If you are using Java 5.0 (1.5) or above rewrite the Student class to use generics with ArrayList and List.

Question

What will be an ideal response?

Answer 1

```
mport j a v a . i o . ? ;
import j a v a . u t i l . ? ;
/? ?
? C l a s s t h a t d e s c r i b e s a s t u d e n t . A s t u d e n t has a name and an
? l i s t o f g r a d e s . You can g e t i n f o r m a t i o n a b o u t a s t u d e n t
? such as h e r / h i s name and g r a d e a v e r a g e . A s t u d e n t may
? a l s o have a p i c t u r e .
?
? @author Barb E r i c s o n
?/
public c l a s s Student
{
// ////////// f i e l d s //////////////////
/? ? t h e name o f t h e s t u d e n t : f i r s t l a s t ?/
private S t r i n g name ;
/? ? a l i s t o f g r a d e s f o r t h i s s t u d e n t ?/
private L i s t g r a d e L i s t ;
/? ? a p i c t u r e o f t h i s s t u d e n t ?/
private P i c t u r e p i c t u r e ;
// ////////// c o n s t r u c t o r s ///////////
/? ?
? No argument c o n s t r u c t o r . Leave s
? a l l f i e l d s with d e f a u l t values
?/
public Student ( ) {}
/? ?
? C o n s t r u c t o r t h a t t a k e s t h e name
? @param theName t h e s t u d e n t ’ s name
?/
public Student ( S t r i n g theName )
{
t h i s . name = theName ;
}
/? ?
? C o n s t r u c t o r t h a t t a k e s a name and
? t h e number o f g r a d e s
? @param theName t h e s t u d e n t ’ s name
? @param numGrades t h e number o f g r a d e s
?/
public Student ( S t r i n g theName , i n t numGrades )
{
t h i s . name = name ;
t h i s . g r a d e L i s t = new A r r a y L i s t ( numGrades ) ;
}
/? ?
? C o n s t r u c t o r t h a t t a k e s t h e name
? and a l i s t o f g r a d e s
? @param theName t h e s t u d e n t ’ s name
? @param t h e G r a d e L i s t t h e l i s t o f g r a d e s
?/
public Student ( S t r i n g theName ,
L i s t t h e G r a d e L i s t )
{
t h i s . name = theName ;
this . gradeList = theGradeList ;
}
/? ?
? Constructor that takes a delimited string , the
? name d e l i m i t e r , and t h e g r a d e d e l i m i t e r .It f i l l s
? i n t h e f i e l d s from t h e d e l i m i t e d s t r i n g .
? @param d e l i m S t r i n g s t u d e n t i n f o r m a t i o n as a
? delimited string
? @param nameDelim what d e l i m i t s t h e name f i e l d
? from t h e g r a d e s
? @param gradeDelim what d e l i m i t s t h e g r a d e s
?/
public Student ( S t r i n g d e l i m S t r i n g ,
S t r i n g nameDelim ,
S t r i n g gradeDelim )
{
// c r e a t e t h e l i s t f o r t h e g r a d e s , i f needed
i f ( t h i s . g r a d e L i s t == null )
t h i s . g r a d e L i s t = new A r r a y L i s t ( ) ;
// s p l i t s t r i n g b a s e d on name d e l i m i t e r
S t r i n g [ ] s p l i t A r r a y = d e l i m S t r i n g . s p l i t ( nameDelim ) ;
t h i s . name = s p l i t A r r a y [ 0 ] . t r i m ( ) ;
// g e t t h e g r a d e s t r i n g and b r e a k i t and c o n v e r t t o d o u b l e
String grades = splitArray [ 1 ] ;
S t r i n g [ ] g r a d e S t r A r r a y = null ;
i f ( g r a d e s != null )
{
g r a d e S t r A r r a y = g r a d e s . s p l i t ( gradeDelim ) ;
f o r ( i nt i = 0 ; i < g r a d e S t r A r r a y . l e n g t h ; i ++)
{
t h i s . g r a d e L i s t . add (
Double . p a r s e D o u b l e ( g r a d e S t r A r r a y [ i ] ) ) ;
}
}
}
// ///////// methods ///////////////
/? ?
