/*
 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.lang.reflect;

import java.lang.annotation.*;
import java.util.Map;
import java.util.Objects;
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}.
 * <P>
 * <P> 它的主要功能是从Method和Constructor抽取出两者可以共用的一些方法例如注解的操作,参数的操作等等
 * <P>
 * @since 1.8
 */
@SuppressWarnings("ALL")
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();

 /**
 * Accessor method to allow code sharing
 */
 abstract Executable getRoot();

 /**
 * 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(types[j].getTypeName());
 if (j < (types.length - 1))
 sb.append(",");
 }

 }

 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('(');
 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, boolean isDefault) {
 try {
 StringBuilder sb = new StringBuilder();

 printModifiersIfNonzero(sb, modifierMask, isDefault);

 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].getTypeName();
 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 (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&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();
 }

 /**
 * 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&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.
 * @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&trade; 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);
 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 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 Map<Class<? extends Annotation>, Annotation> declaredAnnotations;

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

 /**
 * 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(),
 sun.misc.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 Executable object. The receiver type of a method/constructor is
 * available only if the method/constructor has a <em>receiver
 * parameter</em> (JLS 8.4.1).
 *
 * If this {@code Executable} object represents a constructor or instance
 * method that does not have a 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, then the
 * return value is null.
 *
 * @return an object representing the receiver type of the method or
 * constructor represented by this {@code Executable}
 */
 public AnnotatedType getAnnotatedReceiverType() {
 if (Modifier.isStatic(this.getModifiers()))
 return null;
 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
 sun.misc.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(),
 sun.misc.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(),
 sun.misc.SharedSecrets.getJavaLangAccess().
 getConstantPool(getDeclaringClass()),
 this,
 getDeclaringClass(),
 getGenericExceptionTypes(),
 TypeAnnotation.TypeAnnotationTarget.THROWS);
 }

}