com.github.yin.flags

Class Flags

java.lang.Object

com.github.yin.flags.Flags

public class Flags
extends Object

Parses program arguments in a specified format and initializes registered static class fields in different application components. Flags provides static API to the client application and client should not attempt to manipulate own instances of Flags. One exception might be testing. Here, we provide method initForTesting(Map)). Example:

{@code

Author:

yin

Method Summary

Modifier and Type	Method and Description
com.github.yin.flags.Flags.ArgumentIndex	arguments() Returns an ArgumentIndex instance used to query for argument values.
static void	clear() Clears the argument values.
static <T> Flag<T>	create(Class<T> type, String name) Returns flag value accessor, which can be used to retrieve the actual flag value supplied by command line arguments or by other mechanism (such as initForTesting()).
TypeConversion	getTypeConversion() Type conversions used by Flags.
static void	init(String[] args) Initializes flag values from command-line style arguments.
static void	initForTesting(Map<String,String> options) Indexes flag values from a Map.
static void	printUsage(String packagePrefix) Prints user-readable usage help for all flags in a given package
static Flag<String>	string(String name) Returns flag value accessor for String type.

Methods inherited from class java.lang.Object

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

Method Detail

init

public static void init(String[] args)

Initializes flag values from command-line style arguments.

Parameters:

args - command-line arguments to parse values from

string

public static Flag<String> string(String name)

Returns flag value accessor for String type. See create().

create

public static <T> Flag<T> create(Class<T> type,
                                 String name)

Returns flag value accessor, which can be used to retrieve the actual flag value supplied by command line arguments or by other mechanism (such as initForTesting()). Preferably the typespecific variants (string(), ...) should be used for readability reasons.

 &at;FlagDesc("Specifies path to input file")
 private static final Flag<String> flag_inputPath = Flags.create(String.class, "inputPath");
 

Type Parameters:

T - is the same as flag value type

Parameters:

type - of the provided flag value

name - of the flag. This is must match the name the field or name attribute in @FlagDesc annotation.

Returns:

Flag accessor for flag value identified by name

printUsage

public static void printUsage(String packagePrefix)

Prints user-readable usage help for all flags in a given package

initForTesting

public static void initForTesting(Map<String,String> options)

Indexes flag values from a Map. This is useful for mocking flag values in integration testing. Please do not misuse this function, there will be better way to inject your logic into flag processing, surely use this only in your tests.

Parameters:

options - Map of flags and their intended values

clear

public static void clear()

Clears the argument values.

arguments

public com.github.yin.flags.Flags.ArgumentIndex arguments()

Returns an ArgumentIndex instance used to query for argument values.

getTypeConversion

public TypeConversion getTypeConversion()

Type conversions used by Flags.