Bug 1237 - Clarify IOUtil.getResource(..) for better efficiency, i.e. allow caller to skip relative futile lookup

IOUtil.getResource(..) and IOUtil.ClassResources, needs more clarity.

ClassLoader shall be passed explicitly next to the optional
relative context Class instance.

This allows better efficiency, i.e. caller can pass ClassLoader
but skip a possible relative lookup, if not existing.

1 files changed, 63 insertions, 23 deletions

diff --git a/src/java/com/jogamp/common/util/IOUtil.java b/src/java/com/jogamp/common/util/IOUtil.java
index 0638f11..433e119 100644
--- a/src/java/com/jogamp/common/util/IOUtil.java
+++ b/src/java/com/jogamp/common/util/IOUtil.java
@@ -432,7 +432,7 @@ public class IOUtil {
 
     /***
      *
-     * RESOURCE LOCATION STUFF
+     * RESOURCE LOCATION HELPER
      *
      */
 
@@ -441,7 +441,10 @@ public class IOUtil {
      * to be {@link #resolve(int) resolved} at a later time.
      */
     public static class ClassResources {
-        /** Class instance used to {@link #resolve(int)} the {@link #resourcePaths}. */
+        /** Optional {@link ClassLoader} used to {@link #resolve(int)} {@link #resourcePaths}. */
+        public final ClassLoader classLoader;
+
+        /** Optional class instance used to {@link #resolve(int)} relative {@link #resourcePaths}. */
         public final Class<?> contextCL;
 
         /** Resource paths, see {@link #resolve(int)}. */
@@ -453,23 +456,34 @@ public class IOUtil {
         /**
          * @param contextCL class instance to {@link #resolve(int)} {@link #resourcePaths}.
          * @param resourcePaths array of strings denominating multiple resource paths. None shall be null.
+         * @deprecated Use {@link #IOUtil(String[], ClassLoader, Class)} for clarity!
          */
         public ClassResources(final Class<?> contextCL, final String[] resourcePaths) {
+            this(resourcePaths, contextCL.getClassLoader(), contextCL);
+        }
+        /**
+         * @param resourcePaths multiple relative or absolute resource locations
+         * @param classLoader optional {@link ClassLoader}, see {@link IOUtil#getResource(String, ClassLoader, Class)}
+         * @param relContext optional relative context, see {@link IOUtil#getResource(String, ClassLoader, Class)}
+         */
+        public ClassResources(final String[] resourcePaths, final ClassLoader classLoader, final Class<?> relContext) {
             for(int i=resourcePaths.length-1; i>=0; i--) {
                 if( null == resourcePaths[i] ) {
                     throw new IllegalArgumentException("resourcePath["+i+"] is null");
                 }
             }
-            this.contextCL = contextCL;
+            this.classLoader = classLoader;
+            this.contextCL = relContext;
             this.resourcePaths = resourcePaths;
         }
 
         /**
-         * Resolving one of the {@link #resourcePaths} indexed by <code>uriIndex</code> using {@link #contextCL} and {@link IOUtil#getResource(Class, String)}.
+         * Resolving one of the {@link #resourcePaths} indexed by <code>uriIndex</code> using
+         * {@link #classLoader}, {@link #contextCL} through {@link IOUtil#getResource(String, ClassLoader, Class)}.
          * @throws ArrayIndexOutOfBoundsException if <code>uriIndex</code> is < 0 or >= {@link #resourceCount()}.
          */
         public URLConnection resolve(final int uriIndex) throws ArrayIndexOutOfBoundsException {
-            return getResource(contextCL, resourcePaths[uriIndex]);
+            return getResource(resourcePaths[uriIndex], classLoader, contextCL);
         }
     }
 
