<?xml version="1.0" encoding="iso-8859-1"?>

<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->

<page
    xmlns:cinclude="http://apache.org/cocoon/include/1.0"
>

    <content>
        <p>
            The multi-channel publishing subsystem of Cocoon is based on <em>XML processing pipelines</em>.
        </p>
        <p>
            A pipeline consists of:
            <ul>
                <li>A <em>Generator</em>, which generates XML data for further processing.</li>

                <li>
                    Zero or more <em>Transformers</em>, which process, transform or complete
                    the XML data.
                </li>

                <li>
                    A <em>Serializer</em>, which transforms the XML data into the appropriate
                    text or binary format for the client.
                </li>
            </ul>
        </p>
        <p>
            The are many types of Generators, Transformers and Serializers, but
            a typical pipeline could consist of:
            <ul>
                <li>
                    A <em>FileGenerator</em> which produces XML data by parsing XML files or XML documents
                    retrieved via an HTTP request.
                </li>
                <li>
                    An <em>XSLT transformer</em> which converts the XML vocabulary to another, for example
                    XHTML.
                </li>
                <li>
                    An <em>HTMLSerializer</em> which sets the <em>text/html</em> content-type and sends
                    the XML elements as HTML to the output.
                </li>
            </ul>
        </p>
        <p>
            The building and configuration of the pipelines is controlled by the <em>sitemap</em>, an
            XML document used by Cocoon to dynamically instantiate and activate pipelines.
        </p>
        <p>
            The next pages show several examples using various components.
        </p>
    </content>
</page>
