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/* * Copyright (c) 2001, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.reflect; import java.lang.reflect.*;import java.util.Collections;import java.util.HashMap;import java.util.Map; /** Common utility routines used by both java.lang and    java.lang.reflect */ public class Reflection {     /** Used to filter out fields and methods from certain classes from public        view, where they are sensitive or they may contain VM-internal objects.        These Maps are updated very rarely. Rather than synchronize on        each access, we use copy-on-write */    private static volatile Map<Class,String[]> fieldFilterMap;    private static volatile Map<Class,String[]> methodFilterMap;     static {        Map<Class,String[]> map = new HashMap<Class,String[]>();        map.put(Reflection.class,            new String[] {"fieldFilterMap", "methodFilterMap"});        map.put(System.class, new String[] {"security"});        fieldFilterMap = map;         methodFilterMap = new HashMap<Class,String[]>();    }     /** Returns the class of the method <code>realFramesToSkip</code>        frames up the stack (zero-based), ignoring frames associated        with java.lang.reflect.Method.invoke() and its implementation.        The first frame is that associated with this method, so        <code>getCallerClass(0)</code> returns the Class object for        sun.reflect.Reflection. Frames associated with        java.lang.reflect.Method.invoke() and its implementation are        completely ignored and do not count toward the number of "real"        frames skipped. */    public static native Class getCallerClass(int realFramesToSkip);     /** Retrieves the access flags written to the class file. For        inner classes these flags may differ from those returned by        Class.getModifiers(), which searches the InnerClasses        attribute to find the source-level access flags. This is used        instead of Class.getModifiers() for run-time access checks due        to compatibility reasons; see 4471811. Only the values of the        low 13 bits (i.e., a mask of 0x1FFF) are guaranteed to be        valid. */    private static native int getClassAccessFlags(Class c);     /** A quick "fast-path" check to try to avoid getCallerClass()        calls. */    public static boolean quickCheckMemberAccess(Class memberClass,                                                 int modifiers)    {        return Modifier.isPublic(getClassAccessFlags(memberClass) & modifiers);    }     public static void ensureMemberAccess(Class currentClass,                                          Class memberClass,                                          Object target,                                          int modifiers)        throws IllegalAccessException    {        if (currentClass == null || memberClass == null) {            throw new InternalError();        }         if (!verifyMemberAccess(currentClass, memberClass, target, modifiers)) {            throw new IllegalAccessException("Class " + currentClass.getName() +                                             " can not access a member of class " +                                             memberClass.getName() +                                             " with modifiers \"" +                                             Modifier.toString(modifiers) +                                             "\"");        }    }     public static boolean verifyMemberAccess(Class currentClass,                                             // Declaring class of field                                             // or method                                             Class  memberClass,                                             // May be NULL in case of statics                                             Object target,                                             int    modifiers)    {        // Verify that currentClass can access a field, method, or        // constructor of memberClass, where that member's access bits are        // "modifiers".         boolean gotIsSameClassPackage = false;        boolean isSameClassPackage = false;         if (currentClass == memberClass) {            // Always succeeds            return true;        }         if (!Modifier.isPublic(getClassAccessFlags(memberClass))) {            isSameClassPackage = isSameClassPackage(currentClass, memberClass);            gotIsSameClassPackage = true;            if (!isSameClassPackage) {                return false;            }        }         // At this point we know that currentClass can access memberClass.         if (Modifier.isPublic(modifiers)) {            return true;        }         boolean successSoFar = false;         if (Modifier.isProtected(modifiers)) {            // See if currentClass is a subclass of memberClass            if (isSubclassOf(currentClass, memberClass)) {                successSoFar = true;            }        }         if (!successSoFar && !Modifier.isPrivate(modifiers)) {            if (!gotIsSameClassPackage) {                isSameClassPackage = isSameClassPackage(currentClass,                                                        memberClass);                gotIsSameClassPackage = true;            }             if (isSameClassPackage) {                successSoFar = true;            }        }         if (!successSoFar) {            return false;        }         if (Modifier.isProtected(modifiers)) {            // Additional test for protected members: JLS 6.6.2            Class targetClass = (target == null ? memberClass : target.getClass());            if (targetClass != currentClass) {                