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/*
* Copyright (C) 2002-2022 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 static it.unimi.dsi.fastutil.Size64.sizeOf;
import java.util.function.Consumer;
import java.util.Iterator;
import java.util.Map;
/**
* An abstract class providing basic methods for maps implementing a type-specific interface.
*
*
* Optional operations just throw an {@link UnsupportedOperationException}. Generic versions of
* accessors delegate to the corresponding type-specific counterparts following the interface rules
* (they take care of returning {@code null} on a missing key).
*
*
* As a further help, this class provides a {@link BasicEntry BasicEntry} inner class that
* implements a type-specific version of {@link java.util.Map.Entry}; it is particularly useful for
* those classes that do not implement their own entries (e.g., most immutable maps).
*/
public abstract class AbstractObject2ObjectMap extends AbstractObject2ObjectFunction implements Object2ObjectMap, java.io.Serializable {
private static final long serialVersionUID = -4940583368468432370L;
protected AbstractObject2ObjectMap() {
}
/**
* {@inheritDoc}
*
* @implSpec This implementation does a linear search over the entry set, finding an entry that has
* the key specified.
*
* If you override {@link #keySet()}, you should probably override this method too to take
* advantage of the (presumably) faster {@linkplain java.util.Set#contains key membership
* test} your {@link #keySet()} provides.
*
* If you override this method but not {@link #keySet()}, then the returned key set will
* take advantage of this method.
*/
@Override
public boolean containsKey(final Object k) {
final ObjectIterator> i = object2ObjectEntrySet().iterator();
while (i.hasNext()) if (i.next().getKey() == k) return true;
return false;
}
/**
* {@inheritDoc}
*
* @implSpec This implementation does a linear search over the entry set, finding an entry that has
* the value specified.
*
* If you override {@link #values()}, you should probably override this method too to take
* advantage of the (presumably) faster {@linkplain java.util.Collection#contains value
* membership test} your {@link #values()} provides.
*
* If you override this method but not {@link #values()}, then the returned values
* collection will take advantage of this method.
*/
@Override
public boolean containsValue(final Object v) {
final ObjectIterator> i = object2ObjectEntrySet().iterator();
while (i.hasNext()) if (i.next().getValue() == v) return true;
return false;
}
@Override
public boolean isEmpty() {
return size() == 0;
}
/**
* This class provides a basic but complete type-specific entry class for all those maps
* implementations that do not have entries on their own (e.g., most immutable maps).
*
*
* This class does not implement {@link java.util.Map.Entry#setValue(Object) setValue()}, as the
* modification would not be reflected in the base map.
*/
public static class BasicEntry implements Object2ObjectMap.Entry {
protected K key;
protected V value;
public BasicEntry() {
}
public BasicEntry(final K key, final V value) {
this.key = (key);
this.value = (value);
}
@Override
public K getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(final V value) {
throw new UnsupportedOperationException();
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(final Object o) {
if (!(o instanceof Map.Entry)) return false;
if (o instanceof Object2ObjectMap.Entry) {
final Object2ObjectMap.Entry e = (Object2ObjectMap.Entry)o;
return java.util.Objects.equals(key, e.getKey()) && java.util.Objects.equals(value, e.getValue());
}
final Map.Entry e = (Map.Entry)o;
final Object key = e.getKey();
final Object value = e.getValue();
return java.util.Objects.equals(this.key, (key)) && java.util.Objects.equals(this.value, (value));
}
@Override
public int hashCode() {
return ((key) == null ? 0 : (key).hashCode()) ^ ((value) == null ? 0 : (value).hashCode());
}
@Override
public String toString() {
return key + "->" + value;
}
}
/**
* This class provides a basic implementation for an Entry set which forwards some queries to the
* map.
*/
public abstract static class BasicEntrySet extends AbstractObjectSet> {
protected final Object2ObjectMap map;
public BasicEntrySet(final Object2ObjectMap map) {
this.map = map;
}
@SuppressWarnings("unchecked")
@Override
public boolean contains(final Object o) {
if (!(o instanceof Map.Entry)) return false;
if (o instanceof Object2ObjectMap.Entry) {
final Object2ObjectMap.Entry e = (Object2ObjectMap.Entry)o;
final K k = e.getKey();
return map.containsKey(k) && java.util.Objects.equals(map.get(k), e.getValue());
}
final Map.Entry e = (Map.Entry)o;
final Object k = e.getKey();
final Object value = e.getValue();
return map.containsKey(k) && java.util.Objects.equals(map.get(k), (value));
}
@SuppressWarnings("unchecked")
@Override
public boolean remove(final Object o) {
if (!(o instanceof Map.Entry)) return false;
if (o instanceof Object2ObjectMap.Entry) {
final Object2ObjectMap.Entry e = (Object2ObjectMap.Entry)o;
return map.remove(e.getKey(), e.getValue());
}
Map.Entry e = (Map.Entry)o;
final Object k = e.getKey();
final Object v = e.getValue();
return map.remove(k, v);
}
@Override
public int size() {
return map.size();
}
@Override
public ObjectSpliterator> spliterator() {
return ObjectSpliterators.asSpliterator(iterator(), sizeOf(map), ObjectSpliterators.SET_SPLITERATOR_CHARACTERISTICS);
}
}
/**
* Returns a type-specific-set view of the keys of this map.
