Package: org.codehaus.groovy.runtime

## [Java] Class MetaClassHelper

- org.codehaus.groovy.runtime.MetaClassHelper

- Authors:
    John Wilson
    Jochen Theodorou

- - ### Field Summary

    Fields
    Modifiers | Name | Description
    --- | --- | ---
    `static Object[]` | `ARRAY_WITH_NULL` |
    `static Object[]` | `EMPTY_ARRAY` |
    `static Class[]` | `EMPTY_CLASS_ARRAY` |
    `static Class[]` | `EMPTY_TYPE_ARRAY` |
    `protected static Logger` | `LOG` |

  - ### Methods Summary

    Methods
    Type Params | Return Type | Name and description
    --- | --- | ---
    `` | `static boolean` | `accessibleToConstructor(Class at, Constructor constructor)`
    `` | `static Object` | `asPrimitiveArray(List list, Class parameterType)` @param list the original list
    `` | `static Object[]` | `asWrapperArray(Object parameters, Class componentType)`
    `` | `static long` | `calculateParameterDistance(Class[] arguments, ParameterTypes pt)` note: when shifting with 32 bit, you should only shift on a long.
    `` | `static String` | `capitalize(String property)` In general we want to match the signature that allows us to use as less arguments for the vargs part as possible.
    `` | `static Class[]` | `castArgumentsToClassArray(Object[] argTypes)`
    `` | `static Object` | `chooseEmptyMethodParams(FastArray methods)` @param methods the methods to choose from
    `` | `static Object` | `chooseMostGeneralMethodWith1NullParam(FastArray methods)` Warning: this method does not choose properly if multiple methods with the same distance are encountered
    `` | `static boolean` | `containsMatchingMethod(List list, MetaMethod method)` @param list a list of MetaMethods
    `` | `static String` | `convertPropertyName(String prop)` Converts a String into a standard property name.
    `` | `static Class[]` | `convertToTypeArray(Object[] args)` param instance array to the type array
    `` | `static GroovyRuntimeException` | `createExceptionText(String init, MetaMethod method, Object object, Object[] args, Throwable reason, boolean setReason)`
    `` | `static void` | `doSetMetaClass(Object self, MetaClass mc)` Sets the meta class for an object, by delegating to the appropriate org.codehaus.groovy.runtime.DefaultGroovyMethods helper method.
    `` | `protected static String` | `getClassName(Object object)`
    `` | `static Closure` | `getMethodPointer(Object object, String methodName)` Returns a callable object for the given method name on the object.
    `` | `static boolean` | `isAssignableFrom(Class classToTransformTo, Class classToTransformFrom)`
    `` | `static boolean` | `isGenericSetMethod(MetaMethod method)`
    `` | `protected static boolean` | `isSuperclass(Class clazz, Class superclass)`
    `` | `static void` | `logMethodCall(Object object, String methodName, Object[] arguments)`
    `` | `static Object` | `makeArray(Object obj, Class secondary, int length)`
    `` | `static Object` | `makeCommonArray(Object[] arguments, int offset, Class fallback)`
    `` | `protected static String` | `normalizedValue(Object argument)`
    `` | `static boolean` | `parametersAreCompatible(Class[] arguments, Class[] parameters)`
    `` | `static boolean` | `sameClass(Class[] params, Object arg)`
    `` | `static boolean` | `sameClasses(Class[] params, Object[] arguments, boolean weakNullCheck)`
    `` | `static boolean` | `sameClasses(Class[] params, Object[] arguments)`
    `` | `static boolean` | `sameClasses(Class[] params)`
    `` | `static boolean` | `sameClasses(Class[] params, Object arg1)`
    `` | `static boolean` | `sameClasses(Class[] params, Object arg1, Object arg2)`
    `` | `static boolean` | `sameClasses(Class[] params, Object arg1, Object arg2, Object arg3)`
    `` | `static boolean` | `sameClasses(Class[] params, Object arg1, Object arg2, Object arg3, Object arg4)`
    `` | `protected static String` | `shortName(Object object)`
    `` | `static void` | `unwrap(Object[] arguments)`
    `` | `static Class[]` | `wrap(Class[] classes)`

  - ### Inherited Methods Summary

    Inherited Methods
    Methods inherited from class | Name
    --- | ---
    `class Object` | `wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll`

- - ### Field Detail

    - #### public static final Object[] ARRAY_WITH_NULL

    - #### public static final Object[] EMPTY_ARRAY

    - #### public static final Class[] EMPTY_CLASS_ARRAY

    - #### public static final Class[] EMPTY_TYPE_ARRAY

    - #### protected static final Logger LOG

  - ### Method Detail

    - #### public static boolean accessibleToConstructor(Class at, Constructor constructor)

    - #### public static Object asPrimitiveArray(List list, Class parameterType)

      Parameters:
        `list` - the original list
        `parameterType` - the resulting array type
      Returns:
        the constructed array

