org.stjs.generator.javac.PackageInternalsFinder Maven / Gradle / Ivy

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package org.stjs.generator.javac;

import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.jar.JarEntry;

import javax.tools.JavaFileObject;

import org.stjs.generator.STJSRuntimeException;

import com.google.common.collect.Maps;

/**
 * this class looks for packages in the classpath
 * 
 * @author acraciun
 * 
 */
public class PackageInternalsFinder {
	private final ClassLoader classLoader;
	private static final String CLASS_FILE_EXTENSION = ".class";

	private final Map> cachePackageEntries = Maps.newHashMap();

	public PackageInternalsFinder(ClassLoader classLoader) {
		this.classLoader = classLoader;
	}

	public List find(String packageName, boolean recursive) throws IOException {
		String javaPackageName = packageName.replaceAll("\\.", "/");

		List result = cachePackageEntries.get(javaPackageName);
		if (result != null) {
			return result;
		}

		result = new ArrayList();
		cachePackageEntries.put(javaPackageName, result);

		Enumeration urlEnumeration = classLoader.getResources(javaPackageName);
		while (urlEnumeration.hasMoreElements()) { // one URL for each jar on the classpath that has the given package
			URL packageFolderURL = urlEnumeration.nextElement();
			result.addAll(listUnder(packageName, packageFolderURL, recursive));
		}

		return result;
	}

	private Collection listUnder(String packageName, URL packageFolderURL, boolean recursive) {
		File directory = new File(packageFolderURL.getFile());
		if (directory.isDirectory()) { // browse local .class files - useful for local execution
			return processDir(packageName, directory, recursive);
		} else { // browse a jar file
			return processJar(packageFolderURL, recursive);
		} // maybe there can be something else for more involved class loaders
	}

	private void addFileObject(String jarUri, String name, String rootEntryName, int rootEnd, List result, boolean recursive) {
		boolean acceptCurrentFolder = recursive || name.indexOf('/', rootEnd) == -1;
		if (acceptCurrentFolder && name.startsWith(rootEntryName) && name.endsWith(CLASS_FILE_EXTENSION)) {
			URI uri = URI.create(jarUri + "!/" + name);
			String binaryName = name.replaceAll("/", ".");
			binaryName = binaryName.replaceAll(CLASS_FILE_EXTENSION + "$", "");

			result.add(new CustomJavaFileObject(binaryName, uri));
		}
	}

	private List processJar(URL packageFolderURL, boolean recursive) {
		List result = new ArrayList();

		try {

			URLConnection urlConnection = packageFolderURL.openConnection();
			if (!(urlConnection instanceof JarURLConnection)) {
				// weird file in the classpath
				return Collections.emptyList();
			}
			String jarUri = packageFolderURL.toExternalForm().split("!")[0];
			JarURLConnection jarConn = (JarURLConnection) urlConnection;
			String rootEntryName = jarConn.getEntryName();
			int rootEnd = rootEntryName.length() + 1;

			Enumeration entryEnum = jarConn.getJarFile().entries();
			while (entryEnum.hasMoreElements()) {
				JarEntry jarEntry = entryEnum.nextElement();
				String name = jarEntry.getName();
				addFileObject(jarUri, name, rootEntryName, rootEnd, result, recursive);
			}
		}
		catch (IOException e) {
			throw new STJSRuntimeException("Wasn't able to open " + packageFolderURL + " as a jar file", e);
		}
		return result;
	}

	private List processDir(String packageName, File directory, boolean recursive) {
		List result = new ArrayList();

		File[] childFiles = directory.listFiles();
		for (File childFile : childFiles) {
			if (childFile.isFile() && childFile.getName().endsWith(CLASS_FILE_EXTENSION)) {
				// We only want the .class files.
				String binaryName = packageName + "." + childFile.getName();
				binaryName = binaryName.replaceAll(CLASS_FILE_EXTENSION + "$", "");

				result.add(new CustomJavaFileObject(binaryName, childFile.toURI()));
			} else if (recursive && childFile.isDirectory()) {
				result.addAll(processDir(packageName + "." + childFile.getName(), childFile, recursive));
			}
		}

		return result;
	}
}