/**
* {@inheritDoc}
*
* <p>This method will, on a best-effort basis, throw a {@link
* java.util.ConcurrentModificationException} if the remapping function modified this map during
* computation.
*
* @throws ConcurrentModificationException if it is detected that the remapping function modified
* this map
*/
@Override
public synchronized V computeIfPresent(
K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
Objects.requireNonNull(remappingFunction);
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (Entry<K, V> prev = null; e != null; prev = e, e = e.next) {
if (e.hash == hash && e.key.equals(key)) {
int mc = modCount;
V newValue = remappingFunction.apply(key, e.value);
if (mc != modCount) {
throw new ConcurrentModificationException();
}
if (newValue == null) {
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
modCount = mc + 1;
count--;
} else {
e.value = newValue;
}
return newValue;
}
}
return null;
}
/**
* 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 Object#equals(Object)
* @see #get(Object)
*/
public synchronized V put(K key, V value) {
// Make sure the value is not null
if (value == null) {
throw new NullPointerException();
}
// Makes sure the key is not already in the hashtable.
Entry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (Entry<K, V> e = tab[index]; e != null; e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
V old = e.value;
e.value = value;
return old;
}
}
modCount++;
if (count >= threshold) {
// Rehash the table if the threshold is exceeded
rehash();
tab = table;
index = (hash & 0x7FFFFFFF) % tab.length;
}
// Creates the new entry.
Entry<K, V> e = tab[index];
tab[index] = new Entry<>(hash, key, value, e);
count++;
return null;
}
public int compareTo(Entry e) {
double v1 = value(), v2 = e.value();
if (v1 < v2) {
return -1;
}
if (v1 > v2) {
return 1;
}
return 0;
}
/** Offloaded version of put for null keys */
private V putForNullKey(V value) {
for (Entry<K, V> e = table[0]; e != null; e = e.next) {
if (e.key == null) {
V oldValue = e.value;
e.value = value;
e.recordAccess(this);
return oldValue;
}
}
modCount++;
addEntry(0, null, value, 0);
return null;
}
@Override
public synchronized V replace(K key, V value) {
Objects.requireNonNull(value);
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (; e != null; e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
V oldValue = e.value;
e.value = value;
return oldValue;
}
}
return null;
}
/**
* Associates the specified value with the specified key in this map. If the map previously
* contained a mapping for the key, the old value is replaced.
*
* @param key key with which the specified value is to be associated
* @param value value to be associated with the specified key
* @return the previous value associated with <tt>key</tt>, or <tt>null</tt> if there was no
* mapping for <tt>key</tt>. (A <tt>null</tt> return can also indicate that the map previously
* associated <tt>null</tt> with <tt>key</tt>.)
*/
public V put(K key, V value) {
if (key == null) return putForNullKey(value);
int hash = hash(key);
int i = indexFor(hash, table.length);
for (Entry<K, V> e = table[i]; e != null; e = e.next) {
Object k;
if (e.hash == hash && ((k = e.key) == key || key.equals(k))) {
V oldValue = e.value;
e.value = value;
e.recordAccess(this);
return oldValue;
}
}
modCount++;
addEntry(hash, key, value, i);
return null;
}
@SuppressWarnings("unchecked")
@Override
public synchronized void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
Objects.requireNonNull(function); // explicit check required in case
// table is empty.
final int expectedModCount = modCount;
Entry<K, V>[] tab = (Entry<K, V>[]) table;
for (Entry<K, V> entry : tab) {
while (entry != null) {
entry.value = Objects.requireNonNull(function.apply(entry.key, entry.value));
entry = entry.next;
if (expectedModCount != modCount) {
throw new ConcurrentModificationException();
}
}
}
}
/**
* This method is used instead of put by constructors and pseudoconstructors (clone, readObject).
* It does not resize the table, check for comodification, etc. It calls createEntry rather than
* addEntry.
*/
private void putForCreate(K key, V value) {
int hash = null == key ? 0 : hash(key);
int i = indexFor(hash, table.length);
/**
* Look for preexisting entry for key. This will never happen for clone or deserialize. It will
* only happen for construction if the input Map is a sorted map whose ordering is inconsistent
* w/ equals.
*/
for (Entry<K, V> e = table[i]; e != null; e = e.next) {
Object k;
if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k)))) {
e.value = value;
return;
}
}
createEntry(hash, key, value, i);
}
/**
* Removes the key (and its corresponding value) from this hashtable. This method does nothing if
* the key is not in the hashtable.
