Class MVMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.h2.mvstore.MVMap<K,V>

Type Parameters:

K - the key class

V - the value class

All Implemented Interfaces:

ConcurrentMap<K,V>, Map<K,V>

Direct Known Subclasses:

MVRTreeMap, TransactionStore.TxMapBuilder.TMVMap

public class MVMap<K,V>
extends AbstractMap<K,V>
implements ConcurrentMap<K,V>

A stored map.

All read and write operations can happen concurrently with all other operations, without risk of corruption.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MVMap.BasicBuilder<M extends MVMap<K,V>, K, V>	A builder for this class.
static class	MVMap.Builder<K,V>	A builder for this class.
static enum	MVMap.Decision	The decision on what to do on an update.
static class	MVMap.DecisionMaker<V>	Class DecisionMaker provides callback interface (and should become a such in Java 8) for MVMap.operate method.
private static final class	MVMap.EqualsDecisionMaker<V>
private static final class	MVMap.IntValueHolder
static interface	MVMap.MapBuilder<M extends MVMap<K,V>, K, V>	A builder for maps.
private static final class	MVMap.RewriteDecisionMaker<V>

Nested classes/interfaces inherited from class AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
private final AtomicLong	avgKeySize
private final AtomicLong	avgValSize
private boolean	closed	Whether the map is closed.
private final long	createVersion
private final int	id
(package private) static final long	INITIAL_VERSION	This designates the "last stored" version for a store which was just open for the first time.
private boolean	isVolatile
private final K[]	keysBuffer
private final int	keysPerPage
private final DataType<K>	keyType
private final Object	lock
private boolean	notificationRequested
private boolean	readOnly
private final AtomicReference<RootReference<K,V>>	root	Reference to the current root page.
private final boolean	singleWriter
final MVStore	store	The store.
private final V[]	valuesBuffer
private final DataType<V>	valueType

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MVMap(Map<String,Object> config, DataType<K> keyType, DataType<V> valueType)
protected	MVMap(MVMap<K,V> source)
(package private)	MVMap(MVStore store, int id, DataType<K> keyType, DataType<V> valueType)
private	MVMap(MVStore store, DataType<K> keyType, DataType<V> valueType, int id, long createVersion, AtomicReference<RootReference<K,V>> root, int keysPerPage, boolean singleWriter)

