// Converted, with some major refactors required. Not as memory-efficient as before, could use additional refactoring.
// Perhaps use four different types of HashEntry classes for max efficiency:
// normal HashEntry for HARD,HARD
// HardRefEntry for HARD,(SOFT|WEAK)
// RefHardEntry for (SOFT|WEAK),HARD
// RefRefEntry for (SOFT|WEAK),(SOFT|WEAK)
/*
* Copyright 2002-2004 The Apache Software Foundation
*
* 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 org.jivesoftware.smack.util.collections;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
import java.util.*;
/**
* An abstract implementation of a hash-based map that allows the entries to
* be removed by the garbage collector.
* <p/>
* This class implements all the features necessary for a subclass reference
* hash-based map. Key-value entries are stored in instances of the
* <code>ReferenceEntry</code> 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.
* <p/>
* 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.
* <p/>
* When you construct an <code>AbstractReferenceMap</code>, you can specify what
* kind of references are used to store the map's keys and values.
* If non-hard references are used, then the garbage collector can remove
* mappings if a key or value becomes unreachable, or if the JVM's memory is
* running low. For information on how the different reference types behave,
* see {@link Reference}.
* <p/>
* Different types of references can be specified for keys and values.
* The keys can be configured to be weak but the values hard,
* in which case this class will behave like a
* <a href="http://java.sun.com/j2se/1.4/docs/api/java/util/WeakHashMap.html">
* <code>WeakHashMap</code></a>. However, you can also specify hard keys and
* weak values, or any other combination. The default constructor uses
* hard keys and soft values, providing a memory-sensitive cache.
* <p/>
* This {@link Map} implementation does <i>not</i> allow null elements.
* Attempting to add a null key or value to the map will raise a
* <code>NullPointerException</code>.
* <p/>
* All the available iterators can be reset back to the start by casting to
* <code>ResettableIterator</code> and calling <code>reset()</code>.
* <p/>
* This implementation is not synchronized.
* You can use {@link java.util.Collections#synchronizedMap} to
* provide synchronized access to a <code>ReferenceMap</code>.
*
* @author Paul Jack
* @author Matt Hall, John Watkinson, Stephen Colebourne
* @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $
* @see java.lang.ref.Reference
* @since Commons Collections 3.1 (extracted from ReferenceMap in 3.0)
*/
public abstract class AbstractReferenceMap <K,V> extends AbstractHashedMap<K, V> {
/**
* Constant indicating that hard references should be used
*/
public static final int HARD = 0;
/**
* Constant indicating that soft references should be used
*/
public static final int SOFT = 1;
/**
* Constant indicating that weak references should be used
*/
public static final int WEAK = 2;
/**
* The reference type for keys. Must be HARD, SOFT, WEAK.
*
* @serial
*/
protected int keyType;
/**
* The reference type for values. Must be HARD, SOFT, WEAK.
*
* @serial
*/
protected int valueType;
/**
* Should the value be automatically purged when the associated key has been collected?
*/
protected boolean purgeValues;
/**
* ReferenceQueue used to eliminate stale mappings.
* See purge.
*/
private transient ReferenceQueue queue;
//-----------------------------------------------------------------------
/**
* Constructor used during deserialization.
*/
protected AbstractReferenceMap() {
super();
}
/**
* Constructs a new empty map with the specified reference types,
* load factor and initial capacity.
*
* @param keyType the type of reference to use for keys;
* must be {@link #SOFT} or {@link #WEAK}
* @param valueType the type of reference to use for values;
* must be {@link #SOFT} or {@link #WEAK}
* @param capacity the initial capacity for the map
* @param loadFactor the load factor for the map
* @param purgeValues should the value be automatically purged when the
* key is garbage collected
*/
protected AbstractReferenceMap(int keyType, int valueType, int capacity, float loadFactor, boolean purgeValues) {
super(capacity, loadFactor);
verify("keyType", keyType);
verify("valueType", valueType);
this.keyType = keyType;
this.valueType = valueType;
this.purgeValues = purgeValues;
}
/**
* Initialise this subclass during construction, cloning or deserialization.
