Signature (invokebinder 1.2 API)

java.lang.Object
- com.headius.invokebinder.Signature

```
public class Signature
extends Object
```
Signature represents a series of method arguments plus their symbolic names. In order to make it easier to permute arguments, track their flow, and debug cases where reordering or permuting fails to work properly, the Signature class also tracks symbolic names for all arguments. This allows permuting by name or by name pattern, avoiding the error-prone juggling of int[] for the standard MethodHandles.permuteArguments call. A Signature is created starting using #thatReturns method, and expanded using #withArgument for each named argument in sequence. Order is preserved. A Signature can be mutated into another by manipuating the argument list as with java.lang.invoke.MethodType, but using argument names and name patterns instead of integer offsets. Two signatures can be used to produce a permute array suitable for use in java.lang.invoke.MethodHandles#permuteArguments using the #to methods. The #to method can also accept a list of argument names, as a shortcut.

Author:

headius

Method Summary

Methods
Modifier and Type	Method and Description
`Signature`	`appendArg(String name, Class type)` Append an argument (name + type) to the signature.
`Signature`	`appendArgs(String[] names, Class... types)` Append an argument (name + type) to the signature.
`String`	`argName(int index)` Retrieve the name of the argument at the given index.
`String[]`	`argNames()` The current argument names for this signature.
`int`	`argOffset(String name)` Retrieve the offset of the given argument name in this signature's arguments.
`int`	`argOffsets(String pattern)` Retrieve the offset of the given argument name in this signature's arguments.
`Class`	`argType(int index)` Get the argument type at the given index.
`Signature`	`asFold(Class retval)` Produce a new signature based on this one with a different return type.
`Signature`	`changeReturn(Class retval)` Create a new signature based on this one with a different return type.
`Signature`	`dropArg(int index)` Drops the argument at the given index.
`Signature`	`dropArg(String name)` Drops the first argument with the given name.
`Signature`	`dropFirst()` Drop the first argument from this signature.
`Signature`	`dropLast()` Drop the last argument from this signature.
`Signature`	`exclude(String... excludeArgs)` Create a new signature containing the same return value as this one, but omitting the specified arguments.
`String`	`firstArgName()` Get the first argument name.
`Class`	`firstArgType()` Get the first argument type.
`Signature`	`insertArg(int index, String name, Class type)` Insert an argument (name + type) into the signature.
`Signature`	`insertArg(String beforeName, String name, Class type)` Insert an argument (name + type) into the signature before the argument with the given name.
`Signature`	`insertArgs(int index, String[] names, Class... types)` Insert arguments (names + types) into the signature.
`Signature`	`insertArgs(String beforeName, String[] names, Class... types)` Insert arguments (names + types) into the signature before the argument with the given name.
`String`	`lastArgName()` Get the last argument name.
`Class`	`lastArgType()` Get the last argument type.
`Signature`	`permute(String... permuteArgs)` Create a new signature containing the same return value as this one, but only the specified arguments.
`java.lang.invoke.MethodHandle`	`permuteWith(java.lang.invoke.MethodHandle target, String... permuteArgs)` Produce a method handle permuting the arguments in this signature using the given permute arguments and targeting the given java.lang.invoke.MethodHandle.
`SmartHandle`	`permuteWith(SmartHandle target)` Produce a new SmartHandle by permuting this Signature's arguments to the Signature of a target SmartHandle.
`Signature`	`prependArg(String name, Class type)` Prepend an argument (name + type) to the signature.
`Signature`	`prependArgs(String[] names, Class[] types)` Prepend an argument (name + type) to the signature.
`Signature`	`replaceArg(String oldName, String newName, Class newType)` Replace the named argument with a new name and type.
`static Signature`	`returning(Class retval)` Create a new signature returning the given type.
`Signature`	`spread(String... names)` Spread the trailing [] argument into its component type assigning given names.
`Signature`	`spread(String[] names, Class... types)` Spread the trailing [] argument into the given argument types
`Signature`	`spread(String baseName, int count)` Spread the trailing [] argument into its component type assigning given names.
`int[]`	`to(Signature other)` Generate an array of argument offsets based on permuting this signature to the given signature.
`int[]`	`to(String... otherArgPatterns)` Generate an array of argument offsets based on permuting this signature to the given signature.
`String`	`toString()` Produce a human-readable representation of this signature.
`java.lang.invoke.MethodType`	`type()` The current java.lang.invoke.MethodType for this Signature.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Method Detail
  - toString
```
public String toString()
```
    Produce a human-readable representation of this signature. This representation uses Class#getSimpleName to improve readability.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    a human-readable representation of the signature
  - returning
```
public static Signature returning(Class retval)
```
    Create a new signature returning the given type.
    
