[3/6] git commit: Add findResources method to LoaderUtil.

[ma...@apache.org]

Add findResources method to LoaderUtil.


Project: http://git-wip-us.apache.org/repos/asf/logging-log4j2/repo
Commit: http://git-wip-us.apache.org/repos/asf/logging-log4j2/commit/ba39c4e4
Tree: http://git-wip-us.apache.org/repos/asf/logging-log4j2/tree/ba39c4e4
Diff: http://git-wip-us.apache.org/repos/asf/logging-log4j2/diff/ba39c4e4

Branch: refs/heads/master
Commit: ba39c4e4363b8257dec136e9c4ea8c4712b96ff7
Parents: 0fcb1bf
Author: Matt Sicker <ma...@apache.org>
Authored: Mon Sep 29 21:29:04 2014 -0500
Committer: Matt Sicker <ma...@apache.org>
Committed: Mon Sep 29 21:29:04 2014 -0500

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 .../apache/logging/log4j/util/LoaderUtil.java   | 66 +++++++++++++++++++-
 1 file changed, 65 insertions(+), 1 deletion(-)
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http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/ba39c4e4/log4j-api/src/main/java/org/apache/logging/log4j/util/LoaderUtil.java
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diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/LoaderUtil.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/LoaderUtil.java
index 7c3c7e7..950fe1a 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/LoaderUtil.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/LoaderUtil.java
@@ -16,9 +16,14 @@
  */
 package org.apache.logging.log4j.util;
 
+import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
+import java.net.URL;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.LinkedHashSet;
 
 /**
  * <em>Consider this class private.</em> Utility class for ClassLoaders.
@@ -68,6 +73,7 @@ public final class LoaderUtil {
     public static ClassLoader getThreadContextClassLoader() {
         if (GET_CLASS_LOADER_DISABLED) {
             // we can at least get this class's ClassLoader regardless of security context
+            // however, if this is null, there's really no option left at this point
             return LoaderUtil.class.getClassLoader();
         }
         return SECURITY_MANAGER == null
@@ -79,7 +85,6 @@ public final class LoaderUtil {
         @Override
         public ClassLoader run() {
             final ClassLoader cl = Thread.currentThread().getContextClassLoader();
-            // if the TCCL is null, that means we're using the system CL
             if (cl != null) {
                 return cl;
             }
@@ -161,4 +166,63 @@ public final class LoaderUtil {
         }
         return ignoreTCCL;
     }
+
+    /**
+     * Finds classpath {@linkplain URL resources}.
+     *
+     * @param resource the name of the resource to find.
+     * @return a Collection of URLs matching the resource name. If no resources could be found, then this will be empty.
+     * @since 2.1
+     */
+    public static Collection<URL> findResources(final String resource) {
+        final Collection<UrlResource> urlResources = findUrlResources(resource);
+        final Collection<URL> resources = new LinkedHashSet<URL>(urlResources.size());
+        for (final UrlResource urlResource : urlResources) {
+            resources.add(urlResource.getUrl());
+        }
+        return resources;
+    }
+
+    static Collection<UrlResource> findUrlResources(final String resource) {
+        final ClassLoader[] candidates = {
+            getThreadContextClassLoader(),
+            LoaderUtil.class.getClassLoader(),
+            ClassLoader.getSystemClassLoader()
+        };
+        final Collection<UrlResource> resources = new LinkedHashSet<UrlResource>();
+        for (final ClassLoader cl : candidates) {
+            if (cl != null) {
+                try {
+                    final Enumeration<URL> resourceEnum = cl.getResources(resource);
+                    while (resourceEnum.hasMoreElements()) {
+                        resources.add(new UrlResource(cl, resourceEnum.nextElement()));
+                    }
+                } catch (final IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+        return resources;
+    }
+
+    /**
+     * {@link URL} and {@link ClassLoader} pair.
+     */
+    static class UrlResource {
+        private final ClassLoader classLoader;
+        private final URL url;
+
+        public UrlResource(final ClassLoader classLoader, final URL url) {
+            this.classLoader = classLoader;
+            this.url = url;
+        }
+
+        public ClassLoader getClassLoader() {
+            return classLoader;
+        }
+
+        public URL getUrl() {
+            return url;
+        }
+    }
 }