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A bundle project producing JAX-RS RI bundles. The primary artifact is an "all-in-one" OSGi-fied JAX-RS RI bundle (jaxrs-ri.jar). Attached to that are two compressed JAX-RS RI archives. The first archive (jaxrs-ri.zip) consists of binary RI bits and contains the API jar (under "api" directory), RI libraries (under "lib" directory) as well as all external RI dependencies (under "ext" directory). The secondary archive (jaxrs-ri-src.zip) contains buildable JAX-RS RI source bundle and contains the API jar (under "api" directory), RI sources (under "src" directory) as well as all external RI dependencies (under "ext" directory). The second archive also contains "build.xml" ANT script that builds the RI sources. To build the JAX-RS RI simply unzip the archive, cd to the created jaxrs-ri directory and invoke "ant" from the command line.

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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2010-2013 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * http://glassfish.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
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 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */
package org.glassfish.jersey.internal.util;

import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.glassfish.jersey.internal.LocalizationMessages;
import org.glassfish.jersey.internal.OsgiRegistry;
import org.glassfish.jersey.internal.util.collection.ClassTypePair;

import org.osgi.framework.Bundle;
import org.osgi.framework.FrameworkUtil;

import com.google.common.base.Function;
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

/**
 * Utility methods for Java reflection.
 *
 * @author Paul Sandoz
 */
public class ReflectionHelper {

    private static final Logger LOGGER = Logger.getLogger(ReflectionHelper.class.getName());

    /**
     * Get the declaring class of an accessible object. Supported are {@link Method},
     * {@link Field} and {@link Constructor} accessible object types.
     *
     * @param ao an accessible object.
     * @return the declaring class of an accessible object.
     * @throws IllegalArgumentException in case the type of the accessible object
     *                                  is not supported.
     */
    public static Class getDeclaringClass(AccessibleObject ao) {
        if (ao instanceof Method) {
            return ((Method) ao).getDeclaringClass();
        } else if (ao instanceof Field) {
            return ((Field) ao).getDeclaringClass();
        } else if (ao instanceof Constructor) {
            return ((Constructor) ao).getDeclaringClass();
        } else {
            throw new IllegalArgumentException("Unsupported accessible object type: " + ao.getClass().getName());
        }
    }

    /**
     * Create a string representation of an object.
     * 

     * Returns a string consisting of the name of the class of which the
     * object is an instance, the at-sign character {@code '@'}, and
     * the unsigned hexadecimal representation of the hash code of the
     * object. In other words, this method returns a string equal to the
     * value of:
     * 

     * 
     * o.getClass().getName() + '@' + Integer.toHexString(o.hashCode())
     * 

     *
     * @param o the object.
     * @return the string representation of the object.
     */
    public static String objectToString(Object o) {
        if (o == null) {
            return "null";
        }
        StringBuilder sb = new StringBuilder();
        sb.append(o.getClass().getName()).
                append('@').append(Integer.toHexString(o.hashCode()));
        return sb.toString();
    }

    /**
     * Create a string representation of a method and an instance whose
     * class implements the method.
     * 

     * Returns a string consisting of the name of the class of which the object
     * is an instance, the at-sign character {@code '@'},
     * the unsigned hexadecimal representation of the hash code of the
     * object, the character {@code '.'}, the name of the method,
     * the character {@code '('}, the list of method parameters, and
     * the character {@code ')'}. In other words, those method returns a
     * string equal to the value of:
     * 

     * 
     * o.getClass().getName() + '@' + Integer.toHexString(o.hashCode()) +
     * '.' + m.getName() + '(' + <parameters> + ')'.
     * 

     *
     * @param o the object whose class implements {@code m}.
     * @param m the method.
     * @return the string representation of the method and instance.
     */
    public static String methodInstanceToString(Object o, Method m) {
        StringBuilder sb = new StringBuilder();
        sb.append(o.getClass().getName()).
                append('@').append(Integer.toHexString(o.hashCode())).
                append('.').append(m.getName()).append('(');

        Class[] params = m.getParameterTypes();
        for (int i = 0; i < params.length; i++) {
            sb.append(getTypeName(params[i]));
            if (i < (params.length - 1)) {
                sb.append(",");
            }
        }

        sb.append(')');

        return sb.toString();
    }

    /**
     * @param type
     * @return
     */
    private static String getTypeName(Class type) {
        if (type.isArray()) {
            try {
                Class cl = type;
                int dimensions = 0;
                while (cl.isArray()) {
                    dimensions++;
                    cl = cl.getComponentType();
                }
                StringBuilder sb = new StringBuilder();
                sb.append(cl.getName());
                for (int i = 0; i < dimensions; i++) {
                    sb.append("[]");
                }
                return sb.toString();
            } catch (Throwable e) { /*FALLTHRU*/ }
        }
        return type.getName();
    }

