001 // Copyright 2004, 2005 The Apache Software Foundation
002 //
003 // Licensed under the Apache License, Version 2.0 (the "License");
004 // you may not use this file except in compliance with the License.
005 // You may obtain a copy of the License at
006 //
007 // http://www.apache.org/licenses/LICENSE-2.0
008 //
009 // Unless required by applicable law or agreed to in writing, software
010 // distributed under the License is distributed on an "AS IS" BASIS,
011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012 // See the License for the specific language governing permissions and
013 // limitations under the License.
014
015 package org.apache.tapestry.engine;
016
017 /**
018 * Contains the information needed to encode a request for a service; the servlet path plus and
019 * query parameters. The service encoding is passed to each
020 * {@link org.apache.tapestry.engine.ServiceEncoder} , which is allowed to modify the encoding
021 * (typically, by changing the servlet path and settting query parameters to null). From this
022 * modified encoding, an {@link org.apache.tapestry.engine.ILink}can be constructed.
023 * <p>
024 * Additionally, when a request is dispatched by Tapestry, an SRE is also created and passed to each
025 * {@link org.apache.tapestry.engine.ServiceEncoder} for decoding. Here, the query parameters
026 * that may have been nulled out by the encoding are restored.
027 *
028 * @author Howard M. Lewis Ship
029 * @since 4.0
030 * @see org.apache.tapestry.services.ServiceConstants
031 */
032 public interface ServiceEncoding
033 {
034
035 /**
036 * Returns the value for the named parameter. If multiple values are stored for the query
037 * parameter, only the first is returned.
038 *
039 * @parameter name the name of the query parameter to access
040 * @return the value, or null if no such query parameter exists
041 */
042
043 public String getParameterValue(String name);
044
045 /**
046 * Returns the value for the named parameter.
047 *
048 * @parameter name the name of the query parameter to access
049 * @return the values, or null if no such query parameter exists
050 */
051 public String[] getParameterValues(String name);
052
053 /**
054 * Updates the servlet path for the encoding. In some cases, this is a combination of the
055 * servlet and additional path info.
056 */
057
058 public void setServletPath(String servletPath);
059
060 /**
061 * Sets the value for the named query parameter to the provided string.
062 *
063 * @param name
064 * the name of the parameter to set.
065 * @param value
066 * the new value, which may be null.
067 */
068 public void setParameterValue(String name, String value);
069
070 /**
071 * Sets the values for a named query parameter.
072 */
073
074 public void setParameterValues(String name, String[] values);
075
076 /**
077 * Returns the servlet path for the request. This is the portion of the URL recognized as the
078 * servlet. When the URL pattern (in web.xml) ends in a "*" (such as "/book/*"), this method
079 * will return the matched servlet portion ("/book/") and {#link #getPathInfo} will return the
080 * rest of the URL.
081 */
082
083 public String getServletPath();
084
085 /**
086 * Returns the portion of the URL after the servlet itself.
087 *
088 * @return pathInfo if path info was supplied in the request, or null otherwise.
089 */
090 public String getPathInfo();
091
092 /**
093 * Returns an array of parameter names. The names are returned in alphabetically sorted order.
094 * This list includes all parameter names, even those for which the stored value is null.
095 */
096
097 public String[] getParameterNames();
098 }