Package org.apache.logging.log4j.util
Class Unbox
java.lang.Object
org.apache.logging.log4j.util.Unbox
Utility for preventing primitive parameter values from being auto-boxed. Auto-boxing creates temporary objects
which contribute to pressure on the garbage collector. With this utility users can convert primitive values directly
into text without allocating temporary objects.
Example usage:
import static org.apache.logging.log4j.util.Unbox.box; ... long longValue = 123456L; double doubleValue = 3.14; // prevent primitive values from being auto-boxed logger.debug("Long value={}, double value={}", box(longValue), box(doubleValue));
This class manages a small thread-local ring buffer of StringBuilders.
Each time one of the box()
methods is called, the next slot in the ring buffer is used, until the ring
buffer is full and the first slot is reused. By default the Unbox ring buffer has 32 slots, so user code can
have up to 32 boxed primitives in a single logger call.
If more slots are required, set system property log4j.unbox.ringbuffer.size
to the desired ring buffer size.
Note that the specified number will be rounded up to the nearest power of 2.
- Since:
- 2.6
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
private static class
State implementation that only puts JDK classes in ThreadLocals, so this is safe to be used from web applications. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final int
private static final Logger
private static final int
private static final int
private static final int
private static ThreadLocal<Unbox.State>
private static Unbox.WebSafeState
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic StringBuilder
box
(boolean value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(byte value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(char value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(double value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(float value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(int value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(long value) Returns aStringBuilder
containing the text representation of the specified primitive value.static StringBuilder
box
(short value) Returns aStringBuilder
containing the text representation of the specified primitive value.private static int
calculateRingBufferSize
(String propertyName) private static int
ceilingNextPowerOfTwo
(int x) Calculate the next power of 2, greater than or equal to x.(package private) static int
For testing.private static StringBuilder
getSB()
private static Unbox.State
getState()
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Field Details
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LOGGER
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BITS_PER_INT
private static final int BITS_PER_INT- See Also:
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RINGBUFFER_MIN_SIZE
private static final int RINGBUFFER_MIN_SIZE- See Also:
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RINGBUFFER_SIZE
private static final int RINGBUFFER_SIZE -
MASK
private static final int MASK -
threadLocalState
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webSafeState
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Constructor Details
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Unbox
private Unbox()
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Method Details
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calculateRingBufferSize
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ceilingNextPowerOfTwo
private static int ceilingNextPowerOfTwo(int x) Calculate the next power of 2, greater than or equal to x.From Hacker's Delight, Chapter 3, Harry S. Warren Jr.
- Parameters:
x
- Value to round up- Returns:
- The next power of 2 from x inclusive
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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box
Returns aStringBuilder
containing the text representation of the specified primitive value. This method will not allocate temporary objects.- Parameters:
value
- the value whose text representation to return- Returns:
- a
StringBuilder
containing the text representation of the specified primitive value
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getState
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getSB
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getRingbufferSize
static int getRingbufferSize()For testing.
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