structure
Class StructCollection

java.lang.Object
  structure.StructCollection

All Implemented Interfaces:

java.lang.Iterable, java.util.Collection

public class StructCollection
extends java.lang.Object
implements java.util.Collection

This utility class converts a Structure to a Collection. Users are advised to make use of the values method that is part of every Structure that returns a Collection.

This class is necessary because there are certain basic differences in the interfaces of the two classes.

This class works provides a facade: methods of the Collection interface are directly referred to the base Structure, or simple code supports the interface.

Since:

Java Structures, 2nd edition

Field Summary

protected Structure

base The subordinate Structure

Constructor Summary

StructCollection(Structure s)
Constructs a Collection, based on the contents of the subordinate Structure object.

Method Summary

boolean	add(java.lang.Object o) Add an object to the subordinate Structure, and return boolean indicating success.
boolean	addAll(java.util.Collection c) Adds all the elements of another collection (c) into this Structure.
void	clear() Remove all elements from the Structure.
boolean	contains(java.lang.Object o) Returns true iff object o is contained within the subordinate structure.
boolean	containsAll(java.util.Collection c) Returns true if all of the elements of c are contained within the subordinate structure.
boolean	equals(java.lang.Object o) Compare one StructCollection with another.
int	hashCode() Return hash code.
boolean	isEmpty() Detect an empty structure.
java.util.Iterator	iterator() Return an iterator to traverse the subordinate structure.
boolean	remove(java.lang.Object o) Removes an instance of object o, if it appears within structure.
boolean	removeAll(java.util.Collection c) Removes all objects found within collection c from this collection.
boolean	retainAll(java.util.Collection c) Retains elements of this Collection that are also in c.
int	size() Determine the number of elements in this collection.
java.lang.Object[]	toArray() Construct an array of values found in the subordinate Structure.
java.lang.Object[]	toArray(java.lang.Object[] target) Copy elements of this structure into target array.
java.lang.String	toString() Construct a string representation of this class.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

base

protected Structure base

The subordinate Structure

Constructor Detail

StructCollection

public StructCollection(Structure s)

Constructs a Collection, based on the contents of the subordinate Structure object.

Postcondition:

the Collection is a facade for manipulations to a subordinate Structure.

Method Detail

add

public boolean add(java.lang.Object o)

Add an object to the subordinate Structure, and return boolean indicating success.

Specified by:

add in interface java.util.Collection

Returns:

true.

Postcondition:

the object o is added to the Structure, and true is returned

addAll

public boolean addAll(java.util.Collection c)

Adds all the elements of another collection (c) into this Structure. A boolean value of true is returned.

Specified by:

addAll in interface java.util.Collection

Returns:

true if each of the adds returned true.

Precondition:

c is a valid collection

Postcondition:

the elements of c have been added to the Structure, and the value true is returned if all adds returned true.

clear

public void clear()

Remove all elements from the Structure.

Specified by:

clear in interface java.util.Collection

Postcondition:

the subordinate structure is empty

contains

public boolean contains(java.lang.Object o)

Returns true iff object o is contained within the subordinate structure.

Specified by:

contains in interface java.util.Collection

Precondition:

o is a non-null object

Postcondition:

returns true if o is equal to some object in the subordinate structure.

containsAll

public boolean containsAll(java.util.Collection c)

Returns true if all of the elements of c are contained within the subordinate structure.

Specified by:

containsAll in interface java.util.Collection

Returns:

true if c is a subset of this

Precondition:

c is a valid Collection

Postcondition:

returns true if all elements of c appear in this Structure

equals

public boolean equals(java.lang.Object o)

Compare one StructCollection with another.

Specified by:

equals in interface java.util.Collection

Overrides:

equals in class java.lang.Object

Returns:

true iff Structures are equals

Precondition:

o is of similar type to base Structure

Postcondition:

returns true if both objects appear equal as Structures

hashCode

public int hashCode()

Return hash code.

Specified by:

hashCode in interface java.util.Collection

Overrides:

hashCode in class java.lang.Object

Returns:

hash code of subordinate structure.

Postcondition:

hash code returned is the hashcode of the subordinate structure.

isEmpty

public boolean isEmpty()

Detect an empty structure.

Specified by:

isEmpty in interface java.util.Collection

Returns:

true iff subordinate structure is empty.

Postcondition:

returns true iff subordinate structure is empty

iterator

public java.util.Iterator iterator()

Return an iterator to traverse the subordinate structure.

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Returns:

the iterator over the subordinate structure.

Postcondition:

returns an iterator over subordinate strucutre

remove

public boolean remove(java.lang.Object o)

Removes an instance of object o, if it appears within structure.

Specified by:

remove in interface java.util.Collection

Returns:

returns true if instance was found and removed.

Precondition:

o is non-null

Postcondition:

removes up to one instance of o from structure

removeAll

public boolean removeAll(java.util.Collection c)

Removes all objects found within collection c from this collection.

Specified by:

removeAll in interface java.util.Collection

Returns:

true if every element of c could be removed from this.

Precondition:

c is a valid collection

Postcondition:

a copy of each element c is removed from this, if it exists

retainAll

public boolean retainAll(java.util.Collection c)

Retains elements of this Collection that are also in c.

Specified by:

retainAll in interface java.util.Collection

Returns:

true iff this Collection was changed by this operation

Precondition:

c is a valid Collection

Postcondition:

this collection retains only those elements found within both this and c.

size

public int size()

Determine the number of elements in this collection.

Specified by:

size in interface java.util.Collection

Returns:

the number of elements in this collection.

Postcondition:

returns the number of elements in this collection

toArray

public java.lang.Object[] toArray()

Construct an array of values found in the subordinate Structure.

Specified by:

toArray in interface java.util.Collection

Returns:

array containing exactly the elements of this structure

Postcondition:

returns an array of objects containing the values of structure

toArray

public java.lang.Object[] toArray(java.lang.Object[] target)

Copy elements of this structure into target array.

Specified by:

toArray in interface java.util.Collection

Returns:

the array of values

Precondition:

target is valid

Postcondition:

values are copied to target; target is enlarged if necessary to contain the values of this collection; ultimate target is returned.

toString

public java.lang.String toString()

Construct a string representation of this class.

Overrides:

toString in class java.lang.Object

Returns:

string representing this class

Precondition:

base class can stringify itself

Postcondition:

string representation of this class is returned