point(location.x + trim.x - getViewer().getTextWidget().getLeftMargin(), y - trim.height - trim.y);
	}
	super.setLocation(loc);
	}

	@Override
	public Point computeSizeConstraints(int widthInChars, int heightInChars) {
	if (doShiftUp && fUpwardShiftInLines > 0) {
	Point sizeConstraints= super.computeSizeConstraints(widthInChars, heightInChars);
	return new Point(sizeConstraints.x, 0); //set height as 0 to ensure selection of bottom anchor in AbstractInformationControlManager.computeInformationControlLocation(...)
	} else {
	return super.computeSizeConstraints(widthInChars, heightInChars);
	}
	}

	@Override
	public void setSize(int width, int height) {
	if (doShiftUp && fUpwardShiftInLines != 0) {
	//compute the correct height of hover, this was set to 0 in computeSizeConstraints(..)
	Point size= super.computeSizeConstraints(0, fUpwardShiftInLines);
	Rectangle trim= computeTrim();
	super.setSize(width, size.y + trim.height - trim.y);
	} else {
	super.setSize(width, height);
	}
	}

	@Override
	public IInformationControlCreator getInformationPresenterControlCreator() {
	if (doShiftUp && fUpwardShiftInLines > 0) {
	// Hack: We don't wan't to have auto-enrichment when the mouse moves into the hover,
	// but we do want F2 to persist the hover. The framework has no way to distinguish the
	// two requests, so we have to implement this aspect.
	for (StackTraceElement element : Thread.currentThread().getStackTrace()) {
	if ("canMoveIntoInformationControl".equals(element.getMethodName()) //$NON-NLS-1$
	&& "org.eclipse.jface.text.AbstractHoverInformationControlManager".equals(element.getClassName())) //$NON-NLS-1$
	return null; //do not enrich bracket hover
	}
	return JavaSourceHover.this.createInformationControlCreator(isResizable && !isResizable, statusFieldText, false);
	} else {
	return super.getInformationPresenterControlCreator();
	}
	}
	};
	}
	};
	}
	}