*
* @param key the key that needs to be removed
* @return the value to which the key had been mapped in this hashtable, or <code>null</code> if
* the key did not have a mapping
* @throws NullPointerException if the key is <code>null</code>
*/
public synchronized V remove(Object key) {
Entry tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (Entry<K, V> e = tab[index], prev = null; e != null; prev = e, e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
modCount++;
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
count--;
V oldValue = e.value;
e.value = null;
return oldValue;
}
}
return null;
}
@Override
public synchronized boolean replace(K key, V oldValue, V newValue) {
Objects.requireNonNull(oldValue);
Objects.requireNonNull(newValue);
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (; e != null; e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
if (e.value.equals(oldValue)) {
e.value = newValue;
return true;
} else {
return false;
}
}
}
return false;
}
public boolean remove(Object o) {
if (!(o instanceof Map.Entry)) return false;
Map.Entry<K, V> entry = (Map.Entry<K, V>) o;
K key = entry.getKey();
Entry[] tab = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
for (Entry<K, V> e = tab[index], prev = null; e != null; prev = e, e = e.next) {
if (e.hash == hash && e.equals(entry)) {
modCount++;
if (prev != null) prev.next = e.next;
else tab[index] = e.next;
count--;
e.value = null;
return true;
}
}
return false;
}
/**
* Removes the key (and its corresponding value) from this hashtable. This method does nothing if
* the key is not in the hashtable.
*
* @param key the key that needs to be removed
* @return the value to which the key had been mapped in this hashtable, or {@code null} if the
* key did not have a mapping
* @throws NullPointerException if the key is {@code null}
*/
public synchronized V remove(Object key) {
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (Entry<K, V> prev = null; e != null; prev = e, e = e.next) {
if ((e.hash == hash) && e.key.equals(key)) {
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
modCount++;
count--;
V oldValue = e.value;
e.value = null;
return oldValue;
}
}
return null;
}
@Override
public synchronized V putIfAbsent(K key, V value) {
Objects.requireNonNull(value);
// Makes sure the key is not already in the hashtable.
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> entry = (Entry<K, V>) tab[index];
for (; entry != null; entry = entry.next) {
if ((entry.hash == hash) && entry.key.equals(key)) {
V old = entry.value;
if (old == null) {
entry.value = value;
}
return old;
}
}
addEntry(hash, key, value, index);
return null;
}
public boolean remove(Object o) {
if (!(o instanceof Map.Entry)) return false;
Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
Object key = entry.getKey();
Entry<?, ?>[] tab = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (Entry<K, V> prev = null; e != null; prev = e, e = e.next) {
if (e.hash == hash && e.equals(entry)) {
if (prev != null) prev.next = e.next;
else tab[index] = e.next;
e.value = null; // clear for gc.
modCount++;
count--;
return true;
}
}
return false;
}
/**
* Maps the specified {@code key} to the specified {@code value} in this hashtable. Neither the
* key nor the value can be {@code null}.
*
* <p>The value can be retrieved by calling the {@code get} 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} if it did
* not have one
* @exception NullPointerException if the key or value is {@code null}
* @see Object#equals(Object)
* @see #get(Object)
*/
public synchronized V put(K key, V value) {
// Make sure the value is not null
if (value == null) {
throw new NullPointerException();
}
// Makes sure the key is not already in the hashtable.
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> entry = (Entry<K, V>) tab[index];
for (; entry != null; entry = entry.next) {
if ((entry.hash == hash) && entry.key.equals(key)) {
V old = entry.value;
entry.value = value;
return old;
}
}
addEntry(hash, key, value, index);
return null;
}
@Override
public synchronized boolean remove(Object key, Object value) {
Objects.requireNonNull(value);
Entry<?, ?> tab[] = table;
int hash = key.hashCode();
int index = (hash & 0x7FFFFFFF) % tab.length;
@SuppressWarnings("unchecked")
Entry<K, V> e = (Entry<K, V>) tab[index];
for (Entry<K, V> prev = null; e != null; prev = e, e = e.next) {
if ((e.hash == hash) && e.key.equals(key) && e.value.equals(value)) {
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
e.value = null; // clear for gc
modCount++;
count--;
return true;
}
}
return false;
}
