public class POSIXCommandLine extends CommandLine
-" character
- (e.g., -nek)
-f path1,path2,path3).
cat -u x y,
x and y are operands.)
-- signals the end of options. All
remaining words on the command line are operands
-" should mean standard input or output.
POSIXCommandLine does not enforce the alphanumeric property
of option characters, nor that options with arguments must be alone
on a line (-nekfpath vs. -nek
-fpath). POSIXCommandLine also recognizes the common
style of using a -? option to get command usage;
nothing prevents you from adding your own option for this purpose.
POSIXCommandLine does not aid in splitting up multiple
arguments to one option; java.util.StringTokenizer does
this quite well enough.
To use POSIXCommandLine, create a POSIXCommandLine
object with the array of strings you wish to parse (typically the
array passed to the utility's main method), and then
consume options from it, providing default values in case the option
is not specified by the user. When you have consumed all the
options, you invoke the POSIXCommandLine object's
getOperands method to return the remaining operands on
the command line. If -- is specified it is neither an
option nor an operand, just a separator between the two lists. The
CommandLine.BadInvocationException is used to signal
errors in the construction of the strings, that is, a user error,
such as specifying a option that takes an argument but forgetting to
provide that argument. See the documentation for
POSIXCommandLine.main for an example.
You must call getOperands for proper behavior, even if
you do not use any operands in your command. getOperands
checks for several user errors, including unknown options. If you
do not expect to use operands, you should check the return value of
getOperands and complain if any are specified.
You must consume (check for) all options that take arguments before
you consume any boolean (no-argument) option. Further, no options
can be consumed after getOperands is invoked. Each
option character may be used only once. Failure to follow these
rule is a programmer error that will result in a
CommandLine.ProgrammingException.
POSIXCommandLine provides you several methods to get input
streams from the command line. If these do not suffice for your
particular needs, you can get the argument as a String
and do your own processing.
StringTokenizerCommandLine.BadInvocationException, CommandLine.HelpOnlyException, CommandLine.ProgrammingException| Constructor and Description |
|---|
POSIXCommandLine(String[] args)
Create a new
CommandLine object that will return
specified options, arguments, and operands. |
POSIXCommandLine(String prog,
String[] args)
Create a new
CommandLine object that will return
specified options, arguments, and operands. |
| Modifier and Type | Method and Description |
|---|---|
boolean |
getBoolean(char opt)
Return
true if the given option is specified on the
command line. |
double |
getDouble(char opt,
double defaultValue)
Return the value of the given
double from the command line. |
InputStream |
getInputStream(char opt,
InputStream defaultValue)
Return a
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option. |
InputStream |
getInputStream(char opt,
String path)
Return a
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option. |
int |
getInt(char opt,
int defaultValue)
Return the argument of the given
int option from
the command line. |
long |
getLong(char opt,
long defaultValue)
Return the argument of the given
long option from
the command line. |
String[] |
getOperands()
Return the command line operands that come after the options.
|
OutputStream |
getOutputStream(char opt,
OutputStream defaultValue)
Return a
OutputStream that is the result of creating a new
FileOutputStream object for the file named by the given
option. |
OutputStream |
getOutputStream(char opt,
String path)
Return a
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option. |
RandomAccessFile |
getRandomAccessFile(char opt,
RandomAccessFile defaultValue,
String mode)
Return a
RandomAccessFile that is the result of
creating a new RandomAccessFile object for the file
named by the given option, using the given mode. |
RandomAccessFile |
getRandomAccessFile(char opt,
String path,
String mode)
Return a
RandomAccessFile that is the result of
creating a new RandomAccessFile object for the file
named by the given option, using the given mode. |
Reader |
getReader(char opt,
Reader defaultValue)
Return a
Reader that is the result of creating a new
FileReader object for the file named by the given
option. |
Reader |
getReader(char opt,
String path)
Return a
Reader that is the result of creating a new
FileReader object for the file named by the given
option. |
String |
getString(char opt,
String defaultValue)
Return the argument of the given string option from the command
line.
