create an interface for calculating hash values
create a default hash calculator
change the type of a field in AbstractCrdCreator
change the type of the argument in hash calculator from string to astnode
create a class for detecting code fragments and crd from a given ast
add a constant that represents the interval for monitoring thread
create classes for detecting code fragments with multiple threads
implement a function to detect code fragments with single thread
add a field for CRDRegistererA
implement a function to call the function to detect code fragments from the main functionality
[bug fix] add a null-check
[minor change] reformatting
[bug fix] a mismatch between the real number of columns in the table of fragments and the specified value was fixed
[bug fix] a bug was fixed that the number of elements that are registered at the final step in CodeFragmentIdentifier was not counted
[bug fix] the endless loop was fixed