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 * 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
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
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package com.sun.el.util;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import javax.el.ELContext;
import javax.el.ELException;
import javax.el.MethodNotFoundException;
import javax.el.PropertyNotFoundException;

import com.sun.el.lang.ELSupport;

/**
 * Utilities for Managing Serialization and Reflection
 * 
 * @author Jacob Hookom [[email protected]]
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: kchung $
 */
public class ReflectionUtil {

    protected static final String[] EMPTY_STRING = new String[0];

    protected static final String[] PRIMITIVE_NAMES = new String[] { "boolean",
            "byte", "char", "double", "float", "int", "long", "short", "void" };

    protected static final Class[] PRIMITIVES = new Class[] { boolean.class,
            byte.class, char.class, double.class, float.class, int.class,
            long.class, short.class, Void.TYPE };

    /**
     * 
     */
    private ReflectionUtil() {
        super();
    }

    public static Class forName(String name) throws ClassNotFoundException {
        if (null == name || "".equals(name)) {
            return null;
        }
        Class c = forNamePrimitive(name);
        if (c == null) {
            if (name.endsWith("[]")) {
                String nc = name.substring(0, name.length() - 2);
                c = Class.forName(nc, true, Thread.currentThread().getContextClassLoader());
                c = Array.newInstance(c, 0).getClass();
            } else {
                c = Class.forName(name, true, Thread.currentThread().getContextClassLoader());
            }
        }
        return c;
    }

    protected static Class forNamePrimitive(String name) {
        if (name.length() <= 8) {
            int p = Arrays.binarySearch(PRIMITIVE_NAMES, name);
            if (p >= 0) {
                return PRIMITIVES[p];
            }
        }
        return null;
    }

    /**
     * Converts an array of Class names to Class types
     * @param s
     * @return The array of Classes
     * @throws ClassNotFoundException
     */
    public static Class[] toTypeArray(String[] s) throws ClassNotFoundException {
        if (s == null)
            return null;
        Class[] c = new Class[s.length];
        for (int i = 0; i < s.length; i++) {
            c[i] = forName(s[i]);
        }
        return c;
    }

    /**
     * Converts an array of Class types to Class names
     * @param c
     * @return The array of Classes
     */
    public static String[] toTypeNameArray(Class[] c) {
        if (c == null)
            return null;
        String[] s = new String[c.length];
        for (int i = 0; i < c.length; i++) {
            s[i] = c[i].getName();
        }
        return s;
    }

    /**
     * @param base The base object
     * @param property The property
     * @return The PropertyDescriptor for the base with the given property
     * @throws ELException
     * @throws PropertyNotFoundException
     */
    public static PropertyDescriptor getPropertyDescriptor(Object base,
            Object property) throws ELException, PropertyNotFoundException {
        String name = ELSupport.coerceToString(property);
        PropertyDescriptor p = null;
        try {
            PropertyDescriptor[] desc = Introspector.getBeanInfo(
                    base.getClass()).getPropertyDescriptors();
            for (int i = 0; i < desc.length; i++) {
                if (desc[i].getName().equals(name)) {
                    return desc[i];
                }
            }
        } catch (IntrospectionException ie) {
            throw new ELException(ie);
        }
        throw new PropertyNotFoundException(MessageFactory.get(
                "error.property.notfound", base, name));
    }

    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    public static Object invokeMethod(ELContext context,
                               Method m, Object base, Object[] params) {

        Object[] parameters = buildParameters(
                context, m.getParameterTypes(), m.isVarArgs(), params);
        try {
            return m.invoke(base, parameters);
        } catch (IllegalAccessException iae) {
            throw new ELException(iae);
        } catch (IllegalArgumentException iae) {
            throw new ELException(iae);
        } catch (InvocationTargetException ite) {
            throw new ELException(ite.getCause());
        }
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    public static Method findMethod(Class clazz, String methodName,
            Class[] paramTypes, Object[] paramValues) {

        if (clazz == null || methodName == null) {
            throw new MethodNotFoundException(MessageFactory.get(
                    "error.method.notfound", clazz, methodName, paramString(paramTypes)));
        }

        if (paramTypes == null) {
            paramTypes = getTypesFromValues(paramValues);
        }

        Method[] methods = clazz.getMethods();

        List wrappers = Wrapper.wrap(methods, methodName);

        Wrapper result = findWrapper(
                clazz, wrappers, methodName, paramTypes, paramValues);

        if (result == null) {
            return null;
        }
        return getMethod(clazz, (Method) result.unWrap());
    }

    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static Wrapper findWrapper(Class clazz, List wrappers,
            String name, Class[] paramTypes, Object[] paramValues) {

