MetsHeaderScanner.java

package edu.unc.lib.dl.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import edu.unc.lib.dl.fedora.PID;
import edu.unc.lib.dl.xml.NamespaceConstants;

/**
 * An quick SAX extractor of METS header information.
 * 
 * @author count0
 * 
 */
public class MetsHeaderScanner extends DefaultHandler {
	Logger log = LoggerFactory.getLogger(MetsHeaderScanner.class);
	
	PID objID = null;
	String label = null;
	String createDate = null;
	String lastModDate = null;
	String profile = null;
	String type = null;
	String id = null;
	List<String> names = new ArrayList<String>();
	StringBuilder nameBuffer = null;
	
	public List<String> getNames() {
		return names;
	}

	String metsURI = NamespaceConstants.METS_URI;

	public PID getObjID() {
		return objID;
	}

	public String getLabel() {
		return label;
	}

	public String getCreateDate() {
		return createDate;
	}

	public String getLastModDate() {
		return lastModDate;
	}

	public String getProfile() {
		return profile;
	}

	public String getType() {
		return type;
	}

	public String getId() {
		return id;
	}

	@Override
	public void startElement(String uri, String localName, String qName,
			Attributes attr) throws SAXException {
		if(!NamespaceConstants.METS_URI.equals(uri)) return;
		if (localName.equals("mets")) {
			for (int i = 0; i < attr.getLength(); i++) {
				String n = attr.getLocalName(i);
				if (n.equals("OBJID")) {
					objID = new PID(attr.getValue(i));
				} else if (n.equals("ID")) {
					id = attr.getValue(i);
				} else if (n.equals("LABEL")) {
					label = attr.getValue(i);
				} else if (n.equals("PROFILE")) {
					profile = attr.getValue(i);
				} else if (n.equals("TYPE")) {
					type = attr.getValue(i);
				}
			}
		} else if (localName.equals("metsHdr")) {
			for (int i = 0; i < attr.getLength(); i++) {
				String n = attr.getLocalName(i);
				if (n.equals("CREATEDATE")) {
					createDate = attr.getValue(i);
				} else if (n.equals("LASTMODDATE")) {
					lastModDate = attr.getValue(i);
				}
			}
		} else if (localName.equals("name")) {
			nameBuffer = new StringBuilder();
		}
		super.startElement(uri, localName, qName, attr);
	}

	@Override
	public void characters(char[] ch, int start, int length)
			throws SAXException {
		if(nameBuffer != null) nameBuffer.append(ch, start, length);
		super.characters(ch, start, length);
	}

	@Override
	public void endElement(String uri, String localName, String qName)
			throws SAXException {
		if(!NamespaceConstants.METS_URI.equals(uri)) return;
		if (localName.equals("name")) {
			if(nameBuffer != null) {
				names.add(nameBuffer.toString());
				nameBuffer = null;
			}
		}
		super.endElement(uri, localName, qName);
	}

	public void scan(File f, String filename) throws Exception {
		@SuppressWarnings("resource")
		InputStream toParse = null;
		try {
			if (filename.endsWith(".zip")) {
				log.debug("scanning for METS within a zip file");
				@SuppressWarnings("resource")
				ZipArchiveInputStream zis = new ZipArchiveInputStream(
						new FileInputStream(f));
				ArchiveEntry entry = null;
				while ((entry = zis.getNextZipEntry()) != null) {
					if (!entry.isDirectory()) {
						if (entry.getName().equals("METS.xml")
								|| entry.getName().equals("mets.xml")) {
							log.debug("Found METS entry in ZIP: {}", entry.getName());
							toParse = zis;
							break;
						}
					}
				}
			} else {
				log.debug("scanning METS file");
				toParse = new FileInputStream(f);
			}
			SAXParserFactory factory = SAXParserFactory.newInstance();
			factory.setFeature("http://xml.org/sax/features/namespaces", true);
			SAXParser saxParser = null;
			saxParser = factory.newSAXParser();
			saxParser.parse(toParse, this);
		} finally {
			if (toParse != null) {
				try {
					toParse.close();
				} catch (IOException ignored) {
				}
			}
		}
	}

}