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scorex package for Java SCORE
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package scorex.util;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/*
* A hash table based implementation of the Map interface.
*/
public class HashMap implements Map {
static final int DEFAULT_INITIAL_CAPACITY = 16;
static final int MAXIMUM_CAPACITY = 1 << 16;
static final float DEFAULT_LOAD_FACTOR = 0.75f;
private final float loadFactor;
private int threshold;
private Entry[] table;
private int size;
private int modCount;
private Set keySet;
private Collection values;
private Set> entrySet;
@SuppressWarnings("unchecked")
public HashMap(int initialCapacity, float loadFactor) {
if (initialCapacity < 0)
throw new IllegalArgumentException("Illegal initial capacity: " + initialCapacity);
if (initialCapacity > MAXIMUM_CAPACITY)
initialCapacity = MAXIMUM_CAPACITY;
if (loadFactor <= 0 || Float.isNaN(loadFactor))
throw new IllegalArgumentException("Illegal load factor: " + loadFactor);
// Find a power of 2 >= initialCapacity
int capacity = 1;
while (capacity < initialCapacity)
capacity <<= 1;
this.loadFactor = loadFactor;
threshold = (int)(capacity * loadFactor);
table = (Entry[]) new Entry[capacity];
}
public HashMap(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
@SuppressWarnings("unchecked")
public HashMap() {
this.loadFactor = DEFAULT_LOAD_FACTOR;
this.threshold = (int)(DEFAULT_INITIAL_CAPACITY * DEFAULT_LOAD_FACTOR);
table = (Entry[]) new Entry[DEFAULT_INITIAL_CAPACITY];
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
static int hash(int h) {
h ^= (h >>> 20) ^ (h >>> 12);
return h ^ (h >>> 7) ^ (h >>> 4);
}
private int indexFor(int h, int length) {
return h & (length-1);
}
@Override
public V get(Object key) {
Entry e = getEntry(key);
if (e != null)
return e.value;
return null;
}
@Override
public boolean containsKey(Object key) {
return getEntry(key) != null;
}
private Entry getEntry(Object key) {
int hash = (key == null) ? 0 : hash(key.hashCode());
for (Entry e = table[indexFor(hash, table.length)]; e != null; e = e.next) {
Object k;
if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k))))
return e;
}
return null;
}
@Override
public V put(K key, V value) {
int hash = (key == null) ? 0 : hash(key.hashCode());
int i = indexFor(hash, table.length);
for (Entry e = table[i]; e != null; e = e.next) {
Object k;
if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k)))) {
V oldValue = e.value;
e.value = value;
return oldValue;
}
}
modCount++;
addEntry(hash, key, value, i);
return null;
}
private void addEntry(int hash, K key, V value, int index) {
Entry e = table[index];
table[index] = new Entry(hash, key, value, e);
if (size++ >= threshold)
resize(2 * table.length);
}
private void resize(int newCapacity) {
Entry[] oldTable = table;
int oldCapacity = oldTable.length;
if (oldCapacity == MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return;
}
@SuppressWarnings("unchecked")
Entry[] newTable = (Entry[]) new Entry[newCapacity];
transfer(newTable);
table = newTable;
threshold = (int)(newCapacity * loadFactor);
}
private void transfer(Entry[] newTable) {
Entry[] src = table;
int newCapacity = newTable.length;
for (int j = 0; j < src.length; j++) {
Entry e = src[j];
if (e != null) {
src[j] = null;
do {
Entry next = e.next;
int i = indexFor(e.hash, newCapacity);
e.next = newTable[i];
newTable[i] = e;
e = next;
} while (e != null);
}
}
}
@Override
public V remove(Object key) {
Entry e = removeEntryForKey(key);
return (e == null ? null : e.value);
}
private Entry removeEntryForKey(Object key) {
int hash = (key == null) ? 0 : hash(key.hashCode());
int i = indexFor(hash, table.length);
Entry prev = table[i];
Entry e = prev;
while (e != null) {
Entry next = e.next;
Object k;
if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k)))) {
modCount++;
size--;
if (prev == e)
table[i] = next;
else
prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
@Override
public String toString() {
Iterator> i = entrySet().iterator();
if (! i.hasNext())
return "{}";
StringBuilder sb = new StringBuilder();
sb.append('{');
for (;;) {
Map.Entry e = i.next();
K key = e.getKey();
V value = e.getValue();
sb.append(key == this ? "(this Map)" : key);
sb.append('=');
sb.append(value == this ? "(this Map)" : value);
if (!i.hasNext())
return sb.append('}').toString();
sb.append(',').append(' ');
}
}
static class Entry implements Map.Entry {
final K key;
V value;
Entry next;
final int hash;
Entry(int h, K k, V v, Entry n) {
hash = h;
key = k;
value = v;
next = n;
}
