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/* java.lang.reflect.Constructor - reflection of Java constructors

   Copyright (C) 1998, 2001 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package java.lang.reflect;

import java.util.Arrays;

/**

 * The Constructor class represents a constructor of a class. It also allows

 * dynamic creation of an object, via reflection. Invocation on Constructor

 * objects knows how to do widening conversions, but throws

 * {@link IllegalArgumentException} if a narrowing conversion would be

 * necessary. You can query for information on this Constructor regardless

 * of location, but construction access may be limited by Java language

 * access controls. If you can't do it in the compiler, you can't normally

 * do it here either.<p>

 *

 * <B>Note:</B> This class returns and accepts types as Classes, even

 * primitive types; there are Class types defined that represent each

 * different primitive type.  They are <code>java.lang.Boolean.TYPE,

 * java.lang.Byte.TYPE,</code>, also available as <code>boolean.class,

 * byte.class</code>, etc.  These are not to be confused with the

 * classes <code>java.lang.Boolean, java.lang.Byte</code>, etc., which are

 * real classes.<p>

 *

 * Also note that this is not a serializable class.  It is entirely feasible

 * to make it serializable using the Externalizable interface, but this is

 * on Sun, not me.

 *

 * @author John Keiser

 * @author Eric Blake <ebb9@email.byu.edu>

 * @see Member

 * @see Class

 * @see java.lang.Class#getConstructor(Object[])

 * @see java.lang.Class#getDeclaredConstructor(Object[])

 * @see java.lang.Class#getConstructors()

 * @see java.lang.Class#getDeclaredConstructors()

 * @since 1.1

 * @status updated to 1.4

 */

public final class Constructor

extends AccessibleObject implements Member

{

  private Class clazz;

  private int slot;

  /**

   * This class is uninstantiable except from native code.

   */

  private Constructor(Class declaringClass,int slot)

  {

    this.clazz = declaringClass;

    this.slot = slot;

  }

  private Constructor()

  {

  }

  /**

   * Gets the class that declared this constructor.

   * @return the class that declared this member

   */

  public Class getDeclaringClass()

  {

    return clazz;

  }

  /**

   * Gets the name of this constructor (the non-qualified name of the class

   * it was declared in).

   * @return the name of this constructor

   */

  public String getName()

  {

    return getDeclaringClass().getName();

  }

  /**

   * Gets the modifiers this constructor uses.  Use the <code>Modifier</code>

   * class to interpret the values. A constructor can only have a subset of the

   * following modifiers: public, private, protected.

   *

   * @return an integer representing the modifiers to this Member

   * @see Modifier

   */

  public native int getModifiers();

  /**

   * Get the parameter list for this constructor, in declaration order. If the

   * constructor takes no parameters, returns a 0-length array (not null).

   *

   * @return a list of the types of the constructor's parameters

   */

  public native Class[] getParameterTypes();

  /**

   * Get the exception types this constructor says it throws, in no particular

   * order. If the constructor has no throws clause, returns a 0-length array

   * (not null).

   *

   * @return a list of the types in the constructor's throws clause

   */

  public native Class[] getExceptionTypes();

  /**

   * Compare two objects to see if they are semantically equivalent.

   * Two Constructors are semantically equivalent if they have the same

   * declaring class and the same parameter list.  This ignores different

   * exception clauses, but since you can't create a Method except through the

   * VM, this is just the == relation.

   *

   * @param o the object to compare to

   * @return <code>true</code> if they are equal; <code>false</code> if not.

   */

  public boolean equals(Object o)

  {

    if (!(o instanceof Constructor))

      return false;

    Constructor that = (Constructor)o;

    if (this.getDeclaringClass() != that.getDeclaringClass())

      return false;

    if (!Arrays.equals(this.getParameterTypes(), that.getParameterTypes()))

      return false;

    return true;

  }

  /**

   * Get the hash code for the Constructor. The Constructor hash code is the

   * hash code of the declaring class's name.

   *

   * @return the hash code for the object

   */

  public int hashCode()

  {

    return getDeclaringClass().getName().hashCode();

  }

  /**

   * Get a String representation of the Constructor. A Constructor's String

   * representation is "<modifier> <classname>(<paramtypes>)

   * throws <exceptions>", where everything after ')' is omitted if

   * there are no exceptions.<br> Example:

   * <code>public java.io.FileInputStream(java.lang.Runnable)

   * throws java.io.FileNotFoundException</code>

   *

   * @return the String representation of the Constructor

   */

  public String toString()

  {

    // 128 is a reasonable buffer initial size for constructor

    StringBuffer sb = new StringBuffer(128);

    Modifier.toString(getModifiers(), sb).append(' ');

    sb.append(getDeclaringClass().getName()).append('(');

    Class[] c = getParameterTypes();

    if (c.length > 0)

      {

        sb.append(c[0].getName());

        for (int i = 1; i < c.length; i++)

          sb.append(',').append(c[i].getName());

      }

    sb.append(')');

    c = getExceptionTypes();

    if (c.length > 0)

      {

        sb.append(" throws ").append(c[0].getName());

        for (int i = 1; i < c.length; i++)

          sb.append(',').append(c[i].getName());

      }

    return sb.toString();

  }

  /**

   * Create a new instance by invoking the constructor. Arguments are

   * automatically unwrapped and widened, if needed.<p>

   *

   * If this class is abstract, you will get an

   * <code>InstantiationException</code>. If the constructor takes 0

   * arguments, you may use null or a 0-length array for <code>args</code>.<p>

   *

   * If this Constructor enforces access control, your runtime context is

   * evaluated, and you may have an <code>IllegalAccessException</code> if

   * you could not create this object in similar compiled code. If the class

   * is uninitialized, you trigger class initialization, which may end in a

   * <code>ExceptionInInitializerError</code>.<p>

   *

   * Then, the constructor is invoked. If it completes normally, the return

   * value will be the new object. If it completes abruptly, the exception is

   * wrapped in an <code>InvocationTargetException</code>.

   *

   * @param args the arguments to the constructor

   * @return the newly created object

   * @throws IllegalAccessException if the constructor could not normally be

   *         called by the Java code (i.e. it is not public)

   * @throws IllegalArgumentException if the number of arguments is incorrect;

   *         or if the arguments types are wrong even with a widening

   *         conversion

   * @throws InstantiationException if the class is abstract

   * @throws InvocationTargetException if the constructor throws an exception

   * @throws ExceptionInInitializerError if construction triggered class

   *         initialization, which then failed

   */

  public Object newInstance(Object args[])

    throws InstantiationException, IllegalAccessException,

           InvocationTargetException

  {

    return constructNative(args, clazz, slot);

  }

  private native Object constructNative(Object[] args, Class declaringClass,

                                        int slot)

    throws InstantiationException, IllegalAccessException,

           InvocationTargetException;

}