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	/*
	* Copyright (c) 2012, 2017, 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 java.lang.reflect;

	import java.lang.annotation.*;
	import java.util.Map;
	import java.util.Objects;
	import java.util.StringJoiner;

	import jdk.internal.misc.SharedSecrets;
	import sun.reflect.annotation.AnnotationParser;
	import sun.reflect.annotation.AnnotationSupport;
	import sun.reflect.annotation.TypeAnnotationParser;
	import sun.reflect.annotation.TypeAnnotation;
	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,
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	getDeclaringClass());
	}

	void printModifiersIfNonzero(StringBuilder sb, int mask, boolean isDefault) {
	int mod = getModifiers() & mask;

	if (mod != 0 && !isDefault) {
	sb.append(Modifier.toString(mod)).append(' ');
	} else {
	int access_mod = mod & Modifier.ACCESS_MODIFIERS;
	if (access_mod != 0)
	sb.append(Modifier.toString(access_mod)).append(' ');
	if (isDefault)
	sb.append("default ");
	mod = (mod & ~Modifier.ACCESS_MODIFIERS);
	if (mod != 0)
	sb.append(Modifier.toString(mod)).append(' ');
	}
	}

	String sharedToString(int modifierMask,
	boolean isDefault,
	Class<?>[] parameterTypes,
	Class<?>[] exceptionTypes) {
	try {
	StringBuilder sb = new StringBuilder();

	printModifiersIfNonzero(sb, modifierMask, isDefault);
	specificToStringHeader(sb);
	sb.append('(');
	StringJoiner sj = new StringJoiner(",");
	for (Class<?> parameterType : parameterTypes) {
	sj.add(parameterType.getTypeName());
	}
	sb.append(sj.toString());
	sb.append(')');

	if (exceptionTypes.length > 0) {
	StringJoiner joiner = new StringJoiner(",", " throws ", "");
	for (Class<?> exceptionType : exceptionTypes) {
	joiner.add(exceptionType.getTypeName());
	}
	sb.append(joiner.toString());
	}
	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, boolean isDefault) {
	try {
	StringBuilder sb = new StringBuilder();

	printModifiersIfNonzero(sb, modifierMask, isDefault);

	TypeVariable<?>[] typeparms = getTypeParameters();
	if (typeparms.length > 0) {
	StringJoiner sj = new StringJoiner(",", "<", "> ");
	for(TypeVariable<?> typeparm: typeparms) {
	sj.add(typeparm.getTypeName());
	}
	sb.append(sj.toString());
	}

	specificToGenericStringHeader(sb);

	sb.append('(');
	StringJoiner sj = new StringJoiner(",");
	Type[] params = getGenericParameterTypes();
	for (int j = 0; j < params.length; j++) {
	String param = params[j].getTypeName();
	if (isVarArgs() && (j == params.length - 1)) // replace T[] with T...
	param = param.replaceFirst("\\[\\]$", "...");
	sj.add(param);
	}
	sb.append(sj.toString());
	sb.append(')');

	Type[] exceptionTypes = getGenericExceptionTypes();
	if (exceptionTypes.length > 0) {
	StringJoiner joiner = new StringJoiner(",", " throws ", "");
	for (Type exceptionType : exceptionTypes) {
	joiner.add(exceptionType.getTypeName());
	}
	sb.append(joiner.toString());
	}
	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™ Virtual Machine Specification</cite>
	*/
	public abstract TypeVariable<?>[] getTypeParameters();

	// returns shared array of parameter types - must never give it out
	// to the untrusted code...
	abstract Class<?>[] getSharedParameterTypes();

	// returns shared array of exception types - must never give it out
	// to the untrusted code...
	abstract Class<?>[] getSharedExceptionTypes();

	/**
	* 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 (whether explicitly
	* declared or implicitly declared or neither) 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™ 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();
	}

	/**
	* Behaves like {@code getGenericParameterTypes}, but returns type
	* information for all parameters, including synthetic parameters.
	*/
	Type[] getAllGenericParameterTypes() {
	final boolean genericInfo = hasGenericInformation();

	// Easy case: we don't have generic parameter information. In
	// this case, we just return the result of
	// getParameterTypes().
	if (!genericInfo) {
	return getParameterTypes();
	} else {
	final boolean realParamData = hasRealParameterData();
	final Type[] genericParamTypes = getGenericParameterTypes();
	final Type[] nonGenericParamTypes = getParameterTypes();
	final Type[] out = new Type[nonGenericParamTypes.length];
	final Parameter[] params = getParameters();
	int fromidx = 0;
	// If we have real parameter data, then we use the
	// synthetic and mandate flags to our advantage.
	if (realParamData) {
	for (int i = 0; i < out.length; i++) {
	final Parameter param = params[i];
	if (param.isSynthetic() \|\| param.isImplicit()) {
	// If we hit a synthetic or mandated parameter,
	// use the non generic parameter info.
	out[i] = nonGenericParamTypes[i];
	} else {
	// Otherwise, use the generic parameter info.
	out[i] = genericParamTypes[fromidx];
	fromidx++;
	}
	}
	} else {
	// Otherwise, use the non-generic parameter data.
	// Without method parameter reflection data, we have
	// no way to figure out which parameters are
	// synthetic/mandated, thus, no way to match up the
	// indexes.
	return genericParamTypes.length == nonGenericParamTypes.length ?
	genericParamTypes : nonGenericParamTypes;
	}
	return out;
	}
	}