    /**
     * Get the Class from the class name.
     * 

     * The context class loader will be utilized if accessible and non-null.
     * Otherwise the defining class loader of this class will
     * be utilized.
     *
     * @param   class type.
     * @param name the class name.
     * @return the Class, otherwise null if the class cannot be found.
     */
    public static  Class classForName(String name) {
        return classForName(name, getContextClassLoader());
    }

    /**
     * Get the Class from the class name.
     *
     * @param   class type.
     * @param name the class name.
     * @param cl   the class loader to use, if null then the defining class loader
     *             of this class will be utilized.
     * @return the Class, otherwise null if the class cannot be found.
     */
    @SuppressWarnings("unchecked")
    public static  Class classForName(String name, ClassLoader cl) {
        if (cl != null) {
            try {
                return (Class) Class.forName(name, false, cl);
            } catch (ClassNotFoundException ex) {
                if (LOGGER.isLoggable(Level.FINE)) {
                    LOGGER.log(Level.FINE, "Unable to load class " + name + " using the supplied classloader " + cl.getClass().getName() + ".", ex);
                }
            }
        }
        try {
            return (Class) Class.forName(name);
        } catch (ClassNotFoundException ex) {
            if (LOGGER.isLoggable(Level.FINE)) {
                LOGGER.log(Level.FINE, "Unable to load class " + name + " using the current classloader.", ex);
            }
        }

        return null;
    }

    /**
     * Get the Class from the class name.
     * 

     * The context class loader will be utilized if accessible and non-null.
     * Otherwise the defining class loader of this class will
     * be utilized.
     *
     * @param   class type.
     * @param name the class name.
     * @return the Class, otherwise null if the class cannot be found.
     * @throws ClassNotFoundException if the class cannot be found.
     */
    public static  Class classForNameWithException(String name)
            throws ClassNotFoundException {
        return classForNameWithException(name, getContextClassLoader());
    }

    /**
     * Get the Class from the class name.
     *
     * @param   class type.
     * @param name the class name.
     * @param cl   the class loader to use, if null then the defining class loader
     *             of this class will be utilized.
     * @return the Class, otherwise null if the class cannot be found.
     * @throws ClassNotFoundException if the class cannot be found.
     */
    @SuppressWarnings("unchecked")
    public static  Class classForNameWithException(String name, ClassLoader cl)
            throws ClassNotFoundException {
        if (cl != null) {
            try {
                return (Class) Class.forName(name, false, cl);
            } catch (ClassNotFoundException ex) {
            }
        }
        return (Class) Class.forName(name);
    }

    /**
     * Get the context class loader.
     *
     * @return the context class loader, otherwise null security privileges
     *         are not set.
     */
    public static ClassLoader getContextClassLoader() {
        return AccessController.doPrivileged(
                new PrivilegedAction() {

                    @Override
                    public ClassLoader run() {
                        ClassLoader cl = null;
                        try {
                            cl = Thread.currentThread().getContextClassLoader();
                        } catch (SecurityException ex) {
                        }
                        return cl;
                    }
                });
    }

    /**
     * Set the context class loader.
     *
     * @param classLoader the context class loader to be set.
     */
    public static void setContextClassLoader(final ClassLoader classLoader) {
        AccessController.doPrivileged(
                new PrivilegedAction() {

                    @Override
                    public Object run() {
                        try {
                            Thread.currentThread().setContextClassLoader(classLoader);
                        } catch (SecurityException ex) {
                        }
                        return null;
                    }
                });
    }

    /**
     * Set a method to be accessible.
     *
     * @param m the method to be set as accessible
     */
    public static void setAccessibleMethod(final Method m) {
        if (Modifier.isPublic(m.getModifiers())) {
            return;
        }

        AccessController.doPrivileged(new PrivilegedAction() {

            @Override
            public Object run() {
                if (!m.isAccessible()) {
                    m.setAccessible(true);
                }
                return m;
            }
        });
    }

    /**
     * Get the list of classes that represent the type arguments of a
     * {@link ParameterizedType parameterized} input type.
     * 

     * For any given argument in the returned list, following rules apply:
     * 
    
     * 
  • If a type argument is a class then the class is returned.
    • 
     * 
  • If the type argument is a generic array type and the generic component
     * type is a class then class of the array is returned.
    • 
     * 
  • If the type argument is a parameterized type and it's raw type is a
     * class then that class is returned.
    • 
     * 

