RELEASE_2_1_13/src/blocks/serializers/java/org/apache/cocoon/components/serializers/XHTMLSerializer.java

/*
 * 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.
 */
package org.apache.cocoon.components.serializers;

import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.cocoon.components.serializers.encoding.XHTMLEncoder;
import org.apache.cocoon.components.serializers.util.DocType;
import org.xml.sax.SAXException;

/**
 * <p>A pedantic XHTML serializer encoding all recognized entities with their
 * proper HTML names.</p> 
 * 
 * <p>For configuration options of this serializer, please look at the
 * {@link EncodingSerializer}, in addition to those, this serializer also
 * support the specification of a default doctype. This default will be used
 * if no document type is received in the SAX events, and can be configured
 * in the following way:</p>
 *
 * <pre>
 * &lt;serializer class="org.apache.cocoon.components.serializers..." ... &gt;
 *   &lt;doctype-default&gt;mytype&lt;/doctype-default&gt;
 * &lt;/serializer&gt;
 * </pre>
 * 
 * <p>The value <i>mytype</i> can be one of:</p>
 * 
 * <dl>
 *   <dt>"<code>none</code>"</dt>
 *   <dd>Not to emit any document type declaration.</dd> 
 *   <dt>"<code>strict</code>"</dt>
 *   <dd>The XHTML 1.0 Strict document type.</dd> 
 *   <dt>"<code>loose</code>"</dt>
 *   <dd>The XHTML 1.0 Transitional document type.</dd> 
 *   <dt>"<code>frameset</code>"</dt>
 *   <dd>The XHTML 1.0 Frameset document type.</dd>
 *   <dt>"<code>xhtml5</code>"</dt>
 *   <dd>The XHTML5 document type.</dd>
 * </dl> 
 *
 * @version CVS $Id$
 */
public class XHTMLSerializer extends XMLSerializer {

    /** The namespace URI for XHTML 1.0. */
    public static final String XHTML1_NAMESPACE =
            "http://www.w3.org/1999/xhtml";

    /** A representation of the XHTML 1.0 strict document type. */
    public static final DocType XHTML1_DOCTYPE_STRICT = new DocType(
            "html", "-//W3C//DTD XHTML 1.0 Strict//EN",
            "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd");

    /** A representation of the XHTML 1.0 transitional document type. */
    public static final DocType XHTML1_DOCTYPE_TRANSITIONAL = new DocType(
            "html", "-//W3C//DTD XHTML 1.0 Transitional//EN",
            "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd");

    /** A representation of the XHTML 1.0 frameset document type. */
    public static final DocType XHTML1_DOCTYPE_FRAMESET = new DocType(
            "html", "-//W3C//DTD XHTML 1.0 Frameset//EN",
            "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd");

    /** A representation of the XHTML5 document type. */
    public static final DocType XHTML5_DOCTYPE = new DocType("html");

    /* ====================================================================== */

    private static final XHTMLEncoder XHTML_ENCODER = new XHTMLEncoder();

    protected boolean encodeCharacters = true;
    
    /* ====================================================================== */

    /** The <code>DocType</code> instance representing the document. */
    protected DocType doctype_default = null;
    
    /** Define whether to put XML declaration in the head of the document. */
    private String omitXmlDeclaration = null;

    /* ====================================================================== */

    /**
     * Create a new instance of this <code>XHTMLSerializer</code>
     */
    public XHTMLSerializer() {
        super(XHTML_ENCODER);
    }

    /**
     * Create a new instance of this <code>XHTMLSerializer</code>
     */
    protected XHTMLSerializer(XHTMLEncoder encoder) {
        super(encoder);
    }
    
    /**
     * Return the MIME Content-Type produced by this serializer.
     */
    public String getMimeType() {
        if (this.charset == null) return("text/html");
        return("text/html; charset=" + this.charset.getName());
    }

    /**
     * Configure this instance by selecting the default document type to use.
     */
    public void configure(Configuration conf)
    throws ConfigurationException {
        super.configure(conf);

        this.omitXmlDeclaration = conf.getChild("omit-xml-declaration").getValue(null);

