https://github.com/wnameless/apt-constant-generator

Annotation Processing Tool for Java Constant generating
https://github.com/wnameless/apt-constant-generator
java java-annotation-processing java-annotation-processor
Last synced: 2 months ago
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Annotation Processing Tool for Java Constant generating
Host: GitHub
URL: https://github.com/wnameless/apt-constant-generator
Owner: wnameless
License: apache-2.0
Created: 2023-09-02T05:07:07.000Z (over 1 year ago)
Default Branch: main
Last Pushed: 2023-09-02T06:50:48.000Z (over 1 year ago)
Last Synced: 2025-01-21T06:11:49.638Z (4 months ago)
Topics: java, java-annotation-processing, java-annotation-processor
Language: Java
Homepage:
Size: 27.3 KB
Stars: 1
Watchers: 1
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE
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apt-constant-generator

=============

Annotation Processing Tool for Java Constant generating.

## `Goal` - generating classes of Constants based on Java class names

Java Constants(public static final) are widely used during development, however they are lack of flexibility. This apt-constant-generator provides a workaround toward this common issue.

## `Purpose` - easier refactoring and maintenance by utilizing Java Constants

For example, Java annotation only accepts Constant or literal for String. Even though the annotation value may relate to class name somehow, we can't assign Class#getSimpleName or Class#getName to an annotation String attribute which makes refactoring and maintenance difficult sometimes.

## `Furthermore` - optional Constants by annotation driven configuration

Constants such as String, primitive, Class and Enum can also be generated by annotation driven configuration and stored in the same generated class.

# Maven Repo

```xml

	com.github.wnameless.apt

	apt-constant-generator

	${newestVersion}

	

```

# DEMO

Traditional approach:

```java

@RequestMapping("/bars")

@Controller

public class BarController {}

// Spring Controller for Bar entity

```

Solution brought by apt-constant-generator:

```java

// NRBar is a class of constants, which is automatically generated by spring-boot-up-apt

@RequestMapping(NRBar.RESOURCE_PATH)

@Controller

public class BarController {}

```

```java

@NamedResource

public class Bar {}

```

# Quick Start

Annotate `@NamedResource` with any class, enum or interface

```java

@NamedResource

public class Bar {}

```

Maven dependencies

```xml

  com.github.wnameless.apt

  apt-constant-generator

  ${newestVersion}

```

Maven plugins

```xml

  org.apache.maven.plugins

  maven-compiler-plugin

  

    

      

        com.github.wnameless.apt

        apt-constant-generator

        ${newestVersion}

      

    

  

```

# Feature List

| Name | option | Description | Since |

| --- | --- | --- | --- |

| [NamedResource](#1.0.0-1) || Generate a class of constants based on the annotated class name | v1.0.0 |

|| [default](#1.0.0-1.1) | Default behavior of @NamedResource | v1.0.0 |

|| [injectable](#1.0.0-1.2) | Add jakarta.inject.Named or javax.inject.Named to the generated class | v1.0.0 |

|| [markerInterface](#1.0.0-1.3) | Option to implement marker interface INamedResource for the generated class | v1.0.0 |

|| [classNamePrefix
classNameSuffix](#1.0.0-1.4) | Add prefix or suffix to the generated class name | v1.0.0 |

|| [singular](#1.0.0-1.5) | Change singular name for the annotated class  | v1.0.0 |

|| [plural](#1.0.0-1.6) | Change plural name for the annotated class | v1.0.0 |

|| [inferredConstants](#1.0.0-1.7) | Infer other String constants by given naming formats | v1.0.0 |

|| [literalSingularConstants](#1.0.0-1.8) | Create constants of literal singular names in different naming formats | v1.0.0 |

|| [literalPluralConstants](#1.0.0-1.9) | Create constants of literal plural names in different naming formats | v1.0.0 |

|| [constants](#1.0.0-1.10) | Add optional String constants | v1.0.0 |

|| [primitiveConstants](#1.0.0-1.11) | Add optional primitive constants | v1.0.0 |

