ComboBoxWidget.java

package org.aplikator.client.local.widgets;

import java.io.Serializable;

import org.aplikator.client.shared.data.ListItem;
import org.aplikator.client.shared.descriptor.PropertyDTO;
import org.gwtbootstrap3.client.ui.ListBox;

import com.google.gwt.event.dom.client.ChangeEvent;
import com.google.gwt.event.dom.client.ChangeHandler;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;

public class ComboBoxWidget<T extends Serializable> extends DataFieldBase implements DataField<T> {
    private ListBox box = new ListBox();

    public ComboBoxWidget(String caption, PropertyDTO property, int size) {
        super(caption, property);
        resetItemList();
        controlHolder.add(box);
        box.addChangeHandler(new ChangeHandler() {
            public void onChange(ChangeEvent event) {
                setDirty(true);
                ValueChangeEvent.fire(ComboBoxWidget.this, null);
            }
        });

        setGridSize(size);

    }

    private void resetItemList() {
        box.clear();
        for (ListItem item : property.getListValues()) {
            box.addItem(item.getName(), item.getValue().toString());
        }
    }

    public void setValue(T value) {
        resetItemList();
        box.setSelectedIndex(-1);
        for (int i = 0; i < getProperty().getListValues().size(); i++) {
            if (((ListItem) getProperty().getListValues().get(i)).getValue().equals(value)) {
                box.setSelectedIndex(i);
                return;
            }
        }
        if (value != null) {
            box.addItem("! " + value.toString(), value.toString());
            box.setSelectedIndex(getProperty().getListValues().size());
        }

    }

    @SuppressWarnings("unchecked")
    public T getValue() {
        int index = box.getSelectedIndex();
        if (index == -1) {
            return null;
        }
        return (T) ((ListItem) getProperty().getListValues().get(index)).getValue();
    }

    public HandlerRegistration addValueChangeHandler(ValueChangeHandler<T> handler) {
        return addHandler(handler, ValueChangeEvent.getType());
    }

    public void setEnabled(boolean enabled) {
        if (property.getRefferedThrough() != null) {
            enabled = false;
        }
        box.setEnabled(enabled);
    }

}