question: merges fields specified by a fieldmask from one message to another . concode_field_sep String FIELD_SEPARATOR_REGEX concode_elem_sep String FIELD_PATH_SEPARATOR concode_elem_sep String FIELD_PATH_SEPARATOR_REGEX concode_elem_sep boolean replaceMessageFields concode_elem_sep boolean replaceRepeatedFields concode_field_sep FieldMask fromStringList concode_elem_sep void setReplaceRepeatedFields concode_elem_sep boolean isValid concode_elem_sep boolean isValid concode_elem_sep boolean isValid concode_elem_sep boolean isValid concode_elem_sep FieldMask normalize concode_elem_sep FieldMask intersection concode_elem_sep boolean replaceMessageFields concode_elem_sep String toString concode_elem_sep FieldMask fromFieldNumbers concode_elem_sep FieldMask fromFieldNumbers concode_elem_sep FieldMask union concode_elem_sep void setReplaceMessageFields concode_elem_sep FieldMask fromString concode_elem_sep FieldMask fromString concode_elem_sep boolean replaceRepeatedFields
target: void function ( FieldMask arg0 , Message arg1 , Message . Builder arg2 , MergeOptions arg3 ) { new FieldMaskTree ( arg0 ) . merge ( arg1 , arg2 , arg3 ) ; }