*/
protected void init() {
queue = new ReferenceQueue();
}
//-----------------------------------------------------------------------
/**
* Checks the type int is a valid value.
*
* @param name the name for error messages
* @param type the type value to check
* @throws IllegalArgumentException if the value if invalid
*/
private static void verify(String name, int type) {
if ((type < HARD) || (type > WEAK)) {
throw new IllegalArgumentException(name + " must be HARD, SOFT, WEAK.");
}
}
//-----------------------------------------------------------------------
/**
* Gets the size of the map.
*
* @return the size
*/
public int size() {
purgeBeforeRead();
return super.size();
}
/**
* Checks whether the map is currently empty.
*
* @return true if the map is currently size zero
*/
public boolean isEmpty() {
purgeBeforeRead();
return super.isEmpty();
}
/**
* Checks whether the map contains the specified key.
*
* @param key the key to search for
* @return true if the map contains the key
*/
public boolean containsKey(Object key) {
purgeBeforeRead();
Entry entry = getEntry(key);
if (entry == null) {
return false;
}
return (entry.getValue() != null);
}
/**
* 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) {
purgeBeforeRead();
if (value == null) {
return false;
}
return super.containsValue(value);
}
/**
* Gets the value mapped to the key specified.
*
* @param key the key
* @return the mapped value, null if no match
*/
public V get(Object key) {
purgeBeforeRead();
Entry<K, V> entry = getEntry(key);
if (entry == null) {
return null;
}
return entry.getValue();
}
/**
* Puts a key-value mapping into this map.
* Neither the key nor the value may be null.
*
* @param key the key to add, must not be null
* @param value the value to add, must not be null
* @return the value previously mapped to this key, null if none
* @throws NullPointerException if either the key or value is null
*/
public V put(K key, V value) {
if (key == null) {
throw new NullPointerException("null keys not allowed");
}
if (value == null) {
throw new NullPointerException("null values not allowed");
}
purgeBeforeWrite();
return super.put(key, value);
}
/**
* Removes the specified mapping from this map.
*
* @param key the mapping to remove
* @return the value mapped to the removed key, null if key not in map
*/
public V remove(Object key) {
if (key == null) {
return null;
}
purgeBeforeWrite();
return super.remove(key);
}
/**
* Clears this map.
*/
public void clear() {
super.clear();
while (queue.poll() != null) {
} // drain the queue
}
//-----------------------------------------------------------------------
/**
* Gets a MapIterator over the reference map.
* The iterator only returns valid key/value pairs.
*
* @return a map iterator
*/
public MapIterator<K, V> mapIterator() {
return new ReferenceMapIterator<K, V>(this);
}
/**
* Returns a set view of this map's entries.
* An iterator returned entry is valid until <code>next()</code> is called again.
* The <code>setValue()</code> method on the <code>toArray</code> entries has no effect.
*
* @return a set view of this map's entries
*/
public Set<Map.Entry<K, V>> entrySet() {
if (entrySet == null) {
entrySet = new ReferenceEntrySet<K, V>(this);
}
return entrySet;
}
/**
* Returns a set view of this map's keys.
*
* @return a set view of this map's keys
*/
public Set<K> keySet() {
if (keySet == null) {
keySet = new ReferenceKeySet<K, V>(this);
}
return keySet;
}
/**
* Returns a collection view of this map's values.
*
* @return a set view of this map's values
*/
public Collection<V> values() {
if (values == null) {
values = new ReferenceValues<K, V>(this);
}
return values;
}
//-----------------------------------------------------------------------
/**
* Purges stale mappings from this map before read operations.
* <p/>
* This implementation calls {@link #purge()} to maintain a consistent state.
*/
protected void purgeBeforeRead() {
purge();
}
/**
* Purges stale mappings from this map before write operations.
* <p/>
* This implementation calls {@link #purge()} to maintain a consistent state.
*/
protected void purgeBeforeWrite() {
purge();
}
/**
* Purges stale mappings from this map.
* <p/>
* Note that this method is not synchronized! Special
* care must be taken if, for instance, you want stale
* mappings to be removed on a periodic basis by some
* background thread.
