/**
* Maps the specified <code>key</code> to the specified <code>value</code> in this hashtable.
* Neither the key nor the value can be <code>null</code>.
*
* <p>The value can be retrieved by calling the <code>get</code> method with a key that is equal
* to the original key.
*
* @param key the hashtable key.
* @param value the value.
* @return the previous value of the specified key in this hashtable, or <code>null</code> if it
* did not have one.
* @exception NullPointerException if the key or value is <code>null</code>.
* @see java.lang.Object#equals(java.lang.Object)
* @see java.util.Hashtable#get(java.lang.Object)
* @since JDK1.0
*/
public Object put(Object key, Object value) {
// Make sure the value is not null
if (value == null) {
throw new NullPointerException();
}
// Makes sure the key is not already in the hashtable.
HashtableEntry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry e = tab[index]; e != null; e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
Object old = e.value;
e.value = value;
return old;
}
}
if (count >= threshold) {
// Rehash the table if the threshold is exceeded
rehash();
return put(key, value);
}
// Creates the new entry.
HashtableEntry e = new HashtableEntry();
e.hash = hash;
e.key = key;
e.value = value;
e.next = tab[index];
tab[index] = e;
count++;
return null;
}
/**
* Associate the specified value with the specified key in this {@code Hashtable}. If the key
* already exists, the old value is replaced. The key and value cannot be null.
*
* @param key the key to add.
* @param value the value to add.
* @return the old value associated with the specified key, or {@code null} if the key did not
* exist.
* @see #elements
* @see #get
* @see #keys
* @see java.lang.Object#equals
*/
public synchronized V put(K key, V value) {
if (key == null) {
throw new NullPointerException("key == null");
} else if (value == null) {
throw new NullPointerException("value == null");
}
int hash = secondaryHash(key.hashCode());
HashtableEntry<K, V>[] tab = table;
int index = hash & (tab.length - 1);
HashtableEntry<K, V> first = tab[index];
for (HashtableEntry<K, V> e = first; e != null; e = e.next) {
if (e.hash == hash && key.equals(e.key)) {
V oldValue = e.value;
e.value = value;
return oldValue;
}
}
// No entry for key is present; create one
modCount++;
if (size++ > threshold) {
rehash(); // Does nothing!!
tab = doubleCapacity();
index = hash & (tab.length - 1);
first = tab[index];
}
tab[index] = new HashtableEntry<K, V>(key, value, hash, first);
return null;
}
protected Object clone() {
HashtableEntry entry = new HashtableEntry();
entry.hash = hash;
entry.key = key;
entry.value = value;
entry.next = (next != null) ? (HashtableEntry) next.clone() : null;
return entry;
}
/**
* Puts the key and the value in the table. If there already is a key equal ignore case to the one
* passed the new value exchhanes the old one.
*
* @param key String key
* @param value object to put
* @return old value if any, or null if none
* @exception IllegalArgumentException if key is not a string
*/
public synchronized Object put(Object key, Object value) throws IllegalArgumentException {
if (value == null) {
throw new NullPointerException();
}
if (table == null) initTable(MIN_CAPACITY);
try {
// Makes sure the key is not already in the hashtable.
int hash = hashCode((String) key);
int index;
HashtableEntry[] tab = null;
do {
tab = table;
index = (hash & 0x7FFFFFFF) % tab.length;
for (HashtableEntry e = tab[index]; e != null; e = e.next) {
if ((e.hash == hash) && e.key.equalsIgnoreCase((String) key)) {
Object old = e.value;
e.value = value;
return old;
}
}
if (count >= threshold) {
// Rehash the table if the threshold is exceeded
rehash();
continue;
}
break;
} while (true);
// Creates the new entry.
HashtableEntry e = new HashtableEntry();
e.hash = hash;
e.key = (String) key;
e.value = value;
e.next = tab[index];
tab[index] = e;
count++;
return null;
} catch (ClassCastException cce) {
throw new IllegalArgumentException("Non string keys are not accepted!");
}
}
/**
* This method is just like put, except that it doesn't do things that are inappropriate or
* unnecessary for constructors and pseudo-constructors (i.e., clone, readObject). In particular,
* this method does not check to ensure that capacity is sufficient, and does not increment
* modCount.
*/
private void constructorPut(K key, V value) {
if (key == null) {
throw new NullPointerException("key == null");
} else if (value == null) {
throw new NullPointerException("value == null");
}
int hash = secondaryHash(key.hashCode());
HashtableEntry<K, V>[] tab = table;
int index = hash & (tab.length - 1);
HashtableEntry<K, V> first = tab[index];
for (HashtableEntry<K, V> e = first; e != null; e = e.next) {
if (e.hash == hash && key.equals(e.key)) {
e.value = value;
return;
}
}
// No entry for key is present; create one
tab[index] = new HashtableEntry<K, V>(key, value, hash, first);
size++;
}