Java: Please help me writing a single interface called "Space" in this program about 2-Dimemsional Packaging.

Please read and help me if you can. Thank you

The space into which shapes will be packed is a rectangle comprised of blocks which are empty or filled. Each block in a space is referenced by its row/column coordinate which starts at 0 (in the upper-left corner).

........ .......| .....||| 

The dots (periods) represent empty blocks into which shapes may be put while the permanently filled blocks are drawn as vertical lines (pipes). For clarity, here is the same space with numbers around it to indicate the rows and columns.

 01234567 0 ........ 0 1 .......| 1 2 .....||| 2 01234567 

The space has height 3 and width 8. All blocks are empty except the following filled blocks: (1,7), (2,5), (2,6), (2,7).

There is no requirement that permanently filled blocks must exist on the edges of the space or be contiguous. The following is another valid space demonstrating the arbitrariness of filled block placement.

|....... ..|||..| ..|.|... ........

Below is the task for this interface

Space Interface

The Space interface is also provided in the code pack and you will need to implement one or more classes which cooperate to fulfill the interface requirements.

// A Space is a rectangular grid of empty and filled blocks. On being // initialized, some blocks of a space are permanently filled. // Instances of Shape may be placed in the space so long as they are // in bounds and do not conflict with any filled blocks. Space classes // provide mechanisms to check whether shapes fit at a location in the // space, place shapes at a location, remove shapes, and display the // present contents of the space. public interface Space{ // Return the number of rows of the space public int getHeight(); // Return the number of columns of the space public int getWidth(); // Return true if the space has a filled block at the given row/col // position and false if the block is empty. A block may be filled // if it is permanently filled or if a shape has been placed in a // position such that the space's block is filled by the shape's block // If the position is out of bounds, return true as there is implicit // fill all around the space. DO NOT THROW EXCEPTIONS from this // method. public boolean isFilledAt(int row, int col); // Determine if the given shape may be placed at the indicated // row/col position. The row,col indicates where the upper left // corner [block (0,0)] of the shape would be placed. A shape would // not fit if one of its filled blocks would conflict with an // existing filled block in the space or would be out of bounds in // the space. public boolean shapeFitsAt(int row, int col, Shape shape); // Place the given shape at the given row/col position. The row,col // indicates where the upper left corner [block (0,0)] of the shape // would be placed. The shape should be removable and when // displaying info on the placed shapes, they must be shown in order // of their display characters (shape A before B before C...). // There may be more than one shape in a space with the same display // character. If the shape would not fit at the specified row/col // position, raise a FitItException with an informative message. public void placeShapeAt(int row, int col, Shape shape); // Remove the shape with the display character indicated by dc from this // space. Update all internal state so that blocks in the space that // were filled by the removed shape are emptied. public void removeShapeByDisplayChar(char dc); // Return how many shapes have been placed in this space. public int placedShapeCount(); // Return a string representing the space and the shapes that have // been fit into it. The following character conventions must be // used. // | : vertical bar for permanently filled blocks // . : period for empty blocks // displaychar : any space filled by a shape uses its display char // // Example: // aa.....e // aacddd.| // cccdd||| public String fitString(); // Give a listing of all the placed shapes. This should start with // the number of placed shapes, show the position of each shape, and // use the toString() of each shape. Shapes must be reported in // sorted order based on their display character (shape A before B // before C...). // // Example: // // 3 shapes placed // Shape at (0,0) // SHAPE a // height: 2 width: 2 rotation: CW90 // aa // aa // // Shape at (0,2) // SHAPE b // height: 1 width: 4 rotation: CW180 // bbbb // // Shape at (1,0) // SHAPE c // height: 2 width: 3 rotation: CW270 // ..c // ccc public String placedShapeInfo(); // Print a verbose string representation of the space. Start with // the string SPACE: then follow with the fitString() of the space // and finally the placedShapeInfo() string. // // Example: // // SPACE: // height: 3 width: 8 // aabbbbfe // aacdddf| // cccdd||| // // 6 shapes placed // Shape at (0,0) // SHAPE a // height: 2 width: 2 rotation: CW90 // aa // aa // // Shape at (0,2) // SHAPE b // height: 1 width: 4 rotation: CW180 // bbbb // ... public String toString(); }