*/
protected void purge() {
Reference ref = queue.poll();
while (ref != null) {
purge(ref);
ref = queue.poll();
}
}
/**
* Purges the specified reference.
*
* @param ref the reference to purge
*/
protected void purge(Reference ref) {
// The hashCode of the reference is the hashCode of the
// mapping key, even if the reference refers to the
// mapping value...
int hash = ref.hashCode();
int index = hashIndex(hash, data.length);
HashEntry<K, V> previous = null;
HashEntry<K, V> entry = data[index];
while (entry != null) {
if (((ReferenceEntry<K, V>) entry).purge(ref)) {
if (previous == null) {
data[index] = entry.next;
} else {
previous.next = entry.next;
}
this.size--;
return;
}
previous = entry;
entry = entry.next;
}
}
//-----------------------------------------------------------------------
/**
* Gets the entry mapped to the key specified.
*
* @param key the key
* @return the entry, null if no match
*/
protected HashEntry<K, V> getEntry(Object key) {
if (key == null) {
return null;
} else {
return super.getEntry(key);
}
}
/**
* Gets the hash code for a MapEntry.
* Subclasses can override this, for example to use the identityHashCode.
*
* @param key the key to get a hash code for, may be null
* @param value the value to get a hash code for, may be null
* @return the hash code, as per the MapEntry specification
*/
protected int hashEntry(Object key, Object value) {
return (key == null ? 0 : key.hashCode()) ^ (value == null ? 0 : value.hashCode());
}
/**
* Compares two keys, in internal converted form, to see if they are equal.
* <p/>
* This implementation converts the key from the entry to a real reference
* before comparison.
*
* @param key1 the first key to compare passed in from outside
* @param key2 the second key extracted from the entry via <code>entry.key</code>
* @return true if equal
*/
protected boolean isEqualKey(Object key1, Object key2) {
//if ((key1 == null) && (key2 != null) || (key1 != null) || (key2 == null)) {
// return false;
//}
// GenericsNote: Conversion from reference handled by getKey() which replaced all .key references
//key2 = (keyType > HARD ? ((Reference) key2).get() : key2);
return (key1 == key2 || key1.equals(key2));
}
/**
* Creates a ReferenceEntry instead of a HashEntry.
*
* @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
*/
public HashEntry<K, V> createEntry(HashEntry<K, V> next, int hashCode, K key, V value) {
return new ReferenceEntry<K, V>(this, (ReferenceEntry<K, V>) next, hashCode, key, value);
}
/**
* Creates an entry set iterator.
*
* @return the entrySet iterator
*/
protected Iterator<Map.Entry<K, V>> createEntrySetIterator() {
return new ReferenceEntrySetIterator<K, V>(this);
}
/**
* Creates an key set iterator.
*
* @return the keySet iterator
*/
protected Iterator<K> createKeySetIterator() {
return new ReferenceKeySetIterator<K, V>(this);
}
/**
* Creates an values iterator.
*
* @return the values iterator
*/
protected Iterator<V> createValuesIterator() {
return new ReferenceValuesIterator<K, V>(this);
}
//-----------------------------------------------------------------------
/**
* EntrySet implementation.
*/
static class ReferenceEntrySet <K,V> extends EntrySet<K, V> {
protected ReferenceEntrySet(AbstractHashedMap<K, V> parent) {
super(parent);
}
public Object[] toArray() {
return toArray(new Object[0]);
}
public <T> T[] toArray(T[] arr) {
// special implementation to handle disappearing entries
ArrayList<Map.Entry<K, V>> list = new ArrayList<Map.Entry<K, V>>();
Iterator<Map.Entry<K, V>> iterator = iterator();
while (iterator.hasNext()) {
Map.Entry<K, V> e = iterator.next();
list.add(new DefaultMapEntry<K, V>(e.getKey(), e.getValue()));
}
return list.toArray(arr);
}
}
//-----------------------------------------------------------------------
/**
* KeySet implementation.