Method Summary

Modifier and Type	Method	Description
void	append(K key, V value)	Appends entry to this map.
(package private) static <X> boolean	areValuesEqual(DataType<X> datatype, X a, X b)	Check whether the two values are equal.
protected String	asString(String name)	Get the map metadata as a string.
protected final void	beforeWrite()	This method is called before writing to the map.
private static <T> int	calculateMemory(DataType<T> keyType, T[] storage, int count)
final K	ceilingKey(K key)	Get the smallest key that is larger or equal to this key.
void	clear()	Remove all entries.
(package private) RootReference<K,V>	clearIt()	Remove all entries and return the root reference.
protected MVMap<K,V>	cloneIt()	Clone the current map.
(package private) final void	close()	Close the map.
(package private) final int	compare(K a, K b)	Compare two keys.
(package private) final boolean	compareAndSetRoot(RootReference<K,V> expectedRootReference, RootReference<K,V> updatedRootReference)	Compare and set the root reference.
final boolean	containsKey(Object key)
private void	copy(Page<K,V> source, Page<K,V> parent, int index)
(package private) final void	copyFrom(MVMap<K,V> sourceMap)	Copy a map.
protected Page<K,V>	createEmptyLeaf()	Create empty leaf node page.
protected Page<K,V>	createEmptyNode()	Create empty internal node page.
final Cursor<K,V>	cursor(K from)	Get a cursor to iterate over a number of keys and values in the latest version of this map.
final Cursor<K,V>	cursor(K from, K to, boolean reverse)	Get a cursor to iterate over a number of keys and values in the latest version of this map.
Cursor<K,V>	cursor(RootReference<K,V> rootReference, K from, K to, boolean reverse)	Get a cursor to iterate over a number of keys and values.
final Set<Map.Entry<K,V>>	entrySet()
final boolean	equals(Object o)
(package private) final int	evaluateMemoryForKey(K key)
(package private) final int	evaluateMemoryForKeys(K[] storage, int count)
(package private) final int	evaluateMemoryForValue(V value)
(package private) final int	evaluateMemoryForValues(V[] storage, int count)
final K	firstKey()	Get the first key, or null if the map is empty.
final K	floorKey(K key)	Get the largest key that is smaller or equal to this key.
RootReference<K,V>	flushAndGetRoot()	Get the root reference, flushing any current append buffer.
private RootReference<K,V>	flushAppendBuffer(RootReference<K,V> rootReference, boolean fullFlush)	If map was used in append mode, this method will ensure that append buffer is flushed - emptied with all entries inserted into map as a new leaf.
final V	get(Object key)	Get the value for the given key, or null if not found.
V	get(Page<K,V> p, K key)	Get the value for the given key from a snapshot, or null if not found.
protected int	getChildPageCount(Page<K,V> p)	Get the child page count for this page.
(package private) final long	getCreateVersion()
private K	getFirstLast(boolean first)	Get the first (lowest) or last (largest) key.
private K	getFirstLast(Page<K,V> p, boolean first)
final int	getId()	Get the map id.
final K	getKey(long index)	Get the key at the given index.
final long	getKeyIndex(K key)	Get the index of the given key in the map.
final DataType<K>	getKeyType()	Get the key type.
(package private) static String	getMapKey(int mapId)	Get the metadata key for the given map id.
(package private) static String	getMapRootKey(int mapId)	Get the metadata key for the root of the given map id.
private K	getMinMax(K key, boolean min, boolean excluding)	Get the smallest or largest key using the given bounds.
private K	getMinMax(Page<K,V> p, K key, boolean min, boolean excluding)
private K	getMinMax(RootReference<K,V> rootRef, K key, boolean min, boolean excluding)
final String	getName()	Get the map name.
RootReference<K,V>	getRoot()
final Page<K,V>	getRootPage()	The current root page (may not be null).
final MVStore	getStore()
String	getType()	Get the map type.
final DataType<V>	getValueType()	Get the value type.
final long	getVersion()	Get version of the map, which is the version of the store, at the moment when map was modified last time.
(package private) final boolean	hasChangesSince(long version)	Does the root have changes since the specified version?
final int	hashCode()
final K	higherKey(K key)	Get the smallest key that is larger than the given key (next key in ascending order), or null if no such key exists.
final K	higherKey(RootReference<K,V> rootRef, K key)	Get the smallest key that is larger than the given key, for the given root page, or null if no such key exists.
final boolean	isClosed()
boolean	isEmpty()
(package private) final boolean	isMemoryEstimationAllowed()
protected final boolean	isPersistent()
final boolean	isReadOnly()
(package private) boolean	isSingleWriter()
final boolean	isVolatile()	Whether this is volatile map, meaning that changes are not persisted.
final Iterator<K>	keyIterator(K from)	Iterate over a number of keys.
final Iterator<K>	keyIteratorReverse(K from)	Iterate over a number of keys in reverse order
final List<K>	keyList()	Get the key list.
Set<K>	keySet()
final K	lastKey()	Get the last key, or null if the map is empty.
private RootReference<K,V>	lockRoot(RootReference<K,V> rootReference, int attempt)
final K	lowerKey(K key)	Get the largest key that is smaller than the given key, or null if no such key exists.
final K	lowerKey(RootReference<K,V> rootRef, K key)	Get the largest key that is smaller than the given key, for the given root page, or null if no such key exists.
private void	notifyWaiters()
(package private) final MVMap<K,V>	openReadOnly(long rootPos, long version)	Open a copy of the map in read-only mode.
private MVMap<K,V>	openReadOnly(Page<K,V> root, long version)
final MVMap<K,V>	openVersion(long version)	Open an old version for the given map.
V	operate(K key, V value, MVMap.DecisionMaker<? super V> decisionMaker)	Add, replace or remove a key-value pair.
V	put(K key, V value)	Add or replace a key-value pair.
final V	putIfAbsent(K key, V value)	Add a key-value pair if it does not yet exist.
private Page<K,V>	readOrCreateRootPage(long rootPos)
(package private) final Page<K,V>	readPage(long pos)	Read a page.
V	remove(Object key)	Remove a key-value pair, if the key exists.
boolean	remove(Object key, Object value)	Remove a key-value pair if the value matches the stored one.
private void	removeUnusedOldVersions(RootReference<K,V> rootReference)	Forget those old versions that are no longer needed.
final V	replace(K key, V value)	Replace a value for an existing key.
final boolean	replace(K key, V oldValue, V newValue)	Replace a value for an existing key, if the value matches.
private static <K,V> Page<K,V>	replacePage(CursorPos<K,V> path, Page<K,V> replacement, MVMap.IntValueHolder unsavedMemoryHolder)
(package private) final boolean	rewritePage(long pagePos)
(package private) boolean	rollbackRoot(long version)	Roll the root back to the specified version.
(package private) final void	rollbackTo(long version)	Rollback to the given version.
(package private) static int	samplingPct(AtomicLong stats)
(package private) final void	setInitialRoot(Page<K,V> rootPage, long version)	Set the initial root.
(package private) final void	setRootPos(long rootPos, long version)	Set the position of the root page.
final void	setVolatile(boolean isVolatile)	Set the volatile flag of the map.
(package private) final RootReference<K,V>	setWriteVersion(long writeVersion)
final int	size()	Get the number of entries, as a integer.
final long	sizeAsLong()	Get the number of entries, as a long.
final String	toString()
void	trimLast()	Removes last entry from this map.
protected RootReference<K,V>	tryLock(RootReference<K,V> rootReference, int attempt)	Try to lock the root.
private RootReference<K,V>	unlockRoot()	Unlock the root page, the new root being null.
private void	unlockRoot(int appendCounter)
protected RootReference<K,V>	unlockRoot(Page<K,V> newRootPage)	Unlock the root page.
private RootReference<K,V>	unlockRoot(Page<K,V> newRootPage, int appendCounter)
protected static <K,V> boolean	updateRoot(RootReference<K,V> expectedRootReference, Page<K,V> newRootPage, int attemptUpdateCounter)	Use the new root page from now on.