|
Writer |
getWriter(char opt,
String path)
Return a
Writer that is the result of creating a new
FileWriter object for the file named by the given
option. |
Writer |
getWriter(char opt,
Writer defaultValue)
Return a
Writer that is the result of creating a new
FileWriter object for the file named by the given
option. |
void |
usage()
Print out a summary of the commands usage, inferred from the
requested options.
|
parseDouble, parseInputStream, parseInputStream, parseInt, parseLong, parseOutputStream, parseOutputStream, parseRandomAccessFile, parseRandomAccessFile, parseReader, parseReader, parseString, parseWriter, parseWriterpublic POSIXCommandLine(String[] args)
CommandLine object that will return
specified options, arguments, and operands.public boolean getBoolean(char opt)
true if the given option is specified on the
command line.public String getString(char opt, String defaultValue) throws CommandLine.BadInvocationException
defaultValue.public int getInt(char opt,
int defaultValue)
throws CommandLine.BadInvocationException,
NumberFormatException
int option from
the command line. If the option is not specified, return
defaultValue.public long getLong(char opt,
long defaultValue)
throws CommandLine.BadInvocationException,
NumberFormatException
long option from
the command line. If the option is not specified, return
defaultValue.public double getDouble(char opt,
double defaultValue)
throws CommandLine.BadInvocationException,
NumberFormatException
double from the command line.
If the option is not specified, return defaultValue.public Writer getWriter(char opt, Writer defaultValue) throws IOException, CommandLine.BadInvocationException
Writer that is the result of creating a new
FileWriter object for the file named by the given
option.
If the option is not specified, return defaultValue.public Writer getWriter(char opt, String path) throws IOException, CommandLine.BadInvocationException
Writer that is the result of creating a new
FileWriter object for the file named by the given
option.
If the option is not specified, the string path is used
as the file name.public Reader getReader(char opt, Reader defaultValue) throws IOException, CommandLine.BadInvocationException
Reader that is the result of creating a new
FileReader object for the file named by the given
option.
If the option is not specified, return defaultValue.public Reader getReader(char opt, String path) throws IOException, CommandLine.BadInvocationException
Reader that is the result of creating a new
FileReader object for the file named by the given
option.
If the option is not specified, the string path is used
as the file name.public OutputStream getOutputStream(char opt, OutputStream defaultValue) throws IOException, CommandLine.BadInvocationException
OutputStream that is the result of creating a new
FileOutputStream object for the file named by the given
option. If the argument is - then
System.out is returned.
If the option is not specified, return defaultValue.public OutputStream getOutputStream(char opt, String path) throws IOException, CommandLine.BadInvocationException
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option.
If the option is not specified, the string path is used
as the file name.public InputStream getInputStream(char opt, InputStream defaultValue) throws IOException, CommandLine.BadInvocationException
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option.
If the option is not specified, return defaultValue.public InputStream getInputStream(char opt, String path) throws IOException, CommandLine.BadInvocationException
InputStream that is the result of creating a new
FileInputStream object for the file named by the given
option.
If the option is not specified, the string path is used
as the file name.public RandomAccessFile getRandomAccessFile(char opt, RandomAccessFile defaultValue, String mode) throws IOException, CommandLine.BadInvocationException
RandomAccessFile that is the result of
creating a new RandomAccessFile object for the file
named by the given option, using the given mode.
If the option is not specified, return defaultValue.public RandomAccessFile getRandomAccessFile(char opt, String path, String mode) throws IOException, CommandLine.BadInvocationException
RandomAccessFile that is the result of
creating a new RandomAccessFile object for the file
named by the given option, using the given mode.
If the option is not specified, the string path is used
as the file name.public String[] getOperands() throws CommandLine.BadInvocationException, CommandLine.HelpOnlyException
This is also where -? is handled. If the user
specifies -? then the method usage is
invoked and HelpOnlyException is thrown. The
program is expected to catch this exception and simply exit
successfully.
CommandLine.BadInvocationExceptionCommandLine.HelpOnlyExceptionusage()public void usage()
getOperands
has been (or is being) called. Adds ... for
operands.getOperands()Copyright © 2016–2018. All rights reserved.