        List assignableCandidates = new ArrayList();
        List coercibleCandidates = new ArrayList();
        List varArgsCandidates = new ArrayList();

        int paramCount;
        if (paramTypes == null) {
            paramCount = 0;
        } else {
            paramCount = paramTypes.length;
        }

        for (Wrapper w : wrappers) {
            Class[] mParamTypes = w.getParameterTypes();
            int mParamCount;
            if (mParamTypes == null) {
                mParamCount = 0;
            } else {
                mParamCount = mParamTypes.length;
            }

            // Check the number of parameters
            if (!(paramCount == mParamCount ||
                    (w.isVarArgs() && paramCount >= mParamCount - 1))) {
                // Method has wrong number of parameters
                continue;
            }

            // Check the parameters match
            boolean assignable = false;
            boolean coercible = false;
            boolean varArgs = false;
            boolean noMatch = false;
            for (int i = 0; i < mParamCount; i++) {
                if (i == (mParamCount - 1) && w.isVarArgs()) {
                    varArgs = true;
                    // exact var array type match
                    if (mParamCount == paramCount) {
                        if (mParamTypes[i] == paramTypes[i]) {
                            continue;
                        }
                    }
                    
                    // unwrap the array's component type
                    Class varType = mParamTypes[i].getComponentType();
                    for (int j = i; j < paramCount; j++) {
                        if (!isAssignableFrom(paramTypes[j], varType) 
                                && !(paramValues != null && j < paramValues.length && isCoercibleFrom(paramValues[j], varType))) {
                            noMatch = true;
                            break;
                        }
                    }
                } else if (mParamTypes[i].equals(paramTypes[i])) {
                } else if (isAssignableFrom(paramTypes[i], mParamTypes[i])) {
                    assignable = true;
                } else {
                    if (paramValues == null  || i >= paramValues.length) {
                        noMatch = true;
                        break;
                    } else {
                        if (isCoercibleFrom(paramValues[i], mParamTypes[i])) {
                            coercible = true;
                        } else {
                            noMatch = true;
                            break;
                        }
                    }
                }
            }
            if (noMatch) {
                continue;
            }
            
            if (varArgs) {
                varArgsCandidates.add(w);
            } else if (coercible) {
                coercibleCandidates.add(w);
            } else if (assignable) {
                assignableCandidates.add(w);
            } else {
                // If a method is found where every parameter matches exactly,
                // return it
                return w;
            }
            
        }
        
        String errorMsg = MessageFactory.get(
                "error.method.ambiguous", clazz, name, paramString(paramTypes));
        if (!assignableCandidates.isEmpty()) {
            return findMostSpecificWrapper(assignableCandidates, paramTypes, false, errorMsg);
        } else if (!coercibleCandidates.isEmpty()) {
            return findMostSpecificWrapper(coercibleCandidates, paramTypes, true, errorMsg);
        } else if (!varArgsCandidates.isEmpty()) {
            return findMostSpecificWrapper(varArgsCandidates, paramTypes, true, errorMsg);
        } else {
            throw new MethodNotFoundException(MessageFactory.get(
                    "error.method.notfound", clazz, name, paramString(paramTypes)));
        }

    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static Wrapper findMostSpecificWrapper(List candidates, 
            Class[] matchingTypes, boolean elSpecific, String errorMsg) {
        List ambiguouses = new ArrayList();
        for (Wrapper candidate : candidates) {
            boolean lessSpecific = false;
            
            Iterator it = ambiguouses.iterator();
            while(it.hasNext()) {
                int result = isMoreSpecific(candidate, it.next(), matchingTypes, elSpecific);
                if (result == 1) {
                    it.remove();
                } else if (result == -1) {
                    lessSpecific = true;
                }
            }
            
            if (!lessSpecific) {
                ambiguouses.add(candidate);
            }
        }
        
        if (ambiguouses.size() > 1) {
            throw new MethodNotFoundException(errorMsg);
        }
        
        return ambiguouses.get(0);
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static int isMoreSpecific(Wrapper wrapper1, Wrapper wrapper2, 
            Class[] matchingTypes, boolean elSpecific) {
        Class[] paramTypes1 = wrapper1.getParameterTypes();
        Class[] paramTypes2 = wrapper2.getParameterTypes();
        
        if (wrapper1.isVarArgs()) {
            //JLS8 15.12.2.5 Choosing the Most Specific Method
            int length =  Math.max(Math.max(paramTypes1.length, paramTypes2.length), matchingTypes.length);
            paramTypes1 = getComparingParamTypesForVarArgsMethod(paramTypes1, length);
            paramTypes2 = getComparingParamTypesForVarArgsMethod(paramTypes2, length);
            
            if (length > matchingTypes.length) {
                Class[] matchingTypes2 = new Class[length];
                System.arraycopy(matchingTypes, 0, matchingTypes2, 0, matchingTypes.length);
                matchingTypes = matchingTypes2;
            }
        }
        
