Mega Code Archive
Int HashMap from jodd org
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// Copyright (c) 2003-2009, Jodd Team (jodd.org). All Rights Reserved.
import java.io.IOException;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* A Map that accepts int or Integer keys only. The implementation is based on
* <code>java.util.HashMap</code>. IntHashMap is about 25% faster.
*
* @see java.util.HashMap
*/
public class IntHashMap extends AbstractMap implements Cloneable, Serializable {
/**
* The hash table data.
*/
private transient Entry table[];
/**
* The total number of mappings in the hash table.
*/
private transient int count;
/**
* The table is rehashed when its size exceeds this threshold. (The value of
* this field is (int)(capacity * loadFactor).)
*/
private int threshold;
/**
* The load factor for the hashtable.
*/
private float loadFactor;
/**
* The number of times this IntHashMap has been structurally modified
* Structural modifications are those that change the number of mappings in
* the IntHashMap or otherwise modify its internal structure (e.g., rehash).
* This field is used to make iterators on Collection-views of the IntHashMap
* fail-fast.
*/
private transient int modCount;
/**
* Constructs a new, empty map with the specified initial
* capacity and the specified load factor.
*
* @param initialCapacity
* the initial capacity of the IntHashMap.
* @param loadFactor the load factor of the IntHashMap
*
* @throws IllegalArgumentException
* if the initial capacity is less
* than zero, or if the load factor is non-positive.
*/
public IntHashMap(int initialCapacity, float loadFactor) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("Illegal Initial Capacity: "+ initialCapacity);
}
if (loadFactor <= 0) {
throw new IllegalArgumentException("Illegal Load factor: "+ loadFactor);
}
if (initialCapacity == 0) {
initialCapacity = 1;
}
this.loadFactor = loadFactor;
table = new Entry[initialCapacity];
threshold = (int)(initialCapacity * loadFactor);
}
/**
* Constructs a new, empty map with the specified initial capacity
* and default load factor, which is 0.75.
*
* @param initialCapacity
* the initial capacity of the IntHashMap.
*
* @throws IllegalArgumentException
* if the initial capacity is less
* than zero.
*/
public IntHashMap(int initialCapacity) {
this(initialCapacity, 0.75f);
}
/**
* Constructs a new, empty map with a default capacity and load
* factor, which is 0.75.
*/
public IntHashMap() {
this(101, 0.75f);
}
/**
* Constructs a new map with the same mappings as the given map. The
* map is created with a capacity of twice the number of mappings in
* the given map or 11 (whichever is greater), and a default load factor,
* which is 0.75.
*/
public IntHashMap(Map t) {
this(Math.max(2 * t.size(), 11), 0.75f);
putAll(t);
}
/**
* Returns the number of key-value mappings in this map.
*
* @return the number of key-value mappings in this map.
*/
@Override
public int size() {
return count;
}
/**
* Returns <code>true</code> if this map contains no key-value mappings.
*
* @return <code>true</code> if this map contains no key-value mappings.
*/
@Override
public boolean isEmpty() {
return count == 0;
}
/**
* Returns <code>true</code> if this map maps one or more keys to the
* specified value.
*
* @param value value whose presence in this map is to be tested.
*
* @return <code>true</code> if this map maps one or more keys to the
* specified value.
*/
@Override
public boolean containsValue(Object value) {
Entry tab[] = table;
if (value == null) {
for (int i = tab.length; i-- > 0 ;) {
for (Entry e = tab[i] ; e != null ; e = e.next) {
if (e.value == null) {
return true;
}
}
}
} else {
for (int i = tab.length; i-- > 0 ;) {
for (Entry e = tab[i]; e != null; e = e.next) {
if (value.equals(e.value)) {
return true;
}
}
}
}
return false;
}
/**
* Returns <code>true</code> if this map contains a mapping for the specified
* key.
*
* @param key key whose presence in this Map is to be tested.
*
* @return <code>true</code> if this map contains a mapping for the specified
* key.
*/
@Override
public boolean containsKey(Object key) {
if (key instanceof Number) {
return containsKey( ((Number)key).intValue() );
} else {
return false;
}
}
/**
* Returns <code>true</code> if this map contains a mapping for the specified
* key.
*
* @param key key whose presence in this Map is to be tested.
*
* @return <code>true</code> if this map contains a mapping for the specified
* key.
