/*

 * 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

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package java.lang.reflect;

import java.lang.annotation.*;

import java.util.Collections;

import java.util.Map;

import java.util.Objects;

import sun.reflect.annotation.AnnotationParser;

import sun.reflect.annotation.AnnotationSupport;

import sun.reflect.generics.repository.ConstructorRepository;

/**

 * A shared superclass for the common functionality of {@link Method}

 * and {@link Constructor}.

 *

 * @since 1.8

 */

public abstract class Executable extends AccessibleObject

    implements Member, GenericDeclaration {

    /*

     * Only grant package-visibility to the constructor.

     */

    Executable() {}

    /**

     * Accessor method to allow code sharing

     */

    abstract byte[] getAnnotationBytes();

    /**

     * Does the Executable have generic information.

     */

    abstract boolean hasGenericInformation();

    abstract ConstructorRepository getGenericInfo();

    boolean equalParamTypes(Class<?>[] params1, Class<?>[] params2) {

        /* Avoid unnecessary cloning */

        if (params1.length == params2.length) {

            for (int i = 0; i < params1.length; i++) {

                if (params1[i] != params2[i])

                    return false;

            }

            return true;

        }

        return false;

    }

    Annotation[][] parseParameterAnnotations(byte[] parameterAnnotations) {

        return AnnotationParser.parseParameterAnnotations(

               parameterAnnotations,

               sun.misc.SharedSecrets.getJavaLangAccess().

               getConstantPool(getDeclaringClass()),

               getDeclaringClass());

    }

    void separateWithCommas(Class<?>[] types, StringBuilder sb) {

        for (int j = 0; j < types.length; j++) {

            sb.append(Field.getTypeName(types[j]));

            if (j < (types.length - 1))

                sb.append(",");

        }

    }

    void printModifiersIfNonzero(StringBuilder sb, int mask) {

        int mod = getModifiers() & mask;

        if (mod != 0) {

            sb.append(Modifier.toString(mod)).append(' ');

        }

    }

    String sharedToString(int modifierMask,

                          Class<?>[] parameterTypes,

                          Class<?>[] exceptionTypes) {

        try {

            StringBuilder sb = new StringBuilder();

            printModifiersIfNonzero(sb, modifierMask);

            specificToStringHeader(sb);

            sb.append('(');

            separateWithCommas(parameterTypes, sb);

            sb.append(')');

            if (exceptionTypes.length > 0) {

                sb.append(" throws ");

                separateWithCommas(exceptionTypes, sb);

            }

            return sb.toString();

        } catch (Exception e) {

            return "<" + e + ">";

        }

    }

    /**

     * Generate toString header information specific to a method or

     * constructor.

     */

    abstract void specificToStringHeader(StringBuilder sb);

    String sharedToGenericString(int modifierMask) {

        try {

            StringBuilder sb = new StringBuilder();

            printModifiersIfNonzero(sb, modifierMask);

            TypeVariable<?>[] typeparms = getTypeParameters();

            if (typeparms.length > 0) {

                boolean first = true;

                sb.append('<');

                for(TypeVariable<?> typeparm: typeparms) {

                    if (!first)

                        sb.append(',');

                    // Class objects can't occur here; no need to test

                    // and call Class.getName().

                    sb.append(typeparm.toString());

                    first = false;

                }

                sb.append("> ");

            }

            specificToGenericStringHeader(sb);

            sb.append('(');

            Type[] params = getGenericParameterTypes();

            for (int j = 0; j < params.length; j++) {

                String param = (params[j] instanceof Class)?

                    Field.getTypeName((Class)params[j]):

                    (params[j].toString());

                if (isVarArgs() && (j == params.length - 1)) // replace T[] with T...

                    param = param.replaceFirst("\\[\\]$", "...");

                sb.append(param);

                if (j < (params.length - 1))

                    sb.append(',');

            }

            sb.append(')');

            Type[] exceptions = getGenericExceptionTypes();

            if (exceptions.length > 0) {

                sb.append(" throws ");

                for (int k = 0; k < exceptions.length; k++) {

                    sb.append((exceptions[k] instanceof Class)?

                              ((Class)exceptions[k]).getName():

                              exceptions[k].toString());

                    if (k < (exceptions.length - 1))

                        sb.append(',');

                }

            }

            return sb.toString();

        } catch (Exception e) {

            return "<" + e + ">";

        }

    }

    /**

     * Generate toGenericString header information specific to a

     * method or constructor.