     * If the {@code type} is not an instance of ParameterizedType an empty
     * list is returned.
     *
     * @param type parameterized type.
     * @return the list of classed representing the actual type arguments. May be empty,
     *         but may never be {@code null}.
     * @throws IllegalArgumentException if any of the generic type arguments is
     *                                  not a class, or a generic array type, or the generic component type
     *                                  of the generic array type is not class, or not a parameterized type
     *                                  with a raw type that is not a class.
     */
    public static List> getGenericTypeArgumentClasses(final Type type) throws IllegalArgumentException {
        final Type[] types = getTypeArguments(type);
        if (types == null) {
            return Collections.emptyList();
        }

        return Lists.newArrayList(Collections2.transform(Arrays.asList(types), new Function>() {

            @Override
            public Class apply(Type input) {
                return erasure(input);
            }
        }));
    }

    /**
     * Get the list of class-type pairs that represent the type arguments of a
     * {@link ParameterizedType parameterized} input type.
     * 

     * For any given {@link ClassTypePair#rawClass() class} part of each pair
     * in the returned list, following rules apply:
     * 
    
     * 
  • If a type argument is a class then the class is returned as raw class.
    • 
     * 
  • If the type argument is a generic array type and the generic component
     * type is a class then class of the array is returned as raw class.
    • 
     * 
  • If the type argument is a parameterized type and it's raw type is a
     * class then that class is returned as raw class.
    • 
     * 

     * If the {@code type} is not an instance of ParameterizedType an empty
     * list is returned.
     *
     * @param type parameterized type.
     * @return the list of class-type pairs representing the actual type arguments.
     *         May be empty, but may never be {@code null}.
     * @throws IllegalArgumentException if any of the generic type arguments is
     *                                  not a class, or a generic array type, or the generic component type
     *                                  of the generic array type is not class, or not a parameterized type
     *                                  with a raw type that is not a class.
     */
    public static List getTypeArgumentAndClass(final Type type) throws IllegalArgumentException {
        final Type[] types = getTypeArguments(type);
        if (types == null) {
            return Collections.emptyList();
        }

        return Lists.newArrayList(Collections2.transform(Arrays.asList(types), new Function() {

            @Override
            public ClassTypePair apply(Type input) {
                return ClassTypePair.of(erasure(input), input);
            }
        }));
    }

    /**
     * Check if the given type is a primitive type.
     *
     * @param type type to be checked.
     */
    public static boolean isPrimitive(Type type) {
        if (type instanceof Class) {
            Class c = (Class) type;
            return c.isPrimitive();
        }
        return false;
    }

    /**
     * Get the type arguments for a parameterized type.
     * 

     * In case the type is not a {@link ParameterizedType parameterized type},
     * the method returns {@code null}.
     *
     * @param type parameterized type.
     * @return type arguments for a parameterized type, or {@code null} in case the input type is
     *         not a parameterized type.
     */
    public static Type[] getTypeArguments(Type type) {
        if (!(type instanceof ParameterizedType)) {
            return null;
        }

        return ((ParameterizedType) type).getActualTypeArguments();
    }

    /**
     * Get a type argument at particular index for a parameterized type.
     * 

     * In case the type is not a {@link ParameterizedType parameterized type},
     * the method returns {@code null}.
     *
     * @param type  parameterized type.
     * @param index type parameter index.
     * @return type argument for a parameterized type at a given index, or {@code null}
     *         in case the input type is not a parameterized type.
     */
    public static Type getTypeArgument(Type type, int index) {
        if (type instanceof ParameterizedType) {
            ParameterizedType p = (ParameterizedType) type;
            return fix(p.getActualTypeArguments()[index]);
        }

        return null;
    }

    /**
     * JDK 5.0 has a bug of creating {@link GenericArrayType} where it shouldn't.
     * fix that manually to work around the problem.
     * 

     * See bug 6202725.
     */
    private static Type fix(Type t) {
        if (!(t instanceof GenericArrayType))
            return t;

        GenericArrayType gat = (GenericArrayType) t;
        if (gat.getGenericComponentType() instanceof Class) {
            Class c = (Class) gat.getGenericComponentType();
            return Array.newInstance(c, 0).getClass();
        }

        return t;
    }

    /**
     * Implements the logic for {@link #erasure(Type)}.
     */
    private static final TypeVisitor eraser = new TypeVisitor() {
        @Override
        protected Class onClass(Class clazz) {
            return clazz;
        }