*/
public boolean containsKey(int key) {
Entry tab[] = table;
int index = (key & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index]; e != null; e = e.next) {
if (e.key == key) {
return true;
}
}
return false;
}
/**
* Returns the value to which this map maps the specified key. Returns
* <code>null</code> if the map contains no mapping for this key. A return
* value of <code>null</code> does not <i>necessarily</i> indicate that the
* map contains no mapping for the key; it's also possible that the map
* explicitly maps the key to <code>null</code>. The <code>containsKey</code>
* operation may be used to distinguish these two cases.
*
* @param key key whose associated value is to be returned.
*
* @return the value to which this map maps the specified key.
*/
@Override
public Object get(Object key) {
if (key instanceof Number) {
return get( ((Number)key).intValue() );
} else {
return null;
}
}
/**
* Returns the value to which this map maps the specified key. Returns
* <code>null</code> if the map contains no mapping for this key. A return
* value of <code>null</code> does not <i>necessarily</i> indicate that the
* map contains no mapping for the key; it's also possible that the map
* explicitly maps the key to <code>null</code>. The <code>containsKey</code>
* operation may be used to distinguish these two cases.
*
* @param key key whose associated value is to be returned.
*
* @return the value to which this map maps the specified key.
*/
public Object get(int key) {
Entry tab[] = table;
int index = (key & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index]; e != null; e = e.next) {
if (e.key == key) {
return e.value;
}
}
return null;
}
/**
* Rehashes the contents of this map into a new <code>IntHashMap</code>
* instance with a larger capacity. This method is called automatically when
* the number of keys in this map exceeds its capacity and load factor.
*/
private void rehash() {
int oldCapacity = table.length;
Entry oldMap[] = table;
int newCapacity = (oldCapacity << 1) + 1;
Entry newMap[] = new Entry[newCapacity];
modCount++;
threshold = (int)(newCapacity * loadFactor);
table = newMap;
for (int i = oldCapacity ; i-- > 0 ;) {
for (Entry old = oldMap[i] ; old != null ; ) {
Entry e = old;
old = old.next;
int index = (e.key & 0x7FFFFFFF) % newCapacity;
e.next = newMap[index];
newMap[index] = e;
}
}
}
/**
* Associates the specified value with the specified key in this map. If the
* map previously contained a mapping for this 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 previous value associated with specified key, or <code>null</code> if
* there was no mapping for key. A <code>null</code> return can also indicate
* that the IntHashMap previously associated <code>null</code> with the
* specified key.
*/
@Override
public Object put(Object key, Object value) {
if (key instanceof Number) {
return put( ((Number)key).intValue(), value );
} else {
throw new UnsupportedOperationException
("IntHashMap key must be a number");
}
}
/**
* Associates the specified value with the specified key in this map. If the
* map previously contained a mapping for this 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 previous value associated with specified key, or <code>null</code> if
* there was no mapping for key. A <code>null</code> return can also indicate
* that the IntHashMap previously associated <code>null</code> with the
* specified key.
*/
public Object put(int key, Object value) {
// makes sure the key is not already in the IntHashMap.
Entry tab[] = table;
int index = (key & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index] ; e != null ; e = e.next) {
if (e.key == key) {
Object old = e.value;
e.value = value;
return old;
}
}
modCount++;
if (count >= threshold) {
// rehash the table if the threshold is exceeded
rehash();
tab = table;
index = (key & 0x7FFFFFFF) % tab.length;
}
// creates the new entry.
tab[index] = new Entry(key, value, tab[index]);
count++;
return null;
}
/**
* Removes the mapping for this key from this map if present.
*
* @param key key whose mapping is to be removed from the map.
*
* @return previous value associated with specified key, or <code>null</code> if
* there was no mapping for key. A <code>null</code> return can also indicate
* that the map previously associated <code>null</code> with the specified
* key.
*/
@Override
public Object remove(Object key) {
if (key instanceof Number) {
return remove( ((Number)key).intValue() );
} else {
return null;
}
}
/**
* Removes the mapping for this key from this map if present.
*
* @param key key whose mapping is to be removed from the map.
*
* @return previous value associated with specified key, or <code>null</code> if
* there was no mapping for key. A <code>null</code> return can also indicate
* that the map previously associated <code>null</code> with the specified
* key.
*/
public Object remove(int key) {
Entry tab[] = table;
int index = (key & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index], prev = null; e != null;
prev = e, e = e.next) {
if (e.key == key) {
modCount++;
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
count--;
Object oldValue = e.value;
e.value = null;
return oldValue;
}
}
return null;
}
/**
* Copies all of the mappings from the specified map to this one.
