it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceMap Maven / Gradle / Ivy
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/*
* Copyright (C) 2002-2017 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 it.unimi.dsi.fastutil.objects.ReferenceCollection;
import it.unimi.dsi.fastutil.objects.AbstractReferenceCollection;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
import it.unimi.dsi.fastutil.objects.AbstractObjectIterator;
import it.unimi.dsi.fastutil.objects.ObjectSet;
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 AbstractReference2ReferenceMap extends AbstractReference2ReferenceFunction implements Reference2ReferenceMap , java.io.Serializable {
private static final long serialVersionUID = -4940583368468432370L;
protected AbstractReference2ReferenceMap() {}
@Override
public boolean containsValue(Object v) {
return values().contains(v);
}
@Override
public boolean containsKey(Object k) {
ObjectIterator > i = reference2ReferenceEntrySet().iterator();
while(i.hasNext())
if (i.next().getKey() == k)
return true;
return false;
}
/** Puts all pairs in the given map.
* If the map implements the interface of this map,
* it uses the faster iterators.
*
* @param m a map.
*/
public void putAll(Map m) {
int n = m.size();
final Iterator> i = m.entrySet().iterator();
if (m instanceof Reference2ReferenceMap) {
Reference2ReferenceMap.Entry e;
while(n-- != 0) {
e = (Reference2ReferenceMap.Entry )i.next();
put(e.getKey(), e.getValue());
}
}
else {
Map.Entry e;
while(n-- != 0) {
e = i.next();
put(e.getKey(), e.getValue());
}
}
}
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 Reference2ReferenceMap.Entry {
protected K key;
protected V value;
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();
}
@Override
public boolean equals(final Object o) {
if (!(o instanceof Map.Entry)) return false;
final Map.Entry e = (Map.Entry)o;
return ( (key) == ((e.getKey())) ) && ( (value) == ((e.getValue())) );
}
@Override
public int hashCode() {
return ( System.identityHashCode(key) ) ^ ( (value) == null ? 0 : System.identityHashCode(value) );
}
@Override
public String toString() {
return key + "->" + value;
}
}
/** Returns a type-specific-set view of the keys of this map.
*
* The view is backed by the set returned by {@link #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 ReferenceSet keySet() {
return new AbstractReferenceSet () {
public boolean contains(final Object k) { return containsKey(k); }
public int size() { return AbstractReference2ReferenceMap.this.size(); }
public void clear() { AbstractReference2ReferenceMap.this.clear(); }
public ObjectIterator iterator() {
return new AbstractObjectIterator () {
final ObjectIterator> i = entrySet().iterator();
@Override
public K next() { return ((Reference2ReferenceMap.Entry )i.next()).getKey(); };
@Override
public boolean hasNext() { return i.hasNext(); }
@Override
public void remove() { i.remove(); }
};
}
};
}
/** Returns a type-specific-set view of the values of this map.
*
* The view is backed by the set returned by {@link #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 ReferenceCollection values() {
return new AbstractReferenceCollection () {
public boolean contains(final Object k) { return containsValue(k); }
public int size() { return AbstractReference2ReferenceMap.this.size(); }
public void clear() { AbstractReference2ReferenceMap.this.clear(); }
public ObjectIterator iterator() {
return new AbstractObjectIterator () {
final ObjectIterator> i = entrySet().iterator();
/** {@inheritDoc}
* @deprecated Please use the corresponding type-specific method instead. */
@Deprecated
public V next() { return ((Reference2ReferenceMap.Entry )i.next()).getValue(); };
public boolean hasNext() { return i.hasNext(); }
};
}
};
}
/** {@inheritDoc} */
@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
public ObjectSet> entrySet() {
return (ObjectSet)reference2ReferenceEntrySet();
}
/** 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 = entrySet().iterator();
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;
Map m = (Map)o;
if (m.size() != size()) return false;
return entrySet().containsAll(m.entrySet());
}
@Override
public String toString() {
final StringBuilder s = new StringBuilder();
final ObjectIterator> i = entrySet().iterator();
int n = size();
Reference2ReferenceMap.Entry e;
boolean first = true;
s.append("{");
while(n-- != 0) {
if (first) first = false;
else s.append(", ");
e = (Reference2ReferenceMap.Entry )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();
}
}