Package io.confound.config

Class BaseConfiguration<T>

java.lang.Object

io.confound.config.AbstractConfiguration

io.confound.config.BaseConfiguration<T>

Type Parameters:

T - The type of values used in the underlying storage.

All Implemented Interfaces:

Configuration, Parameters

Direct Known Subclasses:

AbstractObjectConfiguration, AbstractStringConfiguration

public abstract class BaseConfiguration<T>
extends AbstractConfiguration

Abstract configuration implementation providing common base functionality.

Concrete implementations must override findParameterImpl(String), and may also override hasParameterImpl(String) for added efficiency.

This class provides a facility normalizeKey(String) for modifying the requested key if necessary before ultimate retrieval via findParameterImpl(String). Most implementations will not need this facility, and will use the default implementation which uses the requested key unmodified. In any case, the implementation must use the original key, not the normalized key, when delegating to the parent configuration, if any.

Author:

Garret Wilson

Constructor Summary

Constructors

Constructor	Description
BaseConfiguration(Configuration parentConfiguration)	Parent configuration constructor.

Method Summary

Modifier and Type	Method	Description
protected java.util.Optional<T>	findParameter(java.lang.String key)	Tries to retrieves a general parameter from the underlying storage.
protected abstract java.util.Optional<T>	findParameterImpl(java.lang.String key)	Implementation to retrieves a general parameter that may not be present from the underlying storage.
<P> java.util.Optional<P>	getOptionalParameter(java.lang.String key)	Retrieves a general parameter that may not be present.
boolean	hasParameter(java.lang.String key)	Determines whether a parameter of some type exists for the given parameter key.
protected boolean	hasParameterImpl(java.lang.String key)	Determines whether a parameter is present in the underlying storage.
protected java.lang.String	normalizeKey(java.lang.String key)	Normalizes a requested key if required by this implementation.

Methods inherited from class io.confound.config.AbstractConfiguration

getParentConfiguration, or

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.confound.config.Parameters

getBoolean, getDouble, getInt, getLong, getOptionalBoolean, getOptionalDouble, getOptionalInt, getOptionalLong, getOptionalPath, getOptionalString, getOptionalUri, getParameter, getPath, getString, getUri, requireParameter, resolvePath

Constructor Detail

BaseConfiguration

public BaseConfiguration(@Nullable
                         Configuration parentConfiguration)

Parent configuration constructor.

Parameters:

parentConfiguration - The parent configuration to use for fallback lookup, or null if there is no parent configuration.

Method Detail

normalizeKey

protected java.lang.String normalizeKey(@Nonnull
                                        java.lang.String key)

Normalizes a requested key if required by this implementation.

The default implementation returns the key unmodified after checking for null.

Parameters:

key - The parameter key.

Returns:

The requested parameter key, modified as needed for lookup in this implementation.

hasParameter

public boolean hasParameter(@Nonnull
                            java.lang.String key)
                     throws ConfigurationException

Determines whether a parameter of some type exists for the given parameter key.

This implementation normalizes the key and delegates to hasParameterImpl(String). Most subclasses should not override this method, and instead override hasParameterImpl(String).

Parameters:

key - The parameter key.

Returns:

true if a parameter of type type could be retrieved from these parameters using the given key.

Throws:

java.lang.NullPointerException - if the given key is null.

java.lang.SecurityException - If a security manager exists and it doesn't allow access to the specified parameter.

ConfigurationException - if there is a parameter value stored in an invalid format.

hasParameterImpl

protected boolean hasParameterImpl(@Nonnull
                                   java.lang.String key)
                            throws ConfigurationException

Determines whether a parameter is present in the underlying storage.

The given parameter key is assumed to already be normalized, and should not be modified.

This method must not fall back to parent configuration; only local values must be returned.

The default implementation delegates to findParameterImpl(String).

Parameters:

key - The normalized parameter key.

Returns:

true if a parameter of type type could be retrieved from these parameters using the given key.

Throws:

java.lang.NullPointerException - if the given key is null.

java.lang.SecurityException - If a security manager exists and it doesn't allow access to the specified parameter.

ConfigurationException - if there is a parameter value stored in an invalid format.

getOptionalParameter

public <P> java.util.Optional<P> getOptionalParameter(java.lang.String key)
                                               throws ConfigurationException

Retrieves a general parameter that may not be present.

This implementation delegates to findParameter(String).

Type Parameters:

P - The type of parameter expected.

Parameters:

key - The parameter key.

Returns:

The optional value of the parameter associated with the given key.

Throws:

ConfigurationException - if there is a parameter value stored in an invalid format.

findParameter

protected java.util.Optional<T> findParameter(@Nonnull
                                              java.lang.String key)
                                       throws ConfigurationException

Tries to retrieves a general parameter from the underlying storage. The key need not be normalized; it will be normalized as necessary.

This method must not fall back to parent configuration; only local strings must be returned.

This is an internal API call that should be used by child classes to funnel requests to the underlying storage. Normally child classes will not override this method, but override findParameterImpl(String) instead.

Parameters:

key - The parameter key, which may not be normalized.

Returns:

The optional value of the parameter associated with the given key.

Throws:

java.lang.NullPointerException - if the given key is null.

java.lang.SecurityException - If a security manager exists and it doesn't allow access to the specified parameter.

ConfigurationException - if there is a parameter value stored in an invalid format.

See Also:

normalizeKey(String)

findParameterImpl

protected abstract java.util.Optional<T> findParameterImpl(@Nonnull
                                                           java.lang.String key)
                                                    throws ConfigurationException

Implementation to retrieves a general parameter that may not be present from the underlying storage.

The given parameter key is assumed to already be normalized, and should not be modified.

This method must not fall back to parent configuration; only local values must be returned.

Parameters:

key - The normalized parameter key.

Returns:

The optional value of the parameter associated with the given key.

Throws:

java.lang.NullPointerException - if the given key is null.

java.lang.SecurityException - If a security manager exists and it doesn't allow access to the specified parameter.

ConfigurationException - if there is a parameter value stored in an invalid format.