I try to create list of column names based on sql file in groovy using the following funtion:

def get_column_names() {
        def create_sql = new File("../create.sql").text.replaceAll("\n", '')
        def result = (create_sql =~ /\(.*?\);/).findAll().first().replace('(', '').split(',')
        return result.stream().map({ x -> x.split(' ')[0] }).toList()
    }

Here is an example of create.sql file :

CREATE TABLE test_table (
id varchar(5) PRIMARY KEY,
created BIGINT,
company TEXT,
income FLOAT,
percent FLOAT
);

but after executing I get the following error:

java.util.NoSuchElementException: Cannot access first() element from an empty List

Othersides when I try to execute the same in groovy console, where I use sql as a string I get correct list:

def create_sql = """

CREATE TABLE test_table (
id varchar(5) PRIMARY KEY,
created BIGINT,
company TEXT,
income FLOAT,
percent FLOAT
);
"""

def create_sql1 = create_sql.replaceAll("\n", '')
def result = (create_sql1 =~ /\(.*?\);/).findAll().first().replace('(', '').split(',')
def result1= result.stream().map({ x -> x.split(' ')[0] }).toList()

Result: [id, created, company, income, percent]

Any idea what is wrong with the function or how to extract list of columns from file on other way?

CodePudding user response：

It may be that the file was created in Windows, where newlines are typically \r\n. If that's the case, maybe you can try to match \r also:

def create_sql = "\r\n\r\nCREATE TABLE test_table (\r\n\r\nid varchar(5) PRIMARY KEY,\r\ncreated BIGINT,\r\ncompany TEXT,\r\nincome FLOAT,\r\npercent FLOAT\r\n);"

def create_sql1 = create_sql.replaceAll("[\r\n] ", '')
def result = (create_sql1 =~ /\(.*?\);/).findAll().first().replace('(', '').split(',')
def result1= result.stream().map({ x -> x.split(' ')[0] }).toList()
println(result1) //[id, created, company, income, percent]