com.linecorp.armeria.internal.common.util

Class TemporaryThreadLocals

java.lang.Object

com.linecorp.armeria.internal.common.util.TemporaryThreadLocals

public final class TemporaryThreadLocals
extends Object

Provides various thread-local variables used by Armeria internally, mostly to avoid allocating short-living objects, such as byte[] and StringBuilder. Keep in mind that the variables provided by this class must be used with extreme care, because otherwise it will result in unpredictable behavior.

Most common mistake is to call or recurse info a method that uses the same thread-local variable. For example, the following code will produce a garbled string:

 > class A {
 >     @Override
 >     public String toString() {
 >         return TemporaryThreadLocals.get().append('"').append(new B()).append('"').toString();
 >     }
 > }
 > class B {
 >     @Override
 >     public String toString() {
 >         return TemporaryThreadLocals.get().append("foo").toString();
 >     }
 > }
 > // The following assertion fails, because A.toString() returns "foofoo\"".
 > assert "\"foo\"".equals(new A().toString());
 

A rule of thumb is to use the thread-local variables provided by this class in a narrow scope where there's no chance of recursion or reentrance.

Method Summary

Modifier and Type	Method and Description
byte[]	byteArray(int minCapacity) Returns a thread-local byte array whose length is equal to or greater than the specified minCapacity.
char[]	charArray(int minCapacity) Returns a thread-local character array whose length is equal to or greater than the specified minCapacity.
static TemporaryThreadLocals	get() Returns the current Thread's TemporaryThreadLocals.
StringBuilder	stringBuilder() Returns a thread-local StringBuilder.

Methods inherited from class java.lang.Object

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

Method Detail

get

public static TemporaryThreadLocals get()

Returns the current Thread's TemporaryThreadLocals.

byteArray

public byte[] byteArray(int minCapacity)

Returns a thread-local byte array whose length is equal to or greater than the specified minCapacity.

charArray

public char[] charArray(int minCapacity)

Returns a thread-local character array whose length is equal to or greater than the specified minCapacity.

stringBuilder

public StringBuilder stringBuilder()

Returns a thread-local StringBuilder.