*/
static class ReferenceKeySet <K,V> extends KeySet<K, V> {
protected ReferenceKeySet(AbstractHashedMap<K, V> parent) {
super(parent);
}
public Object[] toArray() {
return toArray(new Object[0]);
}
public <T> T[] toArray(T[] arr) {
// special implementation to handle disappearing keys
List<K> list = new ArrayList<K>(parent.size());
for (Iterator<K> it = iterator(); it.hasNext();) {
list.add(it.next());
}
return list.toArray(arr);
}
}
//-----------------------------------------------------------------------
/**
* Values implementation.
*/
static class ReferenceValues <K,V> extends Values<K, V> {
protected ReferenceValues(AbstractHashedMap<K, V> parent) {
super(parent);
}
public Object[] toArray() {
return toArray(new Object[0]);
}
public <T> T[] toArray(T[] arr) {
// special implementation to handle disappearing values
List<V> list = new ArrayList<V>(parent.size());
for (Iterator<V> it = iterator(); it.hasNext();) {
list.add(it.next());
}
return list.toArray(arr);
}
}
//-----------------------------------------------------------------------
/**
* A MapEntry implementation for the map.
* <p/>
* If getKey() or getValue() returns null, it means
* the mapping is stale and should be removed.
*
* @since Commons Collections 3.1
*/
protected static class ReferenceEntry <K,V> extends HashEntry<K, V> {
/**
* The parent map
*/
protected final AbstractReferenceMap<K, V> parent;
protected Reference<K> refKey;
protected Reference<V> refValue;
/**
* Creates a new entry object for the ReferenceMap.
*
* @param parent the parent map
* @param next the next entry in the hash bucket
* @param hashCode the hash code of the key
* @param key the key
* @param value the value
*/
public ReferenceEntry(AbstractReferenceMap<K, V> parent, ReferenceEntry<K, V> next, int hashCode, K key, V value) {
super(next, hashCode, null, null);
this.parent = parent;
if (parent.keyType != HARD) {
refKey = toReference(parent.keyType, key, hashCode);
} else {
this.setKey(key);
}
if (parent.valueType != HARD) {
refValue = toReference(parent.valueType, value, hashCode); // the key hashCode is passed in deliberately
} else {
this.setValue(value);
}
}
/**
* Gets the key from the entry.
* This method dereferences weak and soft keys and thus may return null.
*
* @return the key, which may be null if it was garbage collected
*/
public K getKey() {
return (parent.keyType > HARD) ? refKey.get() : super.getKey();
}
/**
* Gets the value from the entry.
* This method dereferences weak and soft value and thus may return null.
*
* @return the value, which may be null if it was garbage collected
*/
public V getValue() {
return (parent.valueType > HARD) ? refValue.get() : super.getValue();
}
/**
* Sets the value of the entry.
*
* @param obj the object to store
* @return the previous value
*/
public V setValue(V obj) {
V old = getValue();
if (parent.valueType > HARD) {
refValue.clear();
refValue = toReference(parent.valueType, obj, hashCode);
} else {
super.setValue(obj);
}
return old;
}
/**
* Compares this map entry to another.
* <p/>
* This implementation uses <code>isEqualKey</code> and
* <code>isEqualValue</code> on the main map for comparison.
*
* @param obj the other map entry to compare to
* @return true if equal, false if not
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof Map.Entry == false) {
return false;
}
Map.Entry entry = (Map.Entry) obj;
Object entryKey = entry.getKey(); // convert to hard reference
Object entryValue = entry.getValue(); // convert to hard reference
if ((entryKey == null) || (entryValue == null)) {
return false;
}
// compare using map methods, aiding identity subclass
// note that key is direct access and value is via method
return parent.isEqualKey(entryKey, getKey()) && parent.isEqualValue(entryValue, getValue());
}
/**
* Gets the hashcode of the entry using temporary hard references.
* <p/>
* This implementation uses <code>hashEntry</code> on the main map.
*
* @return the hashcode of the entry
*/
public int hashCode() {
return parent.hashEntry(getKey(), getValue());
}
/**
* Constructs a reference of the given type to the given referent.
* The reference is registered with the queue for later purging.
