/*
 * Copyright (c) 1996, 2006, 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 sun.reflect.CallerSensitive;
import sun.reflect.ConstructorAccessor;
import sun.reflect.Reflection;
import sun.reflect.generics.repository.ConstructorRepository;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.scope.ConstructorScope;
import java.lang.annotation.Annotation;
import java.util.Map;
import sun.reflect.annotation.AnnotationParser;
import java.lang.annotation.AnnotationFormatError;
import java.lang.reflect.Modifier;

Constructor provides information about, and access to, a single constructor for a class. 
Constructor permits widening conversions to occur when matching the actual parameters to newInstance() with the underlying constructor's formal parameters, but throws an IllegalArgumentException if a narrowing conversion would occur. 
Author:
     Kenneth Russell,      Nakul Saraiya
Type parameters:
<T> – the class in which the constructor is declared
See Also:
Member
Class
Class.getConstructors()
Class.getConstructor(Class[])
Class.getDeclaredConstructors()/**
 * {@code Constructor} provides information about, and access to, a single
 * constructor for a class.
 *
 * <p>{@code Constructor} permits widening conversions to occur when matching the
 * actual parameters to newInstance() with the underlying
 * constructor's formal parameters, but throws an
 * {@code IllegalArgumentException} if a narrowing conversion would occur.
 *
 * @param <T> the class in which the constructor is declared
 *
 * @see Member
 * @see java.lang.Class
 * @see java.lang.Class#getConstructors()
 * @see java.lang.Class#getConstructor(Class[])
 * @see java.lang.Class#getDeclaredConstructors()
 *
 * @author      Kenneth Russell
 * @author      Nakul Saraiya
 */
public final
    class Constructor<T> extends AccessibleObject implements
                                                    GenericDeclaration,
                                                    Member {

    private Class<T>            clazz;
    private int                 slot;
    private Class<?>[]          parameterTypes;
    private Class<?>[]          exceptionTypes;
    private int                 modifiers;
    // Generics and annotations support
    private transient String    signature;
    // generic info repository; lazily initialized
    private transient ConstructorRepository genericInfo;
    private byte[]              annotations;
    private byte[]              parameterAnnotations;

    // For non-public members or members in package-private classes,
    // it is necessary to perform somewhat expensive security checks.
    // If the security check succeeds for a given class, it will
    // always succeed (it is not affected by the granting or revoking
    // of permissions); we speed up the check in the common case by
    // remembering the last Class for which the check succeeded.
    private volatile Class securityCheckCache;

    // Modifiers that can be applied to a constructor in source code
    private static final int LANGUAGE_MODIFIERS =
        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE;

    // Generics infrastructure
    // Accessor for factory
    private GenericsFactory getFactory() {
        // create scope and factory
        return CoreReflectionFactory.make(this, ConstructorScope.make(this));
    }

    // Accessor for generic info repository
    private ConstructorRepository getGenericInfo() {
        // lazily initialize repository if necessary
        if (genericInfo == null) {
            // create and cache generic info repository
            genericInfo =
                ConstructorRepository.make(getSignature(),
                                           getFactory());
        }
        return genericInfo; //return cached repository
    }

    private volatile ConstructorAccessor constructorAccessor;
    // For sharing of ConstructorAccessors. This branching structure
    // is currently only two levels deep (i.e., one root Constructor
    // and potentially many Constructor objects pointing to it.)
    private Constructor<T>      root;

    
Package-private constructor used by ReflectAccess to enable
instantiation of these objects in Java code from the java.lang
package via sun.reflect.LangReflectAccess.
/**
     * Package-private constructor used by ReflectAccess to enable
     * instantiation of these objects in Java code from the java.lang
     * package via sun.reflect.LangReflectAccess.
     */
    Constructor(Class<T> declaringClass,
                Class<?>[] parameterTypes,
                Class<?>[] checkedExceptions,
                int modifiers,
                int slot,
                String signature,
                byte[] annotations,
                byte[] parameterAnnotations)
    {
        this.clazz = declaringClass;
        this.parameterTypes = parameterTypes;
        this.exceptionTypes = checkedExceptions;
        this.modifiers = modifiers;
        this.slot = slot;
        this.signature = signature;
        this.annotations = annotations;
        this.parameterAnnotations = parameterAnnotations;
    }

