Scanner.java

/*
 * Copyright (c) 2007, James Leigh All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution. 
 * - Neither the name of the openrdf.org nor the names of its contributors may
 *   be used to endorse or promote products derived from this software without
 *   specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 */
package org.openrdf.repository.object.managers.helpers;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Scans directories and jars for classes that have one or more RDF annotation.
 * 
 * @author James Leigh
 * 
 */
public class Scanner {
	private final Logger logger = LoggerFactory
			.getLogger(HierarchicalRoleMapper.class);

	private String resource;

	private CheckForConcept checker;

	public Scanner(CheckForConcept checker) {
		this(checker, null);
	}

	public Scanner(CheckForConcept checker, String resource) {
		this.checker = checker;
		this.resource = resource;
	}

	public List<String> scan(URL url, String forType, String marker) throws IOException {
		String urlPath = URLDecoder.decode(url.getFile(), "UTF-8");
		if (resource != null) {
			assert urlPath.endsWith(resource);
			urlPath = urlPath
					.substring(0, urlPath.length() - resource.length());
		}
		if (urlPath.startsWith("file:")) {
			urlPath = urlPath.substring(5);
		}
		if (urlPath.lastIndexOf('!') > 0) {
			urlPath = urlPath.substring(0, urlPath.lastIndexOf('!'));
		}
		List<String> roles = new ArrayList<String>();
		File file = new File(urlPath);
		if (file.isDirectory()) {
			if (!exists(file, marker)) {
				logger.info("Scanning {} for {}", file, forType);
				roles.addAll(scanDirectory(file, null, 256));
			}
		} else {
			ZipFile zip = new ZipFile(file);
			if (!exists(zip, marker)) {
				logger.info("Scanning {} for {}", file, forType);
				Enumeration<? extends ZipEntry> entries = zip.entries();
				while (entries.hasMoreElements()) {
					ZipEntry entry = entries.nextElement();
					String ename = entry.getName();
					if (ename.endsWith(".class") && !ename.contains("-")) {
						String name = getClassName(ename, zip
								.getInputStream(entry));
						if (name != null) {
							roles.add(name);
						}
					}
				}
			}
		}
		return roles;
	}

	private boolean exists(ZipFile zip, String marker) {
		if (marker == null)
			return false;
		return zip.getEntry(marker) != null;
	}

	private boolean exists(File file, String marker) {
		if (marker == null)
			return false;
		return new File(file, marker).exists();
	}

	private List<String> scanDirectory(File file, String path, int max)
			throws IOException {
		if (max < 0)
			throw new AssertionError("Recursive Path: " + file);
		List<String> roles = new ArrayList<String>();
		for (File child : file.listFiles()) {
			String newPath = path == null ? child.getName() : path + '/'
					+ child.getName();
			if (child.isDirectory()) {
				roles.addAll(scanDirectory(child, newPath, max - 1));
			} else if (newPath.endsWith(".class") && !newPath.contains("-")) {
				String name = getClassName(newPath, new FileInputStream(child));
				if (name != null) {
					roles.add(name);
				}
			}
		}
		return roles;
	}

	private String getClassName(String name, InputStream in) throws IOException {
		try {
			return checker.getClassName(name, in);
		} catch (Exception e) {
			logger.warn("Cannot decode {}", name);
			logger.debug("Cannot decode " + name, e);
		} finally {
			in.close();
		}
		return null;
	}
}