Oracle插入或更新或抛出异常

There is a table 'EXAMPLE_TABLE' which contains two columns. The first column 'ID' store value '5555' and the second 'IS_EXIST' store char 1 byte '0'. How create a procedure which will do 'INSERT INTO' if this values doesn't exist, or 'UPDATE' if 'ID' the same as in a query and 'IS_EXIST' == 0, or throw some exception which will be handled in java if 'ID' the same and 'IS_EXIST' != 0. I considered the merge and primarily insert ways to resolve this problem.There is a table 'EXAMPLE_TABLE' which contains