bboss.org.apache.velocity.util

类 MapFactory

java.lang.Object

bboss.org.apache.velocity.util.MapFactory

public class MapFactory
extends java.lang.Object

Factory class for creating Maps. The main purpose of this class is to take advantage of Java 5 Concurrent classes if they are available. We use reflection to instantiate java.util.concurrent classes to avoid compile time dependency on Java 5. See Issue 607 for more info on this class.

从以下版本开始:

1.6

构造器概要

构造器

构造器和说明
MapFactory()

方法概要

限定符和类型	方法和说明
static java.util.Map	create(boolean allowNullKeys) Creates a new instance of a class that implements Map interface using the JDK defaults for initial size, load factor, etc.
static java.util.Map	create(int size, float loadFactor, int concurrencyLevel, boolean allowNullKeys) Creates a new instance of a class that implements Map interface.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

MapFactory

public MapFactory()

方法详细资料

create

public static java.util.Map create(boolean allowNullKeys)

Creates a new instance of a class that implements Map interface using the JDK defaults for initial size, load factor, etc. Note that there is a small performance penalty because concurrent maps are created using reflection.

参数:

allowNullKeys - if true, the returned Map instance supports null keys

返回:

one of ConcurrentHashMap, HashMap, Hashtable

create

public static java.util.Map create(int size,
                                   float loadFactor,
                                   int concurrencyLevel,
                                   boolean allowNullKeys)

Creates a new instance of a class that implements Map interface. Note that there is a small performance penalty because concurrent maps are created using reflection.

参数:

size - initial size of the map

loadFactor - smaller value = better performance, larger value = better memory utilization

concurrencyLevel - estimated number of writer Threads. If this is smaller than 1, HashMap is always returned which is not threadsafe.

allowNullKeys - if true, the returned Map instance supports null keys

返回:

one of ConcurrentHashMap, HashMap, Hashtable