ObjSort Specification Sheet


ObjectPak Objective C Class Library

ObjSort

Inherits from:ObjPak

Class Description

ObjSort instances are groups of objects that are kept in sorted order (by default, the first object is the smallest with respect to compare:). Inserting and searching objects in such a sorted collection can be faster than using, say an ObjCltn object collection.

Creating An Instance

The method new creates an instance that sorts its elements with respect to compare:. The method newDictCompare sends dictCompare: messages to compare pairs of elements.

Adding Objects

Normally, you insert an object with the add: method. This method allows you to add an object to the collection, even when it is equal to an element in the collection (when the comparison method returns zero; because you can use a different method than compare:, this doesn't necessarily mean that isEqual: returns YES).

You can also choose not to add duplicate entries. The addNTest: method adds if the object was absent and returns a value that can be used to test whether the object was found or not. The filter: method frees a new entry when it's a duplicate. The replace: method always replaces duplicates (returning the object that was previously in the collection).

Method Types

Creation

Interrogation

Comparing

Adding

Removing

Adding and Removing Contents

Locating

Printing

NextStep Archiving

Methods



new

+ new

Returns a new instance that sorts its contents with respect to compare:.



newDictCompare

+ newDictCompare

Returns a new instance that sorts its contents with respect to dictCompare:.



copy

- copy

Returns a new copy of the object (without copying the elements).



deepCopy

- deepCopy

Returns a new copy of the object. The elements in the new copy are deep copies of the elements in the original object.



emptyYourself

- emptyYourself

Empties all the members of the object (without freeing them). Returns the receiver.



freeContents

- freeContents

Removes and frees the contents of the object, but doesn't free the object itself. Returns the receiver.



free

- free

Frees the object, but not its contents. Returns nil. Do :

aSort = [[aSort freeObjects] free];
if you want to free the object and its contents.



size

- (unsigned) size

Returns the number of elements in the object.



isEmpty

- (BOOL) isEmpty

Whether the number of elements is equal to zero.



eachElement

- eachElement

Returns a sequence of sorted elements. The first element in the sequence is the smallest with respect to the ordering.

aSeq = [aSort eachElement];
while ((anElement = [aSeq next])) {
    /* do something */
}
aSeq = [aSeq free];


hash

- (unsigned) hash

Returns a hash value based on the receiver's address and the results of sending the hash message to the contents.



isEqual:

- (BOOL) isEqual : aSort

Returns YES if aSort is an ObjSort instance, and if each member of its contents responds affirmatively to the message isEqual: when compared to the corresponding member of the receiver's contents.



add:

- add : anObject

Adds anObject to the receiver, keeping the contents of the object sorted. Duplicate entries are allowed. Returns the receiver.



addNTest:

- addNTest : anObject

Adds anObject if it was not previously in the set. Returns anObject if the addition takes place, otherwise returns nil.



filter:

- filter : anObject

If anObject compares equally to some object in the contents of the receiver, then anObject is freed, and the matching object is returned. Otherwise, anObject is added and returned.



replace:

- replace : anObject

If a matching object is found, then anObject replaces that object, and the matching object is returned. If there is no matching object, anObject is added to the receiver, and nil is returned.



remove:

- remove : oldObject

Removes oldObject or the element that matches (when the compare method returns zero). Returns the removed entry, or nil if there is no matching entry.

Note: Not implemented



addContentsTo:

- addContentsTo : aCol

Adds every element of the receiver to aCol and returns aCol. If aCol is nil, returns nil. The argument aCol need not actually be a collection, as long as it responds to add: in the same way as collections do.



addContentsOf:

- addContentsOf : aCol

Adds each member of aCol to the receiver. Returns the receiver. If aCol is nil, no action is taken. The argument aCol need not be a collection, so long as it responds to eachElement in the same way as collections do.



removeContentsOf:

- removeContentsOf : aCol

Removes each of the members of aCol from the receiver. Returns the receiver. The argument aCol need not be a collection, as long as it responds to eachElement as collections do.

If aCol is the same object as the receiver, it empties itself using emptyYourself and returns the receiver.



removeContentsFrom:

- removeContentsFrom : aCol

Removes each of the members of the receiver from aCol. Returns the receiver. The argument aCol need not be a collection, as long as it responds to remove: in the same way as collections.



find:

- find : anObject

Returns any element in the receiver which isEqual: to anObject. Otherwise, returns nil.



contains:

- (BOOL) contains : anObject

Returns YES if the receiver contains anObject. Otherwise, returns NO. Implementation is in terms of the receiver's find: method.



printToFile:

- printToFile :(FILE *) aFile

Prints a comma separated list of the objects in the set by sending each individual object a printToFile: message. Returns the receiver.



write:

- write :(NXTypedStream *) stream

Writes the set and all its elements to the typed stream stream. Returns the receiver.



read:

- read :(NXTypedStream *) stream

Reads the set and all its elements from the typed stream stream. Returns the receiver.