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Java Fundamental Classes Reference

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The java.util Package
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Dictionary

Name

Dictionary

Synopsis

Class Name:

java.util.Dictionary

Superclass:

java.lang.Object

Immediate Subclasses:

java.util.Hashtable

Interfaces Implemented:

None

Availability:

JDK 1.0 or later

Description

The Dictionary class is an abstract class that associates keys with values. Any non-null object can be used as a key or as a value. Key/value pairs can be stored in a Dictionary, and values can be retrieved or removed using their associated keys.

A subclass of Dictionary should use the equals() method to decide if two keys are equivalent.

Class Summary

public abstract class java.util.Dictionary extends java.lang.Object {
  // Instance Methods
  public abstract Enumeration elements();
  public abstract Object get(Object key);
  public abstract boolean isEmpty();
  public abstract Enumeration keys();
  public abstract Object put(Object key, Object value);
  public abstract Object remove(Object key);
  public abstract int size();
}

Instance Methods

elements

public abstract Enumeration elements()

Returns

The values in the dictionary as an Enumeration.

Description

This method returns an Enumeration that iterates through the values in this Dictionary.

get

public abstract Object get(Object key)

Parameters

key

The key of the value to retrieve.

Returns

The value that corresponds to this key.

Description

This method returns the value that is associated with the given key.

isEmpty

public abstract boolean isEmpty()

Returns

true if there are no values in the Dictionary7thinsp;; false otherwise.

Description

This method returns a boolean value that indicates whether or not the Dictionary is empty.

keys

public abstract Enumeration keys()

Returns

The keys in the dictionary as an Enumeration.

Description

This method returns an Enumeration that iterates through the keys in this Dictionary.

put

public abstract Object put(Object key, Object value)

Parameters

key

A key object.

value

A value object.

Returns

The previous value associated with the given key or null if key has not previously been associated with a value.

Throws

NullPointerException

If either the key or the value is null.

Description

This method associates the given key with the given value in this Dictionary.

remove

public abstract Object remove(Object key)

Parameters

key

The key of the value to remove.

Returns

The value associated with the given key or null if key is not associated with a value.

Description

This method removes a key/value pair from this Dictionary. If the given key is not in the Dictionary, the method does nothing.

size

public abstract int size()

Returns

The number of keys in the Dictionary.

Description

This method returns the number of key/value pairs in this Dictionary.

Inherited Methods

Method

Inherited From

Method

Inherited From

clone()

Object

equals(Object)

Object

finalize()

Object

getClass()

Object

hashCode()

Object

notify()

Object

notifyAll()

Object

toString()

Object

wait()

Object

wait(long)

Object

wait(long, int)

Object

   

See Also

Enumeration, Hashtable, NullPointerException


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