* These mappings replace any mappings that this map had for any of the
* keys currently in the specified Map.
*
* @param t Mappings to be stored in this map.
*/
@Override
public void putAll(Map t) {
for (Object o : t.entrySet()) {
Map.Entry e = (Map.Entry) o;
put(e.getKey(), e.getValue());
}
}
/**
* Removes all mappings from this map.
*/
@Override
public void clear() {
Entry tab[] = table;
modCount++;
for (int index = tab.length; --index >= 0; ) {
tab[index] = null;
}
count = 0;
}
/**
* Returns a shallow copy of this <code>IntHashMap</code> instance: the keys and
* values themselves are not cloned.
*
* @return a shallow copy of this map.
*/
@Override
public Object clone() {
try {
IntHashMap t = (IntHashMap)super.clone();
t.table = new Entry[table.length];
for (int i = table.length ; i-- > 0 ; ) {
t.table[i] = (table[i] != null)
? (Entry)table[i].clone() : null;
}
t.keySet = null;
t.entrySet = null;
t.values = null;
t.modCount = 0;
return t;
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError();
}
}
// views
private transient Set keySet;
private transient Set entrySet;
private transient Collection values;
/**
* Returns a set view of the keys contained in this map. The set is backed by
* the map, so changes to the map are reflected in the set, and vice-versa.
* The set supports element removal, which removes the corresponding mapping
* from this map, via the <code>Iterator.remove</code>,
* <code>Set.remove</code>, <code>removeAll</code>, <code>retainAll</code>,
* and <code>clear</code> operations. It does not support the
* <code>add</code> or <code>addAll</code> operations.
*
* @return a set view of the keys contained in this map.
*/
@Override
public Set keySet() {
if (keySet == null) {
keySet = new AbstractSet() {
@Override
public Iterator iterator() {
return new IntHashIterator(KEYS);
}
@Override
public int size() {
return count;
}
@Override
public boolean contains(Object o) {
return containsKey(o);
}
@Override
public boolean remove(Object o) {
return IntHashMap.this.remove(o) != null;
}
@Override
public void clear() {
IntHashMap.this.clear();
}
};
}
return keySet;
}
/**
* Returns a collection view of the values contained in this map. The
* collection is backed by the map, so changes to the map are reflected in
* the collection, and vice-versa. The collection supports element removal,
* which removes the corresponding mapping from this map, via the
* <code>Iterator.remove</code>, <code>Collection.remove</code>,
* <code>removeAll</code>, <code>retainAll</code>, and <code>clear</code>
* operations. It does not support the <code>add</code> or
* <code>addAll</code> operations.
*
* @return a collection view of the values contained in this map.
*/
@Override
public Collection values() {
if (values==null) {
values = new AbstractCollection() {
@Override
public Iterator iterator() {
return new IntHashIterator(VALUES);
}
@Override
public int size() {
return count;
}
@Override
public boolean contains(Object o) {
return containsValue(o);
}
@Override
public void clear() {
IntHashMap.this.clear();
}
};
}
return values;
}
/**
* Returns a collection view of the mappings contained in this map. Each
* element in the returned collection is a <code>Map.Entry</code>. The
* collection is backed by the map, so changes to the map are reflected in
* the collection, and vice-versa. The collection supports element removal,
* which removes the corresponding mapping from the map, via the
* <code>Iterator.remove</code>, <code>Collection.remove</code>,
* <code>removeAll</code>, <code>retainAll</code>, and <code>clear</code>
* operations. It does not support the <code>add</code> or
* <code>addAll</code> operations.
*
* @return a collection view of the mappings contained in this map.
* @see java.util.Map.Entry
*/
@Override
public Set entrySet() {
if (entrySet==null) {
entrySet = new AbstractSet() {
@Override
public Iterator iterator() {
return new IntHashIterator(ENTRIES);
}
@Override
public boolean contains(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==null ? 0 : key.hashCode());
int index = (hash & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index]; e != null; e = e.next) {
if (e.key == hash && e.equals(entry)) {
return true;
}
}
return false;
}
@Override
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==null ? 0 : key.hashCode());
int index = (hash & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[index], prev = null; e != null;
prev = e, e = e.next) {
if (e.key == 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;
}
@Override
public int size() {
return count;
}
@Override
public void clear() {
IntHashMap.this.clear();
}
};
}
return entrySet;
}
/**
* IntHashMap collision list entry.