    Parameters:
    retval - the return type for the new signature
    
    Returns:
    the new signature
  - changeReturn
```
public Signature changeReturn(Class retval)
```
    Create a new signature based on this one with a different return type.
    
    Parameters:
    retval - the class for the new signature's return type
    
    Returns:
    the new signature
  - asFold
```
public Signature asFold(Class retval)
```
    Produce a new signature based on this one with a different return type.
    
    Parameters:
    retval - the new return type for the new signature
    
    Returns:
    the new signature
  - appendArg
```
public Signature appendArg(String name,
                  Class type)
```
    Append an argument (name + type) to the signature.
    
    Parameters:
    name - the name of the argument
    type - the type of the argument
    
    Returns:
    a new signature
  - appendArgs
```
public Signature appendArgs(String[] names,
                   Class... types)
```
    Append an argument (name + type) to the signature.
    
    Parameters:
    name - the name of the argument
    type - the type of the argument
    
    Returns:
    a new signature
  - prependArg
```
public Signature prependArg(String name,
                   Class type)
```
    Prepend an argument (name + type) to the signature.
    
    Parameters:
    name - the name of the argument
    type - the type of the argument
    
    Returns:
    a new signature
  - prependArgs
```
public Signature prependArgs(String[] names,
                    Class[] types)
```
    Prepend an argument (name + type) to the signature.
    
    Parameters:
    name - the name of the argument
    type - the type of the argument
    
    Returns:
    a new signature
  - insertArg
```
public Signature insertArg(int index,
                  String name,
                  Class type)
```
    Insert an argument (name + type) into the signature.
    
    Parameters:
    index - the index at which to insert
    name - the name of the new argument
    type - the type of the new argument
    
    Returns:
    a new signature
  - insertArg
```
public Signature insertArg(String beforeName,
                  String name,
                  Class type)
```
    Insert an argument (name + type) into the signature before the argument with the given name.
    
    Parameters:
    beforeName - the name of the argument before which to insert
    name - the name of the new argument
    type - the type of the new argument
    
    Returns:
    a new signature
  - insertArgs
```
public Signature insertArgs(int index,
                   String[] names,
                   Class... types)
```
    Insert arguments (names + types) into the signature.
    
    Parameters:
    index - the index at which to insert
    names - the names of the new arguments
    types - the types of the new arguments
    
    Returns:
    a new signature
  - insertArgs
```
public Signature insertArgs(String beforeName,
                   String[] names,
                   Class... types)
```
    Insert arguments (names + types) into the signature before the argument with the given name.
    
    Parameters:
    beforeName - the name of the argument before which to insert
    names - the names of the new arguments
    types - the types of the new arguments
    
    Returns:
  - dropArg
```
public Signature dropArg(String name)
```
    Drops the first argument with the given name.
    
    Parameters:
    name - the name of the argument to drop
    
    Returns:
    a new signature
  - dropArg
```
public Signature dropArg(int index)
```
    Drops the argument at the given index.
    
    Parameters:
    index - the index of the argument to drop
    
    Returns:
    a new signature
  - dropLast
```
public Signature dropLast()
```
    Drop the last argument from this signature.
    
    Returns:
    a new signature
  - dropFirst
```
public Signature dropFirst()
```
    Drop the first argument from this signature.
    
    Returns:
    a new signature
  - replaceArg
```
public Signature replaceArg(String oldName,
                   String newName,
                   Class newType)
```
    Replace the named argument with a new name and type.
    
    Parameters:
    oldName - the old name of the argument
    newName - the new name of the argument; can be the same as old
    oldName - the new type of the argument; can be the same as old
  - spread
```
public Signature spread(String[] names,
               Class... types)
```
    Spread the trailing [] argument into the given argument types
  - spread
```
public Signature spread(String... names)
```
    Spread the trailing [] argument into its component type assigning given names.
  - spread
```
public Signature spread(String baseName,
               int count)
```
    Spread the trailing [] argument into its component type assigning given names.
  - type
```
public java.lang.invoke.MethodType type()
```
    The current java.lang.invoke.MethodType for this Signature.
    
