net.shibboleth.utilities.java.support.collection.ClassToInstanceMultiMap Maven / Gradle / Ivy
/*
* Licensed to the University Corporation for Advanced Internet Development,
* Inc. (UCAID) under one or more contributor license agreements. See the
* NOTICE file distributed with this work for additional information regarding
* copyright ownership. The UCAID licenses this file to You 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 net.shibboleth.utilities.java.support.collection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import javax.annotation.concurrent.NotThreadSafe;
/**
* An append-only multimap where each entry associates a raw type (i.e. class) to instances of that class. In addition
* the map may also associate any supertype (i.e. all superclasses and interfaces implemented by the class) with the
* class.
*
* Null values are not supported.
*
* @param a bound for the types of values in the map
*/
@NotThreadSafe
public class ClassToInstanceMultiMap {
/** Whether supertypes should also be indexed. */
private final boolean indexSupertypes;
/** Map which backs this map. */
private final HashMap, List> backingMap;
/** List of values that are indexed. */
private final List values;
/** Constructor. Does not index supertypes. */
public ClassToInstanceMultiMap() {
this(false);
}
/**
* Constructor.
*
* @param isIndexingSupertypes indicates whether supertypes of a value should be indexed
*/
public ClassToInstanceMultiMap(final boolean isIndexingSupertypes) {
backingMap = new HashMap<>();
values = new ArrayList<>();
indexSupertypes = isIndexingSupertypes;
}
/** Removes all mappings from this map. */
public void clear() {
values.clear();
backingMap.clear();
}
/**
* Returns true if the map contains a mapping for the given key.
*
* @param key key to check for in the map
*
* @return true if the map contains a mapping for the specified key
*/
public boolean containsKey(final Class key) {
if (key == null) {
return false;
}
return backingMap.containsKey(key);
}
/**
* Returns true if the map contains a mapping to the given value.
*
* @param value value to check for in this map
*
* @return true if the map contains a mapping to the specified value
*/
public boolean containsValue(final B value) {
if (value == null) {
return false;
}
return values.contains(value);
}
/**
* Gets the instances mapped to the given type or an empty list, immutable, list otherwise.
*
* @param type identifier
* @param type map key
*
* @return instances mapped to the given type or an empty list, immutable, list otherwise
*/
public List get(final Class type) {
if (type == null) {
return Collections.emptyList();
}
final List indexedValues = (List) backingMap.get(type);
if (indexedValues == null) {
return Collections.emptyList();
}
return Collections.unmodifiableList(indexedValues);
}
/**
* Returns true if this map contains no entries, false otherwise.
*
* @return true if this map contains no entries, false otherwise
*/
public boolean isEmpty() {
return values.isEmpty();
}
/**
* Gets the set of keys contained in this map. The set is backed by the map so changes made to the map are reflected
* in the set. However the set does not allow direct modification, any changes need to be done through this map.
*
* @return set of keys contained in this map
*/
public Set> keys() {
return Collections.unmodifiableSet(backingMap.keySet());
}
/**
* Adds a value to this map. If {@link #indexSupertypes} is false only the values class type is used as a key to the
* value. If {@link #indexSupertypes} is true, then the class types, all its supertypes, and all implemented
* interfaces are used as keys to the value.
*
* Duplicate values, as determined by the values {@link Object#hashCode()} and {@link Object#equals(Object)}
* methods, are not stored. Only one instance of the value is ever stored in the map.
*
* @param value value to be stored in the map
*/
public void put(final B value) {
if (value == null) {
return;
}
if (!values.contains(value)) {
values.add(value);
}
List indexValues;
for (Class indexKey : getIndexTypes(value)) {
indexValues = backingMap.get(indexKey);
if (indexValues == null) {
indexValues = new ArrayList<>();
backingMap.put(indexKey, indexValues);
}
if (!indexValues.contains(value)) {
indexValues.add(value);
}
}
}
/**
* Adds all the values to the map.
*
* @param newValues values to be added
*
* @see ClassToInstanceMultiMap#put(Object)
*/
public void putAll(final Iterable newValues) {
if (newValues == null) {
return;
}
for (B value : newValues) {
put(value);
}
}
/**
* Adds all the values to the map. This operations operates only on the given map's value collection. Therefore,
* regardless of the given map's policy on indexing by value supertypes, this map will index values based on its
* policy.