if (!gotIsSameClassPackage) {                    isSameClassPackage = isSameClassPackage(currentClass, memberClass);                    gotIsSameClassPackage = true;                }                if (!isSameClassPackage) {                    if (!isSubclassOf(targetClass, currentClass)) {                        return false;                    }                }            }        }         return true;    }     private static boolean isSameClassPackage(Class c1, Class c2) {        return isSameClassPackage(c1.getClassLoader(), c1.getName(),                                  c2.getClassLoader(), c2.getName());    }     /** Returns true if two classes are in the same package; classloader        and classname information is enough to determine a class's package */    private static boolean isSameClassPackage(ClassLoader loader1, String name1,                                              ClassLoader loader2, String name2)    {        if (loader1 != loader2) {            return false;        } else {            int lastDot1 = name1.lastIndexOf('.');            int lastDot2 = name2.lastIndexOf('.');            if ((lastDot1 == -1) || (lastDot2 == -1)) {                // One of the two doesn't have a package.  Only return true                // if the other one also doesn't have a package.                return (lastDot1 == lastDot2);            } else {                int idx1 = 0;                int idx2 = 0;                 // Skip over '['s                if (name1.charAt(idx1) == '[') {                    do {                        idx1++;                    } while (name1.charAt(idx1) == '[');                    if (name1.charAt(idx1) != 'L') {                        // Something is terribly wrong.  Shouldn't be here.                        throw new InternalError("Illegal class name " + name1);                    }                }                if (name2.charAt(idx2) == '[') {                    do {                        idx2++;                    } while (name2.charAt(idx2) == '[');                    if (name2.charAt(idx2) != 'L') {                        // Something is terribly wrong.  Shouldn't be here.                        throw new InternalError("Illegal class name " + name2);                    }                }                 // Check that package part is identical                int length1 = lastDot1 - idx1;                int length2 = lastDot2 - idx2;                 if (length1 != length2) {                    return false;                }                return name1.regionMatches(false, idx1, name2, idx2, length1);            }        }    }     static boolean isSubclassOf(Class queryClass,                                Class ofClass)    {        while (queryClass != null) {            if (queryClass == ofClass) {                return true;            }            queryClass = queryClass.getSuperclass();        }        return false;    }     // fieldNames must contain only interned Strings    public static synchronized void registerFieldsToFilter(Class containingClass,                                              String ... fieldNames) {        fieldFilterMap =            registerFilter(fieldFilterMap, containingClass, fieldNames);    }     // methodNames must contain only interned Strings    public static synchronized void registerMethodsToFilter(Class containingClass,                                              String ... methodNames) {        methodFilterMap =            registerFilter(methodFilterMap, containingClass, methodNames);    }     private static Map<Class,String[]> registerFilter(Map<Class,String[]> map,            Class containingClass, String ... names) {        if (map.get(containingClass) != null) {            throw new IllegalArgumentException                            ("Filter already registered: " + containingClass);        }        map = new HashMap<Class,String[]>(map);        map.put(containingClass, names);        return map;    }     public static Field[] filterFields(Class containingClass,                                       Field[] fields) {        if (fieldFilterMap == null) {            // Bootstrapping            return fields;        }        return (Field[])filter(fields, fieldFilterMap.get(containingClass));    }     public static Method[] filterMethods(Class containingClass, Method[] methods) {        if (methodFilterMap == null) {            // Bootstrapping            return methods;        }        return (Method[])filter(methods, methodFilterMap.get(containingClass));    }     private static Member[] filter(Member[] members, String[] filteredNames) {        if ((filteredNames == null) || (members.length == 0)) {            return members;        }        int numNewMembers = 0;        for (Member member : members) {            boolean shouldSkip = false;            for (String filteredName : filteredNames) {                if (member.getName() == filteredName) {                    shouldSkip = true;                    break;                }            }            if (!shouldSkip) {                ++numNewMembers;            }        }        Member[] newMembers =            (Member[])Array.newInstance(members[0].getClass(), numNewMembers);        int destIdx = 0;        for (Member member : members) {            boolean shouldSkip = false;            for (String filteredName : filteredNames) {                if (member.getName() == filteredName) {                    shouldSkip = true;                    break;                }            }            if (!shouldSkip) {                newMembers[destIdx++] = member;            }        }        return newMembers;    }}