	/**
	* 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.
	*
	* <p>The parameters of the underlying executable do not necessarily
	* have unique names, or names that are legal identifiers in the
	* Java programming language (JLS 3.8).
	*
	* @throws MalformedParametersException if the class file contains
	* a MethodParameters attribute that is improperly formatted.
	* @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 void verifyParameters(final Parameter[] parameters) {
	final int mask = Modifier.FINAL \| Modifier.SYNTHETIC \| Modifier.MANDATED;

	if (getParameterTypes().length != parameters.length)
	throw new MalformedParametersException("Wrong number of parameters in MethodParameters attribute");

	for (Parameter parameter : parameters) {
	final String name = parameter.getRealName();
	final int mods = parameter.getModifiers();

	if (name != null) {
	if (name.isEmpty() \|\| name.indexOf('.') != -1 \|\|
	name.indexOf(';') != -1 \|\| name.indexOf('[') != -1 \|\|
	name.indexOf('/') != -1) {
	throw new MalformedParametersException("Invalid parameter name \"" + name + "\"");
	}
	}

	if (mods != (mods & mask)) {
	throw new MalformedParametersException("Invalid parameter modifiers");
	}
	}
	}

	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
	try {
	tmp = getParameters0();
	} catch(IllegalArgumentException e) {
	// Rethrow ClassFormatErrors
	throw new MalformedParametersException("Invalid constant pool index");
	}

	// If we get back nothing, then synthesize parameters
	if (tmp == null) {
	hasRealParameterData = false;
	tmp = synthesizeAllParams();
	} else {
	hasRealParameterData = true;
	verifyParameters(tmp);
	}

	parameters = tmp;
	}

	return tmp;
	}

	boolean hasRealParameterData() {
	// If this somehow gets called before parameters gets
	// initialized, force it into existence.
	if (parameters == null) {
	privateGetParameters();
	}
	return hasRealParameterData;
	}

	private transient volatile boolean hasRealParameterData;
	private transient volatile Parameter[] parameters;

	private native Parameter[] getParameters0();
	native byte[] getTypeAnnotationBytes0();

	// Needed by reflectaccess
	byte[] getTypeAnnotationBytes() {
	return getTypeAnnotationBytes0();
	}

	/**
	* 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™ 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.
	* @return 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™ Language Specification</cite>.
	* @jls 13.1 The Form of a Binary
	*/
	public boolean isSynthetic() {
	return Modifier.isSynthetic(getModifiers());
	}

	/**
	* Returns an array of arrays of {@code Annotation}s that
	* represent the annotations on the formal parameters, in
	* declaration order, of the {@code Executable} represented by
	* this object. Synthetic and mandated parameters (see
	* explanation below), such as the outer "this" parameter to an
	* inner class constructor will be represented in the returned
	* array. If the executable has no parameters (meaning no formal,
	* no synthetic, and no mandated parameters), a zero-length array
	* will be returned. If the {@code 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.
	*
	* A compiler may add extra parameters that are implicitly
	* declared in source ("mandated"), as well as parameters that
	* are neither implicitly nor explicitly declared in source
	* ("synthetic") to the parameter list for a method. See {@link
	* java.lang.reflect.Parameter} for more information.
	*
	* @see java.lang.reflect.Parameter
	* @see java.lang.reflect.Parameter#getAnnotations
	* @return an array of arrays that represent the annotations on
	* the formal and implicit 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)) {
	Annotation[][] tmp = new Annotation[result.length+1][];
	// Shift annotations down one to account for an implicit leading parameter
	System.arraycopy(result, 0, tmp, 1, result.length);
	tmp[0] = new Annotation[0];
	result = tmp;
	}
	return result;
	}

	abstract boolean handleParameterNumberMismatch(int resultLength, int numParameters);

	/**
	* {@inheritDoc}
	* @throws NullPointerException {@inheritDoc}
	*/
	public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
	Objects.requireNonNull(annotationClass);
	return annotationClass.cast(declaredAnnotations().get(annotationClass));
	}