     */

    abstract void specificToGenericStringHeader(StringBuilder sb);

    /**

     * Returns the {@code Class} object representing the class or interface

     * that declares the executable represented by this object.

     */

    public abstract Class<?> getDeclaringClass();

    /**

     * Returns the name of the executable represented by this object.

     */

    public abstract String getName();

    /**

     * Returns the Java language {@linkplain Modifier modifiers} for

     * the executable represented by this object.

     */

    public abstract int getModifiers();

    /**

     * Returns an array of {@code TypeVariable} objects that represent the

     * type variables declared by the generic declaration represented by this

     * {@code GenericDeclaration} object, in declaration order.  Returns an

     * array of length 0 if the underlying generic declaration declares no type

     * variables.

     *

     * @return an array of {@code TypeVariable} objects that represent

     *     the type variables declared by this generic declaration

     * @throws GenericSignatureFormatError if the generic

     *     signature of this generic declaration does not conform to

     *     the format specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     */

    public abstract TypeVariable<?>[] getTypeParameters();

    /**

     * Returns an array of {@code Class} objects that represent the formal

     * parameter types, in declaration order, of the executable

     * represented by this object.  Returns an array of length

     * 0 if the underlying executable takes no parameters.

     *

     * @return the parameter types for the executable this object

     * represents

     */

    public abstract Class<?>[] getParameterTypes();

    /**

     * Returns the number of formal parameters (including any

     * synthetic or synthesized parameters) for the executable

     * represented by this object.

     *

     * @return The number of formal parameters for the executable this

     * object represents

     */

    public int getParameterCount() {

        throw new AbstractMethodError();

    }

    /**

     * Returns an array of {@code Type} objects that represent the formal

     * parameter types, in declaration order, of the executable represented by

     * this object. Returns an array of length 0 if the

     * underlying executable takes no parameters.

     *

     * <p>If a formal parameter type is a parameterized type,

     * the {@code Type} object returned for it must accurately reflect

     * the actual type parameters used in the source code.

     *

     * <p>If a formal parameter type is a type variable or a parameterized

     * type, it is created. Otherwise, it is resolved.

     *

     * @return an array of {@code Type}s that represent the formal

     *     parameter types of the underlying executable, in declaration order

     * @throws GenericSignatureFormatError

     *     if the generic method signature does not conform to the format

     *     specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if any of the parameter

     *     types of the underlying executable refers to a non-existent type

     *     declaration

     * @throws MalformedParameterizedTypeException if any of

     *     the underlying executable's parameter types refer to a parameterized

     *     type that cannot be instantiated for any reason

     */

    public Type[] getGenericParameterTypes() {

        if (hasGenericInformation())

            return getGenericInfo().getParameterTypes();

        else

            return getParameterTypes();

    }

    /**

     * Returns an array of {@code Parameter} objects that represent

     * all the parameters to the underlying executable represented by

     * this object.  Returns an array of length 0 if the executable

     * has no parameters.

     *

     * @return an array of {@code Parameter} objects representing all

     * the parameters to the executable this object represents

     */

    public Parameter[] getParameters() {

        // TODO: This may eventually need to be guarded by security

        // mechanisms similar to those in Field, Method, etc.

        //

        // Need to copy the cached array to prevent users from messing

        // with it.  Since parameters are immutable, we can

        // shallow-copy.

        return privateGetParameters().clone();

    }

    private Parameter[] synthesizeAllParams() {

        final int realparams = getParameterCount();

        final Parameter[] out = new Parameter[realparams];

        for (int i = 0; i < realparams; i++)

            // TODO: is there a way to synthetically derive the

            // modifiers?  Probably not in the general case, since

            // we'd have no way of knowing about them, but there

            // may be specific cases.

            out[i] = new Parameter("arg" + i, 0, this, i);

        return out;

    }

    private Parameter[] privateGetParameters() {

        // Use tmp to avoid multiple writes to a volatile.

        Parameter[] tmp = parameters;

        if (tmp == null) {

            // Otherwise, go to the JVM to get them

            tmp = getParameters0();

            // If we get back nothing, then synthesize parameters

            if (tmp == null)

                tmp = synthesizeAllParams();

            parameters = tmp;

        }

        return tmp;

    }

    private transient volatile Parameter[] parameters;

    private native Parameter[] getParameters0();

    /**

     * Returns an array of {@code Class} objects that represent the

     * types of exceptions declared to be thrown by the underlying

     * executable represented by this object.  Returns an array of

     * length 0 if the executable declares no exceptions in its {@code

     * throws} clause.

