Package io.github.qubitpi.athena.config

Class LayeredFileSystemConfig

java.lang.Object

io.github.qubitpi.athena.config.LayeredFileSystemConfig

All Implemented Interfaces:

SystemConfig

@Singleton
@Immutable
@ThreadSafe
public class LayeredFileSystemConfig
extends Object
implements SystemConfig

A class to hold and fetch configuration values from the environment and runtime.

LayeredFileSystemConfig uses a layered model with the highest priority granted to runtime variable modifications, followed by environment variables. It also uses a Property resource to allow runtime override of configured behavior.

Constructor Summary

Constructors

Constructor	Description
LayeredFileSystemConfig()	Constructor.

Method Summary

Modifier and Type	Method	Description
void	clearProperty(String key)	Removes property from the use-defined runtime configuration.
Optional<Boolean>	getBooleanProperty(String key)	Returns property value as boolean value wrapped inside an Optional for a key or empty if no such property exists.
Optional<Double>	getDoubleProperty(String key)	Returns property value as a double wrapped inside an Optional for a key or empty if no such property exists.
Optional<Float>	getFloatProperty(String key)	Returns property value as float value wrapped inside an Optional for a key or empty if no such property exists.
Optional<Integer>	getIntProperty(String key)	Returns property value as int value wrapped inside an Optional for a key or empty if no such property exists.
Optional<Long>	getLongProperty(String key)	Returns property value as long value wrapped inside an Optional for a key or empty if no such property exists.
String	getPackageVariableName(String suffix)	Gets a package scoped variable name.
Properties	getRuntimeProperties()	Returns the properties used to hold the highest-priority config values.
Optional<String>	getStringProperty(String key)	Returns property value as String value wrapped inside an Optional for a key or empty if no such property exists.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.github.qubitpi.athena.config.SystemConfig

resetProperty, setProperty

Constructor Details

LayeredFileSystemConfig

public LayeredFileSystemConfig()

Constructor.

Throws:

IllegalStateException - if loading an existing userConfig.properties file fails

Method Details

getPackageVariableName

public String getPackageVariableName(String suffix)

Description copied from interface: SystemConfig

Gets a package scoped variable name.

Specified by:

getPackageVariableName in interface SystemConfig

Parameters:

suffix - The variable name of the configuration variable without the package prefix

Returns:

variable name

getStringProperty

public Optional<String> getStringProperty(String key)

Description copied from interface: SystemConfig

Returns property value as String value wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getStringProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getIntProperty

public Optional<Integer> getIntProperty(String key)

Description copied from interface: SystemConfig

Returns property value as int value wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getIntProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getBooleanProperty

public Optional<Boolean> getBooleanProperty(String key)

Description copied from interface: SystemConfig

Returns property value as boolean value wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getBooleanProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getLongProperty

public Optional<Long> getLongProperty(String key)

Description copied from interface: SystemConfig

Returns property value as long value wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getLongProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getDoubleProperty

public Optional<Double> getDoubleProperty(String key)

Description copied from interface: SystemConfig

Returns property value as a double wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getDoubleProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getFloatProperty

public Optional<Float> getFloatProperty(String key)

Description copied from interface: SystemConfig

Returns property value as float value wrapped inside an Optional for a key or empty if no such property exists.

Specified by:

getFloatProperty in interface SystemConfig

Parameters:

key - The key for which value needs to be fetched

Returns:

an Optional value for the requested key or Optional.empty()

getRuntimeProperties

public Properties getRuntimeProperties()

Description copied from interface: SystemConfig

Returns the properties used to hold the highest-priority config values.

This method is intended primarily for interface support and not for client interactions

Notes: this is a design flaw based on how it is used in method such as SystemConfig.setProperty(String, String). If implementations produces a shallow copy of the runtime properties, then SystemConfig.setProperty(String, String) will fail to accomplish what it supposed to do. The fact that this method is "not being called by client" pushes us to look at problem at a higher level: this method assumes the returned properties are directly mutable and will mutate the config instance directly. This violates encapsulation. we should remove this method and ask client to implement SystemConfig.setProperty(String, String)

Specified by:

getRuntimeProperties in interface SystemConfig

Returns:

a properties object which act as a runtime mask against other configuration properties

clearProperty

public void clearProperty(String key)

Description copied from interface: SystemConfig

Removes property from the use-defined runtime configuration.

Specified by:

clearProperty in interface SystemConfig

Parameters:

key - The key of the property to remove