tapestry/tapestry-framework/src/java/org/apache/tapestry/web/WebUtils.java

// Copyright 2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.web;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.apache.hivemind.util.Defense;

/**
 * @author Howard M. Lewis Ship
 * @since 4.0
 */
public final class WebUtils
{
    /* defeat insantiation */
    private WebUtils() { }
    
    /**
     * Converts an Enumeration of Strings into an unmodifiable List of Strings, sorted into
     * ascending order.
     */

    public static List toSortedList(Enumeration e)
    {
        Defense.notNull(e, "e");

        List list = new ArrayList();
        while (e.hasMoreElements())
            list.add(e.nextElement());

        if (list.isEmpty())
            return Collections.EMPTY_LIST;

        Collections.sort(list);

        return Collections.unmodifiableList(list);
    }

}