Class AttributeExtractor

java.lang.Object

com.loomcache.server.query.AttributeExtractor

public final class AttributeExtractor
extends Object

Extracts attribute values from map keys and values using reflection.

Supports three access patterns:

• "__key" — returns the key itself
• "propertyName" — accesses a JavaBean getter, record component, or Map key on the value
• "nested.path" — dot-separated property path for nested access

Thread-safe: uses a concurrent cache for resolved accessor methods.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	KEY_ATTRIBUTE	Special attribute name that returns the key itself.
static final String	THIS_ATTRIBUTE	Special attribute name that returns the value itself.

Method Summary

Modifier and Type	Method	Description
static <K,V> @Nullable Object	extract(K key, V value, String attribute)	Extracts an attribute value from a map entry.

Methods inherited from class Object

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

Field Details

KEY_ATTRIBUTE

public static final String KEY_ATTRIBUTE

Special attribute name that returns the key itself.

See Also:

• Constant Field Values

THIS_ATTRIBUTE

public static final String THIS_ATTRIBUTE

Special attribute name that returns the value itself.

See Also:

• Constant Field Values

Method Details

extract

public static <K,V> @Nullable Object extract(K key,
 V value,
 String attribute)

Extracts an attribute value from a map entry.

Type Parameters:

K - the key type

V - the value type

Parameters:

key - the map entry key

value - the map entry value

attribute - the attribute path (e.g., "__key", "name", "address.city")

Returns:

the extracted attribute value, or null if not found