it.unimi.dsi.fastutil.objects.Object2ObjectArrayMap Maven / Gradle / Ivy
/*
* Copyright (C) 2007-2017 Sebastiano Vigna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package it.unimi.dsi.fastutil.objects;
import java.util.Map;
import java.util.NoSuchElementException;
import it.unimi.dsi.fastutil.objects.AbstractObjectIterator;
import it.unimi.dsi.fastutil.objects.AbstractObjectSet;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
import it.unimi.dsi.fastutil.objects.ObjectCollection;
import it.unimi.dsi.fastutil.objects.ObjectCollections;
import it.unimi.dsi.fastutil.objects.ObjectArraySet;
import it.unimi.dsi.fastutil.objects.ObjectArrays;
/** A simple, brute-force implementation of a map based on two parallel backing arrays.
*
* The main purpose of this
* implementation is that of wrapping cleanly the brute-force approach to the storage of a very
* small number of pairs: just put them into two parallel arrays and scan linearly to find an item.
*/
public class Object2ObjectArrayMap extends AbstractObject2ObjectMap implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = 1L;
/** The keys (valid up to {@link #size}, excluded). */
private transient Object[] key;
/** The values (parallel to {@link #key}). */
private transient Object[] value;
/** The number of valid entries in {@link #key} and {@link #value}. */
private int size;
/** Creates a new empty array map with given key and value backing arrays. The resulting map will have as many entries as the given arrays.
*
* It is responsibility of the caller that the elements of key are distinct.
*
* @param key the key array.
* @param value the value array (it must have the same length as key).
*/
public Object2ObjectArrayMap(final Object[] key, final Object[] value) {
this.key = key;
this.value = value;
size = key.length;
if(key.length != value.length) throw new IllegalArgumentException("Keys and values have different lengths (" + key.length + ", " + value.length + ")");
}
/** Creates a new empty array map.
*/
public Object2ObjectArrayMap() {
this.key = ObjectArrays.EMPTY_ARRAY;
this.value = ObjectArrays.EMPTY_ARRAY;
}
/** Creates a new empty array map of given capacity.
*
* @param capacity the initial capacity.
*/
public Object2ObjectArrayMap(final int capacity) {
this.key = new Object[capacity];
this.value = new Object[capacity];
}
/** Creates a new empty array map copying the entries of a given map.
*
* @param m a map.
*/
public Object2ObjectArrayMap(final Object2ObjectMap m) {
this(m.size());
putAll(m);
}
/** Creates a new empty array map copying the entries of a given map.
*
* @param m a map.
*/
public Object2ObjectArrayMap(final Map m) {
this(m.size());
putAll(m);
}
/** Creates a new array map with given key and value backing arrays, using the given number of elements.
*
* It is responsibility of the caller that the first size elements of key are distinct.
*
* @param key the key array.
* @param value the value array (it must have the same length as key).
* @param size the number of valid elements in key and value.
*/
public Object2ObjectArrayMap(final Object[] key, final Object[] value, final int size) {
this.key = key;
this.value = value;
this.size = size;
if(key.length != value.length) throw new IllegalArgumentException("Keys and values have different lengths (" + key.length + ", " + value.length + ")");
if (size > key.length) throw new IllegalArgumentException("The provided size (" + size + ") is larger than or equal to the backing-arrays size (" + key.length + ")");
}
private final class EntrySet extends AbstractObjectSet > implements FastEntrySet {
@Override
public ObjectIterator > iterator() {
return new AbstractObjectIterator >() {
int curr = -1, next = 0;
@Override
public boolean hasNext() {
return next < size;
}
@Override
@SuppressWarnings("unchecked")
public Entry next() {
if (! hasNext()) throw new NoSuchElementException();
return new AbstractObject2ObjectMap.BasicEntry ((K) key[curr = next], (V) value[next++]);
}
@Override
public void remove() {
if (curr == -1) throw new IllegalStateException();
curr = -1;
final int tail = size-- - next--;
System.arraycopy(key, next + 1, key, next, tail);
System.arraycopy(value, next + 1, value, next, tail);
key[size] = null;
value[size] = null;
}
};
}
@Override
public ObjectIterator > fastIterator() {
return new AbstractObjectIterator >() {
int next = 0, curr = -1;
final BasicEntry entry = new BasicEntry ((null), (null));
@Override
public boolean hasNext() {
return next < size;
}
@Override
@SuppressWarnings("unchecked")
public Entry next() {
if (! hasNext()) throw new NoSuchElementException();
