/*

 * 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.annotation;

import java.lang.annotation.*;

import java.lang.reflect.*;

import java.io.Serializable;

import java.util.*;

import java.lang.annotation.*;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * InvocationHandler for dynamic proxy implementation of Annotation.

 *

 * @author  Josh Bloch

 * @since   1.5

 */

class AnnotationInvocationHandler implements InvocationHandler, Serializable {

    private static final long serialVersionUID = 6182022883658399397L;

    private final Class<? extends Annotation> type;

    private final Map<String, Object> memberValues;

    AnnotationInvocationHandler(Class<? extends Annotation> type, Map<String, Object> memberValues) {

        this.type = type;

        this.memberValues = memberValues;

    }

    public Object invoke(Object proxy, Method method, Object[] args) {

        String member = method.getName();

        Class<?>[] paramTypes = method.getParameterTypes();

        // Handle Object and Annotation methods

        if (member.equals("equals") && paramTypes.length == 1 &&

            paramTypes[0] == Object.class)

            return equalsImpl(args[0]);

        assert paramTypes.length == 0;

        if (member.equals("toString"))

            return toStringImpl();

        if (member.equals("hashCode"))

            return hashCodeImpl();

        if (member.equals("annotationType"))

            return type;

        // Handle annotation member accessors

        Object result = memberValues.get(member);

        if (result == null)

            throw new IncompleteAnnotationException(type, member);

        if (result instanceof ExceptionProxy)

            throw ((ExceptionProxy) result).generateException();

        if (result.getClass().isArray() && Array.getLength(result) != 0)

            result = cloneArray(result);

        return result;

    }

    /**

     * This method, which clones its array argument, would not be necessary

     * if Cloneable had a public clone method.

     */

    private Object cloneArray(Object array) {

        Class<?> type = array.getClass();

        if (type == byte[].class) {

            byte[] byteArray = (byte[])array;

            return byteArray.clone();

        }

        if (type == char[].class) {

            char[] charArray = (char[])array;

            return charArray.clone();

        }

        if (type == double[].class) {

            double[] doubleArray = (double[])array;

            return doubleArray.clone();

        }

        if (type == float[].class) {

            float[] floatArray = (float[])array;

            return floatArray.clone();

        }

        if (type == int[].class) {

            int[] intArray = (int[])array;

            return intArray.clone();

        }

        if (type == long[].class) {

            long[] longArray = (long[])array;

            return longArray.clone();

        }

        if (type == short[].class) {

            short[] shortArray = (short[])array;

            return shortArray.clone();

        }

        if (type == boolean[].class) {

            boolean[] booleanArray = (boolean[])array;

            return booleanArray.clone();

        }

        Object[] objectArray = (Object[])array;

        return objectArray.clone();

    }

    /**

     * Implementation of dynamicProxy.toString()

     */

    private String toStringImpl() {

        StringBuffer result = new StringBuffer(128);

        result.append('@');

        result.append(type.getName());

        result.append('(');

        boolean firstMember = true;

        for (Map.Entry<String, Object> e : memberValues.entrySet()) {

            if (firstMember)

                firstMember = false;

            else

                result.append(", ");

            result.append(e.getKey());

            result.append('=');

            result.append(memberValueToString(e.getValue()));

        }

        result.append(')');

        return result.toString();

    }

    /**

     * Translates a member value (in "dynamic proxy return form") into a string

     */

    private static String memberValueToString(Object value) {

        Class<?> type = value.getClass();

        if (!type.isArray())    // primitive, string, class, enum const,

                                // or annotation

            return value.toString();

        if (type == byte[].class)

            return Arrays.toString((byte[]) value);

        if (type == char[].class)

            return Arrays.toString((char[]) value);

        if (type == double[].class)

            return Arrays.toString((double[]) value);

        if (type == float[].class)

            return Arrays.toString((float[]) value);

        if (type == int[].class)

            return Arrays.toString((int[]) value);

        if (type == long[].class)

            return Arrays.toString((long[]) value);

        if (type == short[].class)

            return Arrays.toString((short[]) value);

        if (type == boolean[].class)

            return Arrays.toString((boolean[]) value);

        return Arrays.toString((Object[]) value);

    }

    /**

     * Implementation of dynamicProxy.equals(Object o)

     */

    private Boolean equalsImpl(Object o) {

        if (o == this)

            return true;

        if (!type.isInstance(o))

            return false;

        for (Method memberMethod : getMemberMethods()) {

            String member = memberMethod.getName();

            Object ourValue = memberValues.get(member);

            Object hisValue = null;

            AnnotationInvocationHandler hisHandler = asOneOfUs(o);

            if (hisHandler != null) {

                hisValue = hisHandler.memberValues.get(member);

            } else {

                try {

                    hisValue = memberMethod.invoke(o);

                } catch (InvocationTargetException e) {

                    return false;

                } catch (IllegalAccessException e) {

                    throw new AssertionError(e);

                }

            }

            if (!memberValueEquals(ourValue, hisValue))

                return false;

        }

        return true;

    }

    /**

     * Returns an object's invocation handler if that object is a dynamic

     * proxy with a handler of type AnnotationInvocationHandler.

