List Implementations That Use Arrays - Data Structures and Abstractions with Java - page 330

if ((newPosition >= 1) && (newPosition <= list.size() + 1))
list.add(newPosition - 1, newEntry);
else
isSuccessful = false ;
return isSuccessful;
} // end add

13.19

The method replace . The method replace has an implementation similar to the one you just saw.
It uses the statement
list.set(givenPosition - 1, newEntry);
to replace a designated entry in the list.
public boolean replace( int givenPosition, T newEntry)
{

boolean isSuccessful = true ;
if ((givenPosition >= 1) && (givenPosition <= list.size()))
{

assert !isEmpty();
list.set(givenPosition - 1, newEntry);

}
else
isSuccessful = false ;
return isSuccessful;
} // end replace

13.20

The method toArray . We call Vector 's method toArray within the definition of toArray for a list.
The only worry is to take care of the unchecked cast of an array of type Object[] to an array of
type T[] . Thus, the method has the following definition:
public T[] toArray()
{

@SuppressWarnings(“unchecked”);
T[] result = (T[])list.toArray();
return result;
} // end toArray

13.21

The method remove . Our method remove uses Vector 's method remove , which returns the object
it removes from the vector. Like add , Vector 's remove throws an exception when given an illegal
position. Our method, however, will return null in this case. Thus, our remove method has the
following implementation:
public T remove( int givenPosition)
{

T result = null ; // return value
if ((givenPosition >= 1) && (givenPosition <= list.size()))
{

assert !isEmpty();
result = list.remove(givenPosition - 1);
} // end if
return result;
} // end remove

13.22

The method getEntry . The method getEntry has an implementation similar to that of remove . It
uses the expression
list.get(givenPosition - 1);
to retrieve a particular entry from the list.