? Method t o g e t t h e p i c t u r e f o r t h i s
? student
? @return t h e p i c t u r e (may be n u l l )
?/
public P i c t u r e g e t P i c t u r e ( )
{ return t h i s . p i c t u r e ; }
/? ?
? Method t o s e t t h e p i c t u r e f o r t h i s
? student
? @param t h e P i c t u r e t h e p i c t u r e t o u s e
?/
public void s e t P i c t u r e ( P i c t u r e t h e P i c t u r e )
{
this . p i c t u r e = thePicture ;
}
/? ?
? Method t o show t h i s s t u d e n t
? It w i l l display the picture i f there
? i s one e l s e j u s t p r i n t t h e s t u d e n t name
?/
public void show ( )
{
i f ( t h i s . p i c t u r e == null )
{
// u s e t o S t r i n g
System . out . p r i n t l n ( t h i s ) ;
}
else
{
t h i s . p i c t u r e . show ( ) ;
}
}
/? ?
? Method t o r e t u r n t h e name o f t h i s s t u d e n t
? @return t h e s t u d e n t ’ s name
?/
public S t r i n g getName ( ) { return t h i s . name ; }
/? ?
? Method t o s e t t h e name f o r t h i s s t u d e n t
? @param theName t h e new name t o u s e
? @return t r u e i f s u c c e s s e l s e f a l s e
?/
public boolean setName ( S t r i n g theName )
{
boolean r e s u l t = f a l s e ;
i f ( t h i s . name == null )
{
t h i s . name = theName ;
r e s u l t = true ;
}
return r e s u l t ;
}
/? ?
? Method t o g e t t h e g r a d e i n t h e g r a d e l i s t
? at the passed index
? @param i n d e x t h e i n d e x t h a t we want t h e g r a d e f o r
? @return t h e g r a d e i n t h e g r a d e l i s t a t t h i s p a s s e d i n d e x
?/
public double getGrade ( in t i n d e x )
{
return t h i s . g r a d e L i s t . g e t ( i n d e x ) ;
}
/? ?
? Method t o r e p l a c e t h e l i s t o f g r a d e s
? @param t h e A r r a y t h e new l i s t o f g r a d e s t o u s e
? @return t r u e i f s u c e s s , e l s e f a l s e
?/
public boolean setGradeArray ( L i s t t h e L i s t )
{
boolean r e s u l t = f a l s e ;
// o n l y s e t t h e g r a d e L i s t i f
i f ( t h i s . g r a d e L i s t == null )
{
this . gradeList = t h e L i s t ;
r e s u l t = true ;
}
return r e s u l t ;
}
/? ?
? Method t o s e t a g r a d e a t an i n d e x
? @param i n d e x t h e i n d e x t o s e t i t a t
? @param newGrade t h e g r a d e t o u s e
? @return t r u e i f s u c c e s s e l s e f a l s e
?/
public boolean s e t G r a d e ( in t index ,
double newGrade )
{
boolean r e s u l t = f a l s e ;
i f ( newGrade >= 0 | |
t h i s . g r a d e L i s t != null | |
index < this . gradeList . s i z e ( ) | |
i n d e x >= 0 ) {
t h i s . g r a d e L i s t . s e t ( index , newGrade ) ;
r e s u l t = true ;
}
return r e s u l t ;
}
/? ?
? Method t o r e t u r n t h e a v e r a g e o f t h e g r a d e s f o r t h i s s t u d e n t
? @return t h e a v e r a g e o f t h e g r a d e s or 0 . 0 i f no g r a d e l i s t or
? no g r a d e s
?/
public double g e t A v e r a g e ( )
{
double a v e r a g e = 0 . 0 ;
i f ( t h i s . g r a d e L i s t != null && t h i s . g r a d e L i s t . s i z e ( ) > 0 )
{
double sum = 0 . 0 ;
f o r ( i nt i = 0 ; i < t h i s . g r a d e L i s t . s i z e ( ) ; i ++)
{
sum = sum + t h i s . g r a d e L i s t . g e t ( i ) ;
}
a v e r a g e = sum / t h i s . g r a d e L i s t . s i z e ( ) ;
}
return a v e r a g e ;
}
/? ?