        String doctype = conf.getChild("doctype-default").getValue(null);
        if ("none".equalsIgnoreCase(doctype)) {
            this.doctype_default = null;
        } else if ("strict".equalsIgnoreCase(doctype)) {
            this.doctype_default = XHTML1_DOCTYPE_STRICT;
        } else if ("loose".equalsIgnoreCase(doctype)) {
            this.doctype_default = XHTML1_DOCTYPE_TRANSITIONAL;
        } else if ("frameset".equalsIgnoreCase(doctype)) {
            this.doctype_default = XHTML1_DOCTYPE_FRAMESET;
        } else if ("xhtml5".equalsIgnoreCase(doctype)) {
            this.doctype_default = XHTML5_DOCTYPE;
        } else {
            /* Default is transitional */
            this.doctype_default = XHTML1_DOCTYPE_TRANSITIONAL;
        }
    }

    /* ====================================================================== */

    /**
     * Write the XML document header.
     * <p>
     * This method will write out the <code>&lt;?xml version=&quot;1.0&quot
     * ...&gt;</code> header unless omit-xml-declaration is set.
     * </p>
     */
    protected void head()
    throws SAXException {
        if (!"yes".equals(this.omitXmlDeclaration)) {
            super.head();
        }
    }

    /**
     * Receive notification of the beginning of the document body.
     *
     * @param uri The namespace URI of the root element.
     * @param local The local name of the root element.
     * @param qual The fully-qualified name of the root element.
     */
    public void body(String uri, String local, String qual)
    throws SAXException {
        if (this.doctype == null) this.doctype = this.doctype_default;
        if (this.namespaces.getUri("").length() == 0) {
            this.namespaces.push("", XHTML1_NAMESPACE);
        }
        super.body(uri, local, qual);
    }

    /**
     * Receive notification of the beginning of an element.
     *
     * @param uri The namespace URI of the root element.
     * @param local The local name of the root element.
     * @param qual The fully-qualified name of the root element.
     * @param namespaces An array of <code>String</code> objects containing
     *                   the namespaces to be declared by this element.
     * @param attributes An array of <code>String</code> objects containing
     *                   all attributes of this element.
     */
    public void startElementImpl(String uri, String local, String qual,
                                 String namespaces[][], String attributes[][])
    throws SAXException {
        if (uri.length() == 0) uri = XHTML1_NAMESPACE;
        
        if (isCdataElement(local)) {
            this.encodeCharacters = false;
        }

        super.startElementImpl(uri, local, qual, namespaces, attributes);
    }

    /**
     * Receive notification of the end of an element.
     *
     * @param uri The namespace URI of the root element.
     * @param local The local name of the root element.
     * @param qual The fully-qualified name of the root element.
     */
    public void endElementImpl(String uri, String local, String qual)
    throws SAXException {
        if (uri.length() == 0) uri = XHTML1_NAMESPACE;

        if (XHTML1_NAMESPACE.equals(uri)) {
            if ((local.equalsIgnoreCase("textarea")) ||
                (local.equalsIgnoreCase("script")) ||
                (local.equalsIgnoreCase("style"))) {
                this.closeElement(false);
            } else if (local.equalsIgnoreCase("head")) {
                String loc = "meta";
                String qua = this.namespaces.qualify(XHTML1_NAMESPACE, loc, "meta");
                String nsp[][] = new String[0][0];
                String att[][] = new String[2][ATTRIBUTE_LENGTH];

                att[0][ATTRIBUTE_NSURI] = att[1][ATTRIBUTE_NSURI] = "";
                att[0][ATTRIBUTE_LOCAL] = att[0][ATTRIBUTE_QNAME] = "http-equiv";
                att[1][ATTRIBUTE_LOCAL] = att[1][ATTRIBUTE_QNAME] = "content";
                att[0][ATTRIBUTE_VALUE] = "Content-Type";
                att[1][ATTRIBUTE_VALUE] = this.getMimeType();

                this.closeElement(false);
                this.startElementImpl(XHTML1_NAMESPACE, loc, qua, nsp, att);
                this.endElementImpl(XHTML1_NAMESPACE, loc, qua);
            }
        }
        
        if (isCdataElement(local)) {
            this.encodeCharacters = true;
        }

        super.endElementImpl(uri, local, qual);
    }
    
    /**
     * script and style are CDATA sections by default, so no encoding
     * @param localName The local name of the element.
     * @return If the element should be serialized without encoding.
     */
    protected boolean isCdataElement(String localName) {
        String upperCase = localName.toUpperCase();
        return "SCRIPT".equals(upperCase) || "STYLE".equals(upperCase);
    }
    
    /**
     * Encode and write a specific part of an array of characters.
     */
    protected void encode(char data[], int start, int length)
    throws SAXException {
        if (this.encodeCharacters) {
            super.encode(data, start, length);
        } else {
            this.write(data, start, length);
        }
    }
}