/tags/v-2007-09-11-b/src/il/ac/technion/cs/ssdl/utils/ClassPathInfo.java

package il.ac.technion.cs.ssdl.utils;

import static il.ac.technion.cs.ssdl.utils.DBC.sure;
import il.ac.technion.cs.ssdl.testing.TestedBy;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * A data structure representing a Java-like CLASSPATH, i.e., a collection of
 * names of folders and archive files. Tacit is the convention that Java class
 * files are found in these, by replacing each package name by a folder name.
 * <p>
 * This class also makes it possible to enumerate all classes in the class path,
 * where the enumerated classes are represented as a collection of
 * {@link String}, where each string is the fully-qualified Java name of a
 * class, in the same format as in java.lang.class#forName(String);
 * 
 * @author Itay Maman Jul 6, 2006
 */
@TestedBy(Test_ClassPathInfo.class)//
public class ClassPathInfo implements Iterable<String> {
	/**
	 * This is where the collection of elements of the class path are stored.
	 */
	public final File[] files;

	@Override public String toString() {
		return Separator.separateBy(File.pathSeparator, files);
	}

	/**
	 * Intitalize a new instance
	 * 
	 * @param fs
	 *        Array of Files
	 */
	public ClassPathInfo(File... fs) {
		files = new File[fs.length];
		int i = 0;
		for (final File f : fs)
			files[i++] = f.getAbsoluteFile();
	}

	/**
	 * Intitalize a new instance
	 * 
	 */
	public ClassPathInfo() {
		files = new File[0];
	}

	/**
	 * Intitalize a new instance
	 * 
	 * @param fs
	 *        List of Files
	 */
	public ClassPathInfo(Iterable<File> fs) {
		this(Iterables.toArray(fs, File.class));
	}

	/**
	 * Intitalize a new instance
	 * 
	 * @param paths
	 *        Array of strings. Each element is a path to a single file system
	 *        location
	 */
	public ClassPathInfo(String... paths) {
		this(toFile(paths));
	}

	public ClassPathInfo(URI uri) {
		this(new File(uri));
	}

	public ClassPathInfo(Class<?> me) {
		this(fromClass(me));
		sure(files.length > 0);
		sure(Iterables.size(this) > 0);
	}

	private static File[] toFile(String[] paths) {
		final File[] $ = new File[paths.length];
		int i = 0;
		for (final String path : paths)
			$[i++] = new File(path).getAbsoluteFile();
		return $;
	}

	/**
	 * Equivalent to <code>return new ClassPathInfo(fromJre(ignore));</code>
	 * 
	 * @param ignore
	 *        List of paths to ignore
	 * @return A new ClassPathInfo object
	 */
	public static ClassPathInfo makeJREClassPath(File... ignore) {
		return new ClassPathInfo(fromJre(ignore));
	}

	/**
	 * Obtain a ClassPathInfo object that is initialized with the location of
	 * the JRE on the local machine.
	 * 
	 * Note that Java does not have an API that provides this information so we
	 * have to make an intelligent guess as to its whereabouts, follows:
	 * <ul>
	 * <li>If the default class loader is an instance of {@link URLClassLoader},
	 * then use its getURLs() method.
	 * <li>Use the system property "sun.boot.class.path" which points to the
	 * JRE location, but only in JVMs by Sun.
	 * </ul>
	 * 
	 * @param ignore
	 *        An array of file objects. Class path entries that are located
	 *        below one of the array's entires will be excluded.
	 * @return A new ClassPathInfo object
	 */
	public static List<File> fromJre(File... ignore) {
		try {
			final List<File> fs = fromClass(Object.class);
			return fs;
		} catch (final Throwable t) {
			// Abosrb, let's try the other option...
		}
		final List<File> fs = new ArrayList<File>();
		final String cp = System.getProperty("sun.boot.class.path");
		for (final StringTokenizer st = new StringTokenizer(cp, File.pathSeparator); st.hasMoreTokens();) {
			final String entry = st.nextToken();
			// System.out.printf("TOKEN = %s/n", entry);
			fs.add(new File(entry));
		}
		return filter(fs, ignore);
	}

	/**
	 * Obtain the classpath (as a list of files) from the class loaders of the
	 * given classes.
	 * 
	 * @param cs
	 *        An array of classes return
	 * @return A list of files
	 * @throws IllegalArgumentException
	 *         If the class loader of <code>c</code> is not a URLClassLoader
	 */
	public static List<File> fromClass(Class<?>... cs) throws IllegalArgumentException {
		final List<File> $ = new ArrayList<File>();
		for (final Class<?> c : cs) {
			final ClassLoader cl = c.getClassLoader();
			if (!(cl instanceof URLClassLoader))
				throw new IllegalArgumentException("Class loader is not a URLClassLoader. class=" + c.getName());
			sure(((URLClassLoader) cl).getURLs().length > 0);
			for (final URL url : ((URLClassLoader) cl).getURLs()) {
				$.add(new File(url.getFile().substring(1)));
				try {
					$.add(new File(url.toURI()));
				} catch (URISyntaxException e) {
					continue;
				}
			}
		}
		sure($.size() > 0);
		return $;
	}

