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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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 org.apache.commons.collections.map;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import org.apache.commons.collections.MapIterator;
import org.apache.commons.collections.OrderedIterator;
import org.apache.commons.collections.OrderedMap;
import org.apache.commons.collections.OrderedMapIterator;
import org.apache.commons.collections.ResettableIterator;
import org.apache.commons.collections.iterators.EmptyOrderedIterator;
import org.apache.commons.collections.iterators.EmptyOrderedMapIterator;
/**
* An abstract implementation of a hash-based map that links entries to create an
* ordered map and which provides numerous points for subclasses to override.
*
* This class implements all the features necessary for a subclass linked
* hash-based map. Key-value entries are stored in instances of the
* LinkEntry class which can be overridden and replaced.
* The iterators can similarly be replaced, without the need to replace the KeySet,
* EntrySet and Values view classes.
*
* Overridable methods are provided to change the default hashing behaviour, and
* to change how entries are added to and removed from the map. Hopefully, all you
* need for unusual subclasses is here.
*
* This implementation maintains order by original insertion, but subclasses
* may work differently. The OrderedMap interface is implemented
* to provide access to bidirectional iteration and extra convenience methods.
*
* The orderedMapIterator() method provides direct access to a
* bidirectional iterator. The iterators from the other views can also be cast
* to OrderedIterator if required.
*
* All the available iterators can be reset back to the start by casting to
* ResettableIterator and calling reset().
*
* The implementation is also designed to be subclassed, with lots of useful
* methods exposed.
*
* @since Commons Collections 3.0
* @version $Revision$ $Date$
*
* @author java util LinkedHashMap
* @author Stephen Colebourne
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
public class AbstractLinkedMap extends AbstractHashedMap implements OrderedMap {
/**
* Header in the linked list
*/
protected transient LinkEntry header;
/**
* Constructor only used in deserialization, do not use otherwise.
*/
protected AbstractLinkedMap() {
super();
}
/**
* Constructor which performs no validation on the passed in parameters.
*
* @param initialCapacity the initial capacity, must be a power of two
* @param loadFactor the load factor, must be > 0.0f and generally < 1.0f
* @param threshold the threshold, must be sensible
*/
protected AbstractLinkedMap(int initialCapacity, float loadFactor, int threshold) {
super(initialCapacity, loadFactor, threshold);
}
/**
* Constructs a new, empty map with the specified initial capacity.
*
* @param initialCapacity the initial capacity
* @throws IllegalArgumentException if the initial capacity is less than one
*/
protected AbstractLinkedMap(int initialCapacity) {
super(initialCapacity);
}
/**
* Constructs a new, empty map with the specified initial capacity and
* load factor.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
* @throws IllegalArgumentException if the initial capacity is less than one
* @throws IllegalArgumentException if the load factor is less than zero
*/
protected AbstractLinkedMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Constructor copying elements from another map.
*
* @param map the map to copy
* @throws NullPointerException if the map is null
*/
protected AbstractLinkedMap(Map map) {
super(map);
}
/**
* Initialise this subclass during construction.
*
* NOTE: As from v3.2 this method calls
* {@link #createEntry(HashEntry, int, Object, Object)} to create
* the map entry object.
*/
protected void init() {
header = (LinkEntry) createEntry(null, -1, null, null);
header.before = header.after = header;
}
// -----------------------------------------------------------------------
/**
* Checks whether the map contains the specified value.
*
* @param value the value to search for
* @return true if the map contains the value
*/
public boolean containsValue(Object value) {
// override uses faster iterator
if (value == null) {
for (LinkEntry entry = header.after; entry != header; entry = entry.after) {
if (entry.getValue() == null) {
return true;
}
}
} else {
for (LinkEntry entry = header.after; entry != header; entry = entry.after) {
if (isEqualValue(value, entry.getValue())) {
return true;
}
}
}
return false;
}
/**
* Clears the map, resetting the size to zero and nullifying references
* to avoid garbage collection issues.
*/
public void clear() {
// override to reset the linked list
super.clear();
header.before = header.after = header;
}
// -----------------------------------------------------------------------
/**
* Gets the first key in the map, which is the most recently inserted.
*
* @return the most recently inserted key
*/
public Object firstKey() {
if (size == 0) {
throw new NoSuchElementException("Map is empty");
}
return header.after.getKey();
}
/**
* Gets the last key in the map, which is the first inserted.
*
* @return the eldest key
*/
public Object lastKey() {
if (size == 0) {
throw new NoSuchElementException("Map is empty");
}
return header.before.getKey();
}
/**
* Gets the next key in sequence.
