SelectItemUtils.java

/*
 * RHQ Management Platform
 * Copyright (C) 2005-2008 Red Hat, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation version 2 of the License.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.rhq.enterprise.gui.common.converter;

import java.util.List;

import javax.faces.model.SelectItem;

import org.rhq.core.domain.common.composite.OptionItem;
import org.rhq.core.gui.util.FacesContextUtility;

public class SelectItemUtils {

    public static SelectItem ALL = new SelectItem("~~All~~", "All");

    private SelectItemUtils() {
    }

    public static SelectItem[] convertFromListOptionItem(List<? extends OptionItem<?>> items, boolean addAllFilter) {
        SelectItem[] results = init(items.size(), addAllFilter);

        int i = (addAllFilter ? 1 : 0);
        for (OptionItem<?> item : items) {
            results[i++] = new SelectItem(item.getId(), item.getDisplayName());
        }

        return results;
    }

    public static SelectItem[] convertFromListString(List<String> items, boolean addAllFilter) {
        SelectItem[] results = init(items.size(), addAllFilter);

        int i = (addAllFilter ? 1 : 0);
        for (String item : items) {
            results[i++] = new SelectItem(item, item);
        }

        return results;
    }

    public static <T extends Enum<T>> SelectItem[] convertFromEnum(Class<T> e, boolean addAllFilter) {
        T[] enumElements = e.getEnumConstants();
        SelectItem[] results = init(enumElements.length, addAllFilter);

        int i = (addAllFilter ? 1 : 0);
        for (T enumElement : enumElements) {
            results[i++] = new SelectItem(enumElement.name(), enumElement.toString());
        }

        return results;
    }

    public static String getSelectItemFilter(String domIdentifier) {
        String result = FacesContextUtility.getOptionalRequestParameter(domIdentifier);
        result = cleanse(result);
        return result;
    }

    public static String cleanse(String value) {
        if (value == null) {
            return null;
        }
        if (ALL.getValue().equals(value)) {
            return null;
        }
        return value;
    }

    private static SelectItem[] init(int size, boolean addAllFilter) {
        SelectItem[] results = null;

        if (addAllFilter) {
            results = new SelectItem[size + 1];
            results[0] = ALL;
        } else {
            results = new SelectItem[size];
        }

        return results;
    }
}