    001// Copyright 2008, 2010 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
    015package org.apache.tapestry5.services;
    016
    017import org.apache.tapestry5.EventContext;
    018
    019/**
    020 * A service to provide utilities needed for event context encoding and decoding to and from (partial) URL paths. This
    021 * is used for both component event contexts and page activation contexts.
    022 */
    023public interface ContextPathEncoder
    024{
    025    /**
    026     * Encodes a single value via the {@link ContextValueEncoder} service, returning the resulting string. Even null
    027     * is encoded, as per {@link URLEncoder#encode(String)}.
    028     *
    029     * @since 5.2.2
    030     */
    031    String encodeValue(Object value);
    032
    033    /**
    034     * Encodes the context values into a path string. Each context value (if non-null) is first value encoded into a
    035     * string via the {@link org.apache.tapestry5.services.ContextValueEncoder} service. Those values are then encoded,
    036     * via {@link URLEncoder#encode(String)} into URL-safe strings. The URL-safe strings are then concatenated
    037     * together, separated with "/" characters.
    038     *
    039     * @param context
    040     *            an array of objects to encode as the context (may be null)
    041     * @return the path-encoded context, or the blank string if the context is empty
    042     */
    043    String encodeIntoPath(Object[] context);
    044
    045    /**
    046     * Encodes the context into a string. Returns the empty string if the context is empty.
    047     *
    048     * @param context
    049     *            to encode
    050     * @return encoded values separated by "/" characters, or the empty string
    051     * @since 5.1.0.2
    052     */
    053    String encodeIntoPath(EventContext context);
    054
    055    /**
    056     * Inverse of {@link #encodeIntoPath(Object[])}; the path is split into strings, and the string are decoded and
    057     * constructed into an {@link org.apache.tapestry5.EventContext}.
    058     *
    059     * @param path
    060     *            to decode, possibly empty or null
    061     * @return corresponding event context
    062     */
    063    EventContext decodePath(String path);
    064}