structure
Class AbstractStructure

java.lang.Object
  |
  +--structure.AbstractStructure

All Implemented Interfaces:

Structure

Direct Known Subclasses:

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

public abstract class AbstractStructure

extends Object

implements Structure

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

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, notify, notifyAll, registerNatives, 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.

Method Detail

isEmpty

public boolean isEmpty()

Determine if there are elements within the structure.

Specified by:

isEmpty in interface Structure

Postcondition:

return true iff the structure is empty

Returns:

true if the structure is empty; false otherwise

elements

public 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

Precondition:

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

Postcondition:

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

Returns:

a Enumeration for traversing the structure

See Also:

AbstractIterator, Iterator, Enumeration

contains

public boolean contains(Object value)

Determines if the structure contains a value.

Specified by:

contains in interface Structure

Parameters:

value - non-null value to be found within structure

Precondition:

value is non-null

Postcondition:

returns true iff value.equals some value in structure

Returns:

true when some value equals value

hashCode

public int hashCode()

Overrides:

hashCode in class Object

Postcondition:

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

values

public Collection 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

Postcondition:

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

Returns:

a Collection that is equivalent to this structure

See Also:

StructCollection, Collection