/*

 * Copyright (c) 1996, 2010, 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.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;

/**

 * {@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;

    // 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.

     */

    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.

     */

    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<>(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 {@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

     * the binary name of the constructor's declaring class.

     */

    public String getName() {

        return getDeclaringClass().getName();

    }

    /**

     * 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 {@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>

     * @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 {@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 {@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

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

     * @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 {@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 {@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 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

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

     * @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 {@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 {@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 {@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() & Modifier.constructorModifiers();

            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 {@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.

     *

     * If this constructor was declared to take a variable number of

     * arguments, instead of denoting the last parameter as

     * "<tt><i>Type</i>[]</tt>", it is denoted as

     * "<tt><i>Type</i>...</tt>".

     *

     * 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() & Modifier.constructorModifiers();

            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());

                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 + ">";

        }

    }

    /**

     * 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 section 15.9.3 of

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

     *

     * <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

     *              is enforcing 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.

     */

    public T newInstance(Object ... initargs)

        throws InstantiationException, IllegalAccessException,

               IllegalArgumentException, InvocationTargetException

    {

        if (!override) {

            if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {

                Class<?> caller = Reflection.getCallerClass(2);

                checkAccess(caller, clazz, null, modifiers);

            }

        }

        if ((clazz.getModifiers() & Modifier.ENUM) != 0)

            throw new IllegalArgumentException("Cannot reflectively create enum objects");

        ConstructorAccessor ca = constructorAccessor;   // read volatile

        if (ca == null) {

            ca = acquireConstructorAccessor();

        }

        return (T) ca.newInstance(initargs);

    }

    /**

     * 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 {@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

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

     * @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 ConstructorAccessor 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;

        } else {

            // Otherwise fabricate one and propagate it up to the root

            tmp = reflectionFactory.newConstructorAccessor(this);

            setConstructorAccessor(tmp);

        }

        return 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

     */

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

        if (annotationClass == null)

            throw new NullPointerException();

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

    }

    /**

     * @since 1.5

     */

    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) {

            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 {@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;

    }

}