OpenJDK 27 · java.lang.StringConcatHelper · APIdia, the JavaDoc alternative

Modifier and Type	Class and Description
pack-priv static class	StringConcatHelper.Concat1
pack-priv abstract static class	StringConcatHelper.StringConcatBase

Modifier and Type	Field and Description
private static final Unsafe	UNSAFE

Access	Constructor and Description
private	StringConcatHelper()

Method Summary

Modifier and Type	Method and Description
pack-priv static int	Returns: the given parameter value, if valid checkOverflow(int value) Check for overflow, throw exception on overflow.
pack-priv static String	concat(String prefix, Object value, String suffix)
private static String	concat0(String prefix, String str, String suffix)
pack-priv static String	Returns: String resulting string doConcat(String first argument s1, String second argument s2) Perform a simple concatenation between two non-empty strings.
pack-priv static MethodHandle	lookupStatic(String name, MethodType methodType)
pack-priv static byte[]	Returns: the newly allocated byte array newArray(int length) Allocates an uninitialized byte array based on the length
pack-priv static byte[]	Returns: the newly allocated byte array newArrayWithSuffix(String suffix, int final char index in the buffer index, byte coder of the buffer coder) Allocates an uninitialized byte array based on the length and coder information, then prepends the given suffix string at the end of the byte array before returning it.
pack-priv static String	Returns: String resulting string newStringOf(Object the only argument arg) Produce a String from a concatenation of single argument, which we end up using for trivial concatenations like `"" + arg`.
pack-priv static int	Returns: updated index prepend(int final char index in the buffer index, byte coder of the buffer coder, byte[] buffer to append to buf, boolean boolean value to encode value, String a constant to prepend before value prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index.
pack-priv static int	Returns: updated index prepend(int final char index in the buffer index, byte coder of the buffer coder, byte[] buffer to append to buf, char char value to encode value, String a constant to prepend before value prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index.
pack-priv static int	Returns: updated index prepend(int final char index in the buffer index, byte coder of the buffer coder, byte[] buffer to append to buf, int int value to encode value, String a constant to prepend before value prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index.
pack-priv static int	Returns: updated index prepend(int final char index in the buffer index, byte coder of the buffer coder, byte[] buffer to append to buf, long long value to encode value, String a constant to prepend before value prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index.
pack-priv static int	Returns: updated index prepend(int final char index in the buffer index, byte coder of the buffer coder, byte[] buffer to append to buf, String boolean value to encode value, String a constant to prepend before value prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index.
pack-priv static String	Returns: String resulting string simpleConcat(Object first argument first, Object second argument second) Perform a simple concatenation between two objects.
pack-priv static byte	Returns: coder stringCoder(char character value) Return the coder for the character.
pack-priv static String	stringOf(Object value) We need some additional conversion for Objects in general, because `String.valueOf(Object)` may return null.
pack-priv static String	stringOf(float value)
pack-priv static String	stringOf(double value)
pack-priv static int	Returns: new length stringSize(int length length, char value to add stringSize value) return add stringSize of value
pack-priv static int	Returns: new length stringSize(int length length, boolean value to add stringSize value) return add stringSize of value
pack-priv static int	Returns: new length stringSize(int length length, int value value) return add stringSize of value
pack-priv static int	Returns: new length stringSize(int length length, long value to add stringSize value) return add stringSize of value
pack-priv static int	Returns: new length stringSize(int length length, String value to add stringSize value) return add stringSize of value

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

UNSAFE	back to summary
private static final Unsafe UNSAFE

StringConcatHelper	back to summary
private StringConcatHelper()

Method Detail

checkOverflow	back to summary
pack-priv static int checkOverflow(int value) Check for overflow, throw exception on overflow. Returns:int the given parameter value, if valid Annotations @ForceInline

checkOverflow

back to summary

pack-priv static int checkOverflow(int value)

Check for overflow, throw exception on overflow.

Returns:int

the given parameter value, if valid

Annotations

@ForceInline

concat	back to summary
pack-priv static String concat(String prefix, Object value, String suffix) Annotations @ForceInline

concat0	back to summary
private static String concat0(String prefix, String str, String suffix) Annotations @ForceInline

doConcat	back to summary
pack-priv static String doConcat(String s1, String s2) Perform a simple concatenation between two non-empty strings. Parameters s1:String first argument s2:String second argument Returns:String String resulting string Annotations @ForceInline

doConcat

back to summary

pack-priv static String doConcat(String s1, String s2)

Perform a simple concatenation between two non-empty strings.