Methods inherited from class AbstractMap

clone, containsValue, putAll, values

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface ConcurrentMap

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll

Methods inherited from interface Map

containsValue, putAll, values

Field Details

store

public final MVStore store

The store.

root

private final AtomicReference<RootReference<K,V>> root

Reference to the current root page.

id

private final int id

createVersion

private final long createVersion

keyType

private final DataType<K> keyType

valueType

private final DataType<V> valueType

keysPerPage

private final int keysPerPage

singleWriter

private final boolean singleWriter

keysBuffer

private final K[] keysBuffer

valuesBuffer

private final V[] valuesBuffer

lock

private final Object lock

notificationRequested

private volatile boolean notificationRequested

closed

private volatile boolean closed

Whether the map is closed. Volatile so we don't accidentally write to a closed map in multithreaded mode.

readOnly

private boolean readOnly

isVolatile

private boolean isVolatile

avgKeySize

private final AtomicLong avgKeySize

avgValSize

private final AtomicLong avgValSize

INITIAL_VERSION

static final long INITIAL_VERSION

This designates the "last stored" version for a store which was just open for the first time.

See Also:

• Constant Field Values

Constructor Details

MVMap

protected MVMap(Map<String,Object> config,
 DataType<K> keyType,
 DataType<V> valueType)

MVMap

protected MVMap(MVMap<K,V> source)

MVMap

MVMap(MVStore store,
 int id,
 DataType<K> keyType,
 DataType<V> valueType)

MVMap

private MVMap(MVStore store,
 DataType<K> keyType,
 DataType<V> valueType,
 int id,
 long createVersion,
 AtomicReference<RootReference<K,V>> root,
 int keysPerPage,
 boolean singleWriter)

Method Details

cloneIt

protected MVMap<K,V> cloneIt()

Clone the current map.

Returns:

clone of this.

getMapRootKey

static String getMapRootKey(int mapId)

Get the metadata key for the root of the given map id.

