Help with treemap and other stuff

Question

hi guys..
i m new to this forum..
and this is my first post....so if i act a little naive .....please bare with me.
and if this is not the correct place to post ..i m sorry for that.
i have an assignment to submit....i m getting the whole picture ....but not sure how to go about implementing it.
here it is...
Write an Object Oriented solution to the problem in Java. The solution is to consist of:
A TableIndex class
A TableNavigator Interface
A data row class ....class that i have to create.
An application class to use and test your TableIndex class
The following UML class diagrams show the public methods of the classes. Other methods may be specified. Specify data members, inner classes and interfaces as appropriate.
TableIndex Class
The TableIndex class is an index to a collection of objects. The class is to approximate an index to a data table in memory that consists of a number of rows. To control access to the index a current row is defined that specifies the row that can be accessed. To retrieve a row from the index it must be the current row. The get() method is the only method in TableIndex class that retrieves a row from the index. The current row can be changed explicitly using the methods: previous(), next(), first(), last(), gotoBookmark and find(K); and implicitly using insert(K, V), modify(K, V) and remove().
The TableIndex class is to be implemented using the java API's TreeMap class and must use Generics. The data types K and V below are generic types for the Key and Value (row) respectively. An important aspect of the assignment is using the Java API documentation to understand the TreeMap class.
guys ....can u plz help with the starting bit ..
what should be the opening statement of the class...
public class TableIndex<K , V> .....????
and what should be the treemap declaration..??
TreeMap<K , V> indexTable = new TreeMap<K , V>();...???
i m confused....
can u plz explain to me..

Answer 1

hi mate.....didnt quite get you..
can u plz be a bit more simple in explanation..!!!
i will post the whole question ..so that anyone reading will understand better....
Problem Description
You are to develop an index class and associated classes.
Requirements
Write an Object Oriented solution to the problem in Java. The solution is to consist of:
A TableIndex class
A TableNavigator Interface
A data row class
An application class to use and test your TableIndex class
The following UML class diagrams show the public methods of the classes. Other methods may be specified. Specify data members, inner classes and interfaces as appropriate.
TableIndex Class
The TableIndex class is an index to a collection of objects. The class is to approximate an index to a data table in memory that consists of a number of rows. To control access to the index a current row is defined that specifies the row that can be accessed. To retrieve a row from the index it must be the current row. The get() method is the only method in TableIndex class that retrieves a row from the index. The current row can be changed explicitly using the methods: previous(), next(), first(), last(), gotoBookmark and find(K); and implicitly using insert(K, V), modify(K, V) and remove().
The TableIndex class is to be implemented using the java API's TreeMap class and must use Generics. The data types K and V below are generic types for the Key and Value (row) respectively. An important aspect of the assignment is using the Java API documentation to understand the TreeMap class.
TableIndex
+TableIndex()
+TableIndex(name: String, comp: Comparator)
+getName(): String
+isEmpty(): Boolean
+size(): Integer
+hasPrevious(): Boolean
+hasNext(): Boolean
+previous()
+next()
+first()
+last()
+setBookmark(): Boolean
+clearBookmark()
+gotoBookmark(): Boolean
+contains(key: K): Boolean
+find(key: K): Boolean
+get(): V
+insert(key:K, value: V): Boolean
+modify(value: V): Boolean
+modify(key: K, value: V): Boolean
+remove(): V
+iterator(): Iterator
+equals(obj2: Object): Boolean
+toString(): String
Additional Notes:
The table index has an order defined by the compareTo method of the key's class or by the compare method specified in the class that implements the Comparator interface.
getName(): the name of the index, blank by default.
isEmpty(): returns true if there aren't any rows in the table index
size(): returns the number of rows in the table index
hasPrevious(): returns true if there is a row before the current row.
hasNext(): returns true if there is a row after the current row in sequence.
previous(): if there is a row before the current row, move to the row and make it the new current row.
next() if there is a row after the current row, move to the row and make it the new current row.
first(): if the table isn't empty, move to the first row and make it the new current row.
last(): if the table isn't empty, move to the last row and make it the new current row.
setBookmark(): sets a bookmark at the current row. If the bookmark is successfully set the method returns true. The bookmark is cleared if the TableIndex is empty or the row the bookmark was set on is deleted..
clearBookmark(): sets the bookmark to null, indicating there isn't a bookmark.
gotoBookmark(): if a bookmark has been set, go to the bookmarked row. If successful the book marked row becomes the current row and the method returns true.
contains(K): return true if a row with the key specified exists.
find(K): if a row is found with the specified key, the current row is set to the row found.
get(): returns the current row. Null is returned if there isn't a current row.
insert(K, V): inserts a row (value) with the key specified. The key must not be null and must be unique (not already in the TableIndex). The row (value) must not be null. If the row is successfully inserted true is returned, and the row becomes the current row..
modify(V): change the current row's data to the row (value) specified. The key and the current row key are to remain the same. If successful true is returned.
modify(K, V): change the current row's key and data to the key and row (value) specified. If successful the changed row becomes the new current row. If successful true is returned. Note: this is more difficult than modify(V).
remove(): remove the current row. When a row is deleted the next row (if available) becomes the current row, otherwise if there isn't a next row the previous row becomes the current row, otherwise the table is empty therefore the current row is null.
iterator(): returns an iterator to the rows (values) in the index. The rows are to be retrieved in order. The remove method does not need to be implemented (its method body can be empty)..
the equals method uses the name, and the rows (values) in order when testing for equality.
the toString method should return appropriately formatted data members and the rows (values/data) in the index.
TableNavigator Interface
«interface»
TableNavigator
+isEmpty(): Boolean
+hasPrevious(): Boolean
+hasNext(): Boolean
+previous()
+next()
+first()
+last()
+contains(key: K): Boolean
+find(key: K): Boolean
Additional Notes:
The TableIndex class implements the TableNavigator Interface.
The purpose of the above methods is outlined in the TableIndex class.
Your Data Row Class
You are to include a class of your own to represent a row of data in the TableIndex. This is not to be a class that was covered in other programming subjects. It does not need to be complex but must include a range of data types. This class will be used to test your TableIndex class. The class should have an appropriate name and deal with something of interest to you.
Your Application Class
The application class is to make use of the TableIndex class and your data row class. It is to clearly show how the TableIndex class is used, and in doing so, test it. The class should have an appropriate name. The application class should create two indexes of different key data types. One of the indexes must make use of the Comparator interface to have a key that is in descending order.
Output
Output in the test classes/programs is to go to standard out or a text file. There should be no output from the TableIndex class or your data row class. A GUI interface is NOT required. There is no need to input data from the keyboard or file. Use the Unix script command or write output to a text file (etc) to provide example runs of your test programs.