public final Class InternCache

Class Inheritance

extends ConcurrentHashMap<String, String>

java.lang.Object
java.util.AbstractMap
java.util.concurrent.ConcurrentHashMap
com.fasterxml.jackson.core.util.InternCache

Imports

java.util.concurrent.ConcurrentHashMap

Singleton class that adds a simple first-level cache in front of regular String.intern() functionality. This is done as a minor performance optimization, to avoid calling native intern() method in cases where same String is being interned multiple times.

Field Summary

Modifier and Type	Field and Description
public static final InternCache	instance
private final Object	lock As minor optimization let's try to avoid "flush storms", cases where multiple threads might try to concurrently flush the map.
private static final int	MAX_ENTRIES Size to use is somewhat arbitrary, so let's choose something that's neither too small (low hit ratio) nor too large (waste of memory).
private static final long	serialVersionUID Hides java.util.concurrent.ConcurrentHashMap.serialVersionUID.

Constructor Summary

Access	Constructor and Description
public	InternCache()
public	InternCache(int maxSize, float loadFactor, int concurrency)

Method Summary

Modifier and Type	Method and Description
public String	intern(String input)

Field Detail

instance	back to summary
public static final InternCache instance

lock	back to summary
private final Object lock As minor optimization let's try to avoid "flush storms", cases where multiple threads might try to concurrently flush the map.

MAX_ENTRIES back to summary

MAX_ENTRIES	back to summary
private static final int MAX_ENTRIES Size to use is somewhat arbitrary, so let's choose something that's neither too small (low hit ratio) nor too large (waste of memory). One consideration is possible attack via colliding `String#hashCode`; because of this, limit to reasonably low setting.

private static final int MAX_ENTRIES

Size to use is somewhat arbitrary, so let's choose something that's neither too small (low hit ratio) nor too large (waste of memory).

One consideration is possible attack via colliding String#hashCode; because of this, limit to reasonably low setting.

serialVersionUID	back to summary
private static final long serialVersionUID Hides java.util.concurrent.ConcurrentHashMap.serialVersionUID.

Constructor Detail

InternCache	back to summary
public InternCache()

InternCache	back to summary
public InternCache(int maxSize, float loadFactor, int concurrency)

Method Detail

intern	back to summary
public String intern(String input)