*
*
* The view is backed by the set returned by {@link Map#entrySet()}. Note that no attempt is
* made at caching the result of this method, as this would require adding some attributes that
* lightweight implementations would not need. Subclasses may easily override this policy by calling
* this method and caching the result, but implementors are encouraged to write more efficient
* ad-hoc implementations.
*
* @return a set view of the keys of this map; it may be safely cast to a type-specific interface.
*/
@Override
public ObjectSet keySet() {
return new AbstractObjectSet() {
@Override
public boolean contains(final Object k) {
return containsKey(k);
}
@Override
public int size() {
return AbstractObject2ObjectMap.this.size();
}
@Override
public void clear() {
AbstractObject2ObjectMap.this.clear();
}
@Override
public ObjectIterator iterator() {
return new ObjectIterator() {
private final ObjectIterator> i = Object2ObjectMaps.fastIterator(AbstractObject2ObjectMap.this);
@Override
public K next() {
return i.next().getKey();
}
@Override
public boolean hasNext() {
return i.hasNext();
}
@Override
public void remove() {
i.remove();
}
@Override
public void forEachRemaining(final Consumer action) {
i.forEachRemaining(entry -> action.accept(entry.getKey()));
}
};
}
@Override
public ObjectSpliterator spliterator() {
return ObjectSpliterators.asSpliterator(iterator(), sizeOf(AbstractObject2ObjectMap.this), ObjectSpliterators.SET_SPLITERATOR_CHARACTERISTICS);
}
};
}
/**
* Returns a type-specific-set view of the values of this map.
*
*
* The view is backed by the set returned by {@link Map#entrySet()}. Note that no attempt is
* made at caching the result of this method, as this would require adding some attributes that
* lightweight implementations would not need. Subclasses may easily override this policy by calling
* this method and caching the result, but implementors are encouraged to write more efficient
* ad-hoc implementations.
*
* @return a set view of the values of this map; it may be safely cast to a type-specific interface.
*/
@Override
public ObjectCollection values() {
return new AbstractObjectCollection() {
@Override
public boolean contains(final Object k) {
return containsValue(k);
}
@Override
public int size() {
return AbstractObject2ObjectMap.this.size();
}
@Override
public void clear() {
AbstractObject2ObjectMap.this.clear();
}
@Override
public ObjectIterator iterator() {
return new ObjectIterator() {
private final ObjectIterator> i = Object2ObjectMaps.fastIterator(AbstractObject2ObjectMap.this);
@Override
public V next() {
return i.next().getValue();
}
@Override
public boolean hasNext() {
return i.hasNext();
}
@Override
public void remove() {
i.remove();
}
@Override
public void forEachRemaining(final Consumer action) {
i.forEachRemaining(entry -> action.accept(entry.getValue()));
}
};
}
@Override
public ObjectSpliterator spliterator() {
return ObjectSpliterators.asSpliterator(iterator(), sizeOf(AbstractObject2ObjectMap.this), ObjectSpliterators.COLLECTION_SPLITERATOR_CHARACTERISTICS);
}
};
}
/** {@inheritDoc} */
@SuppressWarnings({ "unchecked", "deprecation" })
@Override
public void putAll(final Map m) {
if (m instanceof Object2ObjectMap) {
ObjectIterator> i = Object2ObjectMaps.fastIterator((Object2ObjectMap)m);
while (i.hasNext()) {
final Object2ObjectMap.Entry e = i.next();
put(e.getKey(), e.getValue());
}
} else {
int n = m.size();
final Iterator> i = m.entrySet().iterator();
Map.Entry e;
while (n-- != 0) {
e = i.next();
put(e.getKey(), e.getValue());
}
}
}
/**
* Returns a hash code for this map.
*
* The hash code of a map is computed by summing the hash codes of its entries.
*
* @return a hash code for this map.
*/
@Override
public int hashCode() {
int h = 0, n = size();
final ObjectIterator> i = Object2ObjectMaps.fastIterator(this);
while (n-- != 0) h += i.next().hashCode();
return h;
}
@Override
public boolean equals(Object o) {
if (o == this) return true;
if (!(o instanceof Map)) return false;
final Map m = (Map)o;
if (m.size() != size()) return false;
return object2ObjectEntrySet().containsAll(m.entrySet());
}
@Override
public String toString() {
final StringBuilder s = new StringBuilder();
final ObjectIterator> i = Object2ObjectMaps.fastIterator(this);
int n = size();
Object2ObjectMap.Entry e;
boolean first = true;
s.append("{");
while (n-- != 0) {
if (first) first = false;
else s.append(", ");
e = i.next();
if (this == e.getKey()) s.append("(this map)");
else s.append(String.valueOf(e.getKey()));
s.append("=>");
if (this == e.getValue()) s.append("(this map)");
else s.append(String.valueOf(e.getValue()));
}
s.append("}");
return s.toString();
}
}