        int result = 0;
        for (int i = 0; i < paramTypes1.length; i++) {
            if (paramTypes1[i] != paramTypes2[i]) {
                int r2 = isMoreSpecific(paramTypes1[i], paramTypes2[i], matchingTypes[i], elSpecific);
                if (r2 == 1) {
                    if (result == -1) {
                        return 0;
                    }
                    result = 1;
                } else if (r2 == -1) {
                    if (result == 1) {
                        return 0;
                    }
                    result = -1;
                } else {
                    return 0;
                }
            }
        }
        
        if (result == 0) {
            // The nature of bridge methods is such that it actually
            // doesn't matter which one we pick as long as we pick
            // one. That said, pick the 'right' one (the non-bridge
            // one) anyway.
            result = Boolean.compare(wrapper1.isBridge(), wrapper2.isBridge());
        }
        
        return result;
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static int isMoreSpecific(Class type1, Class type2, Class matchingType, boolean elSpecific) {
        type1 = getBoxingTypeIfPrimitive(type1);
        type2 = getBoxingTypeIfPrimitive(type2);
        if (type2.isAssignableFrom(type1)) {
            return 1;
        } else if (type1.isAssignableFrom(type2)) {
            return -1;
        } else {
            if (elSpecific) {
                /* 
                 * Number will be treated as more specific
                 * 
                 * ASTInteger only return Long or BigInteger, no Byte / Short / Integer.
                 * ASTFloatingPoint also.
                 * 
                 */
                if (matchingType != null && Number.class.isAssignableFrom(matchingType)) {
                    boolean b1 = Number.class.isAssignableFrom(type1) || type1.isPrimitive();
                    boolean b2 = Number.class.isAssignableFrom(type2) || type2.isPrimitive();
                    if (b1 && !b2) {
                        return 1;
                    } else if (b2 && !b1) {
                        return -1;
                    } else {
                        return 0;
                    }
                }
                
                return 0;
            } else {
                return 0;
            }
        }
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static Class getBoxingTypeIfPrimitive(Class clazz) {
        if (clazz.isPrimitive()) {
            if (clazz == Boolean.TYPE) {
                return Boolean.class;
            } else if (clazz == Character.TYPE) {
                return Character.class;
            } else if (clazz == Byte.TYPE) {
                return Byte.class;
            } else if (clazz == Short.TYPE) {
                return Short.class;
            } else if (clazz == Integer.TYPE) {
                return Integer.class;
            } else if (clazz == Long.TYPE) {
                return Long.class;
            } else if (clazz == Float.TYPE) {
                return Float.class;
            } else {
                return Double.class;
            }
        } else {
            return clazz;
        }
        
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static Class[] getComparingParamTypesForVarArgsMethod(Class[] paramTypes, int length) {
        Class[] result = new Class[length];
        System.arraycopy(paramTypes, 0, result, 0, paramTypes.length - 1);
        Class type = paramTypes[paramTypes.length - 1].getComponentType();
        for (int i = paramTypes.length - 1; i < length; i++) {
            result[i] = type;
        }
        
        return result;
    }

    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static final String paramString(Class[] types) {
        if (types != null) {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < types.length; i++) {
                if (types[i] == null) {
                    sb.append("null, ");
                } else {
                    sb.append(types[i].getName()).append(", ");
                }
            }
            if (sb.length() > 2) {
                sb.setLength(sb.length() - 2);
            }
            return sb.toString();
        }
        return null;
    }

    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    static boolean isAssignableFrom(Class src, Class target) {
        // src will always be an object
        // Short-cut. null is always assignable to an object and in EL null
        // can always be coerced to a valid value for a primitive
        if (src == null) {
            return true;
        }
        
        target = getBoxingTypeIfPrimitive(target);

        return target.isAssignableFrom(src);
    }


    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static boolean isCoercibleFrom(Object src, Class target) {
        // TODO: This isn't pretty but it works. Significant refactoring would
        //       be required to avoid the exception.
        try {
            ELSupport.coerceToType(src, target);
        } catch (Exception e) {
            return false;
        }
        return true;
    }

    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static Class[] getTypesFromValues(Object[] values) {
        if (values == null) {
            return null;
        }

        Class result[] = new Class[values.length];
        for (int i = 0; i < values.length; i++) {
            if (values[i] == null) {
                result[i] = null;
            } else {
                result[i] = values[i].getClass();
            }
        }
        return result;
    }


