Package org.apache.juneau.commons.settings

Class RelaxedPropertySource

java.lang.Object

org.apache.juneau.commons.settings.RelaxedPropertySource

All Implemented Interfaces:

PropertySource

public class RelaxedPropertySource
extends Object
implements PropertySource

A PropertySource decorator that adds relaxed binding over a delegate source.

When a property lookup misses against the delegate, this source retries with a small set of canonical name variants derived from the requested name, so a single logical key can be supplied in any of the common environment conventions and still resolve. This is the mechanism that lets a Kubernetes-style environment variable such as MY_SECTION_MY_KEY satisfy a lookup for MySection/myKey, or MY_PROP satisfy my.prop / myProp.

Candidate order

The requested name is always tried verbatim first, so exact-match behavior is preserved unchanged (an already-canonical key resolves with no transformation, and a source that defines the literal name wins). Only on a miss are the relaxed variants tried, in this order:

1. verbatim (the requested name, unchanged);
2. upper underscore — every run of non-alphanumeric characters (and every lower→upper camel-case boundary) becomes a single _, then the whole thing is upper-cased. This is the dominant env-var form: my.prop/my-prop/myProp/MySection/myKey → MY_PROP / MY_SECTION_MY_KEY;
3. lower dotted — the same separator collapse but joined with . and lower-cased (MY_PROP → my.prop), so a dotted-property lookup can be satisfied by an env-style key and vice-versa.

Because the boundary between "section" and "key" in a flat relaxed name (e.g. the underscores in MY_SECTION_MY_KEY) is inherently ambiguous, this decorator deliberately works in the lookup-key → candidate-name direction only (the well-defined direction): the caller asks for a known logical key and the decorator generates the environment-convention spellings to probe. It never tries to reverse a flat env name back into a section/key pair.

Usage

// Wrap the system-env source so env vars bind relaxedly. settings = Settings.create().addSource(new RelaxedPropertySource(Settings.SYSTEM_ENV_SOURCE)).build();

Since:

10.0.0

Constructor Summary

Constructors

Constructor	Description
RelaxedPropertySource(PropertySource delegate)	Constructor.

Method Summary

Modifier and Type	Method	Description
static List<String>	candidates(String name)	Generates the ordered, de-duplicated list of candidate names for a requested name (verbatim first).
PropertyLookupResult	get(String name)	Returns a property in this property source.

Methods inherited from class java.lang.Object

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

Constructor Details

RelaxedPropertySource

public RelaxedPropertySource(PropertySource delegate)

Constructor.

Parameters:

delegate - The wrapped source that the generated candidate names are probed against. Must not be null.

Method Details

get

public PropertyLookupResult get(String name)

Description copied from interface: PropertySource

Returns a property in this property source.

Specified by:

get in interface PropertySource

Parameters:

name - The property name.

Returns:

The property lookup result:

• PropertyLookupResult.missing() if this source does not define the key.
• PropertyLookupResult.present(Optional) with Optional.empty() if the key exists with a null value.
• PropertyLookupResult.present(Optional) with a value if the key exists with a non-null value.

candidates

public static List<String> candidates(String name)

Generates the ordered, de-duplicated list of candidate names for a requested name (verbatim first).

The result is unmodifiable and memoized per name, with the same soft cap and pass-through rule as CachingPropertySource (names beyond CachingPropertySource.MAX_ENTRIES are computed on every call).

Parameters:

name - The requested property name. Must not be null.

Returns:

The candidate names to probe, in priority order. Unmodifiable.

Throws:

NullPointerException - If name is null.

Since:

10.0.0