• Home
• org.apache.tika
• tika-core
• 2.1.0
• source code
• XHTMLContentHandler.java

×

Project download

Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance.
Project price only 1 $

You can buy this project and download/modify it how often you want.

org.apache.tika.sax.XHTMLContentHandler Maven / Gradle / Ivy

/*
 * 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.tika.sax;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;

import org.apache.tika.metadata.Metadata;
import org.apache.tika.metadata.TikaCoreProperties;

/**
 * Content handler decorator that simplifies the task of producing XHTML
 * events for Tika content parsers.
 */
public class XHTMLContentHandler extends SafeContentHandler {

    /**
     * The XHTML namespace URI
     */
    public static final String XHTML = "http://www.w3.org/1999/xhtml";
    /**
     * The elements that get appended with the {@link #NL} character.
     */
    public static final Set ENDLINE =
            unmodifiableSet("p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "ul", "ol", "dl", "pre",
                    "hr", "blockquote", "address", "fieldset", "table", "form", "noscript", "li",
                    "dt", "dd", "noframes", "br", "tr", "select", "option", "link", "script");
    /**
     * The newline character that gets inserted after block elements.
     */
    private static final char[] NL = new char[]{'\n'};
    /**
     * The tab character gets inserted before table cells and list items.
     */
    private static final char[] TAB = new char[]{'\t'};
    /**
     * The elements that are in the  section.
     */
    private static final Set HEAD =
            unmodifiableSet("title", "link", "base", "meta", "script");
    /**
     * The elements that are automatically emitted by lazyStartHead, so
     * skip them if they get sent to startElement/endElement by mistake.
     */
    private static final Set AUTO = unmodifiableSet("head", "frameset");
    /**
     * The elements that get prepended with the {@link #TAB} character.
     */
    private static final Set INDENT =
            unmodifiableSet("li", "dd", "dt", "td", "th", "frame");
    private static final Attributes EMPTY_ATTRIBUTES = new AttributesImpl();
    /**
     * Metadata associated with the document. Used to fill in the
     * <head/> section.
     */
    private final Metadata metadata;
    /**
     * Flag to indicate whether the document has been started.
     */
    private boolean documentStarted = false;
    /**
     * Flags to indicate whether the document head element has been started/ended.
     */
    private boolean headStarted = false;
    private boolean headEnded = false;
    private boolean useFrameset = false;
    public XHTMLContentHandler(ContentHandler handler, Metadata metadata) {
        super(handler);
        this.metadata = metadata;
    }

    private static Set unmodifiableSet(String... elements) {
        return Collections.unmodifiableSet(new HashSet<>(Arrays.asList(elements)));
    }

    /**
     * Starts an XHTML document by setting up the namespace mappings
     * when called for the first time.
     * The standard XHTML prefix is generated lazily when the first
     * element is started.
     */
    @Override
    public void startDocument() throws SAXException {
        if (!documentStarted) {
            documentStarted = true;
            super.startDocument();
            startPrefixMapping("", XHTML);
        }
    }

    /**
     * Generates the following XHTML prefix when called for the first time:
     * 
     * <html>
     *   <head>
     *     <title>...</title>
     *   </head>
     *   <body>
     * 
     */
    private void lazyStartHead() throws SAXException {
        if (!headStarted) {
            headStarted = true;

            // Call directly, so we don't go through our startElement(), which will
            // ignore these elements.
            AttributesImpl htmlAttrs = new AttributesImpl();
            String lang = metadata.get(Metadata.CONTENT_LANGUAGE);
            if (lang != null) {
                htmlAttrs.addAttribute("", "lang", "lang", "CDATA", lang);
            }
            super.startElement(XHTML, "html", "html", htmlAttrs);
            newline();
            super.startElement(XHTML, "head", "head", EMPTY_ATTRIBUTES);
            newline();
        }
    }

    /**
     * Generates the following XHTML prefix when called for the first time:
     * 
     * <html>
     *   <head>
     *     <title>...</title>
     *   </head>
     *   <body> (or <frameset>
     * 
     */
    private void lazyEndHead(boolean isFrameset) throws SAXException {
        lazyStartHead();

        if (!headEnded) {
            headEnded = true;
            useFrameset = isFrameset;

            // TIKA-478: Emit all metadata values (other than title). We have to call
            // startElement() and characters() directly to avoid recursive problems.
            for (String name : metadata.names()) {
                if (name.equals("title")) {
                    continue;
                }

                for (String value : metadata.getValues(name)) {
                    // Putting null values into attributes causes problems, but is
                    // allowed by Metadata, so guard against that.
                    if (value != null) {
                        AttributesImpl attributes = new AttributesImpl();
                        attributes.addAttribute("", "name", "name", "CDATA", name);
                        attributes.addAttribute("", "content", "content", "CDATA", value);
                        super.startElement(XHTML, "meta", "meta", attributes);
                        super.endElement(XHTML, "meta", "meta");
                        newline();
                    }
                }
            }

            super.startElement(XHTML, "title", "title", EMPTY_ATTRIBUTES);
            String title = metadata.get(TikaCoreProperties.TITLE);
            if (title != null && title.length() > 0) {
                char[] titleChars = title.toCharArray();
                super.characters(titleChars, 0, titleChars.length);
            } else {
                // TIKA-725: Prefer  over