        @Override
        protected Class onParameterizedType(ParameterizedType type) {
            // TODO: why getRawType returns Type? not Class?
            return visit(type.getRawType());
        }

        @Override
        protected Class onGenericArray(GenericArrayType type) {
            return Array.newInstance(visit(type.getGenericComponentType()), 0).getClass();
        }

        @Override
        protected Class onVariable(TypeVariable type) {
            return visit(type.getBounds()[0]);
        }

        @Override
        protected Class onWildcard(WildcardType type) {
            return visit(type.getUpperBounds()[0]);
        }

        @Override
        protected RuntimeException createError(Type type) {
            return new IllegalArgumentException(LocalizationMessages.TYPE_TO_CLASS_CONVERSION_NOT_SUPPORTED(type));
        }
    };

    /**
     * Get the {@link Class} representation of the given type.
     * 

     * This corresponds to the notion of the erasure in JSR-14.
     *
     * @param type type to provide the erasure for.
     * @return the given type's erasure.
     */
    @SuppressWarnings("unchecked")
    public static  Class erasure(Type type) {
        return eraser.visit(type);
    }

    /**
     * Check if {@code subType} is a sub-type of {@code superType}.
     *
     * @param subType   sub-type type.
     * @param superType super-type type.
     * @return {@code true} in case the {@code subType} is a sub-type of {@code superType},
     *         {@code false} otherwise.
     */
    public static boolean isSubClassOf(Type subType, Type superType) {
        return erasure(superType).isAssignableFrom(erasure(subType));
    }

    /**
     * Checks if the type is an array type.
     *
     * @param type type to check.
     * @return {@code true} in case the type is an array type, {@code false} otherwise.
     */
    public static boolean isArray(Type type) {
        if (type instanceof Class) {
            Class c = (Class) type;
            return c.isArray();
        }
        return type instanceof GenericArrayType;
    }

    /**
     * Checks if the type is an array of a given component type.
     *
     * @param type          type to check.
     * @param componentType array component type.
     * @return {@code true} in case the type is an array type of a given component type,
     *         {@code false} otherwise.
     */
    public static boolean isArrayOfType(Type type, Class componentType) {
        if (type instanceof Class) {
            Class c = (Class) type;
            return c.isArray() && c != byte[].class;
        }
        if (type instanceof GenericArrayType) {
            final Type arrayComponentType = ((GenericArrayType) type).getGenericComponentType();
            return arrayComponentType == componentType;
        }
        return false;
    }

    /**
     * Gets the component type of the array.
     *
     * @param type must be an array.
     * @return array component type.
     * @throws IllegalArgumentException in case the type is not an array type.
     */
    public static Type getArrayComponentType(Type type) {
        if (type instanceof Class) {
            Class c = (Class) type;
            return c.getComponentType();
        }
        if (type instanceof GenericArrayType)
            return ((GenericArrayType) type).getGenericComponentType();

        throw new IllegalArgumentException();
    }

    /**
     * Get Array class of component type.
     *
     * @param c the component class of the array
     * @return the array class.
     */
    public static Class getArrayForComponentType(Class c) {
        try {
            Object o = Array.newInstance(c, 0);
            return o.getClass();
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    /**
     * Get the static valueOf(String ) method.
     *
     * @param c The class to obtain the method.
     * @return the method, otherwise null if the method is not present.
     */
    @SuppressWarnings("unchecked")
    public static Method getValueOfStringMethod(Class c) {
        try {
            Method m = c.getDeclaredMethod("valueOf", String.class);
            if (!Modifier.isStatic(m.getModifiers()) && m.getReturnType() == c) {
                return null;
            }
            return m;
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Get the static fromString(String ) method.
     *
     * @param c The class to obtain the method.
     * @return the method, otherwise null if the method is not present.
     */
    @SuppressWarnings("unchecked")
    public static Method getFromStringStringMethod(Class c) {
        try {
            Method m = c.getDeclaredMethod("fromString", String.class);
            if (!Modifier.isStatic(m.getModifiers()) && m.getReturnType() == c) {
                return null;
            }
            return m;
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Get the constructor that has a single parameter of String.
     *
     * @param c The class to obtain the constructor.
     * @return the constructor, otherwise null if the constructor is not present.
     */
    public static Constructor getStringConstructor(Class c) {
        try {
            return c.getConstructor(String.class);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Returns collection of all annotation types attached to a given annotated element that have the provided meta
     * annotation attached.
     *
     * @param annotatedElement annotated element.
     * @param metaAnnotation   meta annotation attached to the annotation types we are looking for (if null, annotation
     *                         types of all attached annotations will be returned).
     * @return list of annotation types with a given meta annotation
     */
    public static Collection> getAnnotationTypes(
            AnnotatedElement annotatedElement,
            Class metaAnnotation
    ) {
        Set> result = Sets.newIdentityHashSet();
        for (Annotation a : annotatedElement.getAnnotations()) {
            Class aType = a.annotationType();
            if (metaAnnotation == null || aType.getAnnotation(metaAnnotation) != null) {
                result.add(aType);
            }
        }
        return result;
    }

