Package org.springframework.core.codec

Class Hints

java.lang.Object

org.springframework.core.codec.Hints

public abstract class Hints
extends Object

Constants and convenience methods for working with hints.

Since:

5.1

Author:

Rossen Stoyanchev

See Also:

• ResourceRegionEncoder.BOUNDARY_STRING_HINT

Field Summary

Fields

Modifier and Type	Field	Description
static final String	LOG_PREFIX_HINT	Name of hint exposing a prefix to use for correlating log messages.
static final String	SUPPRESS_LOGGING_HINT	Name of boolean hint whether to avoid logging data either because it's potentially sensitive, or because it has been logged by a composite encoder, e.g.

Constructor Summary

Constructors

Constructor	Description
Hints()

Method Summary

Modifier and Type	Method	Description
static Map<String,Object>	from(String hintName, Object value)	Create a map wit a single hint via Collections.singletonMap(K, V).
static String	getLogPrefix(Map<String,Object> hints)	Obtain the hint LOG_PREFIX_HINT, if present, or an empty String.
static <T> T	getRequiredHint(Map<String,Object> hints, String hintName)	Obtain the value for a required hint.
static boolean	isLoggingSuppressed(Map<String,Object> hints)	Whether to suppress logging based on the hint SUPPRESS_LOGGING_HINT.
static Map<String,Object>	merge(Map<String,Object> hints, String hintName, Object hintValue)	Merge a single hint into a map of hints, possibly creating and copying all hints into a new map, or otherwise if the map of hints is empty, creating a new single entry map.
static Map<String,Object>	merge(Map<String,Object> hints1, Map<String,Object> hints2)	Merge two maps of hints, creating and copying into a new map if both have values, or returning the non-empty map, or an empty map if both are empty.
static Map<String,Object>	none()	Return an empty map of hints via Collections.emptyMap().
static void	touchDataBuffer(DataBuffer buffer, Map<String,Object> hints, Log logger)	If the hints contain a LOG_PREFIX_HINT and the given logger has DEBUG level enabled, apply the log prefix as a hint to the given buffer via DataBufferUtils.touch(DataBuffer, Object).

Methods inherited from class java.lang.Object

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

Field Details

LOG_PREFIX_HINT

public static final String LOG_PREFIX_HINT

Name of hint exposing a prefix to use for correlating log messages.

SUPPRESS_LOGGING_HINT

public static final String SUPPRESS_LOGGING_HINT

Name of boolean hint whether to avoid logging data either because it's potentially sensitive, or because it has been logged by a composite encoder, e.g. for multipart requests.

Constructor Details

Hints

public Hints()

Method Details

from

public static Map<String,Object> from(String hintName,
 Object value)

Create a map wit a single hint via Collections.singletonMap(K, V).

Parameters:

hintName - the hint name

value - the hint value

Returns:

the created map

none

public static Map<String,Object> none()

Return an empty map of hints via Collections.emptyMap().

Returns:

the empty map

getRequiredHint

public static <T> T getRequiredHint(@Nullable
 Map<String,Object> hints,
 String hintName)

Obtain the value for a required hint.

Type Parameters:

T - the hint type to cast to

Parameters:

hints - the hints map

hintName - the required hint name

Returns:

the hint value

Throws:

IllegalArgumentException - if the hint is not found

getLogPrefix

public static String getLogPrefix(@Nullable
 Map<String,Object> hints)

Obtain the hint LOG_PREFIX_HINT, if present, or an empty String.

Parameters:

hints - the hints passed to the encode method

Returns:

the log prefix

isLoggingSuppressed

public static boolean isLoggingSuppressed(@Nullable
 Map<String,Object> hints)

Whether to suppress logging based on the hint SUPPRESS_LOGGING_HINT.

Parameters:

hints - the hints map

Returns:

whether logging of data is allowed

merge

public static Map<String,Object> merge(@Nullable
 Map<String,Object> hints1,
 @Nullable
 Map<String,Object> hints2)

Merge two maps of hints, creating and copying into a new map if both have values, or returning the non-empty map, or an empty map if both are empty.

Parameters:

hints1 - 1st map of hints

hints2 - 2nd map of hints

Returns:

a single map with hints from both

merge

public static Map<String,Object> merge(@Nullable
 Map<String,Object> hints,
 String hintName,
 Object hintValue)

Merge a single hint into a map of hints, possibly creating and copying all hints into a new map, or otherwise if the map of hints is empty, creating a new single entry map.

Parameters:

hints - a map of hints to be merged

hintName - the hint name to merge

hintValue - the hint value to merge

Returns:

a single map with all hints

touchDataBuffer

public static void touchDataBuffer(DataBuffer buffer,
 @Nullable
 Map<String,Object> hints,
 Log logger)

If the hints contain a LOG_PREFIX_HINT and the given logger has DEBUG level enabled, apply the log prefix as a hint to the given buffer via DataBufferUtils.touch(DataBuffer, Object).

Parameters:

buffer - the buffer to touch

hints - the hints map to check for a log prefix

logger - the logger whose level to check

Since:

5.3.2