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com.syntaxphoenix.syntaxapi.reflection.ReflectionHelper Maven / Gradle / Ivy

package com.syntaxphoenix.syntaxapi.reflection;

import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;

/**
 * Helper methods for working with the classpath.
 */
public final class ReflectionHelper {

	/**
	 * Gets the current thread context class loader.
	 * {@code Thread.currentThread().getContextClassLoader()}.
	 * 
	 * @return the context class loader, may be null
	 */
	public static ClassLoader contextClassLoader() {
		return Thread.currentThread().getContextClassLoader();
	}

	/**
	 * Gets the class loader of this library.
	 * {@code ClassCache.class.getClassLoader()}.
	 * 
	 * @return the static library class loader, may be null
	 */
	public static ClassLoader staticClassLoader() {
		return ClassCache.class.getClassLoader();
	}

	/**
	 * Returns an array of class Loaders initialized from the specified array.
	 * 

* If the input is null or empty, it defaults to both * {@link #contextClassLoader()} and {@link #staticClassLoader()} * * @param classLoaders the classLoaders provided * * @return the array of class loaders, not null */ public static ClassLoader[] classLoaders(ClassLoader... classLoaders) { if (classLoaders != null && classLoaders.length != 0) { return classLoaders; } else { ClassLoader contextClassLoader = contextClassLoader(), staticClassLoader = staticClassLoader(); return contextClassLoader != null ? staticClassLoader != null && contextClassLoader != staticClassLoader ? new ClassLoader[] { contextClassLoader, staticClassLoader } : new ClassLoader[] { contextClassLoader } : new ClassLoader[] {}; } } /** * Returns a distinct collection of URLs based on a package name. *

* This searches for the package name as a resource, using * {@link ClassLoader#getResources(String)}. For example, * {@code forPackage(org.reflections)} effectively returns URLs from the * classpath containing packages starting with {@code org.reflections}. *

* If the optional {@link ClassLoader}s are not specified, then both * {@link #contextClassLoader()} and {@link #staticClassLoader()} are used for * {@link ClassLoader#getResources(String)}. *

* The returned URLs retainsthe order of the given {@code classLoaders}. * * @param classLoaders the classLoaders provided * @param name the package name * * @return the collection of URLs, not null */ public static Collection forPackage(String name, ClassLoader... classLoaders) { return forResource(resourceName(name), classLoaders); } /** * Returns a distinct collection of URLs based on a resource. *

* This searches for the resource name, using * {@link ClassLoader#getResources(String)}. For example, * {@code forResource(test.properties)} effectively returns URLs from the * classpath containing files of that name. *

* If the optional {@link ClassLoader}s are not specified, then both * {@link #contextClassLoader()} and {@link #staticClassLoader()} are used for * {@link ClassLoader#getResources(String)}. *

* The returned URLs retains the order of the given {@code classLoaders}. * * @param classLoaders the classLoaders provided * @param resourceName the resource name * * @return the collection of URLs, not null */ public static Collection forResource(String resourceName, ClassLoader... classLoaders) { final List result = new ArrayList<>(); final ClassLoader[] loaders = classLoaders(classLoaders); for (ClassLoader classLoader : loaders) { try { final Enumeration urls = classLoader.getResources(resourceName); while (urls.hasMoreElements()) { final URL url = urls.nextElement(); int index = url.toExternalForm().lastIndexOf(resourceName); if (index != -1) { // Add old url as contextUrl to support exotic url handlers result.add(new URL(url, url.toExternalForm().substring(0, index))); } else { result.add(url); } } } catch (IOException e) { // Ignore for now // TODO: Add logger } } return distinctUrls(result); } /** * Returns the URL that contains a {@code Class}. *

* This searches for the class using {@link ClassLoader#getResource(String)}. *

* If the optional {@link ClassLoader}s are not specified, then both * {@link #contextClassLoader()} and {@link #staticClassLoader()} are used for * {@link ClassLoader#getResources(String)}. * * @param classLoaders the classLoaders provided * @param aClass the class which the url should be get for * * @return the URL containing the class, null if not found */ public static URL forClass(Class aClass, ClassLoader... classLoaders) { final ClassLoader[] loaders = classLoaders(classLoaders); final String resourceName = aClass.getName().replace(".", "/") + ".class"; for (ClassLoader classLoader : loaders) { try { final URL url = classLoader.getResource(resourceName); if (url != null) { final String normalizedUrl = url .toExternalForm() .substring(0, url.toExternalForm().lastIndexOf(aClass.getPackage().getName().replace(".", "/"))); return new URL(normalizedUrl); } } catch (MalformedURLException e) { // Ignore for now // TODO: Add logger } } return null; } /** * Returns a distinct collection of URLs based on URLs derived from class * loaders. *

* This finds the URLs using {@link URLClassLoader#getURLs()} using both * {@link #contextClassLoader()} and {@link #staticClassLoader()}. *

* The returned URLs retains the order of the given {@code classLoaders}. * * @return the collection of URLs, not null */ public static Collection forClassLoader() { return forClassLoader(classLoaders()); } /** * Returns a distinct collection of URLs based on URLs derived from class * loaders. *

* This finds the URLs using {@link URLClassLoader#getURLs()} using the * specified class loader, searching up the parent hierarchy. *

* If the optional {@link ClassLoader}s are not specified, then both * {@link #contextClassLoader()} and {@link #staticClassLoader()} are used for * {@link ClassLoader#getResources(String)}. *