*
* @param key the key to get after
* @return the next key
*/
public Object nextKey(Object key) {
LinkEntry entry = (LinkEntry) getEntry(key);
return (entry == null || entry.after == header ? null : entry.after.getKey());
}
/**
* Gets the previous key in sequence.
*
* @param key the key to get before
* @return the previous key
*/
public Object previousKey(Object key) {
LinkEntry entry = (LinkEntry) getEntry(key);
return (entry == null || entry.before == header ? null : entry.before.getKey());
}
// -----------------------------------------------------------------------
/**
* Gets the key at the specified index.
*
* @param index the index to retrieve
* @return the key at the specified index
* @throws IndexOutOfBoundsException if the index is invalid
*/
protected LinkEntry getEntry(int index) {
if (index < 0) {
throw new IndexOutOfBoundsException("Index " + index + " is less than zero");
}
if (index >= size) {
throw new IndexOutOfBoundsException("Index " + index + " is invalid for size " + size);
}
LinkEntry entry;
if (index < (size / 2)) {
// Search forwards
entry = header.after;
for (int currentIndex = 0; currentIndex < index; currentIndex++) {
entry = entry.after;
}
} else {
// Search backwards
entry = header;
for (int currentIndex = size; currentIndex > index; currentIndex--) {
entry = entry.before;
}
}
return entry;
}
/**
* Adds an entry into this map, maintaining insertion order.
*
* This implementation adds the entry to the data storage table and
* to the end of the linked list.
*
* @param entry the entry to add
* @param hashIndex the index into the data array to store at
*/
protected void addEntry(HashEntry entry, int hashIndex) {
LinkEntry link = (LinkEntry) entry;
link.after = header;
link.before = header.before;
header.before.after = link;
header.before = link;
data[hashIndex] = entry;
}
/**
* Creates an entry to store the data.
*
* This implementation creates a new LinkEntry instance.
*
* @param next the next entry in sequence
* @param hashCode the hash code to use
* @param key the key to store
* @param value the value to store
* @return the newly created entry
*/
protected HashEntry createEntry(HashEntry next, int hashCode, Object key, Object value) {
return new LinkEntry(next, hashCode, key, value);
}
/**
* Removes an entry from the map and the linked list.
*
* This implementation removes the entry from the linked list chain, then
* calls the superclass implementation.
*
* @param entry the entry to remove
* @param hashIndex the index into the data structure
* @param previous the previous entry in the chain
*/
protected void removeEntry(HashEntry entry, int hashIndex, HashEntry previous) {
LinkEntry link = (LinkEntry) entry;
link.before.after = link.after;
link.after.before = link.before;
link.after = null;
link.before = null;
super.removeEntry(entry, hashIndex, previous);
}
// -----------------------------------------------------------------------
/**
* Gets the before field from a LinkEntry.
* Used in subclasses that have no visibility of the field.
*
* @param entry the entry to query, must not be null
* @return the before field of the entry
* @throws NullPointerException if the entry is null
* @since Commons Collections 3.1
*/
protected LinkEntry entryBefore(LinkEntry entry) {
return entry.before;
}
/**
* Gets the after field from a LinkEntry.
* Used in subclasses that have no visibility of the field.
*
* @param entry the entry to query, must not be null
* @return the after field of the entry
* @throws NullPointerException if the entry is null
* @since Commons Collections 3.1
*/
protected LinkEntry entryAfter(LinkEntry entry) {
return entry.after;
}
// -----------------------------------------------------------------------
/**
* Gets an iterator over the map.
* Changes made to the iterator affect this map.
*
* A MapIterator returns the keys in the map. It also provides convenient
* methods to get the key and value, and set the value.
* It avoids the need to create an entrySet/keySet/values object.
*
* @return the map iterator
*/
public MapIterator mapIterator() {
if (size == 0) {
return EmptyOrderedMapIterator.INSTANCE;
}
return new LinkMapIterator(this);
}
/**
* Gets a bidirectional iterator over the map.
* Changes made to the iterator affect this map.
*
* A MapIterator returns the keys in the map. It also provides convenient
* methods to get the key and value, and set the value.
* It avoids the need to create an entrySet/keySet/values object.
*
* @return the map iterator
*/
public OrderedMapIterator orderedMapIterator() {
if (size == 0) {
return EmptyOrderedMapIterator.INSTANCE;
}
return new LinkMapIterator(this);
}
/**
* MapIterator implementation.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static class LinkMapIterator extends LinkIterator implements OrderedMapIterator {
protected LinkMapIterator(AbstractLinkedMap parent) {
super(parent);
}
public Object next() {
return super.nextEntry().getKey();
}
public Object previous() {
return super.previousEntry().getKey();
}
public Object getKey() {
HashEntry current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.GETKEY_INVALID);
}
return current.getKey();
}
public Object getValue() {
HashEntry current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.GETVALUE_INVALID);
}
return current.getValue();
}
public Object setValue(Object value) {
HashEntry current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.SETVALUE_INVALID);
}
return current.setValue(value);
}
}
// -----------------------------------------------------------------------
/**
* Creates an entry set iterator.