Parameters:

mapId - the map id

Returns:

the metadata key

getMapKey

static String getMapKey(int mapId)

Get the metadata key for the given map id.

Parameters:

mapId - the map id

Returns:

the metadata key

put

public V put(K key,
 V value)

Add or replace a key-value pair.

Specified by:

put in interface Map<K,V>

Overrides:

put in class AbstractMap<K,V>

Parameters:

key - the key (may not be null)

value - the value (may not be null)

Returns:

the old value if the key existed, or null otherwise

firstKey

public final K firstKey()

Get the first key, or null if the map is empty.

Returns:

the first key, or null

lastKey

public final K lastKey()

Get the last key, or null if the map is empty.

Returns:

the last key, or null

getKey

public final K getKey(long index)

Get the key at the given index.

This is a O(log(size)) operation.

Parameters:

index - the index

Returns:

the key

keyList

public final List<K> keyList()

Get the key list. The list is a read-only representation of all keys.

The get and indexOf methods are O(log(size)) operations. The result of indexOf is cast to an int.

Returns:

the key list

getKeyIndex

public final long getKeyIndex(K key)

Get the index of the given key in the map.

This is a O(log(size)) operation.

If the key was found, the returned value is the index in the key array. If not found, the returned value is negative, where -1 means the provided key is smaller than any keys. See also Arrays.binarySearch.

Parameters:

key - the key

Returns:

the index

getFirstLast

private K getFirstLast(boolean first)

Get the first (lowest) or last (largest) key.

Parameters:

first - whether to retrieve the first key

Returns:

the key, or null if the map is empty

getFirstLast

private K getFirstLast(Page<K,V> p,
 boolean first)

higherKey

public final K higherKey(K key)

Get the smallest key that is larger than the given key (next key in ascending order), or null if no such key exists.

Parameters:

key - the key

Returns:

the result

higherKey

public final K higherKey(RootReference<K,V> rootRef,
 K key)

Get the smallest key that is larger than the given key, for the given root page, or null if no such key exists.

Parameters:

rootRef - the root reference of the map

key - to start from

Returns:

the result

ceilingKey

public final K ceilingKey(K key)

Get the smallest key that is larger or equal to this key.

Parameters:

key - the key

Returns:

the result

floorKey

public final K floorKey(K key)

Get the largest key that is smaller or equal to this key.

Parameters:

key - the key

Returns:

the result

lowerKey

public final K lowerKey(K key)

Get the largest key that is smaller than the given key, or null if no such key exists.

Parameters:

key - the key

Returns:

the result

lowerKey

public final K lowerKey(RootReference<K,V> rootRef,
 K key)

Get the largest key that is smaller than the given key, for the given root page, or null if no such key exists.

Parameters:

rootRef - the root page

key - the key

Returns:

the result

getMinMax

private K getMinMax(K key,
 boolean min,
 boolean excluding)

Get the smallest or largest key using the given bounds.

Parameters:

key - the key

min - whether to retrieve the smallest key

excluding - if the given upper/lower bound is exclusive

Returns:

the key, or null if no such key exists

getMinMax

private K getMinMax(RootReference<K,V> rootRef,
 K key,
 boolean min,
 boolean excluding)

getMinMax

private K getMinMax(Page<K,V> p,
 K key,
 boolean min,
 boolean excluding)

get

public final V get(Object key)

Get the value for the given key, or null if not found.

Specified by:

get in interface Map<K,V>

Overrides:

get in class AbstractMap<K,V>

Parameters:

key - the key

Returns:

the value, or null if not found

Throws:

ClassCastException - if type of the specified key is not compatible with this map

get

public V get(Page<K,V> p,
 K key)

Get the value for the given key from a snapshot, or null if not found.

Parameters:

p - the root of a snapshot

key - the key

Returns:

the value, or null if not found

Throws:

ClassCastException - if type of the specified key is not compatible with this map

containsKey

public final boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractMap<K,V>

clear

public void clear()

Remove all entries.

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class AbstractMap<K,V>

clearIt

RootReference<K,V> clearIt()

Remove all entries and return the root reference.