    
Package-private routine (exposed to java.lang.Class via
ReflectAccess) which returns a copy of this Constructor. The copy's
"root" field points to this Constructor.
/**
     * Package-private routine (exposed to java.lang.Class via
     * ReflectAccess) which returns a copy of this Constructor. The copy's
     * "root" field points to this Constructor.
     */
    Constructor<T> copy() {
        // This routine enables sharing of ConstructorAccessor objects
        // among Constructor objects which refer to the same underlying
        // method in the VM. (All of this contortion is only necessary
        // because of the "accessibility" bit in AccessibleObject,
        // which implicitly requires that new java.lang.reflect
        // objects be fabricated for each reflective call on Class
        // objects.)
        Constructor<T> res = new Constructor<T>(clazz,
                                                parameterTypes,
                                                exceptionTypes, modifiers, slot,
                                                signature,
                                                annotations,
                                                parameterAnnotations);
        res.root = this;
        // Might as well eagerly propagate this if already present
        res.constructorAccessor = constructorAccessor;
        return res;
    }

    
Returns the Class object representing the class that declares the constructor represented by this Constructor object. /**
     * Returns the {@code Class} object representing the class that declares
     * the constructor represented by this {@code Constructor} object.
     */
    public Class<T> getDeclaringClass() {
        return clazz;
    }

    
Returns the name of this constructor, as a string.  This is
always the same as the simple name of the constructor's declaring
class.
/**
     * Returns the name of this constructor, as a string.  This is
     * always the same as the simple name of the constructor's declaring
     * class.
     */
    public String getName() {
        return getDeclaringClass().getName();
    }

    
Returns the Java language modifiers for the constructor represented by this Constructor object, as an integer. The Modifier class should be used to decode the modifiers. 
See Also:
Modifier/**
     * Returns the Java language modifiers for the constructor
     * represented by this {@code Constructor} object, as an integer. The
     * {@code Modifier} class should be used to decode the modifiers.
     *
     * @see Modifier
     */
    public int getModifiers() {
        return modifiers;
    }

    
Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order. Returns an array of length 0 if the underlying generic declaration declares no type variables. 
Throws:
GenericSignatureFormatError – if the generic
    signature of this generic declaration does not conform to
    the format specified in the Java Virtual Machine Specification,
    3rd edition
Returns:
an array of TypeVariable objects that represent the type variables declared by this generic declaration
Since:
1.5/**
     * 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 the Java Virtual Machine Specification,
     *     3rd edition
     * @since 1.5
     */
    public TypeVariable<Constructor<T>>[] getTypeParameters() {
      if (getSignature() != null) {
        return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
      } else
          return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
    }


    
Returns an array of Class objects that represent the formal parameter types, in declaration order, of the constructor represented by this Constructor object. Returns an array of length 0 if the underlying constructor takes no parameters. 
Returns:
the parameter types for the constructor this object
represents/**
     * Returns an array of {@code Class} objects that represent the formal
     * parameter types, in declaration order, of the constructor
     * represented by this {@code Constructor} object.  Returns an array of
     * length 0 if the underlying constructor takes no parameters.
     *
     * @return the parameter types for the constructor this object
     * represents
     */
    public Class<?>[] getParameterTypes() {
        return (Class<?>[]) parameterTypes.clone();
    }


    
Returns an array of Type objects that represent the formal parameter types, in declaration order, of the method represented by this Constructor object. Returns an array of length 0 if the underlying method takes no parameters. 
If a formal parameter type is a parameterized type, the Type object returned for it must accurately reflect the actual type parameters used in the source code. 
If a formal parameter type is a type variable or a parameterized
type, it is created. Otherwise, it is resolved.
Throws:
GenericSignatureFormatError – 
    if the generic method signature does not conform to the format
    specified in the Java Virtual Machine Specification, 3rd edition
TypeNotPresentException – if any of the parameter
    types of the underlying method refers to a non-existent type
    declaration
MalformedParameterizedTypeException – if any of
    the underlying method's parameter types refer to a parameterized
    type that cannot be instantiated for any reason
Returns:
an array of Types that represent the formal parameter types of the underlying method, in declaration order
Since:
1.5/**
     * Returns an array of {@code Type} objects that represent the formal
     * parameter types, in declaration order, of the method represented by
     * this {@code Constructor} object. Returns an array of length 0 if the
     * underlying method 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 method, in declaration order
     * @throws GenericSignatureFormatError
     *     if the generic method signature does not conform to the format
     *     specified in the Java Virtual Machine Specification, 3rd edition
     * @throws TypeNotPresentException if any of the parameter
     *     types of the underlying method refers to a non-existent type
     *     declaration
     * @throws MalformedParameterizedTypeException if any of
     *     the underlying method's parameter types refer to a parameterized
     *     type that cannot be instantiated for any reason
     * @since 1.5
     */
    public Type[] getGenericParameterTypes() {
        if (getSignature() != null)
            return getGenericInfo().getParameterTypes();
        else
            return getParameterTypes();
    }