    /**
     * Determines whether a given method is {@code getter}.
     *
     * @param method method to be examined.
     * @return {@code true} if the method is {@code getter}, {@code false} otherwise.
     */
    public static boolean isGetter(final Method method) {
        if (method.getParameterTypes().length == 0) {
            final String methodName = method.getName();

            if (methodName.startsWith("get")) {
                return !void.class.equals(method.getReturnType());
            } else if (methodName.startsWith("is")) {
                return boolean.class.equals(method.getReturnType()) || Boolean.class.equals(method.getReturnType());
            }
        }
        return false;
    }

    /**
     * A tuple consisting of a concrete class and a declaring class that declares a
     * generic interface type.
     */
    public static class DeclaringClassInterfacePair {

        /**
         * Concrete class.
         */
        public final Class concreteClass;
        /**
         * Declaring class.
         */
        public final Class declaringClass;
        /**
         * Generic interface type.
         */
        public final Type genericInterface;

        private DeclaringClassInterfacePair(Class concreteClass, Class declaringClass, Type genericInteface) {
            this.concreteClass = concreteClass;
            this.declaringClass = declaringClass;
            this.genericInterface = genericInteface;
        }
    }

    /**
     * Get the parameterized class arguments for a declaring class that
     * declares a generic interface type.
     *
     * @param p the declaring class
     * @return the parameterized class arguments, or null if the generic
     *         interface type is not a parameterized type.
     */
    public static Class[] getParameterizedClassArguments(DeclaringClassInterfacePair p) {
        if (p.genericInterface instanceof ParameterizedType) {
            ParameterizedType pt = (ParameterizedType) p.genericInterface;
            Type[] as = pt.getActualTypeArguments();
            Class[] cas = new Class[as.length];

            for (int i = 0; i < as.length; i++) {
                Type a = as[i];
                if (a instanceof Class) {
                    cas[i] = (Class) a;
                } else if (a instanceof ParameterizedType) {
                    pt = (ParameterizedType) a;
                    cas[i] = (Class) pt.getRawType();
                } else if (a instanceof TypeVariable) {
                    final TypeVariable tv = (TypeVariable) a;
                    ClassTypePair ctp = resolveTypeVariable(p.concreteClass, p.declaringClass, tv);
                    cas[i] = (ctp != null) ? ctp.rawClass() : (Class) (tv.getBounds()[0]);
                } else if (a instanceof GenericArrayType) {
                    final GenericArrayType gat = (GenericArrayType) a;
                    Type t = gat.getGenericComponentType();
                    if (t instanceof Class) {
                        cas[i] = getArrayForComponentType((Class) t);
                    }
                }
            }
            return cas;
        } else {
            return null;
        }
    }

    /**
     * Get the parameterized type arguments for a declaring class that
     * declares a generic interface type.
     *
     * @param p the declaring class
     * @return the parameterized type arguments, or null if the generic
     *         interface type is not a parameterized type.
     */
    public static Type[] getParameterizedTypeArguments(DeclaringClassInterfacePair p) {
        if (p.genericInterface instanceof ParameterizedType) {
            ParameterizedType pt = (ParameterizedType) p.genericInterface;
            Type[] as = pt.getActualTypeArguments();
            Type[] ras = new Type[as.length];

            for (int i = 0; i < as.length; i++) {
                Type a = as[i];
                if (a instanceof Class) {
                    ras[i] = a;
                } else if (a instanceof ParameterizedType) {
                    ras[i] = a;
                } else if (a instanceof TypeVariable) {
                    ClassTypePair ctp = resolveTypeVariable(p.concreteClass, p.declaringClass, (TypeVariable) a);
                    if (ctp == null) {
                        throw new IllegalArgumentException(
                                LocalizationMessages.ERROR_RESOLVING_GENERIC_TYPE_VALUE(p.genericInterface, p.concreteClass));
                    }
                    ras[i] = ctp.type();
                }
            }
            return ras;
        } else {
            return null;
        }
    }

