at.bitandart.zoubek.mervin.swt.diff.tree.TreeDiffViewer.java Source code

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/*******************************************************************************
 * Copyright (c) 2016 Florian Zoubek.
 * 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:
 *    Florian Zoubek - initial API and implementation
 *******************************************************************************/
package at.bitandart.zoubek.mervin.swt.diff.tree;

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

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * A {@link Viewer} that adapts a {@link TreeDiff} control and uses a
 * {@link ITreeDiffItemProvider} to create items for the control. This viewer
 * currently does not support specifying a selection.
 * 
 * @author Florian Zoubek
 *
 */
public class TreeDiffViewer extends Viewer {

    /**
     * the input data.
     */
    private Object input;

    /**
     * the tree control that this viewer adapts.
     */
    private TreeDiff treeDiffControl;

    /**
     * the {@link ITreeDiffItemProvider} that is used to build the items for the
     * {@link TreeDiff} control from the input data.
     */
    private ITreeDiffItemProvider treeDiffItemProvider;

    /**
     * creates a new {@link TreeDiffViewer} and the underlying {@link TreeDiff}
     * as child of the given parent.
     * 
     * @param parent
     *            the parent {@link Composite} of the internal {@link TreeDiff}.
     */
    public TreeDiffViewer(Composite parent) {
        treeDiffControl = new TreeDiff(parent);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.viewers.Viewer#getControl()
     */
    @Override
    public Control getControl() {
        return treeDiffControl;
    }

    /**
     * @return the underlying {@link TreeDiff} control.
     */
    public TreeDiff getTreeDiff() {
        return treeDiffControl;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.viewers.Viewer#getInput()
     */
    @Override
    public Object getInput() {
        return input;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.viewers.Viewer#getSelection()
     */
    @Override
    public ISelection getSelection() {
        return StructuredSelection.EMPTY;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.viewers.Viewer#refresh()
     */
    @Override
    public void refresh() {

        if (treeDiffItemProvider != null) {
            Object[] rootItemObjects = treeDiffItemProvider.getRootItems(input);
            List<TreeDiffItem> rootItems = new ArrayList<>(rootItemObjects.length);
            for (Object itemObj : rootItemObjects) {
                TreeDiffItem treeDiffItem = createTreeDiffItem(itemObj);
                if (treeDiffItem != null) {
                    rootItems.add(treeDiffItem);
                }
            }
            treeDiffControl.setItemData(rootItems);
        }

    }

    /**
     * creates a {@link TreeDiffItem} for the given item object using the
     * current {@link ITreeDiffItemProvider}. This method requires that an
     * {@link ITreeDiffItemProvider} has been set.
     * 
     * @param itemObj
     *            the item object to create the {@link TreeDiffItem} for.
     * @return the {@link TreeDiffItem} for the given item object.
     */
    private TreeDiffItem createTreeDiffItem(Object itemObj) {

        TreeDiffSideItem leftSide = createTreeDiffItemSide(itemObj, TreeDiffSide.LEFT);
        TreeDiffSideItem rightSide = createTreeDiffItemSide(itemObj, TreeDiffSide.RIGHT);
        TreeDiffType diffType = treeDiffItemProvider.getTreeDiffType(itemObj, treeDiffControl.getChangedSide());

        TreeDiffItem item = new TreeDiffItem(null, leftSide, rightSide, diffType);

        Object[] children = treeDiffItemProvider.getChildren(itemObj);
        for (Object childItemObj : children) {
            TreeDiffItem treeDiffItemChild = createTreeDiffItem(childItemObj);
            item.getChildren().add(treeDiffItemChild);
            treeDiffItemChild.setParent(item);

            /*
             * enforce that children of deleted or added items have the same
             * diff type
             */
            if (diffType != treeDiffItemChild.getTreeDiffType()
                    && (diffType == TreeDiffType.ADD || diffType == TreeDiffType.DELETE)) {

                treeDiffItemChild.setTreeDiffType(diffType);
            }
        }

        return item;
    }

    /**
     * creates a {@link TreeDiffSideItem} for the given item object using the
     * current {@link ITreeDiffItemProvider}. This method requires that an
     * {@link ITreeDiffItemProvider} has been set.
     * 
     * @param itemObj
     *            the item object to create the {@link TreeDiffItem} for.
     * @param side
     *            the side to create.
     * @return the {@link TreeDiffSideItem} for the given item object.
     */
    private TreeDiffSideItem createTreeDiffItemSide(Object itemObj, TreeDiffSide side) {

        Image diffItemImage = treeDiffItemProvider.getDiffItemImage(itemObj, side,
                treeDiffControl.getChangedSide());
        String diffItemText = treeDiffItemProvider.getDiffItemText(itemObj, side, treeDiffControl.getChangedSide());

        return new TreeDiffSideItem(diffItemText, diffItemImage);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.viewers.Viewer#setInput(java.lang.Object)
     */
    @Override
    public void setInput(Object input) {
        this.input = input;
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.eclipse.jface.viewers.Viewer#setSelection(org.eclipse.jface.viewers.
     * ISelection, boolean)
     */
    @Override
    public void setSelection(ISelection selection, boolean reveal) {
        // Currently not supported
    }

    /**
     * sets the {@link ITreeDiffItemProvider} to use for extracting the
     * {@link TreeDiff} items from the input data.
     * 
     * @param treeDiffItemProvider
     *            the {@link ITreeDiffItemProvider} to set.
     */
    public void setTreeDiffItemProvider(ITreeDiffItemProvider treeDiffItemProvider) {
        this.treeDiffItemProvider = treeDiffItemProvider;
    }

}