    
Returns an array of Class objects that represent the types of exceptions declared to be thrown by the underlying constructor represented by this Constructor object. Returns an array of length 0 if the constructor declares no exceptions in its throws clause. 
Returns:
the exception types declared as being thrown by the
constructor this object represents/**
     * Returns an array of {@code Class} objects that represent the types
     * of exceptions declared to be thrown by the underlying constructor
     * represented by this {@code Constructor} object.  Returns an array of
     * length 0 if the constructor declares no exceptions in its {@code throws} clause.
     *
     * @return the exception types declared as being thrown by the
     * constructor this object represents
     */
    public Class<?>[] getExceptionTypes() {
        return (Class<?>[])exceptionTypes.clone();
    }


    
Returns an array of Type objects that represent the exceptions declared to be thrown by this Constructor object. Returns an array of length 0 if the underlying method declares no exceptions in its throws clause. 
If an exception type is a parameterized type, the Type object returned for it must accurately reflect the actual type parameters used in the source code. 
If an exception type is a type variable or a parameterized
type, it is created. Otherwise, it is resolved.
Throws:
GenericSignatureFormatError – 
    if the generic method signature does not conform to the format
    specified in the Java Virtual Machine Specification, 3rd edition
TypeNotPresentException – if the underlying method's throws clause refers to a non-existent type declaration
MalformedParameterizedTypeException – if the underlying method's throws clause refers to a parameterized type that cannot be instantiated for any reason
Returns:
an array of Types that represent the exception types
    thrown by the underlying method
Since:
1.5/**
     * Returns an array of {@code Type} objects that represent the
     * exceptions declared to be thrown by this {@code Constructor} object.
     * Returns an array of length 0 if the underlying method declares
     * no exceptions in its {@code throws} clause.
     *
     * <p>If an exception 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 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 method
     * @throws GenericSignatureFormatError
     *     if the generic method signature does not conform to the format
     *     specified in the Java Virtual Machine Specification, 3rd edition
     * @throws TypeNotPresentException if the underlying method's
     *     {@code throws} clause refers to a non-existent type declaration
     * @throws MalformedParameterizedTypeException if
     *     the underlying method's {@code throws} clause refers to a
     *     parameterized type that cannot be instantiated for any reason
     * @since 1.5
     */
      public Type[] getGenericExceptionTypes() {
          Type[] result;
          if (getSignature() != null &&
              ( (result = getGenericInfo().getExceptionTypes()).length > 0  ))
              return result;
          else
              return getExceptionTypes();
      }

    
Compares this Constructor against the specified object. Returns true if the objects are the same. Two Constructor objects are the same if they were declared by the same class and have the same formal parameter types. /**
     * Compares this {@code Constructor} against the specified object.
     * Returns true if the objects are the same.  Two {@code Constructor} objects are
     * the same if they were declared by the same class and have the
     * same formal parameter types.
     */
    public boolean equals(Object obj) {
        if (obj != null && obj instanceof Constructor) {
            Constructor other = (Constructor)obj;
            if (getDeclaringClass() == other.getDeclaringClass()) {
                /* Avoid unnecessary cloning */
                Class[] params1 = parameterTypes;
                Class[] params2 = other.parameterTypes;
                if (params1.length == params2.length) {
                    for (int i = 0; i < params1.length; i++) {
                        if (params1[i] != params2[i])
                            return false;
                    }
                    return true;
                }
            }
        }
        return false;
    }

    
Returns a hashcode for this Constructor. The hashcode is the same as the hashcode for the underlying constructor's declaring class name. /**
     * Returns a hashcode for this {@code Constructor}. The hashcode is
     * the same as the hashcode for the underlying constructor's
     * declaring class name.
     */
    public int hashCode() {
        return getDeclaringClass().getName().hashCode();
    }