@Override
public K getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(V newValue) {
V oldValue = value;
value = newValue;
return oldValue;
}
public final boolean equals(Object o) {
if (!(o instanceof Map.Entry))
return false;
@SuppressWarnings("unchecked")
Map.Entry e = (Map.Entry)o;
Object k1 = getKey();
Object k2 = e.getKey();
if (k1 == k2 || (k1 != null && k1.equals(k2))) {
Object v1 = getValue();
Object v2 = e.getValue();
if (v1 == v2 || (v1 != null && v1.equals(v2)))
return true;
}
return false;
}
public final int hashCode() {
return (key==null ? 0 : key.hashCode()) ^
(value==null ? 0 : value.hashCode());
}
@Override
public final String toString() {
return getKey() + "=" + getValue();
}
}
@Override
@SuppressWarnings("unchecked")
public void putAll(Map m) {
for (Map.Entry e : m.entrySet()) {
this.put((K) e.getKey(), (V) e.getValue());
}
}
@Override
public void clear() {
modCount++;
Entry[] tab = table;
for (int i = 0; i < tab.length; i++) {
tab[i] = null;
}
size = 0;
}
@Override
public boolean containsValue(Object value) {
if (value == null)
return containsNullValue();
Entry[] tab = table;
for (int i = 0; i < tab.length; i++)
for (Entry e = tab[i]; e != null ; e = e.next)
if (value.equals(e.value))
return true;
return false;
}
private boolean containsNullValue() {
Entry[] tab = table;
for (int i = 0; i < tab.length; i++)
for (Entry e = tab[i]; e != null ; e = e.next)
if (e.value == null)
return true;
return false;
}
@Override
public Set keySet() {
Set ks = keySet;
return (ks != null ? ks : (keySet = new KeySet()));
}
@Override
public Collection values() {
Collection vs = values;
return (vs != null ? vs : (values = new Values()));
}
private final class KeySet extends AbstractCollection implements Set {
@Override
public Iterator iterator() {
return new KeyIterator();
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(Object o) {
return containsKey(o);
}
@Override
public boolean remove(Object o) {
return HashMap.this.removeEntryForKey(o) != null;
}
@Override
public void clear() {
HashMap.this.clear();
}
}
private final class Values extends AbstractCollection {
@Override
public Iterator iterator() {
return new ValueIterator();
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(Object o) {
return containsValue(o);
}
@Override
public void clear() {
HashMap.this.clear();
}
}
private final class KeyIterator extends HashIterator {
public K next() {
return nextEntry().getKey();
}
}
private final class ValueIterator extends HashIterator {
public V next() {
return nextEntry().getValue();
}
}
private final class EntryIterator extends HashIterator> {
public Map.Entry next() {
return nextEntry();
}
}
private abstract class HashIterator implements Iterator {
Entry next;
int expectedModCount;
int index;
Entry current;
HashIterator() {
expectedModCount = modCount;
if (size > 0) {
Entry[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
}
public final boolean hasNext() {
return next != null;
}
final Entry nextEntry() {
if (modCount != expectedModCount)
throw new RuntimeException();
Entry e = next;
if (e == null)
throw new NoSuchElementException();
if ((next = e.next) == null) {
Entry[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
current = e;
return e;
}
public void remove() {
if (current == null)
throw new IllegalStateException();
if (modCount != expectedModCount)
throw new RuntimeException();
Object k = current.key;
current = null;
HashMap.this.removeEntryForKey(k);
expectedModCount = modCount;
}
}
@Override
public Set> entrySet() {
Set> es = entrySet;
return es != null ? es : (entrySet = new EntrySet());
}
private final class EntrySet extends AbstractCollection> implements Set> {
@Override
public Iterator> iterator() {
return new EntryIterator();
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
@SuppressWarnings("unchecked")
Map.Entry e = (Map.Entry) o;
Entry candidate = getEntry(e.getKey());
return candidate != null && candidate.equals(e);
}
@Override
public boolean remove(Object o) {
return removeMapping(o) != null;
}
@Override
public void clear() {
HashMap.this.clear();
}
}
final Entry removeMapping(Object o) {
if (!(o instanceof Map.Entry))
return null;
@SuppressWarnings("unchecked")
Map.Entry entry = (Map.Entry) o;
Object key = entry.getKey();
int hash = (key == null) ? 0 : hash(key.hashCode());
int i = indexFor(hash, table.length);
Entry prev = table[i];
Entry e = prev;
while (e != null) {
Entry next = e.next;
if (e.hash == hash && e.equals(entry)) {
modCount++;
size--;
if (prev == e)
table[i] = next;
else
prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
}