     * Returns null otherwise.

     */

    private AnnotationInvocationHandler asOneOfUs(Object o) {

        if (Proxy.isProxyClass(o.getClass())) {

            InvocationHandler handler = Proxy.getInvocationHandler(o);

            if (handler instanceof AnnotationInvocationHandler)

                return (AnnotationInvocationHandler) handler;

        }

        return null;

    }

    /**

     * Returns true iff the two member values in "dynamic proxy return form"

     * are equal using the appropriate equality function depending on the

     * member type.  The two values will be of the same type unless one of

     * the containing annotations is ill-formed.  If one of the containing

     * annotations is ill-formed, this method will return false unless the

     * two members are identical object references.

     */

    private static boolean memberValueEquals(Object v1, Object v2) {

        Class<?> type = v1.getClass();

        // Check for primitive, string, class, enum const, annotation,

        // or ExceptionProxy

        if (!type.isArray())

            return v1.equals(v2);

        // Check for array of string, class, enum const, annotation,

        // or ExceptionProxy

        if (v1 instanceof Object[] && v2 instanceof Object[])

            return Arrays.equals((Object[]) v1, (Object[]) v2);

        // Check for ill formed annotation(s)

        if (v2.getClass() != type)

            return false;

        // Deal with array of primitives

        if (type == byte[].class)

            return Arrays.equals((byte[]) v1, (byte[]) v2);

        if (type == char[].class)

            return Arrays.equals((char[]) v1, (char[]) v2);

        if (type == double[].class)

            return Arrays.equals((double[]) v1, (double[]) v2);

        if (type == float[].class)

            return Arrays.equals((float[]) v1, (float[]) v2);

        if (type == int[].class)

            return Arrays.equals((int[]) v1, (int[]) v2);

        if (type == long[].class)

            return Arrays.equals((long[]) v1, (long[]) v2);

        if (type == short[].class)

            return Arrays.equals((short[]) v1, (short[]) v2);

        assert type == boolean[].class;

        return Arrays.equals((boolean[]) v1, (boolean[]) v2);

    }

    /**

     * Returns the member methods for our annotation type.  These are

     * obtained lazily and cached, as they're expensive to obtain

     * and we only need them if our equals method is invoked (which should

     * be rare).

     */

    private Method[] getMemberMethods() {

        if (memberMethods == null) {

            memberMethods = AccessController.doPrivileged(

                new PrivilegedAction<Method[]>() {

                    public Method[] run() {

                        final Method[] mm = type.getDeclaredMethods();

                        AccessibleObject.setAccessible(mm, true);

                        return mm;

                    }

                });

        }

        return memberMethods;

    }

    private transient volatile Method[] memberMethods = null;

    /**

     * Implementation of dynamicProxy.hashCode()

     */

    private int hashCodeImpl() {

        int result = 0;

        for (Map.Entry<String, Object> e : memberValues.entrySet()) {

            result += (127 * e.getKey().hashCode()) ^

                memberValueHashCode(e.getValue());

        }

        return result;

    }

    /**

     * Computes hashCode of a member value (in "dynamic proxy return form")

     */

    private static int memberValueHashCode(Object value) {

        Class<?> type = value.getClass();

        if (!type.isArray())    // primitive, string, class, enum const,

                                // or annotation

            return value.hashCode();

        if (type == byte[].class)

            return Arrays.hashCode((byte[]) value);

        if (type == char[].class)

            return Arrays.hashCode((char[]) value);

        if (type == double[].class)

            return Arrays.hashCode((double[]) value);

        if (type == float[].class)

            return Arrays.hashCode((float[]) value);

        if (type == int[].class)

            return Arrays.hashCode((int[]) value);

        if (type == long[].class)

            return Arrays.hashCode((long[]) value);

        if (type == short[].class)

            return Arrays.hashCode((short[]) value);

        if (type == boolean[].class)

            return Arrays.hashCode((boolean[]) value);

        return Arrays.hashCode((Object[]) value);

    }

    private void readObject(java.io.ObjectInputStream s)

        throws java.io.IOException, ClassNotFoundException {

        s.defaultReadObject();

        // Check to make sure that types have not evolved incompatibly

        AnnotationType annotationType = null;

        try {

            annotationType = AnnotationType.getInstance(type);

        } catch(IllegalArgumentException e) {

        }

        Map<String, Class<?>> memberTypes = annotationType.memberTypes();

        for (Map.Entry<String, Object> memberValue : memberValues.entrySet()) {

            String name = memberValue.getKey();

            Class<?> memberType = memberTypes.get(name);

            if (memberType != null) {  // i.e. member still exists

                Object value = memberValue.getValue();

                if (!(memberType.isInstance(value) ||

                      value instanceof ExceptionProxy)) {

                    memberValue.setValue(

                        new AnnotationTypeMismatchExceptionProxy(

                            value.getClass() + "[" + value + "]").setMember(

                                annotationType.members().get(name)));

                }

            }

        }

    }

}