	/**
	 * Obtain an iterator over all class names found in the class path
	 * 
	 * @return a new iterator object
	 */
	public Iterator<String> iterator() {
		try {
			return getClasses().iterator();
		} catch (final Exception e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Find all classes on the classpath represented by the receiver
	 * 
	 * @return List of fully qualified names of all such classes
	 */
	public ArrayList<String> getClasses() {
		final ArrayList<String> $ = new ArrayList<String>();
		for (final File f : files)
			addFromDirectory(0, f, f.getAbsolutePath(), $, "");
		return $;
	}

	private static final String DOT_CLASS = ".class";
	private static final String DOT_JAR = ".jar";
	private static final String DOT_ZIP = ".zip";

	/**
	 * Recursively adding all classes residing in specified directory into
	 * cache.
	 * 
	 * @param depth
	 *        0-based depth inside the directory tree
	 * @param dirOrFile
	 *        file or directory
	 * @param root
	 *        the root directory
	 * @param result
	 *        List where results are stored
	 * @param path
	 *        Relative path (dot-separated) from the starting point
	 * @throws Exception
	 */
	private void addFromDirectory(int depth, File dirOrFile, String root, ArrayList<String> result, String path) {
		if (dirOrFile.isDirectory()) {
			final String[] children = dirOrFile.list();
			for (final String s : children) {
				String newPath = concat(path, dirOrFile.getName());
				if (depth == 0)
					newPath = "";
				addFromDirectory(depth + 1, new File(dirOrFile, s), root, result, newPath);
			}
			return;
		}
		final NameDotSuffix nds = new NameDotSuffix(dirOrFile);
		if (nds.suffixIs(DOT_JAR) || nds.suffixIs(DOT_ZIP))
			addFromArchive(dirOrFile.getPath(), result);
		else if (nds.suffixIs(DOT_CLASS))
			result.add(concat(path, nds.name));
	}

	private static class NameDotSuffix {
		public final String name;
		public final String suffix;

		public NameDotSuffix(ZipEntry ze) {
			this(ze.getName().replace('/', '.'));
		}

		public NameDotSuffix(File f) {
			this(f.getName());
		}

		public NameDotSuffix(String s) {
			final int dot = s.lastIndexOf('.');
			if (dot < 0) {
				name = s;
				suffix = "";
				return;
			}
			name = s.substring(0, dot);
			suffix = s.substring(dot);
		}

		public boolean suffixIs(String s) {
			return suffix.equalsIgnoreCase(s);
		}
	}

	/**
	 * Adding all classes residing in archive to cache
	 * 
	 * @param jarFile
	 *        fill path to a jar file
	 * @param result
	 *        List where scanned files are stored
	 * @throws Exception
	 */
	private void addFromArchive(String jarFile, ArrayList<String> result) {
		try {
			if (!new File(jarFile).exists())
				return;
			final ZipFile f = new ZipFile(jarFile);
			final Enumeration<? extends ZipEntry> entries = f.entries();
			while (entries.hasMoreElements()) {
				final ZipEntry ze = entries.nextElement();
				final NameDotSuffix nds = new NameDotSuffix(ze);
				if (!nds.suffixIs(DOT_CLASS))
					continue;
				result.add(nds.name);
			}
		} catch (final IOException e) {
			throw new RuntimeException("Damaged zip file: " + jarFile, e);
		}
	}

	private static String concat(String path, String name) {
		if (path == null || path.length() == 0)
			return name;
		return path + "." + name;
	}

	private static List<File> filter(Iterable<File> fs, File... ignore) {
		final List<File> $ = new ArrayList<File>();
		for (File f : fs) {
			f = f.getAbsoluteFile();
			if (f.exists() && !onDirs(f, ignore))
				$.add(f);
		}
		return $;
	}

	private static boolean onDirs(File f, File... dirs) {
		for (final File d : dirs)
			if (onDir(f, d.getAbsoluteFile()))
				return true;
		return false;
	}

	private static boolean onDir(File f, File d) {
		for (File parent = f; parent != null; parent = parent.getParentFile())
			if (parent.equals(d))
				return true;
		return false;
	}

	public static void main(String[] args) {
		final ClassPathInfo cpi = new ClassPathInfo(new File("D:/tools/jdk-1-6-0/jre/lib/rt.jar"));
		final List<String> list = cpi.getClasses();
		for (int i = 0; i < list.size(); ++i)
			System.out.println(i + " " + list.get(i));
	}
}