structure
Class AbstractStructure<ELTTYPE>

java.lang.Object
  structure.AbstractStructure<ELTTYPE>

All Implemented Interfaces:

java.lang.Iterable<ELTTYPE>, Structure<ELTTYPE>

Direct Known Subclasses:

AbstractLinear, AbstractList, AbstractSet, BinarySearchTree, GraphList, GraphMatrix, OrderedList, OrderedVector, RedBlackSearchTree

public abstract class AbstractStructure<ELTTYPE>
extends java.lang.Object
implements Structure<ELTTYPE>

An abstract implementation of a basic, mutable data structure.

This abstract implementation of the Structure interface provides a good starting point for the implementation of a basic, mutable data structure. This implementation provides a workable implementation of isEmpty, contains, and values.

Where more efficient implementations are possible, the user may wish to override these methods. For example, an implementor may have a structure directly implement the java.util.Collection interface and have the value method simply return this. Because of peculiarities of both systems of designing data structures, it is often best to avoid direct implementation java.util.Collection and Structure in one class.

Since:

Java Structures, 2nd edition

Constructor Summary

AbstractStructure()
The default constructor.

Method Summary

boolean	contains(ELTTYPE value) Determines if the structure contains a value.
java.util.Enumeration	elements() Return an enumeration associated with this structure.
int	hashCode()
boolean	isEmpty() Determine if there are elements within the structure.
java.util.Collection<ELTTYPE>	values() Returns a java.util.Collection wrapping this structure.

Methods inherited from class java.lang.Object

equals, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface structure.Structure

add, clear, iterator, remove, size

Constructor Detail

AbstractStructure

public AbstractStructure()

The default constructor. Initializes any internal variables.

Post:

initializes internal variables

Method Detail

isEmpty

public boolean isEmpty()

Determine if there are elements within the structure.

Specified by:

isEmpty in interface Structure<ELTTYPE>

Returns:

true if the structure is empty; false otherwise

Post:

return true iff the structure is empty

elements

public java.util.Enumeration elements()

Return an enumeration associated with this structure. This implementation returns an AbstractIterator which supports both enumeration at iterator techniques.

Specified by:

elements in interface Structure<ELTTYPE>

Returns:

a Enumeration for traversing the structure

See Also:

AbstractIterator, Iterator, Enumeration

Pre:

this implementation assumes the structure returns an AbstractIterator, which may then be used for generating the Enumeration.

Post:

return an enumeration for traversing the struture; all structure package implementations return an AbstractIterator

contains

public boolean contains(ELTTYPE value)

Determines if the structure contains a value.

Specified by:

contains in interface Structure<ELTTYPE>

Parameters:

value - non-null value to be found within structure

Returns:

true when some value equals value

Pre:

value is non-null

Post:

returns true iff value.equals some value in structure

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

Post:

generate a hashcode for the structure: sum of all the hash codes of elements

values

public java.util.Collection<ELTTYPE> values()

Returns a java.util.Collection wrapping this structure. This particular implementation returns a StructCollection whose methods may not provide the most efficent implementations of non-Structure Collection methods.

Specified by:

values in interface Structure<ELTTYPE>

Returns:

a Collection that is equivalent to this structure

See Also:

StructCollection, Collection

Post:

returns a Collection that may be used with Java's Collection Framework