Java Reference
In-Depth Information
result
=
null
Search the array for an entry containing
key
if
(
an entry containing
key
is found in the array
)
{
result =
value currently associated with
key
Replace
key
's associated value with
value
}
else
//
insert new entry
{
if
(
array is full
)
Double size of array
Insert a new entry containing
key
and
value
after the last entry in the array
Increment the size of the dictionary
}
return
result
FIGURE 20-2
Adding a new entry to an unsorted array-based dictionary
Add a new entry
after all the others
20.5
The method
add
.
The following implementation of the method
add
invokes the private methods
specified in Segment 20.3:
public
V add(K key, V value)
{
V result =
null
;
int
keyIndex = locateIndex(key);
if
(keyIndex < numberOfEntries)
{
// key found; return and replace old value
result = dictionary[keyIndex].getValue();
dictionary[keyIndex].setValue(value);
}
else
{
ensureCapacity();
dictionary[numberOfEntries] =
new
Entry<K, V>(key, value);
numberOfEntries++;
}
// end if
return
result;
}
// end add
To search an unsorted array,
locateIndex
has the following definition:
private int
locateIndex(K key)
{
int
index = 0;
while
( (index < numberOfEntries) &&
!key.equals(dictionary[index].getKey()) )
index++;
return
index;
}
// end locateIndex
