com.taursys.model
Interface CollectionValueHolder

All Superinterfaces:

java.util.Collection, ValueHolder

All Known Subinterfaces:

ListValueHolder

All Known Implementing Classes:

AbstractCollectionValueHolder, AbstractListValueHolder, ObjectArrayValueHolder, VOListValueHolder

public interface CollectionValueHolder

extends ValueHolder, java.util.Collection

This ValueHolder manages a collection of values. It provides access to a current object via an internal iterator. The next and reset methods control the position in the collection. The hasNext indicates whether there is another object in the collection (used before invoking next).

Method Summary

boolean	add(java.lang.Object o) Ensures that the underlying collection of this holder contains the specified element (optional operation).
boolean	addAll(java.util.Collection c) Adds all of the elements in the specified collection to the underlying collection of this holder (optional operation).
void	clear() Removes all of the elements from the underlying collection of this holder (optional operation).
boolean	contains(java.lang.Object o) Returns true if the underlying collection of this holder contains the specified element.
boolean	containsAll(java.util.Collection c) Returns true if the underlying collection of this holder contains all of the elements in the specified collection.
boolean	equals(java.lang.Object o) Compares the specified object with the underlying collection of this holder for equality.
java.lang.Object	getObject() Returns the object in the current position.
int	hashCode() Returns the hash code value for the underlying collection of this holder.
boolean	hasNext() Indicates whether there is another (any) Objects in the collection.
boolean	isEmpty() Returns true if the underlying collection of this holder contains no elements.
java.util.Iterator	iterator() Returns an iterator over the elements in the underlying collection of this holder.
void	next() Makes the next object in the collection available.
boolean	remove(java.lang.Object o) Removes a single instance of the specified element from this collection, if it is present (optional operation).
boolean	removeAll(java.util.Collection c) Removes all the underlying collection of this holder's elements that are also contained in the specified collection (optional operation).
void	reset() Resets this holder so that you can iterate the collection from the beginning.
boolean	retainAll(java.util.Collection c) Retains only the elements in the underlying collection of this holder that are contained in the specified collection (optional operation).
void	setObject(java.lang.Object obj) Sets (replace/copy) the object in the current position.
int	size() Returns the number of elements in the underlying collection of this holder.
java.lang.Object[]	toArray() Returns an array containing all of the elements in the underlying collection of this holder.
java.lang.Object[]	toArray(java.lang.Object[] a) Returns an array containing all of the elements in the underlying collection of this holder whose runtime type is that of the specified array.

Methods inherited from interface com.taursys.model.ValueHolder

addChangeListener, getAlias, getJavaDataType, getPropertyValue, getPropertyValues, removeChangeListener, setPropertyValue, setPropertyValues

Method Detail

hasNext

public boolean hasNext()

Indicates whether there is another (any) Objects in the collection.

next

public void next()

Makes the next object in the collection available. You should invoke the hasNext method BEFORE invoking this method to ensure that there IS a next object.

reset

public void reset()

Resets this holder so that you can iterate the collection from the beginning.

getObject

public java.lang.Object getObject()

Returns the object in the current position. You should ensure that the current position is valid before invoking this method.

setObject

public void setObject(java.lang.Object obj)

Sets (replace/copy) the object in the current position. You should ensure that the current position is valid before invoking this method. Depending on the specific implementation, the given object may either replace the current object in the list, or the property values of the given object may be copied to the current object in the list.

size

public int size()

Returns the number of elements in the underlying collection of this holder. If the underlying collection of this holder contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface java.util.Collection

Returns:

the number of elements in the underlying collection of this holder

isEmpty

public boolean isEmpty()

Returns true if the underlying collection of this holder contains no elements.

Specified by:

isEmpty in interface java.util.Collection

Returns:

true if the underlying collection of this holder contains no elements

contains

public boolean contains(java.lang.Object o)

Returns true if the underlying collection of this holder contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).