Parameters

s1:String: first argument
s2:String: second argument

Returns:String

String resulting string

Annotations

@ForceInline

lookupStatic	back to summary
pack-priv static MethodHandle lookupStatic(String name, MethodType methodType)

newArray	back to summary
pack-priv static byte[] newArray(int length) Allocates an uninitialized byte array based on the length Returns:byte[] the newly allocated byte array Annotations @ForceInline

newArray

back to summary

pack-priv static byte[] newArray(int length)

Allocates an uninitialized byte array based on the length

Returns:byte[]

the newly allocated byte array

Annotations

@ForceInline

newArrayWithSuffix	back to summary
pack-priv static byte[] newArrayWithSuffix(String suffix, int index, byte coder) Allocates an uninitialized byte array based on the length and coder information, then prepends the given suffix string at the end of the byte array before returning it. The calling code must adjust the indexCoder so that it's taken the coder of the suffix into account, but subtracted the length of the suffix. Parameters index:int final char index in the buffer coder:byte coder of the buffer Returns:byte[] the newly allocated byte array Annotations @ForceInline

newArrayWithSuffix

back to summary

pack-priv static byte[] newArrayWithSuffix(String suffix, int index, byte coder)

Allocates an uninitialized byte array based on the length and coder information, then prepends the given suffix string at the end of the byte array before returning it. The calling code must adjust the indexCoder so that it's taken the coder of the suffix into account, but subtracted the length of the suffix.

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer

Returns:byte[]

the newly allocated byte array

Annotations

@ForceInline

newStringOf back to summary

newStringOf	back to summary
pack-priv static String newStringOf(Object arg) Produce a String from a concatenation of single argument, which we end up using for trivial concatenations like `"" + arg`. This will always create a new Object to comply with JLS 15.18.1: "The String object is newly created unless the expression is a compile-time constant expression". Parameters arg:Object the only argument Returns:String String resulting string Annotations @ForceInline

pack-priv static String newStringOf(Object arg)

Produce a String from a concatenation of single argument, which we end up using for trivial concatenations like "" + arg. This will always create a new Object to comply with JLS 15.18.1: "The String object is newly created unless the expression is a compile-time constant expression".

Parameters

arg:Object: the only argument

Returns:String

String resulting string

Annotations

@ForceInline

prepend	back to summary
pack-priv static int prepend(int index, byte coder, byte[] buf, boolean value, String prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes! Parameters index:int final char index in the buffer coder:byte coder of the buffer buf:byte[] buffer to append to value:boolean boolean value to encode prefix:String a constant to prepend before value Returns:int updated index

prepend

back to summary

pack-priv static int prepend(int index, byte coder, byte[] buf, boolean value, String prefix)

Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes!

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer
buf:byte[]: buffer to append to
value:boolean: boolean value to encode
prefix:String: a constant to prepend before value

Returns:int

updated index

prepend	back to summary
pack-priv static int prepend(int index, byte coder, byte[] buf, char value, String prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes! Parameters index:int final char index in the buffer coder:byte coder of the buffer buf:byte[] buffer to append to value:char char value to encode prefix:String a constant to prepend before value Returns:int updated index

prepend

back to summary

pack-priv static int prepend(int index, byte coder, byte[] buf, char value, String prefix)

Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes!

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer
buf:byte[]: buffer to append to
value:char: char value to encode
prefix:String: a constant to prepend before value

Returns:int

updated index

prepend	back to summary
pack-priv static int prepend(int index, byte coder, byte[] buf, int value, String prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes! Parameters index:int final char index in the buffer coder:byte coder of the buffer buf:byte[] buffer to append to value:int int value to encode prefix:String a constant to prepend before value Returns:int updated index

prepend

back to summary

pack-priv static int prepend(int index, byte coder, byte[] buf, int value, String prefix)

Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes!

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer
buf:byte[]: buffer to append to
value:int: int value to encode
prefix:String: a constant to prepend before value

Returns:int

updated index

prepend	back to summary
pack-priv static int prepend(int index, byte coder, byte[] buf, long value, String prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes! Parameters index:int final char index in the buffer coder:byte coder of the buffer buf:byte[] buffer to append to value:long long value to encode prefix:String a constant to prepend before value Returns:int updated index

prepend

back to summary

pack-priv static int prepend(int index, byte coder, byte[] buf, long value, String prefix)

Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes!