*
* @param type HARD, SOFT or WEAK
* @param referent the object to refer to
* @param hash the hash code of the <i>key</i> of the mapping;
* this number might be different from referent.hashCode() if
* the referent represents a value and not a key
*/
protected <T> Reference<T> toReference(int type, T referent, int hash) {
switch (type) {
case SOFT:
return new SoftRef<T>(hash, referent, parent.queue);
case WEAK:
return new WeakRef<T>(hash, referent, parent.queue);
default:
throw new Error("Attempt to create hard reference in ReferenceMap!");
}
}
/**
* Purges the specified reference
*
* @param ref the reference to purge
* @return true or false
*/
boolean purge(Reference ref) {
boolean r = (parent.keyType > HARD) && (refKey == ref);
r = r || ((parent.valueType > HARD) && (refValue == ref));
if (r) {
if (parent.keyType > HARD) {
refKey.clear();
}
if (parent.valueType > HARD) {
refValue.clear();
} else if (parent.purgeValues) {
setValue(null);
}
}
return r;
}
/**
* Gets the next entry in the bucket.
*
* @return the next entry in the bucket
*/
protected ReferenceEntry<K, V> next() {
return (ReferenceEntry<K, V>) next;
}
}
//-----------------------------------------------------------------------
/**
* The EntrySet iterator.
*/
static class ReferenceIteratorBase <K,V> {
/**
* The parent map
*/
final AbstractReferenceMap<K, V> parent;
// These fields keep track of where we are in the table.
int index;
ReferenceEntry<K, V> entry;
ReferenceEntry<K, V> previous;
// These Object fields provide hard references to the
// current and next entry; this assures that if hasNext()
// returns true, next() will actually return a valid element.
K nextKey;
V nextValue;
K currentKey;
V currentValue;
int expectedModCount;
public ReferenceIteratorBase(AbstractReferenceMap<K, V> parent) {
super();
this.parent = parent;
index = (parent.size() != 0 ? parent.data.length : 0);
// have to do this here! size() invocation above
// may have altered the modCount.
expectedModCount = parent.modCount;
}
public boolean hasNext() {
checkMod();
while (nextNull()) {
ReferenceEntry<K, V> e = entry;
int i = index;
while ((e == null) && (i > 0)) {
i--;
e = (ReferenceEntry<K, V>) parent.data[i];
}
entry = e;
index = i;
if (e == null) {
currentKey = null;
currentValue = null;
return false;
}
nextKey = e.getKey();
nextValue = e.getValue();
if (nextNull()) {
entry = entry.next();
}
}
return true;
}
private void checkMod() {
if (parent.modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
}
private boolean nextNull() {
return (nextKey == null) || (nextValue == null);
}
protected ReferenceEntry<K, V> nextEntry() {
checkMod();
if (nextNull() && !hasNext()) {
throw new NoSuchElementException();
}
previous = entry;
entry = entry.next();
currentKey = nextKey;
currentValue = nextValue;
nextKey = null;
nextValue = null;
return previous;
}
protected ReferenceEntry<K, V> currentEntry() {
checkMod();
return previous;
}
public ReferenceEntry<K, V> superNext() {
return nextEntry();
}
public void remove() {
checkMod();
if (previous == null) {
throw new IllegalStateException();
}
parent.remove(currentKey);
previous = null;
currentKey = null;
currentValue = null;
expectedModCount = parent.modCount;
}
}
/**
* The EntrySet iterator.
*/
static class ReferenceEntrySetIterator <K,V> extends ReferenceIteratorBase<K, V> implements Iterator<Map.Entry<K, V>> {
public ReferenceEntrySetIterator(AbstractReferenceMap<K, V> abstractReferenceMap) {
super(abstractReferenceMap);
}
public ReferenceEntry<K, V> next() {
return superNext();
}
}
/**
* The keySet iterator.
*/
static class ReferenceKeySetIterator <K,V> extends ReferenceIteratorBase<K, V> implements Iterator<K> {
ReferenceKeySetIterator(AbstractReferenceMap<K, V> parent) {
super(parent);
}
public K next() {
return nextEntry().getKey();
}
}
/**
* The values iterator.