	/**
	* {@inheritDoc}
	* @throws NullPointerException {@inheritDoc}
	*/
	@Override
	public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {
	Objects.requireNonNull(annotationClass);

	return AnnotationSupport.getDirectlyAndIndirectlyPresent(declaredAnnotations(), annotationClass);
	}

	/**
	* {@inheritDoc}
	*/
	public Annotation[] getDeclaredAnnotations() {
	return AnnotationParser.toArray(declaredAnnotations());
	}

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

	private Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {
	Map<Class<? extends Annotation>, Annotation> declAnnos;
	if ((declAnnos = declaredAnnotations) == null) {
	synchronized (this) {
	if ((declAnnos = declaredAnnotations) == null) {
	Executable root = (Executable)getRoot();
	if (root != null) {
	declAnnos = root.declaredAnnotations();
	} else {
	declAnnos = AnnotationParser.parseAnnotations(
	getAnnotationBytes(),
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	getDeclaringClass()
	);
	}
	declaredAnnotations = declAnnos;
	}
	}
	}
	return declAnnos;
	}

	/**
	* Returns an {@code AnnotatedType} object that represents the use of a type to
	* specify the return type of the method/constructor represented by this
	* Executable.
	*
	* If this {@code Executable} object represents a constructor, the {@code
	* AnnotatedType} object represents the type of the constructed object.
	*
	* If this {@code Executable} object represents a method, the {@code
	* AnnotatedType} object represents the use of a type to specify the return
	* type of the method.
	*
	* @return an object representing the return type of the method
	* or constructor represented by this {@code Executable}
	*/
	public abstract AnnotatedType getAnnotatedReturnType();

	/* Helper for subclasses of Executable.
	*
	* Returns an AnnotatedType object that represents the use of a type to
	* specify the return type of the method/constructor represented by this
	* Executable.
	*/
	AnnotatedType getAnnotatedReturnType0(Type returnType) {
	return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	this,
	getDeclaringClass(),
	returnType,
	TypeAnnotation.TypeAnnotationTarget.METHOD_RETURN);
	}

	/**
	* Returns an {@code AnnotatedType} object that represents the use of a
	* type to specify the receiver type of the method/constructor represented
	* by this {@code Executable} object.
	*
	* The receiver type of a method/constructor is available only if the
	* method/constructor has a receiver parameter (JLS 8.4.1). If this {@code
	* Executable} object <em>represents an instance method or represents a
	* constructor of an inner member class</em>, and the
	* method/constructor <em>either</em> has no receiver parameter or has a
	* receiver parameter with no annotations on its type, then the return
	* value is an {@code AnnotatedType} object representing an element with no
	* annotations.
	*
	* If this {@code Executable} object represents a static method or
	* represents a constructor of a top level, static member, local, or
	* anonymous class, then the return value is null.
	*
	* @return an object representing the receiver type of the method or
	* constructor represented by this {@code Executable} or {@code null} if
	* this {@code Executable} can not have a receiver parameter
	*/
	public AnnotatedType getAnnotatedReceiverType() {
	if (Modifier.isStatic(this.getModifiers()))
	return null;
	return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	this,
	getDeclaringClass(),
	getDeclaringClass(),
	TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
	}

	/**
	* Returns an array of {@code AnnotatedType} objects that represent the use
	* of types to specify formal parameter types of the method/constructor
	* represented by this Executable. The order of the objects in the array
	* corresponds to the order of the formal parameter types in the
	* declaration of the method/constructor.
	*
	* Returns an array of length 0 if the method/constructor declares no
	* parameters.
	*
	* @return an array of objects representing the types of the
	* formal parameters of the method or constructor represented by this
	* {@code Executable}
	*/
	public AnnotatedType[] getAnnotatedParameterTypes() {
	return TypeAnnotationParser.buildAnnotatedTypes(getTypeAnnotationBytes0(),
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	this,
	getDeclaringClass(),
	getAllGenericParameterTypes(),
	TypeAnnotation.TypeAnnotationTarget.METHOD_FORMAL_PARAMETER);
	}

	/**
	* Returns an array of {@code AnnotatedType} objects that represent the use
	* of types to specify the declared exceptions of the method/constructor
	* represented by this Executable. The order of the objects in the array
	* corresponds to the order of the exception types in the declaration of
	* the method/constructor.
	*
	* Returns an array of length 0 if the method/constructor declares no
	* exceptions.
	*
	* @return an array of objects representing the declared
	* exceptions of the method or constructor represented by this {@code
	* Executable}
	*/
	public AnnotatedType[] getAnnotatedExceptionTypes() {
	return TypeAnnotationParser.buildAnnotatedTypes(getTypeAnnotationBytes0(),
	SharedSecrets.getJavaLangAccess().
	getConstantPool(getDeclaringClass()),
	this,
	getDeclaringClass(),
	getGenericExceptionTypes(),
	TypeAnnotation.TypeAnnotationTarget.THROWS);
	}

	}

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