*
* @param map map containing values to be added
*
* @see ClassToInstanceMultiMap#put(Object)
*/
public void putAll(final ClassToInstanceMultiMap map) {
if (map == null) {
return;
}
putAll(map.values());
}
/**
* Remove the specified value from the map and from the value list of all indexes.
*
*
* If the value list for a type index becomes empty due to the value removal, the entire type index will be removed
* and {@link #containsKey(Class)} for that type will then return false.
*
*
* @param value the value to remove
*/
public void remove(final B value) {
if (value == null) {
return;
}
values.remove(value);
List indexValues;
for (Class indexKey : getIndexTypes(value)) {
indexValues = backingMap.get(indexKey);
if (indexValues != null) {
indexValues.remove(value);
if (indexValues.isEmpty()) {
backingMap.remove(indexKey);
}
}
}
}
/**
* Remove the specified values from the map and from the value list of all indexes.
*
*
* If the value list for a type index becomes empty due to a value removal, the entire type index will be removed
* and {@link #containsKey(Class)} for that type will then return false.
*
*
* @param removeValues the values to remove
*/
public void removeAll(final Iterable removeValues) {
if (removeValues == null) {
return;
}
for (B value : removeValues) {
remove(value);
}
}
/**
* Remove the values contained in the specified map from this map and from the value list of all indexes.
*
*
* If the value list for a type index becomes empty due to a value removal, the entire type index will be removed
* and {@link #containsKey(Class)} for that type will then return false.
*
*
* @param map the map containing the values to remove
*/
public void removeAll(final ClassToInstanceMultiMap map) {
if (map == null) {
return;
}
removeAll(map.values());
}
/**
* Remove from the map all values which have the specified type.
*
*
* Note that when a value was indexed by multiple superclass and/or interface types, it will be removed from all
* those type indexes, not just the specified one.
*
*
*
* If the value list for a type index becomes empty due to a value removal, the entire type index will be removed
* and {@link #containsKey(Class)} for that type will then return false.
*
*
* @param type the type of values to remove
*/
public void remove(final Class type) {
if (type == null) {
return;
}
List indexValues = backingMap.remove(type);
if (indexValues != null) {
for (B value : indexValues) {
remove(value);
}
}
}
/**
* The collection of values currently present in the map. This collection is backed by the map so changeds to the
* map will be reflected in the collection. However the collection does not allow direct modification so any changes
* must be done through this map.
*
* @return collection of values currently present in the map
*/
public Collection values() {
return Collections.unmodifiableList(values);
}
/**
* Get the effective set of all class types via which the specified value should be indexed.
*
* @param value the value to index
* @return the set of classes by which to index the value
*/
private Set> getIndexTypes(final B value) {
final HashSet> indexTypes = new HashSet<>();
indexTypes.add(value.getClass());
if (indexSupertypes) {
getSuperTypes(value.getClass(), indexTypes);
}
return indexTypes;
}
/**
* Gets all of the superclasses and interfaces implemented by the given class.
*
* @param clazz class for which supertypes will be determined
* @param accumulator collection to which supertypes are added as they are determined
*/
private void getSuperTypes(final Class clazz, Set> accumulator) {
final Class superclass = clazz.getSuperclass();
if (superclass != null && superclass != Object.class) {
accumulator.add(superclass);
getSuperTypes(superclass, accumulator);
}
final Class[] interfaces = clazz.getInterfaces();
if (interfaces.length > 0) {
for (Class iface : interfaces) {
accumulator.add(iface);
getSuperTypes(iface, accumulator);
}
}
}
/** {@inheritDoc} */
@Override public int hashCode() {
return backingMap.hashCode() + values.hashCode();
}
/** {@inheritDoc} */
@Override public boolean equals(Object obj) {
if (null == obj) {
return false;
}
if (obj instanceof ClassToInstanceMultiMap) {
ClassToInstanceMultiMap cast = (ClassToInstanceMultiMap) obj;
return backingMap.equals(cast.backingMap) && values.equals(cast.values);
}
return false;
}
}