    /**
     * Find the declaring class that implements or extends an interface.
     *
     * @param concrete the concrete class than directly or indirectly
     *                 implements or extends an interface class.
     * @param iface    the interface class.
     * @return the tuple of the declaring class and the generic interface
     *         type.
     */
    public static DeclaringClassInterfacePair getClass(Class concrete, Class iface) {
        return getClass(concrete, iface, concrete);
    }

    private static DeclaringClassInterfacePair getClass(Class concrete, Class iface, Class c) {
        Type[] gis = c.getGenericInterfaces();
        DeclaringClassInterfacePair p = getType(concrete, iface, c, gis);
        if (p != null) {
            return p;
        }

        c = c.getSuperclass();
        if (c == null || c == Object.class) {
            return null;
        }

        return getClass(concrete, iface, c);
    }

    private static DeclaringClassInterfacePair getType(Class concrete, Class iface, Class c, Type[] ts) {
        for (Type t : ts) {
            DeclaringClassInterfacePair p = getType(concrete, iface, c, t);
            if (p != null) {
                return p;
            }
        }
        return null;
    }

    private static DeclaringClassInterfacePair getType(Class concrete, Class iface, Class c, Type t) {
        if (t instanceof Class) {
            if (t == iface) {
                return new DeclaringClassInterfacePair(concrete, c, t);
            } else {
                return getClass(concrete, iface, (Class) t);
            }
        } else if (t instanceof ParameterizedType) {
            ParameterizedType pt = (ParameterizedType) t;
            if (pt.getRawType() == iface) {
                return new DeclaringClassInterfacePair(concrete, c, t);
            } else {
                return getClass(concrete, iface, (Class) pt.getRawType());
            }
        }
        return null;
    }

    /**
     * Resolve generic type parameter(s) of a raw class and it's generic type
     * based on the class that declares the generic type parameter(s) to be resolved
     * and a concrete implementation of the declaring class.
     *
     * @param concreteClass       concrete implementation of the declaring class.
     * @param declaringClass      class declaring the generic type parameter(s) to be
     *                            resolved.
     * @param rawResolvedType     raw class of the generic type to be resolved.
     * @param genericResolvedType generic type information of th type to be resolved.
     * @return a pair of class and the generic type values with the the resolved
     *         generic parameter types.
     */
    public static ClassTypePair resolveGenericType(final Class concreteClass, final Class declaringClass,
                                                   final Class rawResolvedType, final Type genericResolvedType) {
        if (genericResolvedType instanceof TypeVariable) {
            ClassTypePair ct = resolveTypeVariable(
                    concreteClass,
                    declaringClass,
                    (TypeVariable) genericResolvedType);

            if (ct != null) {
                return ct;
            }
        } else if (genericResolvedType instanceof ParameterizedType) {
            final ParameterizedType pt = (ParameterizedType) genericResolvedType;
            final Type[] ptts = pt.getActualTypeArguments();
            boolean modified = false;
            for (int i = 0; i < ptts.length; i++) {
                ClassTypePair ct =
                        resolveGenericType(concreteClass, declaringClass, (Class) pt.getRawType(), ptts[i]);
                if (ct.type() != ptts[i]) {
                    ptts[i] = ct.type();
                    modified = true;
                }
            }
            if (modified) {
                ParameterizedType rpt = new ParameterizedType() {

                    @Override
                    public Type[] getActualTypeArguments() {
                        return ptts.clone();
                    }

                    @Override
                    public Type getRawType() {
                        return pt.getRawType();
                    }

                    @Override
                    public Type getOwnerType() {
                        return pt.getOwnerType();
                    }
                };
                return ClassTypePair.of((Class) pt.getRawType(), rpt);
            }
        } else if (genericResolvedType instanceof GenericArrayType) {
            GenericArrayType gat = (GenericArrayType) genericResolvedType;
            final ClassTypePair ct =
                    resolveGenericType(concreteClass, declaringClass, null, gat.getGenericComponentType());
            if (gat.getGenericComponentType() != ct.type()) {
                try {
                    Class ac = ReflectionHelper.getArrayForComponentType(ct.rawClass());
                    return ClassTypePair.of(ac);
                } catch (Exception e) {
                    LOGGER.log(Level.FINEST, "", e);
                }
            }
        }

