using the code below write the public V add(K key, V value); that ad.pdf

using the code below write the public V add(K key, V value); that adds a new entry into
hashtable if the table (hashTable[index] != null) && (hashTable[index] != AVAILABLE
if the key is the same as keyindex inside the hash replace the old value with the new value
if the key is different from the keyindex go to the next index and count for collisions until will
you find a null space inside the hashtable index
import java.util.Iterator;
public interface DictionaryInterface
{
/** Adds a new entry to this dictionary. If the given search key already
exists in the dictionary, replaces the corresponding value.
@param key An object search key of the new entry.
@param value An object associated with the search key.
@return Either null if the new entry was added to the dictionary
or the value that was associated with key if that value
was replaced. */
public V add(K key, V value);
/** Removes a specific entry from this dictionary.
@param key An object search key of the entry to be removed.
@return Either the value that was associated with the search key
or null if no such object exists. */
public V remove(K key);
/** Retrieves from this dictionary the value associated with a given
search key.
@param key An object search key of the entry to be retrieved.
@return Either the value that is associated with the search key
or null if no such object exists. */
public V getValue(K key);
/** Sees whether a specific entry is in this dictionary.
@param key An object search key of the desired entry.
@return True if key is associated with an entry in the dictionary. */
public boolean contains(K key);

/** Creates an iterator that traverses all search keys in this dictionary.
@return An iterator that provides sequential access to the search
keys in the dictionary. */
public Iterator getKeyIterator();
/** Creates an iterator that traverses all values in this dictionary.
@return An iterator that provides sequential access to the values
in this dictionary. */
public Iterator getValueIterator();
/** Sees whether this dictionary is empty.
@return True if the dictionary is empty. */
public boolean isEmpty();
/** Gets the size of this dictionary.
@return The number of entries (key-value pairs) currently
in the dictionary. */
public int getSize();
/** Removes all entries from this dictionary. */
public void clear();
} // end DictionaryInterface
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* A class that implements the ADT dictionary by using hashing and
* linear probing to resolve collisions.
* The dictionary is unsorted and has distinct search key.
Search keys and associated values are not null.
*/
public class HashedDictionary implements DictionaryInterface
{
// The dictionary:
private int numberOfEntries;
private static final int DEFAULT_CAPACITY = 5; // Must be prime
private static final int MAX_CAPACITY = 10000;
// The hash table:
private Entry[] hashTable;
private int tableSize; // Must be prime

private static final int MAX_SIZE = 2 * MAX_CAPACITY;
private boolean integrityOK = false;
private static final double MAX_LOAD_FACTOR = 0.5; // Fraction of
// hash table that can be filled
private int collisionCount;
protected final Entry AVAILABLE = new Entry<>(null, null);
// Counter to keep track of collisions
public HashedDictionary()
{
this(DEFAULT_CAPACITY); // Call next constructor
} // end default constructor
public HashedDictionary(int initialCapacity)
{
initialCapacity = checkCapacity(initialCapacity);
numberOfEntries = 0; // Dictionary is empty
// Set up hash table:
// Initial size of hash table is same as initialCapacity if it is prime;
// otherwise increase it until it is prime size
tableSize = getNextPrime(initialCapacity);
checkSize(tableSize); // Check that size is not too large
// The cast is safe because the new array contains null entries
@SuppressWarnings("unchecked")
Entry[] temp = (Entry[])new Entry[tableSize];
hashTable = temp;
integrityOK = true;
collisionCount = 0;
} // end constructor
/* Implementations of methods in DictionaryInterface are here. . . .*/

public V add(K key, V value)
{//CODE IMPLEMENTATION
}//end of add
public boolean isEmpty()
{
return this.numberOfEntries == 0;
}//end isEmpty
public Iterator getValueIterator()
{
throw new NoSuchElementException("Value Iterator Not Implemented");
}//end valueIterator
public void clear()
{
checkIntegrity();
for (int index = 0; index < this.hashTable.length; index++)
{
hashTable[index] = null;
}//end of for
this.numberOfEntries = 0;
}//end clear
public Iterator getKeyIterator()
{
return new KeyIterator();
}//end iterator
public boolean contains(K key)
{
return getValue(key) != null;
}//end contains
public int getSize()
{

return this.numberOfEntries;
}//end getSize
public V remove(K key) {
checkIntegrity();
int index = getHashIndex(key);
while (hashTable[index] != null) {
if (hashTable[index].getKey().equals(key)) {
V value = hashTable[index].getValue();
hashTable[index].setValue(null);
hashTable[index] = AVAILABLE;
numberOfEntries--;
return value;
}
index = (index + 1) % hashTable.length;
}
// If the key is not found, return null
return null;
}
public V getValue(K key)
{
checkIntegrity();
V result = null;
int index = getHashIndex(key);
if ((hashTable[index] != null) && (hashTable[index] != AVAILABLE))
result = hashTable[index].getValue(); // Key found; get value
// Else key not found; return null
return result;
} // end getValue
/* END of Implementations of dictionary methods are here^. . . . */