? Method t o r e t u r n t h e a v e r a g e o f t h e g r a d e s a f t e r you drop
? the l o w e s t grade f o r t h i s student
? @return t h e a v e r a g e o f t h e g r a d e s or 0 . 0 i f no g r a d e l i s t or
? no g r a d e s
?/
public double getAverageDropLowest ( )
{
double a v e r a g e = 0 . 0 ;
double l o w e s t = 1 0 0 ;
i n t numGrades = t h i s . g r a d e L i s t . s i z e ( ) ;
i f ( t h i s . g r a d e L i s t != null && numGrades > 0 )
{
double sum = 0 . 0 ;
// l o o p t h r o u g h t h e g r a d e s
f o r ( i nt i = 0 ; i < t h i s . g r a d e L i s t . s i z e ( ) ; i ++)
{
// c h e c k i f t h i s i s l o w e r
i f ( this . gradeList . get ( i ) < lowest )
{
lowest = this . gradeList . get ( i ) ;
}
// add t h i s g r a d e t o t h e sum
sum = sum + t h i s . g r a d e L i s t . g e t ( i ) ;
}
// i f t h e r e was more tha n one g r a d e remove t h e l o w e s t
i f ( numGrades > 1 )
{
sum = sum ? l o w e s t ;
numGrades??;
}
a v e r a g e = sum / numGrades ;
}
return a v e r a g e ;
}
/? ?
? Method t o r e t u r n a s t r i n g w i t h i n f o r m a t i o n a b o u t t h i s s t u d e n t
? @return a s t r i n g w i t h i n f o r m a t i o n a b o u t t h e s t u d e n t
?/
public S t r i n g t o S t r i n g ( ) {
return ” Student o b j e c t named : ” + t h i s . name +
” Average : ” + t h i s . g e t A v e r a g e ( ) ;
}
/? Used t o t e s t ?/
// p u b l i c s t a t i c v o i d main ( S t r i n g [ ] a r g s )
//
//
//
//
//
//
//
//
//
//
//
{
Making Text for the Web
S t u d e n t s t u d e n t 1 = new S t u d e n t (” Barb E r i c s o n ” ) ;
System . o u t . p r i n t l n ( s t u d e n t 1 ) ;
d o u b l e [ ] gradeArray1 = { 9 0 , 8 8 , 9 5 , 9 6 , 9 3 } ;
S t u d e n t s t u d e n t 2 = new S t u d e n t (” Mark G u z d i a l ” , gradeArray1 ) ;
System . o u t . p r i n t l n ( s t u d e n t 2 ) ;
P i c t u r e b a r b = new P i c t u r e ( F i l e C h o o s e r . getMediaPath (” b a r b a r a . j p g ” ) ) ;
student1 . s e t P i c t u r e ( barb ) ;
s t u d e n t 1 . show ( ) ;
s t u d e n t 2 . show ( ) ;
}
/? ?
? Method t o compare t h e c u r r e n t s t u d e n t
? with a passed in o b j e c t
? @param o t h e o b j e c t p a s s e d i n
? @return n e g a t i v e i f t h e c u r r e n t s t u d e n t
? i s l e s s tha n t h e p a s s e d o b j e c t
? 0 i f they are equal
? Positive i f the current student i s
? g r e a t e r th an t h e p a s s e d i n o b j e c t
? Warning t h i s w i l l s a y two s t u d e n t s
? w i t h t h e same name a r e e q u a l !
?/
public i n t compareTo ( Ob jec t o )
{
Student t e s t S t u d e n t = ( Student ) o ;
return t h i s . name . compareTo ( t e s t S t u d e n t . name ) ;
}
/? Used t o t e s t ?/
public s t a t i c void main ( S t r i n g [ ] a r g s )
{
// t e s t t h e c o n s t r u c t o r t h a t t a k e s a d e l i m i t e d s t r i n g
Student s t u d e n t 3 =
new Student ( ” Susan E r i c s o n : 5 0 , 6 0 , 7 0 , 8 0 , 9 0 , 1 0 0 ” , ” : ” , ” , ” ) ;
System . out . p r i n t l n ( s t u d e n t 3 ) ;
System . out . p r i n t l n ( s t u d e n t 3 . getAverageDropLowest ( ) ) ;
}
}
```