        return ClassTypePair.of(rawResolvedType, genericResolvedType);
    }

    /**
     * Given a type variable resolve the Java class of that variable.
     *
     * @param c  the concrete class from which all type variables are resolved.
     * @param dc the declaring class where the type variable was defined.
     * @param tv the type variable.
     * @return the resolved Java class and type, otherwise null if the type variable
     *         could not be resolved.
     */
    public static ClassTypePair resolveTypeVariable(Class c, Class dc, TypeVariable tv) {
        return resolveTypeVariable(c, dc, tv, new HashMap());
    }

    private static ClassTypePair resolveTypeVariable(Class c, Class dc, TypeVariable tv,
                                                     Map map) {
        Type[] gis = c.getGenericInterfaces();
        for (Type gi : gis) {
            if (gi instanceof ParameterizedType) {
                // process pt of interface
                ParameterizedType pt = (ParameterizedType) gi;
                ClassTypePair ctp = resolveTypeVariable(pt, (Class) pt.getRawType(), dc, tv, map);
                if (ctp != null) {
                    return ctp;
                }
            }
        }

        Type gsc = c.getGenericSuperclass();
        if (gsc instanceof ParameterizedType) {
            // process pt of class
            ParameterizedType pt = (ParameterizedType) gsc;
            return resolveTypeVariable(pt, c.getSuperclass(), dc, tv, map);
        } else if (gsc instanceof Class) {
            return resolveTypeVariable(c.getSuperclass(), dc, tv, map);
        }
        return null;
    }

    private static ClassTypePair resolveTypeVariable(ParameterizedType pt, Class c, Class dc, TypeVariable tv,
                                                     Map map) {
        Type[] typeArguments = pt.getActualTypeArguments();

        TypeVariable[] typeParameters = c.getTypeParameters();

        Map submap = new HashMap();
        for (int i = 0; i < typeArguments.length; i++) {
            // Substitute a type variable with the Java class
            if (typeArguments[i] instanceof TypeVariable) {
                Type t = map.get((TypeVariable) typeArguments[i]);
                submap.put(typeParameters[i], t);
            } else {
                submap.put(typeParameters[i], typeArguments[i]);
            }
        }

        if (c == dc) {
            Type t = submap.get(tv);
            if (t instanceof Class) {
                return ClassTypePair.of((Class) t);
            } else if (t instanceof GenericArrayType) {
                GenericArrayType gat = (GenericArrayType) t;
                t = gat.getGenericComponentType();
                if (t instanceof Class) {
                    c = (Class) t;
                    try {
                        return ClassTypePair.of(getArrayForComponentType(c));
                    } catch (Exception e) {
                    }
                    return null;
                } else if (t instanceof ParameterizedType) {
                    Type rt = ((ParameterizedType) t).getRawType();
                    if (rt instanceof Class) {
                        c = (Class) rt;
                    } else {
                        return null;
                    }
                    try {
                        return ClassTypePair.of(getArrayForComponentType(c), gat);
                    } catch (Exception e) {
                        return null;
                    }
                } else {
                    return null;
                }
            } else if (t instanceof ParameterizedType) {
                pt = (ParameterizedType) t;
                if (pt.getRawType() instanceof Class) {
                    return ClassTypePair.of((Class) pt.getRawType(), pt);
                } else {
                    return null;
                }
            } else {
                return null;
            }
        } else {
            return resolveTypeVariable(c, dc, tv, submap);
        }
    }

    /**
     * Find a method on a class given an existing method.
     * 

     * If there exists a public method on the class that has the same name
     * and parameters as the existing method then that public method is
     * returned.
     * 

     * Otherwise, if there exists a public method on the class that has
     * the same name and the same number of parameters as the existing method,
     * and each generic parameter type, in order, of the public method is equal
     * to the generic parameter type, in the same order, of the existing method
     * or is an instance of {@link TypeVariable} then that public method is
     * returned.
     *
     * @param c the class to search for a public method
     * @param m the method to find
     * @return the found public method.
     */
    public static Method findMethodOnClass(Class c, Method m) {
        try {
            return c.getMethod(m.getName(), m.getParameterTypes());
        } catch (NoSuchMethodException ex) {
            for (Method _m : c.getMethods()) {
                if (_m.getName().equals(m.getName())
                        && _m.getParameterTypes().length == m.getParameterTypes().length) {
                    if (compareParameterTypes(m.getGenericParameterTypes(),
                            _m.getGenericParameterTypes())) {
                        return _m;
                    }
                }
            }
        }
        return null;
    }

