structure5
Class StructCollection<E>

java.lang.Object
  structure5.StructCollection<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>

public class StructCollection<E>
extends java.lang.Object
implements java.util.Collection<E>

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.

Example Usage:

 public static void main(String[] argv){
      Structure struct = new Vector();
      for(int i = 0; i < argv.length; i++) struct.add(argv[i]);
      Collection collect = new StructCollection(struct);
 } 
 

Since:

Java Structures, 2nd edition

Field Summary

protected Structure<E>

base The subordinate Structure

Constructor Summary

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

Method Summary

boolean	add(E o) Add an object to the subordinate Structure, and return boolean indicating success.
boolean	addAll(java.util.Collection<? extends E> 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<E>	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.
<T> T[]	toArray(T[] 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<E> base

The subordinate Structure

Constructor Detail

StructCollection

public StructCollection(Structure<E> 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(E o)

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

Specified by:

add in interface java.util.Collection<E>

Returns:

true.

Postcondition:

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

addAll

public boolean addAll(java.util.Collection<? extends E> 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<E>

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<E>

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<E>

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<E>

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<E>

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<E>

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<E>

Returns:

true iff subordinate structure is empty.

Postcondition:

returns true iff subordinate structure is empty

iterator

public java.util.Iterator<E> iterator()

Return an iterator to traverse the subordinate structure.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

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<E>

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<E>

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<E>

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<E>

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<E>

Returns:

array containing exactly the elements of this structure

Postcondition:

returns an array of objects containing the values of structure

toArray

public <T> T[] toArray(T[] target)

Copy elements of this structure into target array.

Specified by:

toArray in interface java.util.Collection<E>

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