Agent System POND 1.2 (28.2.2002)

FIM.Util
Class FilterEnumeration

java.lang.Object
  |
  +--FIM.Util.FilterEnumeration
All Implemented Interfaces:
Enumeration
Direct Known Subclasses:
CookieEnumeration, KeyOrCertificateEnumeration, StatementEnumeration

public abstract class FilterEnumeration
extends Object
implements Enumeration

An enumeration of objects matching a certain criteria. It is based on another enumeration from which only elements will be returned, which match certain criteria. Subclasses must implement the actual filtering function protected boolean matchesFilter(Object toTest).

Version:
1.0, 1.7.2000
Author:
Michael Sonntag

Constructor Summary
protected FilterEnumeration()
          Creates a new enumeration for filtering another enumeration.
 
Method Summary
 boolean hasMoreElements()
          Tests if this enumeration contains more matching elements.
protected abstract  boolean matchesFilter(Object toTest)
          The function implementing the filtering function.
 Object nextElement()
          Returns the next matching element of this enumeration.
protected  void setBaseEnumeration(Enumeration fullEnum)
          Sets the enumeration for filtering objects from another enumeration.
 
Methods inherited from class java.lang.Object
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FilterEnumeration

protected FilterEnumeration()
Creates a new enumeration for filtering another enumeration.
Method Detail

setBaseEnumeration

protected void setBaseEnumeration(Enumeration fullEnum)
Sets the enumeration for filtering objects from another enumeration.
The filtering parameters of the subclass must be set when this function is called. Calls to matchesFilter(Object toTest) must be possible!
Parameters:
fullEnum - the enumeration of all elements which will be filtered
Throws:
IllegalArgumentException - if the parameter is null
IllegalStateException - if the base enumeration is already set

hasMoreElements

public boolean hasMoreElements()
Tests if this enumeration contains more matching elements.
Specified by:
hasMoreElements in interface Enumeration
Returns:
true if this enumeration contains more matching elements; false otherwise
Throws:
IllegalStateException - if the base enumeration is not set

nextElement

public Object nextElement()
Returns the next matching element of this enumeration.
Specified by:
nextElement in interface Enumeration
Returns:
the next matching element of this enumeration
Throws:
NoSuchElementException - if no more matching elements exist
IllegalStateException - if the base enumeration is not set

matchesFilter

protected abstract boolean matchesFilter(Object toTest)
The function implementing the filtering function.
Parameters:
totest - the object to test if it matches the filter
Returns:
true if the element should be returned; false if this element does not match the criteria and should be suppressed

Agent System POND 1.2 (28.2.2002)

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Copyright 2001,2002 Michael Sonntag & Institute for Information Processing and Microprocessor Technology (FIM), Johannes-Kepler-University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.