|| [classConstants](#1.0.0-1.12) | Add optional Class constants | v1.0.0 |

|| [enumConstants](#1.0.0-1.13) | Add optional Enum constants | v1.0.0 |

### [:top:](#top) NamedResource

#### [:top:](#top) Annotation option: `default`

_Config_:

```java

@NamedResource

public SimpleNamedResource {}

```

_Generated_: NRSimpleNamedResource (NR is the default class name prefix)

```java

NRSimpleNamedResource.SINGULAR // SimpleNamedResource

NRSimpleNamedResource.PLURAL   // SimpleNamedResources

NRSimpleNamedResource.CLASS_SIMPLE_NAME // SimpleNamedResource

NRSimpleNamedResource.CLASS_NAME        // model.SimpleNamedResource

NRSimpleNamedResource.PACKAGE_NAME      // model

// 5 naming formats: UPPER_CAMEL, LOWER_CAMEL, UPPER_UNDERSCORE, LOWER_UNDERSCORE, LOWER_HYPHEN

NRSimpleNamedResource.UPPER_CAMEL_SINGULAR      // SimpleNamedResource

NRSimpleNamedResource.LOWER_CAMEL_SINGULAR      // simpleNamedResource

NRSimpleNamedResource.UPPER_UNDERSCORE_SINGULAR // SIMPLE_NAMED_RESOURCE

NRSimpleNamedResource.LOWER_UNDERSCORE_SINGULAR // simple_named_resource

NRSimpleNamedResource.LOWER_HYPHEN_SINGULAR     // simple-named-resource

NRSimpleNamedResource.UPPER_CAMEL_PLURAL        // SimpleNamedResources

NRSimpleNamedResource.LOWER_CAMEL_PLURAL        // simpleNamedResources

NRSimpleNamedResource.UPPER_UNDERSCORE_PLURAL   // SIMPLE_NAMED_RESOURCES

NRSimpleNamedResource.LOWER_UNDERSCORE_PLURAL   // simple_named_resources

NRSimpleNamedResource.LOWER_HYPHEN_PLURAL       // simple-named-resources

// Default inferred constants: RESOURCE, RESOURCES, RESOURCE_PATH

NRSimpleNamedResource.RESOURCE      // simple-named-resource

NRSimpleNamedResource.RESOURCES     // simple-named-resources

NRSimpleNamedResource.RESOURCE_PATH // /simple-named-resources

```

#### [:top:](#top) Annotation option: `injectable`

_Config_:

```java

// Default value is InjectType.NONE

@NamedResource(injectable = InjectType.JAKARTA) // InjectType.JAVAX is available

public class JakartaNamedResource {}

```

_Generated_:

```java

@Named // jakarta.inject.Named

public final class NRJakartaNamedResource implements INamedResource {

  ...

}

```

#### [:top:](#top) Annotation option: `markerInterface`

_Config_:

```java

@NamedResource(markerInterface = false) // Default value is true

public class NoMarkerNamedResource {}

```

_Generated_:

```java

public final class NRJakartaNamedResource { // By default, all generated classes implement INamedResource marker interface

  ...

}

```

#### [:top:](#top) Annotation option: `classNamePrefix` and `classNameSuffix`

_Config_:

```java

@NamedResource(classNamePrefix = "A", classNameSuffix = "Z")

public class PrefixSuffixNamedResource {}

```

_Generated_:

```java

public final class APrefixSuffixNamedResourceZ implements INamedResource {

  ...

}

```

#### [:top:](#top) Annotation option: `singular`

_Config_:

```java

@NamedResource(singular = @Naming(value = "alt-sing-name-rsc", format = NamingFormat.LOWER_HYPHEN))

public class AlteredSingularNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals("alt-sing-name-rsc", NRAlteredSingularNamedResource.SINGULAR);

// singular opt affects plural opt,

// however plural opt can be overridden if both singular and plural opts are existed

assertEquals("alt-sing-name-rscs", NRAlteredSingularNamedResource.PLURAL);

```

#### [:top:](#top) Annotation option: `plural`

_Config_:

```java

@NamedResource(plural = @Naming(value = "alt-pl-name-rscs", format = NamingFormat.LOWER_HYPHEN))

public class AlteredPluralOnlyNamedResource {}

```

_Generated_:

```java

// JUnit

// plural opt won't affect singlur opt

assertEquals("AlteredPluralOnlyNamedResource", NRAlteredPluralOnlyNamedResource.SINGULAR);

assertEquals("alt-pl-name-rscs", NRAlteredPluralOnlyNamedResource.PLURAL);

```

#### [:top:](#top) Annotation option: `inferredConstants`

_Config_:

```java

@NamedResource(inferredConstants = {

    @InferredConstant(name = "ROOT", plural = true,

        format = NamingFormat.UPPER_CAMEL, prefix = "/"),

    @InferredConstant(name = "LIST_ITEM_TEMPLATE", plural = false,

        format = NamingFormat.LOWER_UNDERSCORE, suffix = "_{}")})

public class InferredConstantsNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals("/InferredConstantsNamedResources", NRInferredConstantsNamedResource.ROOT);

assertEquals("inferred_constants_named_resource_{}", NRInferredConstantsNamedResource.LIST_ITEM_TEMPLATE);

```

#### [:top:](#top) Annotation option: `literalSingularConstants`

_Config_:

```java

@NamedResource(singular = @Naming(value = "MountEverest", format = NamingFormat.UPPER_CAMEL),

    literalSingularConstants = {

        NamingFormat.LOWER_CAMEL, NamingFormat.UPPER_CAMEL,

        NamingFormat.LOWER_UNDERSCORE, NamingFormat.UPPER_UNDERSCORE

    })

