fr.sii.ogham.core.builder.configuration

Class ConfigurationValueBuilderDelegate<P,V>

java.lang.Object

fr.sii.ogham.core.fluent.AbstractParent<P>

fr.sii.ogham.core.builder.configuration.ConfigurationValueBuilderDelegate<P,V>

Type Parameters:

P - the type of the parent builder (when calling AbstractParent.and() method)

V - the type of the value

All Implemented Interfaces:

ConfigurationValueBuilder<P,V>, Parent<P>

public class ConfigurationValueBuilderDelegate<P,V>
extends AbstractParent<P>
implements ConfigurationValueBuilder<P,V>

Implementation that just delegates all operations to another builder.

This is useful when a ConfigurationValueBuilder is used for a particular parent and it must be inherited. As the parent types are not the same, you can't directly use the same reference. So this implementation wraps the original reference but as it is a new instance, it can have a different parent builder.

Author:

Aurélien Baudet

Field Summary

Fields inherited from class fr.sii.ogham.core.fluent.AbstractParent

parent

Constructor Summary

Constructors

Constructor and Description
ConfigurationValueBuilderDelegate(P parent, ConfigurationValueBuilder<?,V> delegate) Wraps the delegate builder.

Method Summary

Modifier and Type	Method and Description
ConfigurationValueBuilder<P,V>	defaultValue(MayOverride<V> possibleNewValue) Register a default value only if MayOverride.override(Object) returns true.
ConfigurationValueBuilder<P,V>	defaultValue(V value) Register a default value.
ConfigurationValueBuilder<P,V>	properties(String... properties) Register one or several property keys.
ConfigurationValueBuilder<P,V>	value(Optional<V> optionalValue) Register an optional value only if Optional.isPresent() returns true.

Methods inherited from class fr.sii.ogham.core.fluent.AbstractParent

and

Methods inherited from class java.lang.Object

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

Methods inherited from interface fr.sii.ogham.core.fluent.Parent

and

Constructor Detail

ConfigurationValueBuilderDelegate

public ConfigurationValueBuilderDelegate(P parent,
                                         ConfigurationValueBuilder<?,V> delegate)

Wraps the delegate builder. The delegated builder parent is not used. This instance uses the provided parent instead for chaining.

Parameters:

parent - the new parent used for chaining

delegate - the instance that will really be updated

Method Detail

properties

public ConfigurationValueBuilder<P,V> properties(String... properties)

Description copied from interface: ConfigurationValueBuilder

Register one or several property keys. The developer can later set a value for one of the property keys. This is useful for the developer in order to externalize its configuration (using system properties, a configuration file or anything else):

 .properties("${custom.property.high-priority}", "${custom.property.low-priority}");
 

The properties are not immediately evaluated. The evaluation will be done when the MessagingBuilder.build() method is called. If you provide several property keys, evaluation will be done on the first key and if the property exists (see EnvironmentBuilder), its value is used. If the first property doesn't exist in properties, then it tries with the second one and so on.

The property keys may be provided without ${} expression markers:

         .properties("custom.property.high-priority", "custom.property.low-priority");
 

In this case, the keys are automatically wrapped for later evaluation.

Specified by:

properties in interface ConfigurationValueBuilder<P,V>

Parameters:

properties - the property keys

Returns:

this instance for fluent chaining

defaultValue

public ConfigurationValueBuilder<P,V> defaultValue(V value)

Description copied from interface: ConfigurationValueBuilder

Register a default value. This value is used if the developer has not set any value for property keys. It always override current set value.

If this method is called several times, only the last value is used.

If null value is set, it unregisters previously registered default value.

Specified by:

defaultValue in interface ConfigurationValueBuilder<P,V>

Parameters:

value - the default value

Returns:

this instance for fluent chaining

value

public ConfigurationValueBuilder<P,V> value(Optional<V> optionalValue)

Description copied from interface: ConfigurationValueBuilder

Register an optional value only if Optional.isPresent() returns true. This value is used even if the developer has set a value for a property key.

This is a convenient method for fluent chaining. Without optional, the code would look like this:

 
 builder.host().defaultValue("localhost");
 if (myPortValue != null) {
   builder.port().value(myPortValue);
 }
 if (username != null) {
   builder.username().value(username);
 }
 
 

Thanks to Optional, developer can write:

 
 builder
   .host().defaultValue("localhost").and()
   .port().value(Optional.ofNullable(myPortValue)).and()
   .username().value(Optional.ofNullable(username));
 
 

If this method is called several times, only the last "present" value is used.

WARNING: This is for advanced usage only. Developer that uses Ogham should not set the value of the property using this method because the value set like this takes precedence over properties. It means that the developer can't configure the resulting value from external configuration. This method is designed for particular automatic configuration (using Configurers).

Specified by:

value in interface ConfigurationValueBuilder<P,V>

Parameters:

optionalValue - the optional value to set

Returns:

this instance for fluent chaining

defaultValue

public ConfigurationValueBuilder<P,V> defaultValue(MayOverride<V> possibleNewValue)

Description copied from interface: ConfigurationValueBuilder

Register a default value only if MayOverride.override(Object) returns true.

Automatic configuration is based on priority order. Higher priority is applied first. It means that the lowest priority is applied last and overrides any default value set by a Configurer with higher priority using ConfigurationValueBuilder.defaultValue(Object).

This method gives more control on how Configurers should provide a default value. Each Configurer can decide if its default value should override or not a previously default value set by a Configurer with higher priority. It can also be used to control default value override or not with null value.

If every Configurer uses MayOverride.overrideIfNotSet(Object):

 .defaultValue(MayOverride.overrideIfNotSet(newValue))
 

Then the default value comes from the first applied Configurer (the one with highest priority) that sets a non-null default value. It becomes more consistent with properties declaration (first registered property has highest priority).

Specified by:

defaultValue in interface ConfigurationValueBuilder<P,V>

Parameters:

possibleNewValue - indicates if the new default value should be applied according to previous value

Returns:

this instance for fluent chaining