InlineProjectionAnnotationHover.java

package de.ovgu.cide.language.jdt.editor.inlineprojection;

import java.util.Iterator;

import org.eclipse.jdt.internal.ui.text.java.hover.SourceViewerInformationControl;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.text.BadLocationException;
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.Position;
import org.eclipse.jface.text.source.IAnnotationHover;
import org.eclipse.jface.text.source.IAnnotationHoverExtension;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.jface.text.source.IAnnotationModelExtension;
import org.eclipse.jface.text.source.ILineRange;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.source.ISourceViewerExtension2;
import org.eclipse.jface.text.source.LineRange;
import org.eclipse.jface.text.source.projection.IProjectionPosition;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Shell;

/**
 * Annotation hover for projection annotations.
 * 
 * @since 3.0
 */
@SuppressWarnings(value = { "restriction", "unchecked" })
class InlineProjectionAnnotationHover implements IAnnotationHover,
		IAnnotationHoverExtension {

	private IInformationControlCreator fInformationControlCreator;

	/**
	 * Sets the hover control creator for this projection annotation hover.
	 * 
	 * @param creator
	 *            the creator
	 */
	public void setHoverControlCreator(IInformationControlCreator creator) {
		fInformationControlCreator = creator;
	}

	/*
	 * @see
	 * org.eclipse.jface.text.source.IAnnotationHover#getHoverInfo(org.eclipse
	 * .jface.text.source.ISourceViewer, int)
	 */
	public String getHoverInfo(ISourceViewer sourceViewer, int lineNumber) {
		// this is a no-op as semantics is defined by the implementation of the
		// annotation hover extension
		return null;
	}

	/*
	 * @since 3.1
	 */
	private boolean isCaptionLine(InlineProjectionAnnotation annotation,
			Position position, IDocument document, int line) {
		if (position.getOffset() > -1 && position.getLength() > -1) {
			try {
				int captionOffset;
				if (position instanceof IProjectionPosition)
					captionOffset = ((IProjectionPosition) position)
							.computeCaptionOffset(document);
				else
					captionOffset = 0;
				int startLine = document.getLineOfOffset(position.getOffset()
						+ captionOffset);
				return line == startLine;
			} catch (BadLocationException x) {
			}
		}
		return false;
	}

	private String getProjectionTextAtLine(ISourceViewer viewer, int line,
			int numberOfLines) {

		IAnnotationModel model = null;
		if (viewer instanceof ISourceViewerExtension2) {
			ISourceViewerExtension2 viewerExtension = (ISourceViewerExtension2) viewer;
			IAnnotationModel visual = viewerExtension
					.getVisualAnnotationModel();
			if (visual instanceof IAnnotationModelExtension) {
				IAnnotationModelExtension modelExtension = (IAnnotationModelExtension) visual;
				model = modelExtension
						.getAnnotationModel(InlineProjectionSupport.INLINEPROJECTION);
			}
		}

		if (model != null) {
			try {
				IDocument document = viewer.getDocument();
				Iterator e = model.getAnnotationIterator();
				while (e.hasNext()) {
					InlineProjectionAnnotation annotation = (InlineProjectionAnnotation) e
							.next();
					if (!annotation.isCollapsed())
						continue;

					Position position = model.getPosition(annotation);
					if (position == null)
						continue;

					if (isCaptionLine(annotation, position, document, line))
						return getText(document, position.getOffset(), position
								.getLength(), numberOfLines);

				}
			} catch (BadLocationException x) {
			}
		}

		return null;
	}

	private String getText(IDocument document, int offset, int length,
			int numberOfLines) throws BadLocationException {
		int endOffset = offset + length;

		try {
			int endLine = document.getLineOfOffset(offset)
					+ Math.max(0, numberOfLines - 1);
			IRegion lineInfo = document.getLineInformation(endLine);
			endOffset = Math.min(endOffset, lineInfo.getOffset()
					+ lineInfo.getLength());
		} catch (BadLocationException x) {
		}

		return document.get(offset, endOffset - offset);
	}

	/*
	 * @see
	 * org.eclipse.jface.text.source.IAnnotationHoverExtension#getHoverInfo(
	 * org.eclipse.jface.text.source.ISourceViewer,
	 * org.eclipse.jface.text.source.ILineRange, int)
	 */
	public Object getHoverInfo(ISourceViewer sourceViewer,
			ILineRange lineRange, int visibleLines) {
		return getProjectionTextAtLine(sourceViewer, lineRange.getStartLine(),
				visibleLines);
	}

	/*
	 * @see
	 * org.eclipse.jface.text.source.IAnnotationHoverExtension#getHoverLineRange
	 * (org.eclipse.jface.text.source.ISourceViewer, int)
	 */
	public ILineRange getHoverLineRange(ISourceViewer viewer, int lineNumber) {
		return new LineRange(lineNumber, 1);
	}

	/*
	 * @see
	 * org.eclipse.jface.text.source.IAnnotationHoverExtension#canHandleMouseCursor
	 * ()
	 */
	public boolean canHandleMouseCursor() {
		return false;
	}

	/*
	 * @seeorg.eclipse.jface.text.source.IAnnotationHoverExtension#
	 * getHoverControlCreator()
	 */
	public IInformationControlCreator getHoverControlCreator() {

		if (fInformationControlCreator != null)
			return fInformationControlCreator;

		return new IInformationControlCreator() {
			public IInformationControl createInformationControl(Shell parent) {
				return new SourceViewerInformationControl(parent, true,
						SWT.NONE, JFaceResources.TEXT_FONT);
			}
		};
	}
}