structure
Class KeyIterator

java.lang.Object
  |
  +--structure.AbstractIterator
        |
        +--structure.KeyIterator

All Implemented Interfaces:

Enumeration, Iterator

class KeyIterator

extends AbstractIterator

A private master iterator for filtering the key fields from an Association-returning iterator. This iterator returns objects of the Comparable type, and is publically available throught the Hashtable.keys() method.

Typical use:

      Hashtable h = new Hashtable();
      // ...hashtable gets built up...
      Iterator hi = h.keys();
      while (hi.hasNext())
      {
          System.out.println(ai.next());
      }
 

Field Summary

protected Iterator

slave The underlying iterator.

Constructor Summary

KeyIterator(Iterator slave)
Construct a new key iterator that filters the slave iterator, an Association-returning iterator.

Method Summary

Object	get() Returns the current key from the slave iterator.
boolean	hasNext() Returns true if an association is available for generating a key.
Object	next() Returns the current key, and increments the iterator.
void	reset() Resets the slave iterator (and thus the key iterator) to the first association in the structure.

Methods inherited from class structure.AbstractIterator

hasMoreElements, nextElement, remove, value

Methods inherited from class java.lang.Object

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

Field Detail

slave

protected Iterator slave

The underlying iterator. The slave iterator provides the key iterator values which are Associations. The key iterator returns only the key-portion of the Associations.

Constructor Detail

KeyIterator

public KeyIterator(Iterator slave)

Construct a new key iterator that filters the slave iterator, an Association-returning iterator.

Parameters:

slave - The slave iterator.

Method Detail

reset

public void reset()

Resets the slave iterator (and thus the key iterator) to the first association in the structure.

Overrides:

reset in class AbstractIterator

Postcondition:

resets iterator to point to first key

hasNext

public boolean hasNext()

Returns true if an association is available for generating a key.

Overrides:

hasNext in class AbstractIterator

Postcondition:

returns true if current element is valid

Returns:

True if a valid key can be generated.

next

public Object next()

Returns the current key, and increments the iterator.

Overrides:

next in class AbstractIterator

Precondition:

hasNext()

Postcondition:

returns current value and increments iterator

Returns:

The current key, before iterator is incremented.

get

public Object get()

Returns the current key from the slave iterator.

Overrides:

get in class AbstractIterator

Precondition:

current value is valid

Postcondition:

returns current value

Returns:

The current key associated with the iterator.