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer
buf:byte[]: buffer to append to
value:long: long value to encode
prefix:String: a constant to prepend before value

Returns:int

updated index

prepend	back to summary
pack-priv static int prepend(int index, byte coder, byte[] buf, String value, String prefix) Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes! Parameters index:int final char index in the buffer coder:byte coder of the buffer buf:byte[] buffer to append to value:String boolean value to encode prefix:String a constant to prepend before value Returns:int updated index

prepend

back to summary

pack-priv static int prepend(int index, byte coder, byte[] buf, String value, String prefix)

Prepends constant and the stringly representation of value into buffer, given the coder and final index. Index is measured in chars, not in bytes!

Parameters

index:int: final char index in the buffer
coder:byte: coder of the buffer
buf:byte[]: buffer to append to
value:String: boolean value to encode
prefix:String: a constant to prepend before value

Returns:int

updated index

simpleConcat back to summary

simpleConcat	back to summary
pack-priv static String simpleConcat(Object first, Object second) Perform a simple concatenation between two objects. Added for startup performance, but also demonstrates the code that would be emitted by `java.lang.invoke.StringConcatFactory$MethodHandleInlineCopyStrategy` for two Object arguments. Parameters first:Object first argument second:Object second argument Returns:String String resulting string Annotations @ForceInline

pack-priv static String simpleConcat(Object first, Object second)

Perform a simple concatenation between two objects. Added for startup performance, but also demonstrates the code that would be emitted by java.lang.invoke.StringConcatFactory$MethodHandleInlineCopyStrategy for two Object arguments.

Parameters

first:Object: first argument
second:Object: second argument

Returns:String

String resulting string

Annotations

@ForceInline

stringCoder	back to summary
pack-priv static byte stringCoder(char value) Return the coder for the character. Parameters value:char character Returns:byte coder

stringCoder

back to summary

pack-priv static byte stringCoder(char value)

Return the coder for the character.

Parameters

value:char: character

Returns:byte

coder

stringOf	back to summary
pack-priv static String stringOf(Object value) We need some additional conversion for Objects in general, because `String.valueOf(Object)` may return null. String conversion rules in Java state we need to produce "null" String in this case, so we provide a customized version that deals with this problematic corner case.

stringOf	back to summary
pack-priv static String stringOf(float value)

stringOf	back to summary
pack-priv static String stringOf(double value)

stringSize	back to summary
pack-priv static int stringSize(int length, char value) return add stringSize of value Parameters length:int length value:char value to add stringSize Returns:int new length

stringSize

back to summary

pack-priv static int stringSize(int length, char value)

return add stringSize of value

Parameters

length:int: length
value:char: value to add stringSize

Returns:int

new length

stringSize	back to summary
pack-priv static int stringSize(int length, boolean value) return add stringSize of value Parameters length:int length value:boolean value to add stringSize Returns:int new length

stringSize

back to summary

pack-priv static int stringSize(int length, boolean value)

return add stringSize of value

Parameters

length:int: length
value:boolean: value to add stringSize

Returns:int

new length

stringSize	back to summary
pack-priv static int stringSize(int length, int value) return add stringSize of value Parameters length:int length value:int value Returns:int new length

stringSize

back to summary

pack-priv static int stringSize(int length, int value)

return add stringSize of value

Parameters

length:int: length
value:int: value

Returns:int

new length

stringSize	back to summary
pack-priv static int stringSize(int length, long value) return add stringSize of value Parameters length:int length value:long value to add stringSize Returns:int new length

stringSize

back to summary

pack-priv static int stringSize(int length, long value)

return add stringSize of value

Parameters

length:int: length
value:long: value to add stringSize

Returns:int

new length

stringSize	back to summary
pack-priv static int stringSize(int length, String value) return add stringSize of value Parameters length:int length value:String value to add stringSize Returns:int new length

stringSize

back to summary

pack-priv static int stringSize(int length, String value)

return add stringSize of value

Parameters

length:int: length
value:String: value to add stringSize

Returns:int

new length

Modifier and Type	Method and Description
pack-priv String	concat(boolean value)
pack-priv String	concat(char value)
pack-priv String	concat(int value)
pack-priv String	concat(long value)
pack-priv String	concat(Object value)
pack-priv String	concat(float value)
pack-priv String	concat(double value)
pack-priv String	concat0(String value)

pack-priv final Class StringConcatHelper

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

pack-priv final Class StringConcatHelper.Concat1

Field Summary

Constructor Summary

Method Summary

Constructor Detail

Method Detail

pack-priv abstract Class StringConcatHelper.StringConcatBase

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Modifier and Type	Field and Description
pack-priv final byte	coder
pack-priv final String[]	constants
pack-priv final int	length