java.util
Class Hashtable.Entry

java.lang.Object
  java.util.Hashtable.Entry

All Implemented Interfaces:

Map.Entry

Enclosing class:

Hashtable

private static class Hashtable.Entry

extends Object

implements Map.Entry

Hashtable collision list.

Field Summary

(package private) int	hash
(package private) Object	key
(package private) Hashtable.Entry	next
(package private) Object	value

Constructor Summary

protected

Hashtable.Entry(int hash, Object key, Object value, Hashtable.Entry next)

Method Summary

protected Object	clone() Creates and returns a copy of this object.
boolean	equals(Object o) Compares the specified object with this entry for equality.
Object	getKey() Returns the key corresponding to this entry.
Object	getValue() Returns the value corresponding to this entry.
int	hashCode() Returns the hash code value for this map entry.
Object	setValue(Object value) Replaces the value corresponding to this entry with the specified value (optional operation).
String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

hash

int hash

key

Object key

value

Object value

next

Hashtable.Entry next

Constructor Detail

Hashtable.Entry

protected Hashtable.Entry(int hash,
                          Object key,
                          Object value,
                          Hashtable.Entry next)

Method Detail

clone

protected Object clone()

Description copied from class: Object

Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression:

 x.clone() != x

will be true, and that the expression:

 x.clone().getClass() == x.getClass()

will be true, but these are not absolute requirements. While it is typically the case that:

 x.clone().equals(x)

will be true, this is not an absolute requirement.

By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

The method clone for class Object performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable, then a CloneNotSupportedException is thrown. Note that all arrays are considered to implement the interface Cloneable. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.

The class Object does not itself implement the interface Cloneable, so calling the clone method on an object whose class is Object will result in throwing an exception at run time.

Overrides:

clone in class Object

Returns:

a clone of this instance.

See Also:

Cloneable

getKey

public Object getKey()

Description copied from interface: Map.Entry

Returns the key corresponding to this entry.

Specified by:

getKey in interface Map.Entry

Returns:

the key corresponding to this entry.

getValue

public Object getValue()

Description copied from interface: Map.Entry

Returns the value corresponding to this entry. If the mapping has been removed from the backing map (by the iterator's remove operation), the results of this call are undefined.

Specified by:

getValue in interface Map.Entry

Returns:

the value corresponding to this entry.

setValue

public Object setValue(Object value)

Description copied from interface: Map.Entry

Replaces the value corresponding to this entry with the specified value (optional operation). (Writes through to the map.) The behavior of this call is undefined if the mapping has already been removed from the map (by the iterator's remove operation).

Specified by:

setValue in interface Map.Entry

Parameters:

value - new value to be stored in this entry.

Returns:

old value corresponding to the entry.

equals

public boolean equals(Object o)

Description copied from interface: Map.Entry

Compares the specified object with this entry for equality. Returns true if the given object is also a map entry and the two entries represent the same mapping. More formally, two entries e1 and e2 represent the same mapping if

     (e1.getKey()==null ?
      e2.getKey()==null : e1.getKey().equals(e2.getKey()))  &&
     (e1.getValue()==null ?
      e2.getValue()==null : e1.getValue().equals(e2.getValue()))
 

This ensures that the equals method works properly across different implementations of the Map.Entry interface.

Specified by:

equals in interface Map.Entry

Overrides:

equals in class Object

Parameters:

o - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), Hashtable

hashCode

public int hashCode()

Description copied from interface: Map.Entry

Returns the hash code value for this map entry. The hash code of a map entry e is defined to be:

     (e.getKey()==null   ? 0 : e.getKey().hashCode()) ^
     (e.getValue()==null ? 0 : e.getValue().hashCode())
 

This ensures that e1.equals(e2) implies that e1.hashCode()==e2.hashCode() for any two Entries e1 and e2, as required by the general contract of Object.hashCode.

Specified by:

hashCode in interface Map.Entry

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

toString

public String toString()

Description copied from class: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.