001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005//     http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012package org.apache.tapestry5.services;
013
014import org.apache.tapestry5.Block;
015import org.apache.tapestry5.alerts.Alert;
016import org.apache.tapestry5.commons.services.TypeCoercer;
017import org.apache.tapestry5.dom.Document;
018import org.apache.tapestry5.runtime.RenderCommand;
019
020/**
021 *
022 * Service that provides methods that render {@link Block}s ({@code <t:block>} in the template),
023 * component instances and {@link RenderCommand}s to a {@link String} or 
024 * {@link Document org.apache.tapestry5.dom.Document} in a programatic way.
025 *
026 *
027 * This service was created for situations in which a page or component needs to generate some markup
028 * that wouldn't be rendered normally, but for external use, such as e-mails, returning
029 * HTML for AJAX requests or passing HTML instead of plain string for an {@link Alert}.
030 *
031 *
032 * The name of this interface comes from <a href="https://issues.apache.org/jira/browse/TAP5-938">TAP5-938</a>:
033 * <em>Expose ability to render a portion of a page (a Block, Component, etc.) without using internal services</em>.
034 *
035 * @since 5.4
036 */
037public interface PartialTemplateRenderer
038{
039    /**
040     *
041     * Renders an object, probably a {@link Block} or component instance, to a string. 
042     * This method supposes any kind of initialization needed
043     * was already done. CSS and JavaScript inclusions or importings are ignored.
044     * The object must implement {@link RenderCommand} or being able to be coerced to it
045     * by {@link TypeCoercer}.
046     *
047     * @param object an object, probably a {@link Block} or component instance or {@link RenderCommand}.
048     * @throws IllegalArgumentException if the object isn't a {@link RenderCommand} and cannot be coerced to it by {@link TypeCoercer}.
049     */
050    String render(Object object);
051    
052    /**
053     * Renders an object to a {@link Document} following the same rules as {@link #render(Object)}
054     * This method supposes any kind of initialization needed
055     * was already done. CSS and JavaScript inclusions or importings are ignored.
056     * 
057     * @param object to render, a {@link RenderCommand}, or {@linkplain TypeCoercer coercible} to one
058     * @return a {@link Document}.
059     */
060    Document renderAsDocument(Object object);
061
062}