/* Implementations of private methods are here. . . . */
//precondition: checkIntegrity has been called
private void enlargeHashTable()
{
Entry[] oldTable = hashTable;
int oldSize = hashTable.length;
int newSize = getNextPrime(oldSize + oldSize);
checkSize(newSize);
//The cast is safe because the new array contains null entries
@SuppressWarnings("unchecked")
Entry[] temp = (Entry[]) new Entry[newSize];
hashTable = temp;
numberOfEntries = 0;//reset number of dictionary entries, since it will be incremented by add
during rehash
//rehash dictionary entries from old array to the new and bigger array;
//skip elements that contain null or available
for(int index = 0; index < oldSize; index++)
{
if((oldTable[index] != null) && (oldTable[index] != AVAILABLE))
{
add(oldTable[index].getKey(), oldTable[index].getValue());
}
}// end for
}//end enlargeHashTable
private int getHashIndex(K key)
{
int hashIndex = key.hashCode() % hashTable.length;
if(hashIndex < 0)
{
hashIndex = hashIndex + hashTable.length;

}
return hashIndex;
}//end getHashIndex
private void checkIntegrity()
{
if(!integrityOK)
{
throw new SecurityException("objecy is currupt");
}
}//end checkIntegrity
private boolean isHashTableTooFull()
{
if((numberOfEntries / hashTable.length) >= MAX_LOAD_FACTOR)
{
return true;
}
else
{
return false;
}
}//end isHashTableTooFull
private int checkSize(int size)
{
if(size >= MAX_SIZE){throw new IllegalStateException("Dictionary has become too large.");}
else{return size;}
}//end checksize

private int checkCapacity(int cap)
{
if(cap < DEFAULT_CAPACITY)
{
cap = DEFAULT_CAPACITY;
}
else if (cap > MAX_CAPACITY)
{
throw new IllegalStateException("Attempt to create a dictionary " + "whose capacity is larger
than " + MAX_CAPACITY);
}
return cap;
}//end checkcap
private int getNextPrime(int integer)
{
// if even, add 1 to make od
if (integer % 2 == 0)
{
integer++;
} // end if
// test odd integers
while (!isPrime(integer))
{
integer = integer + 2;
} // end while
return integer;
}//end getnextprime

private boolean isPrime(int integer)
{
boolean result;
boolean done = false;
// 1 and even numbers are not prime
if ( (integer == 1) || (integer % 2 == 0) )
{
result = false;
}
// 2 and 3 are prime
else if ( (integer == 2) || (integer == 3) )
{
result = true;
}
else // integer is odd and >= 5
{
assert (integer % 2 != 0) && (integer >= 5);
// a prime is odd and not divisible by every odd integer up to its square root
result = true; // assume prime
for (int divisor = 3; !done && (divisor * divisor <= integer); divisor = divisor + 2)
{
if (integer % divisor == 0)
{
result = false; // divisible; not prime
done = true;
} // end if
} // end for
} // end if
return result;
} // end isPrime
/* END of Implementations of private methods are here^. . . . */
protected final class Entry
{

private K key;
private V value;
private Entry(K searchKey, V dataValue)
{
key = searchKey;
value = dataValue;
}//end contructor
private K getKey()
{
return key;
}//end getKey
private V getValue()
{
return value;
}//end value
private void setValue(V newValue)
{
value = newValue;
}//end setValue
} // end Entry
private class KeyIterator implements Iterator
{
private int currentIndex; // Current position in hash table
private int numberLeft; // Number of entries left in iteration
private KeyIterator()
{
currentIndex = 0;
numberLeft = numberOfEntries;
} // end default constructor
public boolean hasNext()
{
return numberLeft > 0;
} // end hasNext

public void remove()
{
throw new UnsupportedOperationException();
} // end remove
public K next()
{
K result = null;
if (hasNext())
{
// Skip table locations that do not contain a current entry
while ( (hashTable[currentIndex] == null) ||
(hashTable[currentIndex] == AVAILABLE) )
{
currentIndex++;
} // end while
result = hashTable[currentIndex].getKey();
numberLeft--;
currentIndex++;
}
else
throw new NoSuchElementException();
return result;
} // end next
} // end KeyIterator
//collision method
public int getCollisionCount() {
return collisionCount;
}//end collisionCount
} // end HashedDictionary

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