001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.request;
018
019import java.util.List;
020import java.util.Set;
021
022import org.apache.wicket.util.string.StringValue;
023
024/**
025 * Represents request parameters.
026 * 
027 * @author Matej Knopp
028 */
029public interface IRequestParameters
030{
031        /**
032         * Returns immutable set of all available parameter names.
033         * 
034         * @return list of parameter names
035         */
036        Set<String> getParameterNames();
037
038        /**
039         * Returns single value for parameter with specified name. This method always returns non-null
040         * result even if the parameter does not exist.
041         * 
042         * @see StringValue#isNull()
043         * 
044         * @param name
045         *            parameter name
046         * @return {@link StringValue} wrapping the actual value
047         */
048        StringValue getParameterValue(String name);
049
050        /**
051         * Returns list of values for parameter with specified name. If the parameter does not exist
052         * this method returns <code>null</code>
053         * 
054         * @param name
055         *            parameter name
056         * @return list of all values for given parameter or <code>null</code> if parameter does not
057         *         exist
058         */
059        List<StringValue> getParameterValues(String name);
060}