MapEntryCellModifier.java

/*******************************************************************************
 * Copyright (c) 2010 Neil Bartlett.
 * 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:
 *     Neil Bartlett - initial API and implementation
 ******************************************************************************/
package bndtools.editor.common;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.Map;

import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ICellModifier;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.TextCellEditor;
import org.eclipse.swt.widgets.Item;

public class MapEntryCellModifier<K, V> implements ICellModifier {

    private final PropertyChangeSupport propertySupport = new PropertyChangeSupport(this);

    private static final String PROP_NAME = "NAME";
    private static final String PROP_VALUE = "VALUE";

    private static final String[] PROPS = new String[] {
            PROP_NAME, PROP_VALUE
    };

    private final TableViewer viewer;

    public MapEntryCellModifier(TableViewer viewer) {
        this.viewer = viewer;
    }

    @Override
    public boolean canModify(Object element, String property) {
        return PROP_NAME.equals(property) || PROP_VALUE.equals(property);
    }

    @Override
    public Object getValue(Object element, String property) {
        Object result = null;

        @SuppressWarnings("unchecked")
        K key = (K) element;
        if (PROP_NAME.equals(property)) {
            result = key;
        } else if (PROP_VALUE.equals(property)) {
            @SuppressWarnings("unchecked")
            Map<K,V> map = (Map<K,V>) viewer.getInput();
            result = map.get(key);
        }
        if (result == null)
            result = "";
        return result;
    }

    @Override
    public void modify(Object element, String property, Object editResult) {
        @SuppressWarnings("unchecked")
        Map<K,V> map = (Map<K,V>) viewer.getInput();

        Object e = element;
        if (e instanceof Item) {
            e = ((Item) e).getData();
        }
        @SuppressWarnings("unchecked")
        K key = (K) e;

        boolean changed = false;
        if (PROP_VALUE.equals(property)) {
            @SuppressWarnings("unchecked")
            V newValue = (V) editResult;
            V previous = map.put(key, newValue);

            changed = (newValue == null && previous != null) || (newValue != null && !newValue.equals(previous));
            viewer.refresh(key);
        } else if (PROP_NAME.equals(property)) {
            if (!e.equals(editResult)) {
                V value = map.remove(key);
                viewer.remove(key);

                @SuppressWarnings("unchecked")
                K newKey = (K) editResult;
                map.put(newKey, value);
                viewer.add(newKey);
                changed = true;
            }
        }

        if (changed)
            propertySupport.firePropertyChange(property, null, editResult);
    }

    public static String[] getColumnProperties() {
        return PROPS;
    }

    public void addCellEditorsToViewer() {
        CellEditor[] cellEditors = new CellEditor[PROPS.length];
        for (int i = 0; i < PROPS.length; i++) {
            cellEditors[i] = new TextCellEditor(viewer.getTable());
        }
        viewer.setCellEditors(cellEditors);
    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
        propertySupport.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener) {
        propertySupport.removePropertyChangeListener(listener);
    }
}