zkoss/zk

/* ListboxSelectedItemConverter.java

    Purpose:
        
    Description:
        
    History:
        Aug 17, 2011 6:10:20 PM, Created by henrichen

Copyright (C) 2011 Potix Corporation. All Rights Reserved.
*/

package org.zkoss.bind.converter.sys;

import java.util.Iterator;
import java.util.Set;

import org.zkoss.bind.BindContext;
import org.zkoss.bind.Converter;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.UiException;
import org.zkoss.zul.ListModel;
import org.zkoss.zul.Listbox;
import org.zkoss.zul.Listitem;
import org.zkoss.zul.ext.Selectable;

/**
 * Convert listbox selected listitem to bean and vice versa.
 * @author henrichen
 * @author dennis
 * @since 6.0.0
 */
public class ListboxSelectedItemConverter implements Converter, java.io.Serializable {
    private static final long serialVersionUID = 201108171811L;

    @SuppressWarnings("unchecked")
    public Object coerceToUi(Object val, Component comp, BindContext ctx) {
        Listbox lbx = (Listbox) comp;
        final ListModel<?> model = lbx.getModel();
        //ZK-762 selection of ListModelList is not correct if binding to selectedItem
        if (model != null && !(model instanceof Selectable)) {
            //model has to implement Selectable if binding to selectedItem
            throw new UiException("model doesn't implement Selectable");
        }

        if (val != null) {
            if (model != null) {
                ((Selectable<Object>) model).addToSelection(val);
                return IGNORED_VALUE;
            } else {
                //no model case
                for (final Iterator<?> it = lbx.getItems().iterator(); it.hasNext();) {
                    final Listitem li = (Listitem) it.next();
                    Object bean = li.getValue();
                    if (val.equals(bean)) {
                        return li;
                    }
                }
            }
            //not in the item list
        }

        //nothing matched, clean the old selection
        if (model != null) {
            Set<Object> sels = ((Selectable<Object>) model).getSelection();
            if (sels != null && sels.size() > 0)
                ((Selectable<Object>) model).clearSelection();
            return IGNORED_VALUE;
        }
        return null;
    }

    public Object coerceToBean(Object val, Component comp, BindContext ctx) {
        if (val != null) {
            final Listbox lbx = (Listbox) comp;
            final ListModel<?> model = lbx.getModel();
            if (model != null && !(model instanceof Selectable)) {
                throw new UiException("model doesn't implement Selectable");
            }
            if (model != null) {
                Set<?> selection = ((Selectable<?>) model).getSelection();
                if (selection == null || selection.size() == 0)
                    return null;
                return selection.iterator().next();
            } else { //no model
                return ((Listitem) val).getValue();
            }
        }
        return null;
    }

}