    Returns:
    the current method type
  - argNames
```
public String[] argNames()
```
    The current argument names for this signature.
    
    Returns:
    the current argument names
  - argName
```
public String argName(int index)
```
    Retrieve the name of the argument at the given index.
    
    Parameters:
    index - the index from which to get the argument name
    
    Returns:
    the argument name
  - argOffset
```
public int argOffset(String name)
```
    Retrieve the offset of the given argument name in this signature's arguments. If the argument name is not in the argument list, returns -1.
    
    Parameters:
    name - the argument name to search for
    
    Returns:
    the offset at which the argument name was found or -1
  - argOffsets
```
public int argOffsets(String pattern)
```
    Retrieve the offset of the given argument name in this signature's arguments. If the argument name is not in the argument list, returns -1.
    
    Parameters:
    name - the argument name to search for
    
    Returns:
    the offset at which the argument name was found or -1
  - firstArgName
```
public String firstArgName()
```
    Get the first argument name.
    
    Returns:
    the first argument name
  - lastArgName
```
public String lastArgName()
```
    Get the last argument name.
    
    Returns:
    the last argument name
  - argType
```
public Class argType(int index)
```
    Get the argument type at the given index.
    
    Parameters:
    index - the index from which to get the argument type
    
    Returns:
    the argument type
  - firstArgType
```
public Class firstArgType()
```
    Get the first argument type.
    
    Returns:
    the first argument type
  - lastArgType
```
public Class lastArgType()
```
    Get the last argument type.
    
    Returns:
    the last argument type
  - permute
```
public Signature permute(String... permuteArgs)
```
    Create a new signature containing the same return value as this one, but only the specified arguments.
    
    Parameters:
    permuteArgs - the names of the arguments to preserve
    
    Returns:
    the new signature
  - exclude
```
public Signature exclude(String... excludeArgs)
```
    Create a new signature containing the same return value as this one, but omitting the specified arguments. Blacklisting to #permute's whitelisting.
    
    Parameters:
    excludeArgs - the names of the arguments to exclude
    
    Returns:
    the new signature
  - permuteWith
```
public java.lang.invoke.MethodHandle permuteWith(java.lang.invoke.MethodHandle target,
                                        String... permuteArgs)
```
    Produce a method handle permuting the arguments in this signature using the given permute arguments and targeting the given java.lang.invoke.MethodHandle. Example:
```
 Signature sig = Signature.returning(String.class).appendArg("a", int.class).appendArg("b", int.class);
 MethodHandle handle = handleThatTakesOneInt();
 MethodHandle newHandle = sig.permuteTo(handle, "b");
 
```
    Parameters:
    target - the method handle to target
    permuteArgs - the arguments to permute
    
    Returns:
    a new handle that permutes appropriate positions based on the given permute args
  - permuteWith
```
public SmartHandle permuteWith(SmartHandle target)
```
    Produce a new SmartHandle by permuting this Signature's arguments to the Signature of a target SmartHandle. The new SmartHandle's signature will match this one, permuting those arguments and invoking the target handle.
    
    Parameters:
    target - the SmartHandle to use as a permutation target
    
    Returns:
    a new SmartHandle that permutes this Signature's args into a call to the target SmartHandle.
    See Also:
    permuteWith(java.lang.invoke.MethodHandle, java.lang.String[])
  - to
```
public int[] to(Signature other)
```
    Generate an array of argument offsets based on permuting this signature to the given signature.
    
    Parameters:
    other - the signature to target
    
    Returns:
    an array of argument offsets that will permute to the given signature
  - to
```
public int[] to(String... otherArgPatterns)
```
    Generate an array of argument offsets based on permuting this signature to the given signature. Repeats are permitted, and the patterns will be matched against actual argument names using regex matching.
    
    Parameters:
    otherArgPatterns - the argument name patterns to permute
    
    Returns:
    an array of argument offsets that will permute to the matching argument names

Class Signature

Method Summary

Methods inherited from class java.lang.Object

Method Detail

toString

returning

changeReturn

asFold

appendArg

appendArgs

prependArg

prependArgs

insertArg

insertArg

insertArgs

insertArgs

dropArg

dropArg

dropLast

dropFirst

replaceArg

spread

spread

spread

type

argNames

argName

argOffset

argOffsets

firstArgName

lastArgName

argType

firstArgType

lastArgType

permute

exclude

permuteWith

permuteWith

to

to