net.openhft.chronicle.core.pool

Class StringInterner

java.lang.Object

net.openhft.chronicle.core.pool.StringInterner

public class StringInterner
extends Object

StringInterner only guarantees it will behave in a correct manner. When you ask it for a String for a given input, it must return a String which matches the toString() of that CharSequence.

It doesn't guarantee that all threads see the same data, nor that multiple threads will return the same String object for the same string. It is designed to be a best-effort basis so it can be as lightweight as possible.

So while technically not thread safe, it doesn't prevent it operating correctly when used from multiple threads, but it is faster than added explicit locking or thread safety. NOTE: It does rely on String being thread safe, something which was guaranteed from Java 5.0 onwards c.f. JSR 133.

Discussion https://stackoverflow.com/questions/63383745/string-array-needless-synchronization/63383983

Author:

peter.lawrey

Field Summary

Fields

Modifier and Type	Field and Description
protected @NotNull String[]	interner
protected int	mask
protected int	shift
protected boolean	toggle

Constructor Summary

Constructors

Constructor and Description
StringInterner(int capacity)

Method Summary

Modifier and Type	Method and Description
@Nullable String	intern(@Nullable CharSequence cs)
protected boolean	toggle()
int	valueCount()

Methods inherited from class java.lang.Object

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

Field Detail

interner

@NotNull
protected final @NotNull String[] interner

mask

protected final int mask

shift

protected final int shift

toggle

protected boolean toggle

Constructor Detail

StringInterner

public StringInterner(int capacity)
               throws IllegalArgumentException

Throws:

IllegalArgumentException

Method Detail

intern

@Nullable
public @Nullable String intern(@Nullable
                                         @Nullable CharSequence cs)

toggle

protected boolean toggle()

valueCount

public int valueCount()