Returns:

the new root reference

close

final void close()

Close the map. Accessing the data is still possible (to allow concurrent reads), but it is marked as closed.

isClosed

public final boolean isClosed()

remove

public V remove(Object key)

Remove a key-value pair, if the key exists.

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class AbstractMap<K,V>

Parameters:

key - the key (may not be null)

Returns:

the old value if the key existed, or null otherwise

Throws:

ClassCastException - if type of the specified key is not compatible with this map

putIfAbsent

public final V putIfAbsent(K key,
 V value)

Add a key-value pair if it does not yet exist.

Specified by:

putIfAbsent in interface ConcurrentMap<K,V>

Specified by:

putIfAbsent in interface Map<K,V>

Parameters:

key - the key (may not be null)

value - the new value

Returns:

the old value if the key existed, or null otherwise

remove

public boolean remove(Object key,
 Object value)

Remove a key-value pair if the value matches the stored one.

Specified by:

remove in interface ConcurrentMap<K,V>

Specified by:

remove in interface Map<K,V>

Parameters:

key - the key (may not be null)

value - the expected value

Returns:

true if the item was removed

areValuesEqual

static <X> boolean areValuesEqual(DataType<X> datatype,
 X a,
 X b)

Check whether the two values are equal.

Type Parameters:

X - type of values to compare

Parameters:

datatype - to use for comparison

a - the first value

b - the second value

Returns:

true if they are equal

replace

public final boolean replace(K key,
 V oldValue,
 V newValue)

Replace a value for an existing key, if the value matches.

Specified by:

replace in interface ConcurrentMap<K,V>

Specified by:

replace in interface Map<K,V>

Parameters:

key - the key (may not be null)

oldValue - the expected value

newValue - the new value

Returns:

true if the value was replaced

replace

public final V replace(K key,
 V value)

Replace a value for an existing key.

Specified by:

replace in interface ConcurrentMap<K,V>

Specified by:

replace in interface Map<K,V>

Parameters:

key - the key (may not be null)

value - the new value

Returns:

the old value, if the value was replaced, or null

compare

final int compare(K a,
 K b)

Compare two keys.

Parameters:

a - the first key

b - the second key

Returns:

-1 if the first key is smaller, 1 if bigger, 0 if equal

getKeyType

public final DataType<K> getKeyType()

Get the key type.

Returns:

the key type

getValueType

public final DataType<V> getValueType()

Get the value type.

Returns:

the value type

isSingleWriter

boolean isSingleWriter()

readPage

final Page<K,V> readPage(long pos)

Read a page.

Parameters:

pos - the position of the page

Returns:

the page

setRootPos

final void setRootPos(long rootPos,
 long version)

Set the position of the root page.

Parameters:

rootPos - the position, 0 for empty

version - to set for this map

readOrCreateRootPage

private Page<K,V> readOrCreateRootPage(long rootPos)

keyIterator

public final Iterator<K> keyIterator(K from)

Iterate over a number of keys.

Parameters:

from - the first key to return

Returns:

the iterator

keyIteratorReverse

public final Iterator<K> keyIteratorReverse(K from)

Iterate over a number of keys in reverse order

Parameters:

from - the first key to return

Returns:

the iterator

rewritePage

final boolean rewritePage(long pagePos)

cursor

public final Cursor<K,V> cursor(K from)

Get a cursor to iterate over a number of keys and values in the latest version of this map.

Parameters:

from - the first key to return

Returns:

the cursor

cursor

public final Cursor<K,V> cursor(K from,
 K to,
 boolean reverse)

Get a cursor to iterate over a number of keys and values in the latest version of this map.

Parameters:

from - the first key to return

to - the last key to return

reverse - if true, iterate in reverse (descending) order

Returns:

the cursor

cursor

public Cursor<K,V> cursor(RootReference<K,V> rootReference,
 K from,
 K to,
 boolean reverse)

Get a cursor to iterate over a number of keys and values.

Parameters:

rootReference - of this map's version to iterate over

from - the first key to return

to - the last key to return

reverse - if true, iterate in reverse (descending) order

Returns:

the cursor

entrySet

public final Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

Specified by:

entrySet in class AbstractMap<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

Overrides:

keySet in class AbstractMap<K,V>

getName

public final String getName()

Get the map name.