     *

     * @return the exception types declared as being thrown by the

     * executable this object represents

     */

    public abstract Class<?>[] getExceptionTypes();

    /**

     * Returns an array of {@code Type} objects that represent the

     * exceptions declared to be thrown by this executable object.

     * Returns an array of length 0 if the underlying executable declares

     * no exceptions in its {@code throws} clause.

     *

     * <p>If an exception type is a type variable or a parameterized

     * type, it is created. Otherwise, it is resolved.

     *

     * @return an array of Types that represent the exception types

     *     thrown by the underlying executable

     * @throws GenericSignatureFormatError

     *     if the generic method signature does not conform to the format

     *     specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if the underlying executable's

     *     {@code throws} clause refers to a non-existent type declaration

     * @throws MalformedParameterizedTypeException if

     *     the underlying executable's {@code throws} clause refers to a

     *     parameterized type that cannot be instantiated for any reason

     */

    public Type[] getGenericExceptionTypes() {

        Type[] result;

        if (hasGenericInformation() &&

            ((result = getGenericInfo().getExceptionTypes()).length > 0))

            return result;

        else

            return getExceptionTypes();

    }

    /**

     * Returns a string describing this {@code Executable}, including

     * any type parameters.

     */

    public abstract String toGenericString();

    /**

     * Returns {@code true} if this executable was declared to take a

     * variable number of arguments; returns {@code false} otherwise.

     *

     * @return {@code true} if an only if this executable was declared

     * to take a variable number of arguments.

     */

    public boolean isVarArgs()  {

        return (getModifiers() & Modifier.VARARGS) != 0;

    }

    /**

     * Returns {@code true} if this executable is a synthetic

     * construct; returns {@code false} otherwise.

     *

     * @return true if and only if this executable is a synthetic

     * construct as defined by

     * <cite>The Java&trade; Language Specification</cite>.

     * @jls 13.1 The Form of a Binary

     */

    public boolean isSynthetic() {

        return Modifier.isSynthetic(getModifiers());

    }

    /**

     * Returns an array of arrays that represent the annotations on

     * the formal parameters, in declaration order, of the executable

     * represented by this object. (Returns an array of length zero if

     * the underlying executable is parameterless.  If the executable has

     * one or more parameters, a nested array of length zero is

     * returned for each parameter with no annotations.) The

     * annotation objects contained in the returned arrays are

     * serializable.  The caller of this method is free to modify the

     * returned arrays; it will have no effect on the arrays returned

     * to other callers.

     *

     * @return an array of arrays that represent the annotations on the formal

     *    parameters, in declaration order, of the executable represented by this

     *    object

     */

    public abstract Annotation[][] getParameterAnnotations();

    Annotation[][] sharedGetParameterAnnotations(Class<?>[] parameterTypes,

                                                 byte[] parameterAnnotations) {

        int numParameters = parameterTypes.length;

        if (parameterAnnotations == null)

            return new Annotation[numParameters][0];

        Annotation[][] result = parseParameterAnnotations(parameterAnnotations);

        if (result.length != numParameters)

            handleParameterNumberMismatch(result.length, numParameters);

        return result;

    }

    abstract void handleParameterNumberMismatch(int resultLength, int numParameters);

    /**

     * {@inheritDoc}

     * @throws NullPointerException  {@inheritDoc}

     */

    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        return AnnotationSupport.getOneAnnotation(declaredAnnotations(), annotationClass);

    }

    /**

     * {@inheritDoc}

     * @throws NullPointerException {@inheritDoc}

     * @since 1.8

     */

    public <T extends Annotation> T[] getAnnotations(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        return AnnotationSupport.getMultipleAnnotations(declaredAnnotations(), annotationClass);

    }

    /**

     * {@inheritDoc}

     */

    public Annotation[] getDeclaredAnnotations()  {

        return AnnotationSupport.unpackToArray(declaredAnnotations());

    }

    private transient Map<Class<? extends Annotation>, Annotation> declaredAnnotations;

    private synchronized  Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {

        if (declaredAnnotations == null) {

            declaredAnnotations = AnnotationParser.parseAnnotations(

                getAnnotationBytes(),

                sun.misc.SharedSecrets.getJavaLangAccess().

                getConstantPool(getDeclaringClass()),

                getDeclaringClass());

        }

        return declaredAnnotations;

    }