    
Returns a string describing this Constructor. The string is formatted as the constructor access modifiers, if any, followed by the fully-qualified name of the declaring class, followed by a parenthesized, comma-separated list of the constructor's formal parameter types. For example: 
   public java.util.Hashtable(int,float)

The only possible modifiers for constructors are the access modifiers public, protected or private. Only one of these may appear, or none if the constructor has default (package) access. /**
     * Returns a string describing this {@code Constructor}.  The string is
     * formatted as the constructor access modifiers, if any,
     * followed by the fully-qualified name of the declaring class,
     * followed by a parenthesized, comma-separated list of the
     * constructor's formal parameter types.  For example:
     * <pre>
     *    public java.util.Hashtable(int,float)
     * </pre>
     *
     * <p>The only possible modifiers for constructors are the access
     * modifiers {@code public}, {@code protected} or
     * {@code private}.  Only one of these may appear, or none if the
     * constructor has default (package) access.
     */
    public String toString() {
        try {
            StringBuffer sb = new StringBuffer();
            int mod = getModifiers() & LANGUAGE_MODIFIERS;
            if (mod != 0) {
                sb.append(Modifier.toString(mod) + " ");
            }
            sb.append(Field.getTypeName(getDeclaringClass()));
            sb.append("(");
            Class<?>[] params = parameterTypes; // avoid clone
            for (int j = 0; j < params.length; j++) {
                sb.append(Field.getTypeName(params[j]));
                if (j < (params.length - 1))
                    sb.append(",");
            }
            sb.append(")");
            Class<?>[] exceptions = exceptionTypes; // avoid clone
            if (exceptions.length > 0) {
                sb.append(" throws ");
                for (int k = 0; k < exceptions.length; k++) {
                    sb.append(exceptions[k].getName());
                    if (k < (exceptions.length - 1))
                        sb.append(",");
                }
            }
            return sb.toString();
        } catch (Exception e) {
            return "<" + e + ">";
        }
    }

    
Returns a string describing this Constructor, including type parameters. The string is formatted as the constructor access modifiers, if any, followed by an angle-bracketed comma separated list of the constructor's type parameters, if any, followed by the fully-qualified name of the declaring class, followed by a parenthesized, comma-separated list of the constructor's generic formal parameter types. A space is used to separate access modifiers from one another and from the type parameters or return type. If there are no type parameters, the type parameter list is elided; if the type parameter list is present, a space separates the list from the class name. If the constructor is declared to throw exceptions, the parameter list is followed by a space, followed by the word "throws" followed by a comma-separated list of the thrown exception types. 
The only possible modifiers for constructors are the access modifiers public, protected or private. Only one of these may appear, or none if the constructor has default (package) access. 
Returns:
a string describing this Constructor, include type parameters
Since:
1.5/**
     * Returns a string describing this {@code Constructor},
     * including type parameters.  The string is formatted as the
     * constructor access modifiers, if any, followed by an
     * angle-bracketed comma separated list of the constructor's type
     * parameters, if any, followed by the fully-qualified name of the
     * declaring class, followed by a parenthesized, comma-separated
     * list of the constructor's generic formal parameter types.
     *
     * A space is used to separate access modifiers from one another
     * and from the type parameters or return type.  If there are no
     * type parameters, the type parameter list is elided; if the type
     * parameter list is present, a space separates the list from the
     * class name.  If the constructor is declared to throw
     * exceptions, the parameter list is followed by a space, followed
     * by the word "{@code throws}" followed by a
     * comma-separated list of the thrown exception types.
     *
     * <p>The only possible modifiers for constructors are the access
     * modifiers {@code public}, {@code protected} or
     * {@code private}.  Only one of these may appear, or none if the
     * constructor has default (package) access.
     *
     * @return a string describing this {@code Constructor},
     * include type parameters
     *
     * @since 1.5
     */
    public String toGenericString() {
        try {
            StringBuilder sb = new StringBuilder();
            int mod = getModifiers() & LANGUAGE_MODIFIERS;
            if (mod != 0) {
                sb.append(Modifier.toString(mod) + " ");
            }
            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("> ");
            }
            sb.append(Field.getTypeName(getDeclaringClass()));
            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());
                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 + ">";
        }
    }