* The returned URLs retains the order of the given {@code classLoaders}. * * @param classLoaders the classLoaders provided * * @return the collection of URLs, not null */ public static Collection forClassLoader(ClassLoader... classLoaders) { final Collection result = new ArrayList<>(); final ClassLoader[] loaders = classLoaders(classLoaders); for (ClassLoader classLoader : loaders) { while (classLoader != null) { if (classLoader instanceof URLClassLoader) { URL[] urls = ((URLClassLoader) classLoader).getURLs(); if (urls != null) { result.addAll(Arrays.asList(urls)); } } classLoader = classLoader.getParent(); } } return distinctUrls(result); } /** * Returns a distinct collection of URLs based on the {@code java.class.path} * system property. *

* This finds the URLs using the {@code java.class.path} system property. *

* The returned collection of URLs retains the classpath order. * * @return the collection of URLs, not null */ public static Collection forJavaClassPath() { Collection urls = new ArrayList<>(); String javaClassPath = System.getProperty("java.class.path"); if (javaClassPath != null) { for (String path : javaClassPath.split(File.pathSeparator)) { try { urls.add(new File(path).toURI().toURL()); } catch (Exception e) { // Ignore for now // TODO: Add logger } } } return distinctUrls(urls); } /** * Returns a distinct collection of URLs based on URLs derived from class * loaders expanded with Manifest information. *

* The {@code MANIFEST.MF} file can contain a {@code Class-Path} entry that * defines additional jar files to be included on the classpath. This method * finds the jar files using the {@link #contextClassLoader()} and * {@link #staticClassLoader()}, before searching for any additional manifest * classpaths. * * @return the collection of URLs, not null */ public static Collection forManifest() { return forManifest(forClassLoader()); } /** * Returns a distinct collection of URLs from a single URL based on the Manifest * information. *

* The {@code MANIFEST.MF} file can contain a {@code Class-Path} entry that * defines additional jar files to be included on the classpath. This method * takes a single URL, tries to resolve it as a jar file, and if so, adds any * additional manifest classpaths. The returned collection of URLs will always * contain the input URL. * * @param url the manifest url * * @return the collection of URLs, not null */ @SuppressWarnings("resource") public static Collection forManifest(final URL url) { final Collection result = new ArrayList<>(); result.add(url); try { final String part = cleanPath(url); File jarFile = new File(part); JarFile myJar = new JarFile(part); URL validUrl = tryToGetValidUrl(jarFile.getPath(), new File(part).getParent(), part); if (validUrl != null) { result.add(validUrl); } final Manifest manifest = myJar.getManifest(); if (manifest != null) { final String classPath = manifest.getMainAttributes().getValue(new Attributes.Name("Class-Path")); if (classPath != null) { for (String jar : classPath.split(" ")) { validUrl = tryToGetValidUrl(jarFile.getPath(), new File(part).getParent(), jar); if (validUrl != null) { result.add(validUrl); } } } } } catch (IOException e) { // don't do anything, we're going on the assumption it is a jar, which could be // wrong } return distinctUrls(result); } /** * Returns a distinct collection of URLs by expanding the specified URLs with * Manifest information. *

* The {@code MANIFEST.MF} file can contain a {@code Class-Path} entry that * defines additional jar files to be included on the classpath. This method * takes each URL in turn, tries to resolve it as a jar file, and if so, adds * any additional manifest classpaths. The returned collection of URLs will * always contain all the input URLs. *

* The returned URLs retains the input order. * * @param urls the manifest urls * * @return the collection of URLs, not null */ public static Collection forManifest(final Iterable urls) { Collection result = new ArrayList<>(); // determine if any of the URLs are JARs, and get any dependencies for (URL url : urls) { result.addAll(forManifest(url)); } return distinctUrls(result); } // a little bit cryptic... static URL tryToGetValidUrl(String workingDir, String path, String filename) { try { if (new File(filename).exists()) return new File(filename).toURI().toURL(); if (new File(path + File.separator + filename).exists()) return new File(path + File.separator + filename).toURI().toURL(); if (new File(workingDir + File.separator + filename).exists()) return new File(workingDir + File.separator + filename).toURI().toURL(); if (new File(new URL(filename).getFile()).exists()) return new File(new URL(filename).getFile()).toURI().toURL(); } catch (MalformedURLException e) { // don't do anything, we're going on the assumption it is a jar, which could be // wrong } return null; } /** * Cleans the URL. * * @param url the URL to clean, not null * @return the path, not null */ public static String cleanPath(final URL url) { String path = url.getPath(); try { path = URLDecoder.decode(path, "UTF-8"); } catch (UnsupportedEncodingException e) { /**/ } if (path.startsWith("jar:")) { path = path.substring("jar:".length()); } if (path.startsWith("file:")) { path = path.substring("file:".length()); } if (path.endsWith("!/")) { path = path.substring(0, path.lastIndexOf("!/")) + "/"; } return path; } private static String resourceName(String name) { if (name != null) { String resourceName = name.replace(".", "/"); resourceName = resourceName.replace("\\", "/"); if (resourceName.startsWith("/")) { resourceName = resourceName.substring(1); } return resourceName; } return null; } // http://michaelscharf.blogspot.co.il/2006/11/javaneturlequals-and-hashcode-make.html private static Collection distinctUrls(Collection urls) { Map distinct = new LinkedHashMap<>(urls.size()); for (URL url : urls) { distinct.put(url.toExternalForm(), url); } return distinct.values(); } }





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