*/
static class ReferenceValuesIterator <K,V> extends ReferenceIteratorBase<K, V> implements Iterator<V> {
ReferenceValuesIterator(AbstractReferenceMap<K, V> parent) {
super(parent);
}
public V next() {
return nextEntry().getValue();
}
}
/**
* The MapIterator implementation.
*/
static class ReferenceMapIterator <K,V> extends ReferenceIteratorBase<K, V> implements MapIterator<K, V> {
protected ReferenceMapIterator(AbstractReferenceMap<K, V> parent) {
super(parent);
}
public K next() {
return nextEntry().getKey();
}
public K getKey() {
HashEntry<K, V> current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.GETKEY_INVALID);
}
return current.getKey();
}
public V getValue() {
HashEntry<K, V> current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.GETVALUE_INVALID);
}
return current.getValue();
}
public V setValue(V value) {
HashEntry<K, V> current = currentEntry();
if (current == null) {
throw new IllegalStateException(AbstractHashedMap.SETVALUE_INVALID);
}
return current.setValue(value);
}
}
//-----------------------------------------------------------------------
// These two classes store the hashCode of the key of
// of the mapping, so that after they're dequeued a quick
// lookup of the bucket in the table can occur.
/**
* A soft reference holder.
*/
static class SoftRef <T> extends SoftReference<T> {
/**
* the hashCode of the key (even if the reference points to a value)
*/
private int hash;
public SoftRef(int hash, T r, ReferenceQueue q) {
super(r, q);
this.hash = hash;
}
public int hashCode() {
return hash;
}
}
/**
* A weak reference holder.
*/
static class WeakRef <T> extends WeakReference<T> {
/**
* the hashCode of the key (even if the reference points to a value)
*/
private int hash;
public WeakRef(int hash, T r, ReferenceQueue q) {
super(r, q);
this.hash = hash;
}
public int hashCode() {
return hash;
}
}
//-----------------------------------------------------------------------
/**
* Replaces the superclass method to store the state of this class.
* <p/>
* Serialization is not one of the JDK's nicest topics. Normal serialization will
* initialise the superclass before the subclass. Sometimes however, this isn't
* what you want, as in this case the <code>put()</code> method on read can be
* affected by subclass state.
* <p/>
* The solution adopted here is to serialize the state data of this class in
* this protected method. This method must be called by the
* <code>writeObject()</code> of the first serializable subclass.
* <p/>
* Subclasses may override if they have a specific field that must be present
* on read before this implementation will work. Generally, the read determines
* what must be serialized here, if anything.
*
* @param out the output stream
*/
protected void doWriteObject(ObjectOutputStream out) throws IOException {
out.writeInt(keyType);
out.writeInt(valueType);
out.writeBoolean(purgeValues);
out.writeFloat(loadFactor);
out.writeInt(data.length);
for (MapIterator it = mapIterator(); it.hasNext();) {
out.writeObject(it.next());
out.writeObject(it.getValue());
}
out.writeObject(null); // null terminate map
// do not call super.doWriteObject() as code there doesn't work for reference map
}
/**
* Replaces the superclassm method to read the state of this class.
* <p/>
* Serialization is not one of the JDK's nicest topics. Normal serialization will
* initialise the superclass before the subclass. Sometimes however, this isn't
* what you want, as in this case the <code>put()</code> method on read can be
* affected by subclass state.
* <p/>
* The solution adopted here is to deserialize the state data of this class in
* this protected method. This method must be called by the
* <code>readObject()</code> of the first serializable subclass.
* <p/>
* Subclasses may override if the subclass has a specific field that must be present
* before <code>put()</code> or <code>calculateThreshold()</code> will work correctly.
*
* @param in the input stream
*/
protected void doReadObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
this.keyType = in.readInt();
this.valueType = in.readInt();
this.purgeValues = in.readBoolean();
this.loadFactor = in.readFloat();
int capacity = in.readInt();
init();
data = new HashEntry[capacity];
while (true) {
K key = (K) in.readObject();
if (key == null) {
break;
}
V value = (V) in.readObject();
put(key, value);
}
threshold = calculateThreshold(data.length, loadFactor);
// do not call super.doReadObject() as code there doesn't work for reference map
}
}