org.polymap.kaps.ui.SimplePickList.java Source code

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Here is the source code for org.polymap.kaps.ui.SimplePickList.java

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/*
 * polymap.org Copyright 2013 Polymap GmbH. All rights reserved.
 * 
 * This is free software; you can redistribute it and/or modify it under the terms of
 * the GNU Lesser General Public License as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at your option) any later
 * version.
 * 
 * This software is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 */
package org.polymap.kaps.ui;

import java.util.Collections;
import java.util.SortedMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;

import org.polymap.rhei.form.IFormEditorPageSite;

/**
 * @author <a href="http://www.polymap.de">Steffen Stundzig</a>
 */
public abstract class SimplePickList<T> {

    private Combo combo;

    private SortedMap<String, T> values;

    private T lastSelection;

    private static Log log = LogFactory.getLog(SimplePickList.class);

    public SimplePickList(Composite parent, IFormEditorPageSite pageSite) {
        combo = pageSite.getToolkit().createCombo(parent, Collections.EMPTY_SET, SWT.READ_ONLY | SWT.SINGLE);
        combo.addSelectionListener(new SelectionListener() {

            @Override
            public void widgetSelected(SelectionEvent e) {
                String selected = combo.getText();
                if (values != null) {
                    onSelectionInternal(values.get(selected));
                }
            }

            @Override
            public void widgetDefaultSelected(SelectionEvent e) {
            }
        });
    }

    public void setEnabled(boolean enabled) {
        onSelectionInternal(null);
        if (combo != null && !combo.isDisposed()) {
            combo.deselectAll();
            combo.removeAll();

            if (enabled) {
                values = getValues();
                for (String label : values.keySet()) {
                    combo.add(label);
                }
                if (!values.keySet().isEmpty()) {
                    combo.select(0);
                    onSelectionInternal(values.get(combo.getText()));
                }
            }
            combo.setEnabled(enabled);
        } else {
            log.error("combo.setEnabled(" + enabled + ") is called but combo is disposed");
        }
    }

    private void onSelectionInternal(T object) {
        lastSelection = object;
        onSelection(object);
    }

    protected abstract SortedMap<String, T> getValues();

    protected abstract void onSelection(T select);

    public SimplePickList setLayoutData(FormData data) {
        combo.setLayoutData(data);
        return this;
    }

    public T getSelection() {
        return lastSelection;
    }
}