    
Uses the constructor represented by this Constructor object to create and initialize a new instance of the constructor's declaring class, with the specified initialization parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary. 
If the number of formal parameters required by the underlying constructor is 0, the supplied initargs array may be of length 0 or null. 
If the constructor's declaring class is an inner class in a
non-static context, the first argument to the constructor needs
to be the enclosing instance; see The Java Language
Specification, section 15.9.3.
If the required access and argument checks succeed and the
instantiation will proceed, the constructor's declaring class
is initialized if it has not already been initialized.
If the constructor completes normally, returns the newly
created and initialized instance.
Params:
initargs – array of objects to be passed as arguments to the constructor call; values of primitive types are wrapped in a wrapper object of the appropriate type (e.g. a float in a Float)
Throws:
IllegalAccessException –  if this Constructor object enforces Java language access control and the underlying constructor is inaccessible.
IllegalArgumentException –  if the number of actual
             and formal parameters differ; if an unwrapping
             conversion for primitive arguments fails; or if,
             after possible unwrapping, a parameter value
             cannot be converted to the corresponding formal
             parameter type by a method invocation conversion; if
             this constructor pertains to an enum type.
InstantiationException –    if the class that declares the
             underlying constructor represents an abstract class.
InvocationTargetException – if the underlying constructor
             throws an exception.
ExceptionInInitializerError – if the initialization provoked
             by this method fails.
Returns:
a new object created by calling the constructor
this object represents/**
     * Uses the constructor represented by this {@code Constructor} object to
     * create and initialize a new instance of the constructor's
     * declaring class, with the specified initialization parameters.
     * Individual parameters are automatically unwrapped to match
     * primitive formal parameters, and both primitive and reference
     * parameters are subject to method invocation conversions as necessary.
     *
     * <p>If the number of formal parameters required by the underlying constructor
     * is 0, the supplied {@code initargs} array may be of length 0 or null.
     *
     * <p>If the constructor's declaring class is an inner class in a
     * non-static context, the first argument to the constructor needs
     * to be the enclosing instance; see <i>The Java Language
     * Specification</i>, section 15.9.3.
     *
     * <p>If the required access and argument checks succeed and the
     * instantiation will proceed, the constructor's declaring class
     * is initialized if it has not already been initialized.
     *
     * <p>If the constructor completes normally, returns the newly
     * created and initialized instance.
     *
     * @param initargs array of objects to be passed as arguments to
     * the constructor call; values of primitive types are wrapped in
     * a wrapper object of the appropriate type (e.g. a {@code float}
     * in a {@link java.lang.Float Float})
     *
     * @return a new object created by calling the constructor
     * this object represents
     *
     * @exception IllegalAccessException    if this {@code Constructor} object
     *              enforces Java language access control and the underlying
     *              constructor is inaccessible.
     * @exception IllegalArgumentException  if the number of actual
     *              and formal parameters differ; if an unwrapping
     *              conversion for primitive arguments fails; or if,
     *              after possible unwrapping, a parameter value
     *              cannot be converted to the corresponding formal
     *              parameter type by a method invocation conversion; if
     *              this constructor pertains to an enum type.
     * @exception InstantiationException    if the class that declares the
     *              underlying constructor represents an abstract class.
     * @exception InvocationTargetException if the underlying constructor
     *              throws an exception.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     */
    @CallerSensitive
    public T newInstance(Object ... initargs)
        throws InstantiationException, IllegalAccessException,
               IllegalArgumentException, InvocationTargetException
    {
        if (!override) {
            if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {
                Class<?> caller = Reflection.getCallerClass();
                if (securityCheckCache != caller) {
                    Reflection.ensureMemberAccess(caller, clazz, null, modifiers);
                    securityCheckCache = caller;
                }
            }
        }
        if ((clazz.getModifiers() & Modifier.ENUM) != 0)
            throw new IllegalArgumentException("Cannot reflectively create enum objects");
        if (constructorAccessor == null) acquireConstructorAccessor();
        return (T) constructorAccessor.newInstance(initargs);
    }

    
Returns true if this constructor was declared to take a variable number of arguments; returns false otherwise. 
Returns:
true if an only if this constructor was declared to take a variable number of arguments.
Since:
1.5/**
     * Returns {@code true} if this constructor was declared to take
     * a variable number of arguments; returns {@code false}
     * otherwise.
     *
     * @return {@code true} if an only if this constructor was declared to
     * take a variable number of arguments.
     * @since 1.5
     */
    public boolean isVarArgs() {
        return (getModifiers() & Modifier.VARARGS) != 0;
    }

