java.lang.reflect

Class Constructor

Implemented Interfaces:
Member

public final class Constructor
extends AccessibleObject
implements Member

Fields inherited from interface java.lang.reflect.Member

DECLARED, PUBLIC

Method Summary

boolean
equals(Object o)
Determine whether this Object is semantically equal to another Object.
Class
getDeclaringClass()
Gets the class that declared this member.
Class[]
getExceptionTypes()
int
getModifiers()
Gets the modifiers this member uses.
String
getName()
Gets the simple name of this member.
Class[]
getParameterTypes()
int
hashCode()
Get a value that represents this Object, as uniquely as possible within the confines of an int.
Object
newInstance(args[] )
String
toString()
Convert this Object to a human-readable String.

Methods inherited from class java.lang.reflect.AccessibleObject

isAccessible, setAccessible, setAccessible

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

equals

public boolean equals(Object o)
Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

  • It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
  • It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
  • It must be reflexive. a.equals(a) must always be true.
  • It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
  • a.equals(null) must be false.
  • It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

Overrides:
equals in interface Object

Parameters:

Returns:
whether this Object is semantically equal to another

See Also:
Object.hashCode()


getDeclaringClass

public Class getDeclaringClass()
Gets the class that declared this member. This is not the class where this method was called, or even the class where this Member object came to life, but the class that declares the member this represents.
Specified by:
getDeclaringClass in interface Member

Returns:
the class that declared this member


getExceptionTypes

public Class[] getExceptionTypes()


getModifiers

public int getModifiers()
Gets the modifiers this member uses. Use the Modifier class to interpret the values.
Specified by:
getModifiers in interface Member

Returns:
an integer representing the modifiers to this Member

See Also:
Modifier


getName

public String getName()
Gets the simple name of this member. This will be a valid Java identifier, with no qualification.
Specified by:
getName in interface Member

Returns:
the name of this member


getParameterTypes

public Class[] getParameterTypes()


hashCode

public int hashCode()
Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

  • Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
  • It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)

Overrides:
hashCode in interface Object

Returns:
the hash code for this Object

See Also:
Object.equals(Object), System.identityHashCode(Object)


newInstance

public Object newInstance(args[] )
            throws InstantiationException,
                   IllegalAccessException,
                   InvocationTargetException


toString

public String toString()
Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it into System.out.println() and such.

It is typical, but not required, to ensure that this method never completes abruptly with a RuntimeException.

This method will be called when performing string concatenation with this object. If the result is null, string concatenation will instead use "null".

The default implementation returns getClass().getName() + "@" + Integer.toHexString(hashCode()).

Overrides:
toString in interface Object

Returns:
the String representing this Object, which may be null

See Also:
Object.getClass(), Object.hashCode(), Class.getName(), Integer.toHexString(int)


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.