Java tutorial
/* * 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.image; import javax.imageio.IIOException; import javax.imageio.ImageIO; import javax.imageio.ImageReader; import javax.imageio.metadata.IIOMetadata; import javax.imageio.stream.ImageInputStream; import java.io.IOException; import java.io.InputStream; import java.util.Arrays; import java.util.Collections; import java.util.HashSet; import java.util.Iterator; import java.util.Set; import org.apache.commons.io.input.CloseShieldInputStream; 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; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import org.xml.sax.ContentHandler; import org.xml.sax.SAXException; public class ImageParser extends AbstractParser { /** * Serial version UID */ private static final long serialVersionUID = 7852529269245520335L; private static final Logger LOG = LoggerFactory.getLogger(ImageParser.class); private static final MediaType MAIN_BMP_TYPE = MediaType.image("bmp"); private static final MediaType OLD_BMP_TYPE = MediaType.image("x-ms-bmp"); private static final Set<MediaType> TMP_SUPPORTED; static { TMP_SUPPORTED = new HashSet<>( Arrays.asList(MAIN_BMP_TYPE, OLD_BMP_TYPE, MediaType.image("gif"), MediaType.image("png"), MediaType.image("vnd.wap.wbmp"), MediaType.image("x-icon"), MediaType.image("x-xcf"))); try { Class.forName("com.levigo.jbig2.JBIG2ImageReader"); TMP_SUPPORTED.add(MediaType.image("x-jbig2")); } catch (ClassNotFoundException e) { LOG.warn("JBIG2ImageReader not loaded. jbig2 files will be ignored"); } } private static final Set<MediaType> SUPPORTED_TYPES = Collections.unmodifiableSet(TMP_SUPPORTED); private static void setIfPresent(Metadata metadata, String imageIOkey, String tikaKey) { if (metadata.get(imageIOkey) != null) { metadata.set(tikaKey, metadata.get(imageIOkey)); } } private static void setIfPresent(Metadata metadata, String imageIOkey, Property tikaProp) { if (metadata.get(imageIOkey) != null) { String v = metadata.get(imageIOkey); if (v.endsWith(" ")) { v = v.substring(0, v.lastIndexOf(' ')); } metadata.set(tikaProp, v); } } private static void loadMetadata(IIOMetadata imageMetadata, Metadata metadata) { if (imageMetadata == null) { return; } String[] names = imageMetadata.getMetadataFormatNames(); if (names == null) { return; } for (String name : names) { loadNode(metadata, imageMetadata.getAsTree(name), "", false); } } private static void loadNode(Metadata metadata, Node node, String parents, boolean addThisNodeName) { if (addThisNodeName) { if (parents.length() > 0) { parents += " "; } parents += node.getNodeName(); } NamedNodeMap map = node.getAttributes(); if (map != null) { int length = map.getLength(); if (length == 1) { metadata.add(parents, normalize(map.item(0).getNodeValue())); } else if (length > 1) { StringBuilder value = new StringBuilder(); for (int i = 0; i < length; i++) { if (i > 0) { value.append(", "); } Node attr = map.item(i); value.append(attr.getNodeName()); value.append("="); value.append(normalize(attr.getNodeValue())); } metadata.add(parents, value.toString()); } } Node child = node.getFirstChild(); while (child != null) { // print children recursively loadNode(metadata, child, parents, true); child = child.getNextSibling(); } } private static String normalize(String value) { if (value != null) { value = value.trim(); } else { value = ""; } if (Boolean.TRUE.toString().equalsIgnoreCase(value)) { return Boolean.TRUE.toString(); } else if (Boolean.FALSE.toString().equalsIgnoreCase(value)) { return Boolean.FALSE.toString(); } return value; } public Set<MediaType> getSupportedTypes(ParseContext context) { return SUPPORTED_TYPES; } public void parse(InputStream stream, ContentHandler handler, Metadata metadata, ParseContext context) throws IOException, SAXException, TikaException { String type = metadata.get(Metadata.CONTENT_TYPE); if (type != null) { // If the old (pre-RFC7903) BMP mime type is given, // fix it up to the new one, so Java is happy if (OLD_BMP_TYPE.toString().equals(type)) { type = MAIN_BMP_TYPE.toString(); } try { Iterator<ImageReader> iterator = ImageIO.getImageReadersByMIMEType(type); if (iterator.hasNext()) { ImageReader reader = iterator.next(); try { try (ImageInputStream imageStream = ImageIO .createImageInputStream(new CloseShieldInputStream(stream))) { reader.setInput(imageStream); metadata.set(Metadata.IMAGE_WIDTH, Integer.toString(reader.getWidth(0))); metadata.set(Metadata.IMAGE_LENGTH, Integer.toString(reader.getHeight(0))); metadata.set("height", Integer.toString(reader.getHeight(0))); metadata.set("width", Integer.toString(reader.getWidth(0))); loadMetadata(reader.getImageMetadata(0), metadata); } } finally { reader.dispose(); } } // Translate certain Metadata tags from the ImageIO // specific namespace into the general Tika one setIfPresent(metadata, "CommentExtensions CommentExtension", TikaCoreProperties.COMMENTS); setIfPresent(metadata, "markerSequence com", TikaCoreProperties.COMMENTS); setIfPresent(metadata, "Data BitsPerSample", Metadata.BITS_PER_SAMPLE); } catch (IIOException e) { // TIKA-619: There is a known bug in the Sun API when dealing with GIF images // which Tika will just ignore. if (!(e.getMessage() != null && e.getMessage().equals("Unexpected block type 0!") && type.equals("image/gif"))) { throw new TikaException(type + " parse error", e); } } } XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata); xhtml.startDocument(); xhtml.endDocument(); } }