    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     * 
     * Get a public method form a public class or interface of a given method.
     * Note that if a PropertyDescriptor is obtained for a non-public class that
     * implements a public interface, the read/write methods will be for the
     * class, and therefore inaccessible.  To correct this, a version of the
     * same method must be found in a superclass or interface.
     * 
     */
    static Method getMethod(Class type, Method m) {
        if (m == null || Modifier.isPublic(type.getModifiers())) {
            return m;
        }
        Class[] inf = type.getInterfaces();
        Method mp = null;
        for (int i = 0; i < inf.length; i++) {
            try {
                mp = inf[i].getMethod(m.getName(), m.getParameterTypes());
                mp = getMethod(mp.getDeclaringClass(), mp);
                if (mp != null) {
                    return mp;
                }
            } catch (NoSuchMethodException e) {
                // Ignore
            }
        }
        Class sup = type.getSuperclass();
        if (sup != null) {
            try {
                mp = sup.getMethod(m.getName(), m.getParameterTypes());
                mp = getMethod(mp.getDeclaringClass(), mp);
                if (mp != null) {
                    return mp;
                }
            } catch (NoSuchMethodException e) {
                // Ignore
            }
        }
        return null;
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    static Constructor getConstructor(Class type, Constructor c) {
        if (c == null || Modifier.isPublic(type.getModifiers())) {
            return c;
        }
        Constructor cp = null;
        Class sup = type.getSuperclass();
        if (sup != null) {
            try {
                cp = sup.getConstructor(c.getParameterTypes());
                cp = getConstructor(cp.getDeclaringClass(), cp);
                if (cp != null) {
                    return cp;
                }
            } catch (NoSuchMethodException e) {
                // Ignore
            }
        }
        return null;
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    static Object[] buildParameters(ELContext context, Class[] parameterTypes,
            boolean isVarArgs,Object[] params) {
        Object[] parameters = null;
        if (parameterTypes.length > 0) {
            parameters = new Object[parameterTypes.length];
            int paramCount = params == null ? 0 : params.length;
            if (isVarArgs) {
                int varArgIndex = parameterTypes.length - 1;
                // First argCount-1 parameters are standard
                for (int i = 0; (i < varArgIndex && i < paramCount); i++) {
                    parameters[i] = context.convertToType(params[i],
                            parameterTypes[i]);
                }
                // Last parameter is the varargs
                if (parameterTypes.length == paramCount 
                        && parameterTypes[varArgIndex] == params[varArgIndex].getClass()) {
                    parameters[varArgIndex] = params[varArgIndex];
                } else {
                    Class varArgClass =
                            parameterTypes[varArgIndex].getComponentType();
                    final Object varargs = Array.newInstance(
                            varArgClass,
                            (paramCount - varArgIndex));
                    for (int i = (varArgIndex); i < paramCount; i++) {
                        Array.set(varargs, i - varArgIndex,
                                context.convertToType(params[i], varArgClass));
                    }
                    parameters[varArgIndex] = varargs;
                }
            } else {
                for (int i = 0; i < parameterTypes.length && i < paramCount; i++) {
                    parameters[i] = context.convertToType(params[i],
                            parameterTypes[i]);
                }
            }
        }
        return parameters;
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private abstract static class Wrapper {
        
        public static List wrap(Method[] methods, String name) {
            List result = new ArrayList<>();
            for (Method method : methods) {
                if (method.getName().equals(name)) {
                    result.add(new MethodWrapper(method));
                }
            }
            return result;
        }
        
        public static List wrap(Constructor[] constructors) {
            List result = new ArrayList<>();
            for (Constructor constructor : constructors) {
                result.add(new ConstructorWrapper(constructor));
            }
            return result;
        }
        
        public abstract Object unWrap();
        public abstract Class[] getParameterTypes();
        public abstract boolean isVarArgs();
        public abstract boolean isBridge();
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static class MethodWrapper extends Wrapper {
        private final Method m;
        
        public MethodWrapper(Method m) {
            this.m = m;
        }
        
        @Override
        public Object unWrap() {
            return m;
        }
        
        @Override
        public Class[] getParameterTypes() {
            return m.getParameterTypes();
        }
        
        @Override
        public boolean isVarArgs() {
            return m.isVarArgs();
        }
        
        @Override
        public boolean isBridge() {
            return m.isBridge();
        }
    }
    
    /*
     * This method duplicates code in javax.el.ELUtil. When
     * making changes keep the code in sync.
     */
    private static class ConstructorWrapper extends Wrapper {
        private final Constructor c;
        
        public ConstructorWrapper(Constructor c) {
            this.c = c;
        }
        
        @Override
        public Object unWrap() {
            return c;
        }
        
        @Override
        public Class[] getParameterTypes() {
            return c.getParameterTypes();
        }
        
        @Override
        public boolean isVarArgs() {
            return c.isVarArgs();
        }
        
        @Override
        public boolean isBridge() {
            return false;
        }
    }

}




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