Specified by:

contains in interface java.util.Collection

Parameters:

o - element whose presence in the underlying collection of this holder is to be tested.

Returns:

true if the underlying collection of this holder contains the specified element

iterator

public java.util.Iterator iterator()

Returns an iterator over the elements in the underlying collection of this holder. There are no guarantees concerning the order in which the elements are returned (unless the underlying collection of this holder is an instance of some class that provides a guarantee).

Specified by:

iterator in interface java.util.Collection

Returns:

an Iterator over the elements in the underlying collection of this holder

toArray

public java.lang.Object[] toArray()

Returns an array containing all of the elements in the underlying collection of this holder. If the collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

The returned array will be "safe" in that no references to it are maintained by the underlying collection of this holder. (In other words, this method must allocate a new array even if the underlying collection of this holder is backed by an array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Specified by:

toArray in interface java.util.Collection

Returns:

an array containing all of the elements in the underlying collection of this holder

toArray

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

Returns an array containing all of the elements in the underlying collection of this holder whose runtime type is that of the specified array. If the collection fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of the underlying collection of this holder.

If the underlying collection of this holder fits in the specified array with room to spare (i.e., the array has more elements than the underlying collection of this holder), the element in the array immediately following the end of the collection is set to null. This is useful in determining the length of this collection only if the caller knows that the underlying collection of this holder does not contain any null elements.)

If the underlying collection of this holder makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

Like the toArray method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs

Suppose l is a List known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

     String[] x = (String[]) v.toArray(new String[0]);
 

Note that toArray(new Object[0]) is identical in function to toArray().

Specified by:

toArray in interface java.util.Collection

Parameters:

a - the array into which the elements of the underlying collection of this holder are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of the underlying collection of this holder

Throws:

java.lang.ArrayStoreException - the runtime type of the specified array is not a supertype of the runtime type of every element in this collection.

add

public boolean add(java.lang.Object o)

Ensures that the underlying collection of this holder contains the specified element (optional operation). Returns true if the underlying collection of this holder changed as a result of the call. (Returns false if the underlying collection of this holder does not permit duplicates and already contains the specified element.)

Collections that support this operation may place limitations on what elements may be added to the underlying collection of this holder. In particular, some collections will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. Collection classes should clearly specify in their documentation any restrictions on what elements may be added.

If a collection refuses to add a particular element for any reason other than that it already contains the element, it must throw an exception (rather than returning false). This preserves the invariant that a collection always contains the specified element after this call returns.

Specified by:

add in interface java.util.Collection

Parameters:

o - element whose presence in the underlying collection of this holder is to be ensured.

Returns:

true if the underlying collection of this holder changed as a result of the call

Throws:

java.lang.UnsupportedOperationException - add is not supported by this collection.

java.lang.ClassCastException - class of the specified element prevents it from being added to the underlying collection of this holder.

java.lang.IllegalArgumentException - some aspect of this element prevents it from being added to the underlying collection of this holder.

remove

public boolean remove(java.lang.Object o)

Removes a single instance of the specified element from this collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if the underlying collection of this holder contains one or more such elements. Returns true if the underlying collection of this holder contained the specified element (or equivalently, if the underlying collection of this holder changed as a result of the call).

Specified by:

remove in interface java.util.Collection

Parameters:

o - element to be removed from the underlying collection of this holder, if present.

Returns:

true if the underlying collection of this holder changed as a result of the call

Throws:

java.lang.UnsupportedOperationException - remove is not supported by this collection.

containsAll

public boolean containsAll(java.util.Collection c)

Returns true if the underlying collection of this holder contains all of the elements in the specified collection.

Specified by:

containsAll in interface java.util.Collection

Parameters:

c - collection to be checked for containment in the underlying collection of this holder.

