org.codehaus.groovy.runtime

## Class MethodRankHelper

- java.lang.Object
- - org.codehaus.groovy.runtime.MethodRankHelper

    public class MethodRankHelper
    extends Object

Utility class for MissingMethodException, MissingPropertyException etc. This class contains methods assisting in ranking and listing probable intended methods/fields when a exception is thrown.

Author:
  Hjalmar Ekengren

### Field Summary

Fields
`static int` `DL_CASE`
`static int` `DL_DELETE`
`static int` `DL_SUBSTITUTION`
`static int` `DL_TRANSPOSITION`
`static int` `MAX_CONSTRUCTOR_SCORE`
`static int` `MAX_FIELD_SCORE`
`static int` `MAX_METHOD_SCORE`
`static int` `MAX_RECOMENDATIONS`

### Constructor Summary

Constructors
Constructor and Description
`MethodRankHelper()`

### Method Summary

Methods
`protected static Class` `boxVar(Class c)` If c is a primitive class this method returns a boxed version otherwise c is returned.
`static int` `damerauLevenshteinDistance(Object[] s, Object[] t)` This is a implementation of DL distance between two Object arrays instead of character streams.
`static int` `delDistance(CharSequence s, CharSequence t)` This is a slightly modified version of the Damerau Levenshtein distance algorithm.
`static String` `getConstructorSuggestionString(Class type, Object[] arguments)` Returns a string detailing possible solutions to a missing constructor if no good solutions can be found a empty string is returned.
`static String` `getMethodSuggestionString(String methodName, Class type, Object[] arguments)` Returns a string detailing possible solutions to a missing method if no good solutions can be found a empty string is returned.
`static String` `getPropertySuggestionString(String fieldName, Class type)` Returns a string detailing possible solutions to a missing field or property if no good solutions can be found a empty string is returned.

### Methods inherited from class java.lang.Object

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

### Field Detail

#### DL_SUBSTITUTION

    public static final int DL_SUBSTITUTION

See Also:
  Constant Field Values

#### DL_DELETE

    public static final int DL_DELETE

See Also:
  Constant Field Values

#### DL_TRANSPOSITION

    public static final int DL_TRANSPOSITION

See Also:
  Constant Field Values

#### DL_CASE

    public static final int DL_CASE

See Also:
  Constant Field Values

#### MAX_RECOMENDATIONS

    public static final int MAX_RECOMENDATIONS

See Also:
  Constant Field Values

#### MAX_METHOD_SCORE

    public static final int MAX_METHOD_SCORE

See Also:
  Constant Field Values

#### MAX_CONSTRUCTOR_SCORE

    public static final int MAX_CONSTRUCTOR_SCORE

See Also:
  Constant Field Values

#### MAX_FIELD_SCORE

    public static final int MAX_FIELD_SCORE

See Also:
  Constant Field Values

### Constructor Detail

#### MethodRankHelper

    public MethodRankHelper()

### Method Detail

#### getMethodSuggestionString

    public static String getMethodSuggestionString(String methodName,
                                   Class type,
                                   Object[] arguments)

Returns a string detailing possible solutions to a missing method if no good solutions can be found a empty string is returned.

Parameters:
  `methodName` - the name of the method that doesn't exist
  `type` - the class on which the method is invoked
  `arguments` - the arguments passed to the method
Returns:
  a string with probable solutions to the exception

#### getConstructorSuggestionString

    public static String getConstructorSuggestionString(Class type,
                                        Object[] arguments)

Returns a string detailing possible solutions to a missing constructor if no good solutions can be found a empty string is returned.

Parameters:
  `arguments` - the arguments passed to the constructor
  `type` - the class on which the constructor is invoked
Returns:
  a string with probable solutions to the exception

#### getPropertySuggestionString

    public static String getPropertySuggestionString(String fieldName,
                                     Class type)

Returns a string detailing possible solutions to a missing field or property if no good solutions can be found a empty string is returned.

Parameters:
  `fieldName` - the missing field
  `type` - the class on which the field is sought
Returns:
  a string with probable solutions to the exception

#### boxVar

    protected static Class boxVar(Class c)

If c is a primitive class this method returns a boxed version otherwise c is returned. In java 1.5 this can be simplified thanks to the Type class.

Parameters:
  `c` -
Returns:
  a boxed version of c if c can be boxed, else c

#### delDistance

    public static int delDistance(CharSequence s,
                  CharSequence t)

This is a slightly modified version of the Damerau Levenshtein distance algorithm. It has a additional test to see if a charackter has switched case, in the original algorithm this counts as a substitution. The "cost" for a substitution is given as 10 instead of 1 in this version, this enables transpositions and case modifications to have a lower cost than substitutions. Currently the lowercase versions of t_j and s_i isnt cached, its probable that some speed could be gained from this. This version is based on Chas Emerick's implementation of Lenenshtein Distance for jakarta commons.

Parameters:
  `s` - a CharSequence
  `t` - the CharSequence to be compared to s
Returns:
  a value representing the edit distance between s and t

#### damerauLevenshteinDistance

    public static int damerauLevenshteinDistance(Object[] s,
                                 Object[] t)

This is a implementation of DL distance between two Object arrays instead of character streams. The objects are compared using their equals method. No objects may be null. This implementation is based on Chas Emerick's implementation of Levenshtein Distance for jakarta commons.

Parameters:
  `s` - a Object array
  `t` - this array is compared to s
Returns:
  the edit distance between the two arrays