```
@Target(METHOD)
@Retention(RUNTIME)
public @interface ModifyConstant
```
Specifies that this mixin method should inject a constant modifier callback to itself in the target method(s) identified by method() at the specified LDC (or specialised const opcode) instruction in order to adjust the constant value returned.
ModifyConstant callbacks should always take one argument of the appropriate constant type and return the same type. For example a ModifyConstant for a local of type String should have the signature:
private String methodName(String variable) { ...
The callback receives the original value of the constant, and should return the new value.

Like other Redirect injectors, the callback signature can optionally include the target method arguments by simply appending them to the handler method signature.

Optional Element Summary

Optional Elements
Modifier and Type	Optional Element	Description
`int`	`allow`	Injection points are in general expected to match every candidate instruction in the target method or slice, except in cases where options such as `At.ordinal()` are specified which naturally limit the number of results.
`Constant[]`	`constant`	Discriminator for the constant(s) to match (injection points), if not specified then all constants matching the annotated handler's return type are matched
`java.lang.String`	`constraints`	Returns constraints which must be validated for this injector to succeed.
`int`	`expect`	Like `require()` but only enabled if the `mixin.debug.countInjections` option is set to `true` and defaults to 1.
`java.lang.String[]`	`method`	String representation of one or more `target selectors` which identify the target methods.
`int`	`order`	By default almost all injectors for a target class apply their injections at the same time.
`boolean`	`remap`	By default, the annotation processor will attempt to locate an obfuscation mapping for all `ModifyConstant` methods since it is anticipated that in general the target of a `ModifyConstant` annotation will be an obfuscated method in the target class.
`int`	`require`	In general, injectors are intended to "fail soft" in that a failure to locate the injection point in the target method is not considered an error condition.
`Slice[]`	`slice`	Array of `Slice` annotations which describe the method bisections used in locating target instructions for this modifier.
`Desc[]`	`target`	Literal representation of one or more `@Desc` annotations which identify the target methods.

- Element Detail
  - method
```
java.lang.String[] method
```
    String representation of one or more target selectors which identify the target methods.
    
    Returns:
    
    target method(s) for this injector
    
    Default:
    
    {}
- - target
```
Desc[] target
```
    Literal representation of one or more @Desc annotations which identify the target methods.
    
    Returns:
    
    target method(s) for this injector as descriptors
    
    Default:
    
    {}
- - slice
```
Slice[] slice
```
    Array of Slice annotations which describe the method bisections used in locating target instructions for this modifier.
    
    Returns:
    
    slices
    
    Default:
    
    {}
- - constant
```
Constant[] constant
```
    Discriminator for the constant(s) to match (injection points), if not specified then all constants matching the annotated handler's return type are matched
    
    Returns:
    
    the constant discriminator
    
    Default:
    
    {}
- - remap
```
boolean remap
```
    By default, the annotation processor will attempt to locate an obfuscation mapping for all ModifyConstant methods since it is anticipated that in general the target of a ModifyConstant annotation will be an obfuscated method in the target class. However since it is possible to also apply mixins to non-obfuscated targets (or non- obfuscated methods in obfuscated targets, such as methods added by Forge) it may be necessary to suppress the compiler error which would otherwise be generated. Setting this value to false will cause the annotation processor to skip this annotation when attempting to build the obfuscation table for the mixin.
    
    Returns:
    
    True to instruct the annotation processor to search for obfuscation mappings for this annotation
    
    Default:
    
    true
- - require
```
int require
```
    In general, injectors are intended to "fail soft" in that a failure to locate the injection point in the target method is not considered an error condition. Another transformer may have changed the method structure or any number of reasons may cause an injection to fail. This also makes it possible to define several injections to achieve the same task given expected mutation of the target class and the injectors which fail are simply ignored.
    However, this behaviour is not always desirable. For example, if your application depends on a particular injection succeeding you may wish to detect the injection failure as an error condition. This argument is thus provided to allow you to stipulate a minimum number of successful injections for this callback handler. If the number of injections specified is not achieved then an InjectionError is thrown at application time. Use this option with care.
    
    Returns:
    
    Minimum required number of injected callbacks, default specified by the containing config
    
    Default:
    
    -1
- - expect
```
int expect
```
    Like require() but only enabled if the mixin.debug.countInjections option is set to true and defaults to 1. Use this option during debugging to perform simple checking of your injectors. Causes the injector to throw a InvalidInjectionException if the expected number of injections is not realised.
    
    Returns:
    
    Minimum number of expected callbacks, default 1
    
    Default:
    
    1
- - allow
```
int allow
```
    Injection points are in general expected to match every candidate instruction in the target method or slice, except in cases where options such as At.ordinal() are specified which naturally limit the number of results.
    This option allows for sanity-checking to be performed on the results of an injection point by specifying a maximum allowed number of matches, similar to that afforded by Group.max(). For example if your injection is expected to match 4 invocations of a target method, but instead matches 5, this can become a detectable tamper condition by setting this value to 4.
    Setting any value 1 or greater is allowed. Values less than 1 or less than require() are ignored. require() supercedes this argument such that if allow is less than require the value of require is always used.
    
    Note that this option is not a limit on the query behaviour of this injection point. It is only a sanity check used to ensure that the number of matches is not too high
    
    Returns:
    
    Maximum allowed number of injections for this
    
    Default:
    
    -1
- - constraints
```
java.lang.String constraints
```
    Returns constraints which must be validated for this injector to succeed. See ConstraintParser.Constraint for details of constraint formats.
    
    Returns:
    
    Constraints for this annotation
    
    Default:
    
    ""
- - order
```
int order
```
    By default almost all injectors for a target class apply their injections at the same time. In other words, if multiple mixins target the same class then injectors are applied in priority order (since the mixins themselves are merged in priority order, and injectors run in the order they were merged). Redirect injectors apply in a later pass.
    The default order for redirect injectors is 10000, and all other injectors use 1000.
    
    Specifying a value for order alters this default behaviour and causes the injector to inject either earlier or later than it normally would. For example specifying 9900 will cause the injector to apply before others, while 11000 will apply later. Injectors with the same order will still apply in order of their mixin's priority.
    
    Returns:
    
    the application order for this injector, uses default REDIRECT order (10000) if not specified
    
    Default:
    
    10000

Annotation Type ModifyConstant

Optional Element Summary

Element Detail

method

target

slice

constant

remap

require

expect

allow

constraints

order