    
Returns true if this constructor is a synthetic constructor; returns false otherwise. 
Returns:
true if and only if this constructor is a synthetic
constructor as defined by the Java Language Specification.
Since:
1.5/**
     * Returns {@code true} if this constructor is a synthetic
     * constructor; returns {@code false} otherwise.
     *
     * @return true if and only if this constructor is a synthetic
     * constructor as defined by the Java Language Specification.
     * @since 1.5
     */
    public boolean isSynthetic() {
        return Modifier.isSynthetic(getModifiers());
    }

    // NOTE that there is no synchronization used here. It is correct
    // (though not efficient) to generate more than one
    // ConstructorAccessor for a given Constructor. However, avoiding
    // synchronization will probably make the implementation more
    // scalable.
    private void acquireConstructorAccessor() {
        // First check to see if one has been created yet, and take it
        // if so.
        ConstructorAccessor tmp = null;
        if (root != null) tmp = root.getConstructorAccessor();
        if (tmp != null) {
            constructorAccessor = tmp;
            return;
        }
        // Otherwise fabricate one and propagate it up to the root
        tmp = reflectionFactory.newConstructorAccessor(this);
        setConstructorAccessor(tmp);
    }

    // Returns ConstructorAccessor for this Constructor object, not
    // looking up the chain to the root
    ConstructorAccessor getConstructorAccessor() {
        return constructorAccessor;
    }

    // Sets the ConstructorAccessor for this Constructor object and
    // (recursively) its root
    void setConstructorAccessor(ConstructorAccessor accessor) {
        constructorAccessor = accessor;
        // Propagate up
        if (root != null) {
            root.setConstructorAccessor(accessor);
        }
    }

    int getSlot() {
        return slot;
    }

   String getSignature() {
            return signature;
   }

    byte[] getRawAnnotations() {
        return annotations;
    }

    byte[] getRawParameterAnnotations() {
        return parameterAnnotations;
    }

    
Throws:
NullPointerException – {@inheritDoc}
Since:
1.5/**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.5
     */
    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
        if (annotationClass == null)
            throw new NullPointerException();

        return (T) declaredAnnotations().get(annotationClass);
    }

    private static final Annotation[] EMPTY_ANNOTATION_ARRAY=new Annotation[0];

    
Since:
1.5/**
     * @since 1.5
     */
    public Annotation[] getDeclaredAnnotations()  {
        return declaredAnnotations().values().toArray(EMPTY_ANNOTATION_ARRAY);
    }

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

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

    
Returns an array of arrays that represent the annotations on the formal parameters, in declaration order, of the method represented by this Constructor object. (Returns an array of length zero if the underlying method is parameterless. If the method 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. 
Returns:
an array of arrays that represent the annotations on the formal
   parameters, in declaration order, of the method represented by this
   Constructor object
Since:
1.5/**
     * Returns an array of arrays that represent the annotations on the formal
     * parameters, in declaration order, of the method represented by
     * this {@code Constructor} object. (Returns an array of length zero if the
     * underlying method is parameterless.  If the method 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 method represented by this
     *    Constructor object
     * @since 1.5
     */
    public Annotation[][] getParameterAnnotations() {
        int numParameters = parameterTypes.length;
        if (parameterAnnotations == null)
            return new Annotation[numParameters][0];

        Annotation[][] result = AnnotationParser.parseParameterAnnotations(
            parameterAnnotations,
            sun.misc.SharedSecrets.getJavaLangAccess().
                getConstantPool(getDeclaringClass()),
            getDeclaringClass());
        if (result.length != numParameters) {
            Class<?> declaringClass = getDeclaringClass();
            if (declaringClass.isEnum() ||
                declaringClass.isAnonymousClass() ||
                declaringClass.isLocalClass() )
                ; // Can't do reliable parameter counting
            else {
                if (!declaringClass.isMemberClass() || // top-level
                    // Check for the enclosing instance parameter for
                    // non-static member classes
                    (declaringClass.isMemberClass() &&
                     ((declaringClass.getModifiers() & Modifier.STATIC) == 0)  &&
                     result.length + 1 != numParameters) ) {
                    throw new AnnotationFormatError(
                              "Parameter annotations don't match number of parameters");
                }
            }
        }
        return result;
    }
}