*/
private static class Entry implements Map.Entry, Cloneable {
int key;
Object value;
Entry next;
private Integer objectKey;
Entry(int key, Object value, Entry next) {
this.key = key;
this.value = value;
this.next = next;
}
@Override
protected Object clone() {
return new Entry(key, value,
(next==null ? null : (Entry)next.clone()));
}
// Map.Entry Ops
public Object getKey() {
return(objectKey != null) ? objectKey :
(objectKey = new Integer(key));
}
public Object getValue() {
return value;
}
public Object setValue(Object value) {
Object oldValue = this.value;
this.value = value;
return oldValue;
}
@Override
public boolean equals(Object o) {
if (!(o instanceof Map.Entry)) {
return false;
}
Map.Entry e = (Map.Entry)o;
return(getKey().equals(e.getKey())) &&
(value==null ? e.getValue()==null : value.equals(e.getValue()));
}
@Override
public int hashCode() {
return key ^ (value==null ? 0 : value.hashCode());
}
@Override
public String toString() {
return Integer.toString(key) + '=' + value;
}
}
// types of Iterators
private static final int KEYS = 0;
private static final int VALUES = 1;
private static final int ENTRIES = 2;
private class IntHashIterator implements Iterator {
Entry[] table = IntHashMap.this.table;
int index = table.length;
Entry entry;
Entry lastReturned;
int type;
/**
* The modCount value that the iterator believes that the backing
* List should have. If this expectation is violated, the iterator
* has detected concurrent modification.
*/
private int expectedModCount = modCount;
IntHashIterator(int type) {
this.type = type;
}
public boolean hasNext() {
while (entry == null && index > 0) {
entry = table[--index];
}
return entry != null;
}
public Object next() {
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
while (entry == null && index > 0) {
entry = table[--index];
}
if (entry != null) {
Entry e = lastReturned = entry;
entry = e.next;
return type == KEYS ? e.getKey() :
(type == VALUES ? e.value : e);
}
throw new NoSuchElementException();
}
public void remove() {
if (lastReturned == null) {
throw new IllegalStateException();
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
Entry[] tab = IntHashMap.this.table;
int ndx = (lastReturned.key & 0x7FFFFFFF) % tab.length;
for (Entry e = tab[ndx], prev = null; e != null;
prev = e, e = e.next) {
if (e == lastReturned) {
modCount++;
expectedModCount++;
if (prev == null) {
tab[ndx] = e.next;
} else {
prev.next = e.next;
}
count--;
lastReturned = null;
return;
}
}
throw new ConcurrentModificationException();
}
}
/**
* Save the state of the <code>IntHashMap</code> instance to a stream (i.e.,
* serialize it).
* <p>
* Context The <i>capacity</i> of the IntHashMap (the length of the bucket
* array) is emitted (int), followed by the <i>size</i> of the IntHashMap
* (the number of key-value mappings), followed by the key (Object) and value
* (Object) for each key-value mapping represented by the IntHashMap The
* key-value mappings are emitted in no particular order.
*
* @exception IOException
*/
private void writeObject(java.io.ObjectOutputStream s) throws IOException {
// write out the threshold, loadfactor, and any hidden stuff
s.defaultWriteObject();
// write out number of buckets
s.writeInt(table.length);
// write out size (number of Mappings)
s.writeInt(count);
// write out keys and values (alternating)
for (int index = table.length-1; index >= 0; index--) {
Entry entry = table[index];
while (entry != null) {
s.writeInt(entry.key);
s.writeObject(entry.value);
entry = entry.next;
}
}
}
/**
* Reconstitutes the <code>IntHashMap</code> instance from a stream (i.e.,
* deserialize it).
*
* @exception IOException
* @exception ClassNotFoundException
*/
private void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException {
// read in the threshold, loadfactor, and any hidden stuff
s.defaultReadObject();
// read in number of buckets and allocate the bucket array;
int numBuckets = s.readInt();
table = new Entry[numBuckets];
// read in size (number of Mappings)
int size = s.readInt();
// read the keys and values, and put the mappings in the IntHashMap
for (int i=0; i<size; i++) {
int key = s.readInt();
Object value = s.readObject();
put(key, value);
}
}
int capacity() {
return table.length;
}
float loadFactor() {
return loadFactor;
}
}
]]>