com.github.jknack.antlr4ide.ui.railroad.RailroadSelectionProvider.java Source code

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Here is the source code for com.github.jknack.antlr4ide.ui.railroad.RailroadSelectionProvider.java

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/*******************************************************************************
 * Copyright (c) 2010 itemis AG (http://www.itemis.eu)
 * 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
 * Contributors:
 *   Jan Koehnlein - Initial API and implementation
 *******************************************************************************/
package com.github.jknack.antlr4ide.ui.railroad;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.MouseEvent;
import org.eclipse.draw2d.MouseListener;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;

import com.github.jknack.antlr4ide.ui.railroad.figures.IEObjectReferer;
import com.github.jknack.antlr4ide.ui.railroad.figures.ISelectable;
import com.google.inject.Inject;
import com.google.inject.Singleton;

/**
 * Manages selection and navigation in the railroad diagram view.
 *
 * @author Jan Koehnlein
 */
@Singleton
public class RailroadSelectionProvider implements MouseListener, ISelectionProvider {

    public static class DoubleClickEvent extends SelectionChangedEvent {
        private static final long serialVersionUID = 6328075027502345297L;

        public DoubleClickEvent(final ISelectionProvider source, final ISelection selection) {
            super(source, selection);
        }
    }

    @Inject
    private RailroadView view;

    private ListenerList selectionListeners = new ListenerList();

    private IFigure currentSelectedFigure;

    @Override
    public void mousePressed(final MouseEvent me) {
        setSelection(me, false);
    }

    @Override
    public void mouseReleased(final MouseEvent me) {
        // do nothing
    }

    @Override
    public void mouseDoubleClicked(final MouseEvent me) {
        setSelection(me, true);
    }

    protected void setSelection(final MouseEvent me, final boolean isDoubleClick) {
        IFigure selectedFigure = view.findFigureAt(me.getLocation());
        while (selectedFigure != null && !(selectedFigure instanceof IEObjectReferer)) {
            selectedFigure = selectedFigure.getParent();
        }
        if (selectedFigure != null) {
            setSelection(new StructuredSelection(selectedFigure), isDoubleClick);
        }
    }

    @Override
    public void addSelectionChangedListener(final ISelectionChangedListener listener) {
        selectionListeners.add(listener);
    }

    @Override
    public void removeSelectionChangedListener(final ISelectionChangedListener listener) {
        selectionListeners.remove(listener);
    }

    @Override
    public ISelection getSelection() {
        if (currentSelectedFigure != null) {
            return new StructuredSelection(currentSelectedFigure);
        } else {
            return StructuredSelection.EMPTY;
        }
    }

    protected void setSelection(final ISelection selection, final boolean isDoubleClick) {
        IFigure selectedFigure = getSelectedFigure(selection);
        if (currentSelectedFigure instanceof ISelectable) {
            ((ISelectable) currentSelectedFigure).setSelected(false);
        }
        currentSelectedFigure = selectedFigure;
        if (selectedFigure instanceof ISelectable) {
            ((ISelectable) selectedFigure).setSelected(true);
        }
        SelectionChangedEvent event = isDoubleClick ? new DoubleClickEvent(this, selection)
                : new SelectionChangedEvent(this, selection);
        for (Object listener : selectionListeners.getListeners()) {
            ((ISelectionChangedListener) listener).selectionChanged(event);
        }
    }

    @Override
    public void setSelection(final ISelection selection) {
        setSelection(selection, false);
    }

    protected IFigure getSelectedFigure(final ISelection selection) {
        if (selection instanceof IStructuredSelection && ((IStructuredSelection) selection).size() == 1) {
            Object selectedElement = ((IStructuredSelection) selection).getFirstElement();
            if (selectedElement instanceof IFigure) {
                return (IFigure) selectedElement;
            }
        }
        return null;
    }
}