    - #### public static Object[] asWrapperArray(Object parameters, Class componentType)

    - #### public static long calculateParameterDistance(Class[] arguments, ParameterTypes pt)

      note: when shifting with 32 bit, you should only shift on a long. If you do that with an int, then i==(i<<32), which means you loose the shift information

    - #### public static String capitalize(String property)

      In general we want to match the signature that allows us to use as less arguments for the vargs part as possible. That means the longer signature usually wins if both signatures are vargs, while vargs looses always against a signature without vargs. A vs B : def foo(Object[] a) {1} -> case B def foo(a,b,Object[] c) {2} -> case A assert foo(new Object(),new Object()) == 2 --> A preferred over B A vs C : def foo(Object[] a) {1} -> case B def foo(a,b) {2} -> case C assert foo(new Object(),new Object()) == 2 --> C preferred over A A vs D : def foo(Object[] a) {1} -> case D def foo(a,Object[] b) {2} -> case A assert foo(new Object()) == 2 --> A preferred over D This gives C case B def foo(a,b) {2} -> case C assert foo(new Object(),new Object()) == 2 --> C preferred over B, matches C case B def foo(a,Object[] b) {2} -> case D assert foo(new Object(),new Object()) == 2 --> D preferred over B This gives C

    - #### public static Class[] castArgumentsToClassArray(Object[] argTypes)

    - #### public static Object chooseEmptyMethodParams(FastArray methods)

      Parameters:
        `methods` - the methods to choose from
      Returns:
        the method with 1 parameter which takes the most general type of object (e.g. Object)

    - #### @Deprecated public static Object chooseMostGeneralMethodWith1NullParam(FastArray methods)

      Warning: this method does not choose properly if multiple methods with the same distance are encountered

      deprecated:
      Parameters:
        `methods` - the methods to choose from
      Returns:
        the method with 1 parameter which takes the most general type of object (e.g. Object) ignoring primitive types

    - #### public static boolean containsMatchingMethod(List list, MetaMethod method)

      Parameters:
        `list` - a list of MetaMethods
        `method` - the MetaMethod of interest
      Returns:
        true if a method of the same matching prototype was found in the list

    - #### public static String convertPropertyName(String prop)

      Converts a String into a standard property name.

      Parameters:
        `prop` - the original name
      Returns:
        the converted name

    - #### public static Class[] convertToTypeArray(Object[] args)

      param instance array to the type array

      Parameters:
        `args` - the arguments
      Returns:
        the types of the arguments

    - #### public static GroovyRuntimeException createExceptionText(String init, MetaMethod method, Object object, Object[] args, Throwable reason, boolean setReason)

    - #### public static void doSetMetaClass(Object self, MetaClass mc)

      Sets the meta class for an object, by delegating to the appropriate org.codehaus.groovy.runtime.DefaultGroovyMethods helper method. This method was introduced as a breaking change in 2.0 to solve rare cases of stack overflow. See GROOVY-5285. The method is named doSetMetaClass in order to prevent misusages. Do not use this method directly unless you know what you do.

      Parameters:
        `self` - the object for which to set the meta class
        `mc` - the metaclass

    - #### protected static String getClassName(Object object)

    - #### public static Closure getMethodPointer(Object object, String methodName)

      Returns a callable object for the given method name on the object. The object acts like a Closure in that it can be called, like a closure and passed around - though really its a method pointer, not a closure per se.

      Parameters:
        `object` - the object containing the method
        `methodName` - the method of interest
      Returns:
        the resulting closure-like method pointer

    - #### public static boolean isAssignableFrom(Class classToTransformTo, Class classToTransformFrom)

    - #### public static boolean isGenericSetMethod(MetaMethod method)

    - #### protected static boolean isSuperclass(Class clazz, Class superclass)

    - #### public static void logMethodCall(Object object, String methodName, Object[] arguments)

    - #### public static Object makeArray(Object obj, Class secondary, int length)

    - #### public static Object makeCommonArray(Object[] arguments, int offset, Class fallback)

    - #### protected static String normalizedValue(Object argument)

    - #### public static boolean parametersAreCompatible(Class[] arguments, Class[] parameters)

    - #### public static boolean sameClass(Class[] params, Object arg)

    - #### public static boolean sameClasses(Class[] params, Object[] arguments, boolean weakNullCheck)

    - #### public static boolean sameClasses(Class[] params, Object[] arguments)

    - #### public static boolean sameClasses(Class[] params)

    - #### public static boolean sameClasses(Class[] params, Object arg1)

    - #### public static boolean sameClasses(Class[] params, Object arg1, Object arg2)

    - #### public static boolean sameClasses(Class[] params, Object arg1, Object arg2, Object arg3)

    - #### public static boolean sameClasses(Class[] params, Object arg1, Object arg2, Object arg3, Object arg4)

    - #### protected static String shortName(Object object)

    - #### public static void unwrap(Object[] arguments)

    - #### public static Class[] wrap(Class[] classes)