Returns:

true if the underlying collection of this holder contains all of the elements in the specified collection

See Also:

contains(Object)

addAll

public boolean addAll(java.util.Collection c)

Adds all of the elements in the specified collection to the underlying collection of this holder (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified collection is the underlying collection of this holder, and the underlying collection of this holder is nonempty.)

Specified by:

addAll in interface java.util.Collection

Parameters:

c - elements to be inserted into the underlying collection of this holder.

Returns:

true if the underlying collection of this holder changed as a result of the call

Throws:

java.lang.UnsupportedOperationException - if the underlying collection of this holder does not support the addAll method.

java.lang.ClassCastException - if the class of an element of the specified collection prevents it from being added to the underlying collection of this holder.

java.lang.IllegalArgumentException - some aspect of an element of the specified collection prevents it from being added to this collection.

See Also:

add(Object)

removeAll

public boolean removeAll(java.util.Collection c)

Removes all the underlying collection of this holder's elements that are also contained in the specified collection (optional operation). After this call returns, the underlying collection of this holder will contain no elements in common with the specified collection.

Specified by:

removeAll in interface java.util.Collection

Parameters:

c - elements to be removed from the underlying collection of this holder.

Returns:

true if the underlying collection of this holder changed as a result of the call

Throws:

java.lang.UnsupportedOperationException - if the removeAll method is not supported by the underlying collection of this holder.

See Also:

remove(Object), contains(Object)

retainAll

public boolean retainAll(java.util.Collection c)

Retains only the elements in the underlying collection of this holder that are contained in the specified collection (optional operation). In other words, removes from the underlying collection of this holder all of its elements that are not contained in the specified collection.

Specified by:

retainAll in interface java.util.Collection

Parameters:

c - elements to be retained in the underlying collection of this holder.

Returns:

true if the underlying collection of this holder changed as a result of the call

Throws:

java.lang.UnsupportedOperationException - if the retainAll method is not supported by this Collection.

See Also:

remove(Object), contains(Object)

clear

public void clear()

Removes all of the elements from the underlying collection of this holder (optional operation). This collection will be empty after this method returns unless it throws an exception.

Specified by:

clear in interface java.util.Collection

Throws:

java.lang.UnsupportedOperationException - if the clear method is not supported by the underlying collection of this holder.

equals

public boolean equals(java.lang.Object o)

Compares the specified object with the underlying collection of this holder for equality.

While the Collection interface adds no stipulations to the general contract for the Object.equals, programmers who implement the Collection interface "directly" (in other words, create a class that is a Collection but is not a Set or a List) must exercise care if they choose to override the Object.equals. It is not necessary to do so, and the simplest course of action is to rely on Object's implementation, but the implementer may wish to implement a "value comparison" in place of the default "reference comparison." (The List and Set interfaces mandate such value comparisons.)

The general contract for the Object.equals method states that equals must be symmetric (in other words, a.equals(b) if and only if b.equals(a)). The contracts for List.equals and Set.equals state that lists are only equal to other lists, and sets to other sets. Thus, a custom equals method for a collection class that implements neither the List nor Set interface must return false when the underlying collection of this holder is compared to any list or set. (By the same logic, it is not possible to write a class that correctly implements both the Set and List interfaces.)

Specified by:

equals in interface java.util.Collection

Parameters:

o - Object to be compared for equality with the underlying collection of this holder.

Returns:

true if the specified object is equal to this collection

See Also:

Object.equals(Object)

hashCode

public int hashCode()

Returns the hash code value for the underlying collection of this holder. While the Collection interface adds no stipulations to the general contract for the Object.hashCode method, programmers should take note that any class that overrides the Object.equals method must also override the Object.hashCode method in order to satisfy the general contract for the Object.hashCodemethod. In particular, c1.equals(c2) implies that c1.hashCode()==c2.hashCode().

Specified by:

hashCode in interface java.util.Collection

Returns:

the hash code value for the underlying collection of this holder

See Also:

Object.hashCode(), Object.equals(Object)