@@ -478,10 +492,11 @@ public class IOUtil {
      * <ul>
      *   <li><i>relative</i>: <code>context</code>'s package name-path plus <code>resourcePath</code> via <code>context</code>'s ClassLoader.
      *       This allows locations relative to JAR- and other URLs.
-     *       The <code>resourcePath</code> may start with <code>../</code> to navigate to parent folder.</li>
-     *   <li><i>absolute</i>: <code>context</code>'s ClassLoader and the <code>resourcePath</code> as is (filesystem)</li>
+     *       The <code>resourcePath</code> may start with <code>../</code> to navigate to parent folder.
+     *       This attempt is skipped if {@code context} is {@code null}.</li>
+     *   <li><i>absolute</i>: <code>resourcePath</code> as is via <code>context</code>'s ClassLoader.
+     *       In case {@code context} is {@code null}, this class {@link ClassLoader} is being used.</li>
      * </ul>
-     *
      * <p>
      * Returns the resolved and open URLConnection or null if not found.
      * </p>
@@ -489,29 +504,57 @@ public class IOUtil {
      * @see #getResource(String, ClassLoader)
      * @see ClassLoader#getResource(String)
      * @see ClassLoader#getSystemResource(String)
+     * @deprecated Use {@link IOUtil#getResource(String, ClassLoader, Class)} for clarity!
      */
     public static URLConnection getResource(final Class<?> context, final String resourcePath) {
+        final ClassLoader contextCL = null != context ? context.getClassLoader() : IOUtil.class.getClassLoader();
+        return getResource(resourcePath, contextCL, context);
+    }
+
+    /**
+     * Locating a resource using {@link #getResource(String, ClassLoader)}:
+     * <ul>
+     *   <li><i>relative</i>: <code>relContext</code>'s package name-path plus <code>resourcePath</code> via <code>classLoader</code>.
+     *       This allows locations relative to JAR- and other URLs.
+     *       The <code>resourcePath</code> may start with <code>../</code> to navigate to parent folder.
+     *       This attempt is skipped if {@code relContext} is {@code null}.</li>
+     *   <li><i>absolute</i>: <code>resourcePath</code> as is via <code>classLoader</code>.
+     * </ul>
+     * <p>
+     * Returns the resolved and open URLConnection or null if not found.
+     * </p>
+     *
+     * @param resourcePath the resource path to locate relative or absolute
+     * @param classLoader the optional {@link ClassLoader}, recommended
+     * @param relContext relative context, i.e. position, of the {@code resourcePath},
+     *                   to perform the relative lookup, if not {@code null}.
+     * @see #getResource(String, ClassLoader)
+     * @see ClassLoader#getResource(String)
+     * @see ClassLoader#getSystemResource(String)
+     */
+    public static URLConnection getResource(final String resourcePath, final ClassLoader classLoader, final Class<?> relContext) {
         if(null == resourcePath) {
             return null;
         }
-        final ClassLoader contextCL = (null!=context)?context.getClassLoader():IOUtil.class.getClassLoader();
         URLConnection conn = null;
-        if(null != context) {
+        if(null != relContext) {
             // scoping the path within the class's package
-            final String className = context.getName().replace('.', '/');
+            final String className = relContext.getName().replace('.', '/');
             final int lastSlash = className.lastIndexOf('/');
             if (lastSlash >= 0) {
                 final String pkgName = className.substring(0, lastSlash + 1);
-                conn = getResource(pkgName + resourcePath, contextCL);
+                conn = getResource(pkgName + resourcePath, classLoader);
                 if(DEBUG) {
-                    System.err.println("IOUtil: found <"+resourcePath+"> within class package <"+pkgName+"> of given class <"+context.getName()+">: "+(null!=conn));
+                    System.err.println("IOUtil: found <"+resourcePath+"> within class package <"+pkgName+"> of given class <"+relContext.getName()+">: "+(null!=conn));
                 }
             }
-        } else if(DEBUG) {
-            System.err.println("IOUtil: null context");
+        } else {
+            if(DEBUG) {
+                System.err.println("IOUtil: null context");
+            }
         }
         if(null == conn) {
-            conn = getResource(resourcePath, contextCL);
+            conn = getResource(resourcePath, classLoader);
             if(DEBUG) {
                 System.err.println("IOUtil: found <"+resourcePath+"> by classloader: "+(null!=conn));
             }
@@ -542,8 +585,7 @@ public class IOUtil {
                 return AssetURLContext.createURL(resourcePath, cl).openConnection();
             } catch (final IOException ioe) {
                 if(DEBUG) {
-                    System.err.println("IOUtil: Caught Exception:");
-                    ioe.printStackTrace();
+                    ExceptionUtils.dumpThrowable("IOUtil", ioe);
                 }
                 return null;
             }
@@ -552,8 +594,7 @@ public class IOUtil {
                 return AssetURLContext.resolve(resourcePath, cl);
             } catch (final IOException ioe) {
                 if(DEBUG) {
-                    System.err.println("IOUtil: Caught Exception:");
-                    ioe.printStackTrace();
+                    ExceptionUtils.dumpThrowable("IOUtil", ioe);
                 }
             }
         }
@@ -666,8 +707,7 @@ public class IOUtil {
                 return c;
             } catch (final IOException ioe) {
                 if(DEBUG) {
-                    System.err.println("IOUtil: urlExists("+url+") ["+dbgmsg+"] - false - "+ioe.getClass().getSimpleName()+": "+ioe.getMessage());
-                    ioe.printStackTrace();
+                    ExceptionUtils.dumpThrowable("IOUtil: urlExists("+url+") ["+dbgmsg+"] - false -", ioe);
                 }
             }
         } else if(DEBUG) {
@@ -707,7 +747,7 @@ public class IOUtil {
     }
 
     private static final byte[] readCode(final String fname) throws IOException {
-        final URLConnection con = IOUtil.getResource(IOUtil.class, fname);
+        final URLConnection con = IOUtil.getResource(fname, IOUtil.class.getClassLoader(), IOUtil.class);
         final InputStream in = con.getInputStream();
         byte[] output = null;
         try {