entry.key = (K) key[curr = next];
entry.value = (V) value[next++];
return entry;
}
@Override
public void remove() {
if (curr == -1) throw new IllegalStateException();
curr = -1;
final int tail = size-- - next--;
System.arraycopy(key, next + 1, key, next, tail);
System.arraycopy(value, next + 1, value, next, tail);
key[size] = null;
value[size] = null;
}
};
}
@Override
public int size() {
return size;
}
@Override
@SuppressWarnings("unchecked")
public boolean contains(Object o) {
if (! (o instanceof Map.Entry)) return false;
final Map.Entry e = (Map.Entry)o;
final K k = ((K) e.getKey());
return Object2ObjectArrayMap.this.containsKey(k) && ( (Object2ObjectArrayMap.this.get(k)) == null ? ((e.getValue())) == null : (Object2ObjectArrayMap.this.get(k)).equals((e.getValue())) );
}
@Override
@SuppressWarnings("unchecked")
public boolean remove(final Object o) {
if (!(o instanceof Map.Entry)) return false;
final Map.Entry e = (Map.Entry)o;
final K k = ((K) e.getKey());
final V v = ((V) e.getValue());
final int oldPos = Object2ObjectArrayMap.this.findKey(k);
if (oldPos == -1 || ! ( (v) == null ? (Object2ObjectArrayMap.this.value[oldPos]) == null : (v).equals(Object2ObjectArrayMap.this.value[oldPos]) )) return false;
final int tail = size - oldPos - 1;
System.arraycopy(Object2ObjectArrayMap.this.key, oldPos + 1, Object2ObjectArrayMap.this.key, oldPos, tail);
System.arraycopy(Object2ObjectArrayMap.this.value, oldPos + 1, Object2ObjectArrayMap.this.value, oldPos, tail);
Object2ObjectArrayMap.this.size--;
Object2ObjectArrayMap.this.key[size] = null;
Object2ObjectArrayMap.this.value[size] = null;
return true;
}
}
@Override
public FastEntrySet object2ObjectEntrySet() {
return new EntrySet();
}
private int findKey(final Object k) {
final Object[] key = this.key;
for(int i = size; i-- != 0;) if (( (key[i]) == null ? (k) == null : (key[i]).equals(k) )) return i;
return -1;
}
@Override
@SuppressWarnings("unchecked")
public V get(final Object k) {
final Object[] key = this.key;
for(int i = size; i-- != 0;) if (( (key[i]) == null ? (k) == null : (key[i]).equals(k) )) return (V) value[i];
return defRetValue;
}
@Override
public int size() {
return size;
}
@Override
public void clear() {
for(int i = size; i-- != 0;) {
key[i] = null;
value[i] = null;
}
size = 0;
}
@Override
public boolean containsKey(final Object k) {
return findKey(k) != -1;
}
@Override
public boolean containsValue(Object v) {
for(int i = size; i-- != 0;) if (( (value[i]) == null ? (v) == null : (value[i]).equals(v) )) return true;
return false;
}
@Override
public boolean isEmpty() {
return size == 0;
}
@Override
@SuppressWarnings("unchecked")
public V put(K k, V v) {
final int oldKey = findKey(k);
if (oldKey != -1) {
final V oldValue = (V) value[oldKey];
value[oldKey] = v;
return oldValue;
}
if (size == key.length) {
final Object[] newKey = new Object[size == 0 ? 2 : size * 2];
final Object[] newValue = new Object[size == 0 ? 2 : size * 2];
for(int i = size; i-- != 0;) {
newKey[i] = key[i];
newValue[i] = value[i];
}
key = newKey;
value = newValue;
}
key[size] = k;
value[size] = v;
size++;
return defRetValue;
}
@Override
@SuppressWarnings("unchecked")
public V remove(final Object k) {
final int oldPos = findKey(k);
if (oldPos == -1) return defRetValue;
final V oldValue = (V) value[oldPos];
final int tail = size - oldPos - 1;
System.arraycopy(key, oldPos + 1, key, oldPos, tail);
System.arraycopy(value, oldPos + 1, value, oldPos, tail);
size--;
key[size] = null;
value[size] = null;
return oldValue;
}
@Override
public ObjectSet keySet() {
return new ObjectArraySet (key, size);
}
@Override
public ObjectCollection values() {
return ObjectCollections.unmodifiable(new ObjectArraySet (value, size));
}
/** Returns a deep copy of this map.
*
* This method performs a deep copy of this hash map; the data stored in the
* map, however, is not cloned. Note that this makes a difference only for object keys.
*
* @return a deep copy of this map.
*/
@Override
@SuppressWarnings("unchecked")
public Object2ObjectArrayMap clone() {
Object2ObjectArrayMap c;
try {
c = (Object2ObjectArrayMap )super.clone();
}
catch(CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.key = key.clone();
c.value = value.clone();
return c;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
s.defaultWriteObject();
for(int i = 0; i < size; i++) {
s.writeObject(key[i]);
s.writeObject(value[i]);
}
}
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
key = new Object[size];
value = new Object[size];
for(int i = 0; i < size; i++) {
key[i] = s.readObject();
value[i] = s.readObject();
}
}
}