    /**
     * Find a {@link Method method} that overrides the given {@code method} on the given {@link Class class}.
     *
     * @param clazz  class to find overriding method on.
     * @param method an abstract method to find implementing method for.
     * @return method that overrides the given method or the given method itself if a better alternative cannot be found.
     */
    public static Method findOverridingMethodOnClass(final Class clazz, final Method method) {
        for (final Method _method : clazz.getMethods()) {
            if (!_method.isBridge()
                    && !Modifier.isAbstract(_method.getModifiers())
                    && _method.getName().equals(method.getName())
                    && _method.getParameterTypes().length == method.getParameterTypes().length) {

                if (compareParameterTypes(_method.getGenericParameterTypes(), method.getGenericParameterTypes())) {
                    return _method;
                }
            }
        }

        if (method.isBridge() || Modifier.isAbstract(method.getModifiers())) {
            LOGGER.log(Level.INFO, LocalizationMessages.OVERRIDING_METHOD_CANNOT_BE_FOUND(method, clazz));
        }

        return method;
    }

    /**
     * Compare generic parameter types of two methods.
     *
     * @param ts  generic parameter types of the first method.
     * @param _ts generic parameter types of the second method.
     * @return {@code true} if the given types are understood to be equal, {@code false} otherwise.
     * @see #compareParameterTypes(java.lang.reflect.Type, java.lang.reflect.Type)
     */
    private static boolean compareParameterTypes(Type[] ts, Type[] _ts) {
        for (int i = 0; i < ts.length; i++) {
            if (!ts[i].equals(_ts[i])) {
                if (!compareParameterTypes(ts[i], _ts[i])) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Compare respective generic parameter types of two methods.
     *
     * @param ts  generic parameter type of the first method.
     * @param _ts generic parameter type of the second method.
     * @return {@code true} if the given types are understood to be equal, {@code false} otherwise.
     */
    private static boolean compareParameterTypes(final Type ts, final Type _ts) {
        if (ts instanceof Class) {
            final Class clazz = (Class) ts;

            if (_ts instanceof Class) {
                return ((Class) _ts).isAssignableFrom(clazz);
            } else if (_ts instanceof TypeVariable) {
                return checkTypeBounds(clazz, ((TypeVariable) _ts).getBounds());
            }
        }
        return _ts instanceof TypeVariable;
    }

    private static boolean checkTypeBounds(final Class type, final Type[] bounds) {
        for (final Type bound : bounds) {
            if (bound instanceof Class) {
                if (!((Class) bound).isAssignableFrom(type)) {
                    return false;
                }
            }
        }
        return true;
    }

    private final static Class bundleReferenceClass = lookupBundleReferenceClass();

    private static Class lookupBundleReferenceClass() {
        try {
            return Class.forName("org.osgi.framework.BundleReference");
        } catch (ClassNotFoundException ex) {
            return null;
        }
    }

    /**
     * Returns an {@link OsgiRegistry} instance.
     *
     * @return an {@link OsgiRegistry} instance or {@code null} if the class cannot be instantiated (not in OSGi environment).
     */
    public static OsgiRegistry getOsgiRegistryInstance() {
        try {
            if (bundleReferenceClass != null) {
                return OsgiRegistry.getInstance();
            }
        } catch (Exception e) {
            // Do nothing - instance is null.
        }

        return null;
    }

    /**
     * Lookup resource by given name. If OSGi runtime is detected and the originClass parameter is not null,
     * an attempt will be made to get the resource input stream via OSGi API from the bundle where originClass is included.
     * Otherwise (non OSGi environment) or if OSGi fails to provide the input stream, the return value
     * will be taken from the provided loader getResourceAsStream method.
     *
     * @param loader      class loader where to lookup the resource in non-OSGi environment or if OSGi means fail.
     * @param originClass if not null, and OSGi environment is detected, the resource will be taken from the bundle including the originClass type.
     * @param name        filename of the desired resource.
     * @return an input stream corresponding to the required resource or null if the resource could not be found.
     */
    public static InputStream getResourceAsStream(final ClassLoader loader, final Class originClass, final String name) {
        try {
            if (bundleReferenceClass != null && originClass != null && bundleReferenceClass.isInstance(ReflectionHelper.class.getClassLoader())) {
                final Bundle bundle = FrameworkUtil.getBundle(originClass);
                final URL resourceUrl = (bundle != null) ? bundle.getEntry(name) : null;
                if (resourceUrl != null) {
                    return resourceUrl.openStream();
                }
            }
        } catch (IOException ex) {
            // ignore
        }
        return loader.getResourceAsStream(name);
    }

    /**
     * Prevents instantiation.
     */
    private ReflectionHelper() {
    }
}
    

    

    
            
    
            







    
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