ProductWriter.java

/**
 * Copyright 2005-2014 Restlet
 * 
 * The contents of this file are subject to the terms of one of the following
 * open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
 * select the license that you prefer but you may not use this file except in
 * compliance with one of these Licenses.
 * 
 * You can obtain a copy of the Apache 2.0 license at
 * http://www.opensource.org/licenses/apache-2.0
 * 
 * You can obtain a copy of the EPL 1.0 license at
 * http://www.opensource.org/licenses/eclipse-1.0
 * 
 * See the Licenses for the specific language governing permissions and
 * limitations under the Licenses.
 * 
 * Alternatively, you can obtain a royalty free commercial license with less
 * limitations, transferable or non-transferable, directly at
 * http://restlet.com/products/restlet-framework
 * 
 * Restlet is a registered trademark of Restlet S.A.S.
 */

package org.restlet.engine.header;

import java.util.Iterator;
import java.util.List;

import org.restlet.data.Product;

/**
 * User agent header writer.
 * 
 * @author Thierry Boileau
 */
public class ProductWriter {

    /**
     * Formats the given List of Products to a String.
     * 
     * @param products
     *            The list of products to format.
     * @return the List of Products as String.
     */
    public static String write(List<Product> products) {
        StringBuilder builder = new StringBuilder();

        for (Iterator<Product> iterator = products.iterator(); iterator
                .hasNext();) {
            Product product = iterator.next();

            if ((product.getName() == null)
                    || (product.getName().length() == 0)) {
                throw new IllegalArgumentException(
                        "Product name cannot be null.");
            }

            builder.append(product.getName());

            if (product.getVersion() != null) {
                builder.append("/").append(product.getVersion());
            }

            if (product.getComment() != null) {
                builder.append(" (").append(product.getComment()).append(")");
            }

            if (iterator.hasNext()) {
                builder.append(" ");
            }
        }

        return builder.toString();
    }

}