* Subclasses can override this to return iterators with different properties.
*
* @return the entrySet iterator
*/
protected Iterator createEntrySetIterator() {
if (size() == 0) {
return EmptyOrderedIterator.INSTANCE;
}
return new EntrySetIterator(this);
}
/**
* EntrySet iterator.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static class EntrySetIterator extends LinkIterator {
protected EntrySetIterator(AbstractLinkedMap parent) {
super(parent);
}
public Object next() {
return super.nextEntry();
}
public Object previous() {
return super.previousEntry();
}
}
// -----------------------------------------------------------------------
/**
* Creates a key set iterator.
* Subclasses can override this to return iterators with different properties.
*
* @return the keySet iterator
*/
protected Iterator createKeySetIterator() {
if (size() == 0) {
return EmptyOrderedIterator.INSTANCE;
}
return new KeySetIterator(this);
}
/**
* KeySet iterator.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static class KeySetIterator extends EntrySetIterator {
protected KeySetIterator(AbstractLinkedMap parent) {
super(parent);
}
public Object next() {
return super.nextEntry().getKey();
}
public Object previous() {
return super.previousEntry().getKey();
}
}
// -----------------------------------------------------------------------
/**
* Creates a values iterator.
* Subclasses can override this to return iterators with different properties.
*
* @return the values iterator
*/
protected Iterator createValuesIterator() {
if (size() == 0) {
return EmptyOrderedIterator.INSTANCE;
}
return new ValuesIterator(this);
}
/**
* Values iterator.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static class ValuesIterator extends LinkIterator {
protected ValuesIterator(AbstractLinkedMap parent) {
super(parent);
}
public Object next() {
return super.nextEntry().getValue();
}
public Object previous() {
return super.previousEntry().getValue();
}
}
// -----------------------------------------------------------------------
/**
* LinkEntry that stores the data.
*
* If you subclass AbstractLinkedMap but not LinkEntry
* then you will not be able to access the protected fields.
* The entryXxx() methods on AbstractLinkedMap exist
* to provide the necessary access.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static class LinkEntry extends HashEntry {
/**
* The entry before this one in the order
*/
protected LinkEntry before;
/**
* The entry after this one in the order
*/
protected LinkEntry after;
/**
* Constructs a new entry.
*
* @param next the next entry in the hash bucket sequence
* @param hashCode the hash code
* @param key the key
* @param value the value
*/
protected LinkEntry(HashEntry next, int hashCode, Object key, Object value) {
super(next, hashCode, key, value);
}
}
/**
* Base Iterator that iterates in link order.
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
protected static abstract class LinkIterator implements OrderedIterator, ResettableIterator {
/**
* The parent map
*/
protected final AbstractLinkedMap parent;
/**
* The current (last returned) entry
*/
protected LinkEntry last;
/**
* The next entry
*/
protected LinkEntry next;
/**
* The modification count expected
*/
protected int expectedModCount;
protected LinkIterator(AbstractLinkedMap parent) {
super();
this.parent = parent;
this.next = parent.header.after;
this.expectedModCount = parent.modCount;
}
public boolean hasNext() {
return (next != parent.header);
}
public boolean hasPrevious() {
return (next.before != parent.header);
}
protected LinkEntry nextEntry() {
if (parent.modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
if (next == parent.header) {
throw new NoSuchElementException(AbstractHashedMap.NO_NEXT_ENTRY);
}
last = next;
next = next.after;
return last;
}
protected LinkEntry previousEntry() {
if (parent.modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
LinkEntry previous = next.before;
if (previous == parent.header) {
throw new NoSuchElementException(AbstractHashedMap.NO_PREVIOUS_ENTRY);
}
next = previous;
last = previous;
return last;
}
protected LinkEntry currentEntry() {
return last;
}
public void remove() {
if (last == null) {
throw new IllegalStateException(AbstractHashedMap.REMOVE_INVALID);
}
if (parent.modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
parent.remove(last.getKey());
last = null;
expectedModCount = parent.modCount;
}
public void reset() {
last = null;
next = parent.header.after;
}
public String toString() {
if (last != null) {
return "Iterator[" + last.getKey() + "=" + last.getValue() + "]";
} else {
return "Iterator[]";
}
}
}
}