I started writing a java. With that tiny base, a group of Java aficionados on the nethas gone on to create a reasonably functional replacement for Sun's Javalibraries called Classpath.
Visitthat home page for software downloads, including both tarballs and CVS. Do your due diligence. Mauve is a complementary projectto Classpath formed to create a free Java test suite.
This package will bothserve as a library regression test suite and test conformance to variousJava specification levels. This project is still very rough, but code isavailable by CVS from the home page. To use Getopt, create a Getopt object with a argv array passed to the main method, then call the getopt method in a loop.
It will return an int that contains the value of the option character parsed from the command line. When there are no more options to be parsed, it returns A command line option can be defined to take an argument. If an option has an argument, the value of that argument is stored in an instance variable called optarg, which can be accessed using the getOptarg method. If an option that requires an argument is found, but there is no argument present, then an error message is printed.
Normally getopt returns a '? If an invalid option is encountered, an error message is printed to the standard error and getopt returns a '? The value of the invalid option encountered is stored in the instance variable optopt which can be retrieved using the getOptopt method. To suppress the printing of error messages for this or any other error, set the value of the opterr instance variable to false using the setOpterr method. Between calls to getopt , the instance variable optind is used to keep track of where the object is in the parsing process.
After all options have been returned, optind is the index in argv of the first non-option argument. This variable can be accessed with the getOptind method.
Note that this object expects command line options to be passed in the traditional Unix manner. That is, proceeded by a '-' character. Multiple options can follow the '-'. For example '-abc' is equivalent to '-a -b -c'. If an option takes a required argument, the value of the argument can immediately follow the option character or be present in the next argv element. For example, '-cfoo' and '-c foo' both represent an option character of 'c' with an argument of 'foo' assuming c takes a required argument.
If an option takes an argument that is not required, then any argument must immediately follow the option character in the same argv element. For example, if c takes a non-required argument, then '-cfoo' represents option character 'c' with an argument of 'foo' while '-c foo' represents the option character 'c' with no argument, and a first non-option argv element of 'foo'.
The user can stop getopt from scanning any further into a command line by using the special argument '--' by itself. For example: '-a -- -d' would return an option character of 'a', then return -1 The '--' is discarded and '-d' is pointed to by optind as the first non-option argv element.
In this example, a new Getopt object is created with three params. The first param is the program name. This is for printing error messages in the form 'program: error message'. In the C version, this value is taken from argv[0], but in Java the program name is not passed in that element, thus the need for this parameter. The second param is the argument list that was passed to the main method.
The third param is the list of valid options. Each character represents a valid option. If the character is followed by a single colon, then that option has a required argument.
If the character is followed by two colons, then that option has an argument that is not required. Note in this example that the value returned from getopt is cast to a char prior to printing.
This is required in order to make the value display correctly as a character instead of an integer. If the first character in the option string is a colon, for example ':abc::d', then getopt will return a ':' instead of a '? This allows the caller to distinguish between invalid options and valid options that are simply incomplete. In the traditional Unix getopt , -1 is returned when the first non-option charcter is encountered.
In GNU getopt , the default behavior is to allow options to appear anywhere on the command line. The getopt method permutes the argument to make it appear to the caller that all options were at the beginning of the command line, and all non-options were at the end.
For example, calling getopt with command line args of '-a foo bar -d' returns options 'a' and 'd', then sets optind to point to 'foo'. The program would read the last two argv elements as 'foo' and 'bar', just as if the user had typed '-a -d foo bar'. The user can force getopt to stop scanning the command line with the special argument '--' by itself. Any elements occuring before the '--' are scanned and permuted as normal. Connect and share knowledge within a single location that is structured and easy to search.
I am looking for function which can return me pair of option and it corresponding value like getopt in c. A recent as of late command line parser with a lot of momentum and features is picocli.
Some older, popular ones are commons-cli quite old , args4j and JCommander. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 9 years, 5 months ago. Active 2 years, 1 month ago. Viewed 11k times. The getopt. For example, calling getopt with command line args. The program would read the last two argv elements as.
Any elements occuring before the. Any elements after the "--". For example,. The "--". The first is. Thus "-a foo bar -d" would return 'a' as an option and. The second is to. When a non-option element is ecountered,. When this "return in order" functionality. An example is "-a foo -b -- bar", which would return 'a', then. The difference between the two. To enable. Note that after determining the proper. These are preceeded by a "--" sequence and. Long options provide a more user-friendly. For example, in addition to a.
Required arguments can either be specified by placing an. In this case,. This form of entry is. This causes getopt to treat the name following the. The name can immediately. Option arguments are. If a string follows the.
Otherwise getopt returns. So it is permissible to abbreviate the option name to as. If the name can. Note that when an invalid long option is. These objects are created. If the flag field in the LongOpt object. The val. Note that since the. This can be the character of a short option. The method getLongind will return the. This takes a trailing boolean flag. If set to false, Getopt. If the first character of the option is a valid short option.
0コメント