tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-font-module/src/main/java/org/apache/tika/parser/font/AdobeFontMetricParser.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.tika.parser.font;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import org.apache.fontbox.afm.AFMParser;
import org.apache.fontbox.afm.FontMetrics;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.metadata.Property;
import org.apache.tika.metadata.TikaCoreProperties;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.AbstractParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.sax.XHTMLContentHandler;

/**
 * Parser for AFM Font Files
 */
public class AdobeFontMetricParser extends AbstractParser {
    // TIKA-1325 Replace these with properties, from a well known standard
    static final String MET_AVG_CHAR_WIDTH = "AvgCharacterWidth";
    static final String MET_DOC_VERSION = "DocVersion";
    static final String MET_PS_NAME = "PSName";
    static final String MET_FONT_NAME = "FontName";
    static final String MET_FONT_FULL_NAME = "FontFullName";
    static final String MET_FONT_FAMILY_NAME = "FontFamilyName";
    static final String MET_FONT_SUB_FAMILY_NAME = "FontSubFamilyName";
    static final String MET_FONT_VERSION = "FontVersion";
    static final String MET_FONT_WEIGHT = "FontWeight";
    static final String MET_FONT_NOTICE = "FontNotice";
    static final String MET_FONT_UNDERLINE_THICKNESS = "FontUnderlineThickness";
    /**
     * Serial version UID
     */
    private static final long serialVersionUID = -4820306522217196835L;
    private static final MediaType AFM_TYPE = MediaType.application("x-font-adobe-metric");
    private static final Set<MediaType> SUPPORTED_TYPES = Collections.singleton(AFM_TYPE);

    public Set<MediaType> getSupportedTypes(ParseContext context) {
        return SUPPORTED_TYPES;
    }

    public void parse(InputStream stream, ContentHandler handler, Metadata metadata,
                      ParseContext context) throws IOException, SAXException, TikaException {
        FontMetrics fontMetrics;
        AFMParser parser = new AFMParser(stream);

        // Have FontBox process the file
        fontMetrics = parser.parse();

        // Get the comments in the file to display in xhtml
        List<String> unModifiableComments = fontMetrics.getComments();
        //have to copy because we modify list in extractCreationDate
        List<String> comments = new ArrayList<>(unModifiableComments);
        // Get the creation date
        extractCreationDate(metadata, comments);

        metadata.set(Metadata.CONTENT_TYPE, AFM_TYPE.toString());
        metadata.set(TikaCoreProperties.TITLE, fontMetrics.getFullName());

        // Add metadata associated with the font type
        addMetadataByString(metadata, MET_AVG_CHAR_WIDTH,
                Float.toString(fontMetrics.getAverageCharacterWidth()));
        addMetadataByString(metadata, MET_DOC_VERSION, Float.toString(fontMetrics.getAFMVersion()));
        addMetadataByString(metadata, MET_FONT_NAME, fontMetrics.getFontName());
        addMetadataByString(metadata, MET_FONT_FULL_NAME, fontMetrics.getFullName());
        addMetadataByString(metadata, MET_FONT_FAMILY_NAME, fontMetrics.getFamilyName());
        addMetadataByString(metadata, MET_FONT_VERSION, fontMetrics.getFontVersion());
        addMetadataByString(metadata, MET_FONT_WEIGHT, fontMetrics.getWeight());
        addMetadataByString(metadata, MET_FONT_NOTICE, fontMetrics.getNotice());
        addMetadataByString(metadata, MET_FONT_UNDERLINE_THICKNESS,
                Float.toString(fontMetrics.getUnderlineThickness()));

        // Output the remaining comments as text
        XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
        xhtml.startDocument();

        // Display the comments
        if (comments.size() > 0) {
            xhtml.element("h1", "Comments");
            xhtml.startElement("div", "class", "comments");
            for (String comment : comments) {
                xhtml.element("p", comment);
            }
            xhtml.endElement("div");
        }

        xhtml.endDocument();
    }

    private void addMetadataByString(Metadata metadata, String name, String value) {
        // Add metadata if an appropriate value is passed
        if (value != null) {
            metadata.add(name, value);
        }
    }

    private void addMetadataByProperty(Metadata metadata, Property property, String value) {
        // Add metadata if an appropriate value is passed
        if (value != null) {
            metadata.set(property, value);
        }
    }


    private void extractCreationDate(Metadata metadata, List<String> comments) {
        String date = null;

        for (String value : comments) {
            // Look for the creation date
            if (value.matches(".*Creation\\sDate.*")) {
                date = value.substring(value.indexOf(":") + 2);
                comments.remove(value);

                break;
            }
        }

        // If appropriate date then store as metadata
        if (date != null) {
            addMetadataByProperty(metadata, TikaCoreProperties.CREATED, date);
        }
    }
}