org.opencypher.tools

Interface Option<T>

Type Parameters:

T - The value type of the options interface that this option customizes.

All Superinterfaces:

Serializable

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Option<T>
extends Serializable

Contains utilities for implementing options interfaces.

An options interface is an interface that only declare methods that take no arguments, and return a value object, typically with default value implementations. Example:

 class UserOfOptions {
     public interface MyOptions {
         default Date targetDate() { return new Date(); }
         default Font prettyFont() { return new Font( fontName(), Font.PLAIN, fontSize() ); }
         default String fontName() { return "Verdana"; }
         default int fontSize() { return 11; }
     }
     private final Date targetDate;
     private final Font prettyFont;
     public UserOfOptions( MyOptions options ) {
         this.targetDate = options.targetDate();
         this.prettyFont = options.prettyFont();
     }
 }
 

This class contains a DSL that uses reflection to make it convenient to create a custom instance of an options interface. Example:

 UserOfOptions[] custom = {
     new UserOfOptions( options( UserOfOptions.MyOptions.class,
         fontName -> "Times New Roman",
         fontSize -> 22 ) ),
     new UserOfOptions( options( UserOfOptions.MyOptions.class,
         targetDate -> new Date( 1963, 11, 22 ),
         prettyFont -> new Font( "Arial", Font.BOLD, prettyFont.fontSize() ) ),
 };
 

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Option.OptionHandler<T> Implementation detail: the InvocationHandler used for implementing an options interface.

Method Summary

Modifier and Type	Method and Description
static <T> T	dynamicOptions(Class<T> optionsType, Function<Method,Object> lookup, Option<? super T>... options) Create a dynamic implementation of the supplied options interface using the specified options to define values.
static <T> T	options(Class<T> optionsType, Option<? super T>... options) Create a dynamic implementation of the supplied options interface using the specified options to define values.
Object	value(T options)

Method Detail

value

Object value(T options)

dynamicOptions

@SafeVarargs
static <T> T dynamicOptions(Class<T> optionsType,
                                         Function<Method,Object> lookup,
                                         Option<? super T>... options)

Create a dynamic implementation of the supplied options interface using the specified options to define values. The specified options must be lambdas where the parameter name of the lambda is the name of the option of the options interface that lambda overrides. When the lambda is invoked, the instance of the options interface is given as the sole parameter, this allows custom options that depend on other options of the options interface. For options that are not overridden the lookup function provided is used to lookup the value, and if the lookup function returns null the default value is used.

Type Parameters:

T - the type of the options interface.

Parameters:

optionsType - the options interface to implement.

lookup - the function to use to look up values not explicitly overridden.

options - lambdas that define the overridden options.

Returns:

an instance of the options interface.

options

@SafeVarargs
static <T> T options(Class<T> optionsType,
                                  Option<? super T>... options)

Create a dynamic implementation of the supplied options interface using the specified options to define values. The specified options must be lambdas where the parameter name of the lambda is the name of the option of the options interface that lambda overrides. When the lambda is invoked, the instance of the options interface is given as the sole parameter, this allows custom options that depend on other options of the options interface. For options that are not given, the default value is used.

Type Parameters:

T - the type of the options interface.

Parameters:

optionsType - the options interface to implement.

options - lambdas that define the overridden options.

Returns:

an instance of the options interface.