Package org.alfresco.util

Class ValueProtectingMap<K extends Serializable,V extends Serializable>

java.lang.Object

org.alfresco.util.ValueProtectingMap<K,V>

Type Parameters:

K - the map key type (must extend Serializable)

V - the map value type (must extend Serializable)

All Implemented Interfaces:

Serializable, Map<K,V>

public class ValueProtectingMap<K extends Serializable,V extends Serializable>
extends Object
implements Map<K,V>, Serializable

A map that protects keys and values from accidental modification.

Use this map when keys or values need to be protected against client modification. For example, when a component pulls a map from a common resource it can wrap the map with this class to prevent any accidental modification of the shared resource.

Upon first write to this map , the underlying map will be copied (selectively cloned), the original map handle will be discarded and the copied map will be used. Note that the map copy process will also occur if any mutable value is in danger of being exposed to client modification. Therefore, methods that iterate and retrieve values will also trigger the copy if any values are mutable.

Since:

3.4.9, 4.0.1

Author:

Derek Hulley

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
static final Set<Class<?>>	DEFAULT_IMMUTABLE_CLASSES	Default immutable classes: String BigDecimal BigInteger Byte Double Float Integer Long Short Boolean Date Locale

Constructor Summary

Constructors

Constructor	Description
ValueProtectingMap(Map<K,V> protectedMap)	Construct providing a protected map and using only the default immutable classes
ValueProtectingMap(Map<K,V> protectedMap, Set<Class<?>> immutableClasses)	Construct providing a protected map, complementing the set of default immutable classes

Method Summary

Modifier and Type	Method	Description
void	clear()
static <K extends Serializable, V extends Serializable> Map<K,V>	cloneMap(Map<K,V> map, Set<Class<?>> immutableClasses)	Utility method to clone a map, preserving immutable instances
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()
boolean	equals(Object obj)
V	get(Object key)
int	hashCode()
boolean	isEmpty()
Set<K>	keySet()
static <S extends Serializable> boolean	mustProtectValue(S value, Set<Class<?>> immutableClasses)	Utility method to check if values need to be cloned or not
static <S extends Serializable> S	protectValue(S value, Set<Class<?>> immutableClasses)	Protect a specific value if it is considered mutable
V	put(K key, V value)
void	putAll(Map<? extends K,? extends V> m)
V	remove(Object key)
int	size()
String	toString()
Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Field Details

DEFAULT_IMMUTABLE_CLASSES

public static final Set<Class<?>> DEFAULT_IMMUTABLE_CLASSES

Default immutable classes:

String

BigDecimal

BigInteger

Byte

Double

Float

Integer

Long

Short

Boolean

Date

Locale

Constructor Details

ValueProtectingMap

public ValueProtectingMap(Map<K,V> protectedMap)

Construct providing a protected map and using only the default immutable classes

Parameters:

protectedMap - the map to safeguard

ValueProtectingMap

public ValueProtectingMap(Map<K,V> protectedMap,
 Set<Class<?>> immutableClasses)

Construct providing a protected map, complementing the set of default immutable classes

Parameters:

protectedMap - the map to safeguard

immutableClasses - additional immutable classes over and above the default set (may be null

Method Details

protectValue

public static <S extends Serializable> S protectValue(S value,
 Set<Class<?>> immutableClasses)

Protect a specific value if it is considered mutable

Type Parameters:

S - the type of the value, which must be Serializable

Parameters:

value - the value to protect if it is mutable (may be null)

immutableClasses - a set of classes that can be considered immutable over and above the default set

Returns:

a cloned instance (via serialization) or the instance itself, if immutable

mustProtectValue

public static <S extends Serializable> boolean mustProtectValue(S value,
 Set<Class<?>> immutableClasses)

Utility method to check if values need to be cloned or not

Type Parameters:

S - the type of the value, which must be Serializable

Parameters:

value - the value to check

immutableClasses - a set of classes that can be considered immutable over and above the default set

Returns:

true if the value must NOT be given to the calling clients

cloneMap

public static <K extends Serializable,
V extends Serializable>
Map<K,V> cloneMap(Map<K,V> map,
 Set<Class<?>> immutableClasses)

Utility method to clone a map, preserving immutable instances

Type Parameters:

K - the map key type, which must be Serializable

V - the map value type, which must be Serializable

Parameters:

map - the map to copy

immutableClasses - a set of classes that can be considered immutable over and above the default set

size

public int size()

Specified by:

size in interface Map<K extends Serializable,V extends Serializable>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K extends Serializable,V extends Serializable>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K extends Serializable,V extends Serializable>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K extends Serializable,V extends Serializable>

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<K extends Serializable,V extends Serializable>

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Specified by:

equals in interface Map<K extends Serializable,V extends Serializable>

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

get

public V get(Object key)

Specified by:

get in interface Map<K extends Serializable,V extends Serializable>

put

public V put(K key,
 V value)

Specified by:

put in interface Map<K extends Serializable,V extends Serializable>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K extends Serializable,V extends Serializable>

putAll

public void putAll(Map<? extends K,? extends V> m)

Specified by:

putAll in interface Map<K extends Serializable,V extends Serializable>

clear

public void clear()

Specified by:

clear in interface Map<K extends Serializable,V extends Serializable>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K extends Serializable,V extends Serializable>

values

public Collection<V> values()

Specified by:

values in interface Map<K extends Serializable,V extends Serializable>

entrySet

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

Specified by:

entrySet in interface Map<K extends Serializable,V extends Serializable>