Returns:

the name

getStore

public final MVStore getStore()

isPersistent

protected final boolean isPersistent()

getId

public final int getId()

Get the map id. Please note the map id may be different after compacting a store.

Returns:

the map id

getRootPage

public final Page<K,V> getRootPage()

The current root page (may not be null).

Returns:

the root page

getRoot

public RootReference<K,V> getRoot()

flushAndGetRoot

public RootReference<K,V> flushAndGetRoot()

Get the root reference, flushing any current append buffer.

Returns:

current root reference

setInitialRoot

final void setInitialRoot(Page<K,V> rootPage,
 long version)

Set the initial root.

Parameters:

rootPage - root page

version - initial version

compareAndSetRoot

final boolean compareAndSetRoot(RootReference<K,V> expectedRootReference,
 RootReference<K,V> updatedRootReference)

Compare and set the root reference.

Parameters:

expectedRootReference - the old (expected)

updatedRootReference - the new

Returns:

whether updating worked

rollbackTo

final void rollbackTo(long version)

Rollback to the given version.

Parameters:

version - the version

rollbackRoot

boolean rollbackRoot(long version)

Roll the root back to the specified version.

Parameters:

version - to rollback to

Returns:

true if rollback was a success, false if there was not enough in-memory history

updateRoot

protected static <K,V> boolean updateRoot(RootReference<K,V> expectedRootReference,
 Page<K,V> newRootPage,
 int attemptUpdateCounter)

Use the new root page from now on.

Type Parameters:

K - the key class

V - the value class

Parameters:

expectedRootReference - expected current root reference

newRootPage - the new root page

attemptUpdateCounter - how many attempt (including current) were made to update root

Returns:

new RootReference or null if update failed

removeUnusedOldVersions

private void removeUnusedOldVersions(RootReference<K,V> rootReference)

Forget those old versions that are no longer needed.

Parameters:

rootReference - to inspect

isReadOnly

public final boolean isReadOnly()

setVolatile

public final void setVolatile(boolean isVolatile)

Set the volatile flag of the map.

Parameters:

isVolatile - the volatile flag

isVolatile

public final boolean isVolatile()

Whether this is volatile map, meaning that changes are not persisted. By default (even if the store is not persisted), maps are not volatile.

Returns:

whether this map is volatile

beforeWrite

protected final void beforeWrite()

This method is called before writing to the map. The default implementation checks whether writing is allowed, and tries to detect concurrent modification.

Throws:

UnsupportedOperationException - if the map is read-only, or if another thread is concurrently writing

hashCode

public final int hashCode()

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class AbstractMap<K,V>

equals

public final boolean equals(Object o)

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class AbstractMap<K,V>

size

public final int size()

Get the number of entries, as a integer. Integer.MAX_VALUE is returned if there are more than this entries.

Specified by:

size in interface Map<K,V>

Overrides:

size in class AbstractMap<K,V>

Returns:

the number of entries, as an integer

See Also:

• sizeAsLong()

sizeAsLong

public final long sizeAsLong()

Get the number of entries, as a long.

Returns:

the number of entries

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

Overrides:

isEmpty in class AbstractMap<K,V>

getCreateVersion

final long getCreateVersion()

openVersion

public final MVMap<K,V> openVersion(long version)

Open an old version for the given map. It will restore map at last known state of the version specified. (at the point right before the commit() call, which advanced map to the next version) Map is opened in read-only mode.

Parameters:

version - the version

Returns:

the map

openReadOnly

final MVMap<K,V> openReadOnly(long rootPos,
 long version)

Open a copy of the map in read-only mode.

Parameters:

rootPos - position of the root page

version - to open

Returns:

the opened map

openReadOnly

private MVMap<K,V> openReadOnly(Page<K,V> root,
 long version)

getVersion

public final long getVersion()

Get version of the map, which is the version of the store, at the moment when map was modified last time.

Returns:

version

hasChangesSince

final boolean hasChangesSince(long version)

Does the root have changes since the specified version?