```

_Generated_:

```java

// JUnit

assertEquals("mountEverest", NRLiteralSingularNamedResource.mountEverest);

assertEquals("mount_everest", NRLiteralSingularNamedResource.mount_everest);

assertEquals("MountEverest", NRLiteralSingularNamedResource.MountEverest);

assertEquals("MOUNT_EVEREST", NRLiteralSingularNamedResource.MOUNT_EVEREST);

```

#### [:top:](#top) Annotation option: `literalPluralConstants`

_Config_:

```java

@NamedResource(plural = @Naming(value = "bellBottoms", format = NamingFormat.LOWER_CAMEL),

    literalPluralConstants = {

        NamingFormat.LOWER_CAMEL, NamingFormat.UPPER_CAMEL,

        NamingFormat.LOWER_UNDERSCORE, NamingFormat.UPPER_UNDERSCORE

    })

```

_Generated_:

```java

// JUnit

assertEquals("bellBottoms", NRLiteralPluralNamedResource.bellBottoms);

assertEquals("BellBottoms", NRLiteralPluralNamedResource.BellBottoms);

assertEquals("bell_bottoms", NRLiteralPluralNamedResource.bell_bottoms);

assertEquals("BELL_BOTTOMS", NRLiteralPluralNamedResource.BELL_BOTTOMS);

```

#### [:top:](#top) Annotation option: `constants`

_Config_:

```java

@NamedResource(constants = {

    @Constant(name = "DEATH_CARD", value = "Spade-1"),

    @Constant(name = "BEER_CARD", value = "Diamond-7")})

public class ConstantNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals("Spade-1", NRConstantNamedResource.DEATH_CARD);

assertEquals("Diamond-7", NRConstantNamedResource.BEER_CARD);

```

#### [:top:](#top) Annotation option: `primitive constants`

_Config_:

```java

@NamedResource(

    booleanConstants = {@BooleanConstant(name = "LIE", value = false)},

    byteConstants = {@ByteConstant(name = "BITS", value = 8)},

    charConstants = {@CharConstant(name = "YES", value = 'y')},

    shortConstants = {@ShortConstant(name = "UNIX_EPOCH_YEAR", value = 1970)},

    intConstants = {@IntConstant(name = "MARS_DISTANCE_KM", value = 225000000)},

    longConstants = {@LongConstant(name = "LIGHT_YEAR_M", value = 9460730777119564L)},

    floatConstants = {@FloatConstant(name = "GOLDEN_RATIO", value = 1.618f)},

    doubleConstants = {@DoubleConstant(name = "PI", value = 3.14159265358979323846)}

)

public class ConstantsNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals(false, NRConstantsNamedResource.LIE);

assertEquals(8, NRConstantsNamedResource.BITS);

assertEquals('y', NRConstantsNamedResource.YES);

assertEquals(1970, NRConstantsNamedResource.UNIX_EPOCH_YEAR);

assertEquals(225000000, NRConstantsNamedResource.MARS_DISTANCE_KM);

assertEquals(9460730777119564L, NRConstantsNamedResource.LIGHT_YEAR_M);

assertEquals(1.618f, NRConstantsNamedResource.GOLDEN_RATIO);

assertEquals(3.14159265358979323846, NRConstantsNamedResource.PI);

```

#### [:top:](#top) Annotation option: `classConstants`

_Config_:

```java

@NamedResource(

    classConstants = {@ClassConstant(name = "INTEGER_CLASS", value = Integer.class)}

)

public class ConstantsNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals(Integer.class, NRConstantsNamedResource.INTEGER_CLASS);

```

#### [:top:](#top) Annotation option: `enumConstants`

_Config_:

```java

@NamedResource(

    enumConstants = {

        @EnumConstant(name = "MONTH_SEPTEMBER", valueType = Month.class, valueKey = "SEPTEMBER")}

)

public class ConstantsNamedResource {}

```

_Generated_:

```java

// JUnit

assertEquals(Month.SEPTEMBER, NRConstantsNamedResource.MONTH_SEPTEMBER);

```

_Advanced Usage_:

```java

// Lombok(@FieldNameConstants) - generates String constants for all Enum constant names

@FieldNameConstants

public enum RBG {

  @FieldNameConstants.Include RED,

  @FieldNameConstants.Include BLUE,

  @FieldNameConstants.Include GREEN;

}

```

```java

// To avoid refactoring errors in the future by using RBG.Fields.BLUE as the valueKey

@NamedResource(

    enumConstants = {

        @EnumConstant(name = "RGB_BLUE", valueType = RBG.class, valueKey = RBG.Fields.BLUE)}

)

public class ConstantsNamedResource {}

```

## MISC

| Note| Since |

| --- | --- |

| Java 17 required. | v1.0.0 |
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