Parameters:

version - root version

Returns:

true if has changes

getChildPageCount

protected int getChildPageCount(Page<K,V> p)

Get the child page count for this page. This is to allow another map implementation to override the default, in case the last child is not to be used.

Parameters:

p - the page

Returns:

the number of direct children

getType

public String getType()

Get the map type. When opening an existing map, the map type must match.

Returns:

the map type

asString

protected String asString(String name)

Get the map metadata as a string.

Parameters:

name - the map name (or null)

Returns:

the string

setWriteVersion

final RootReference<K,V> setWriteVersion(long writeVersion)

createEmptyLeaf

protected Page<K,V> createEmptyLeaf()

Create empty leaf node page.

Returns:

new page

createEmptyNode

protected Page<K,V> createEmptyNode()

Create empty internal node page.

Returns:

new page

copyFrom

final void copyFrom(MVMap<K,V> sourceMap)

Copy a map. All pages are copied.

Parameters:

sourceMap - the source map

copy

private void copy(Page<K,V> source,
 Page<K,V> parent,
 int index)

flushAppendBuffer

private RootReference<K,V> flushAppendBuffer(RootReference<K,V> rootReference,
 boolean fullFlush)

If map was used in append mode, this method will ensure that append buffer is flushed - emptied with all entries inserted into map as a new leaf.

Parameters:

rootReference - current RootReference

fullFlush - whether buffer should be completely flushed, otherwise just a single empty slot is required

Returns:

potentially updated RootReference

replacePage

private static <K,V> Page<K,V> replacePage(CursorPos<K,V> path,
 Page<K,V> replacement,
 MVMap.IntValueHolder unsavedMemoryHolder)

append

public void append(K key,
 V value)

Appends entry to this map. this method is NOT thread safe and can not be used neither concurrently, nor in combination with any method that updates this map. Non-updating method may be used concurrently, but latest appended values are not guaranteed to be visible.

Parameters:

key - should be higher in map's order than any existing key

value - to be appended

trimLast

public void trimLast()

Removes last entry from this map. this method is NOT thread safe and can not be used neither concurrently, nor in combination with any method that updates this map. Non-updating method may be used concurrently, but latest removal may not be visible.

toString

public final String toString()

Overrides:

toString in class AbstractMap<K,V>

operate

public V operate(K key,
 V value,
 MVMap.DecisionMaker<? super V> decisionMaker)

Add, replace or remove a key-value pair.

Parameters:

key - the key (may not be null)

value - new value, it may be null when removal is intended

decisionMaker - command object to make choices during transaction.

Returns:

previous value, if mapping for that key existed, or null otherwise

lockRoot

private RootReference<K,V> lockRoot(RootReference<K,V> rootReference,
 int attempt)

tryLock

protected RootReference<K,V> tryLock(RootReference<K,V> rootReference,
 int attempt)

Try to lock the root.

Parameters:

rootReference - the old root reference

attempt - the number of attempts so far

Returns:

the new root reference

unlockRoot

private RootReference<K,V> unlockRoot()

Unlock the root page, the new root being null.

Returns:

the new root reference (never null)

unlockRoot

protected RootReference<K,V> unlockRoot(Page<K,V> newRootPage)

Unlock the root page.

Parameters:

newRootPage - the new root

Returns:

the new root reference (never null)

unlockRoot

private void unlockRoot(int appendCounter)

unlockRoot

private RootReference<K,V> unlockRoot(Page<K,V> newRootPage,
 int appendCounter)

notifyWaiters

private void notifyWaiters()

isMemoryEstimationAllowed

final boolean isMemoryEstimationAllowed()

evaluateMemoryForKeys

final int evaluateMemoryForKeys(K[] storage,
 int count)

evaluateMemoryForValues

final int evaluateMemoryForValues(V[] storage,
 int count)

calculateMemory

private static <T> int calculateMemory(DataType<T> keyType,
 T[] storage,
 int count)

evaluateMemoryForKey

final int evaluateMemoryForKey(K key)

evaluateMemoryForValue

final int evaluateMemoryForValue(V value)

samplingPct

static int samplingPct(AtomicLong stats)