org.unix4j.unix.tail

Class TailArguments

java.lang.Object

org.unix4j.unix.tail.TailArguments

All Implemented Interfaces:

Arguments<TailArguments>

public final class TailArguments
extends Object
implements Arguments<TailArguments>

Arguments and options for the tail command.

Constructor Summary

Constructors

Constructor and Description
TailArguments() Constructor to use if no options are specified.
TailArguments(String... args) Constructor string arguments encoding options and arguments, possibly also containing variable expressions.
TailArguments(TailOptions options) Constructor with option set containing the selected command options.

Method Summary

Methods

Modifier and Type	Method and Description
String[]	getArgs() Returns the <args> operand value: String arguments defining the options and operands for the command.
long	getCount() Returns the <count> operand value: The last count lines of each input file are copied to standard output, starting from 1 (characters instead of lines if the -c option is specified, and offset from start instead of end with -s option).
File[]	getFiles() Returns the <files> operand value: The input files to be filtered; relative paths are not resolved (use the string paths argument to enable relative path resolving based on the current working directory).
TailArguments	getForContext(ExecutionContext context) Returns an arguments object for the given execution context with resolved variables if necessary and possible.
TailOptions	getOptions() Returns the options set containing the selected command options.
String[]	getPaths() Returns the <paths> operand value: Pathnames of the input files to be filtered; wildcards * and ? are supported; relative paths are resolved on the basis of the current working directory.
boolean	isArgsSet() Returns true if the <args> operand has been set.
boolean	isChars() Returns true if the --chars option is set.
boolean	isCountFromStart() Returns true if the --countFromStart option is set.
boolean	isCountSet() Returns true if the <count> operand has been set.
boolean	isFilesSet() Returns true if the <files> operand has been set.
boolean	isPathsSet() Returns true if the <paths> operand has been set.
boolean	isSuppressHeaders() Returns true if the --suppressHeaders option is set.
void	setCount(long count) Sets <count>: The last count lines of each input file are copied to standard output, starting from 1 (characters instead of lines if the -c option is specified, and offset from start instead of end with -s option).
void	setFiles(File... files) Sets <files>: The input files to be filtered; relative paths are not resolved (use the string paths argument to enable relative path resolving based on the current working directory).
void	setPaths(String... paths) Sets <paths>: Pathnames of the input files to be filtered; wildcards * and ? are supported; relative paths are resolved on the basis of the current working directory.
String	toString() Returns a string representation of the command arguments and options.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TailArguments

public TailArguments()

Constructor to use if no options are specified.

TailArguments

public TailArguments(TailOptions options)

Constructor with option set containing the selected command options.

Parameters:

options - the selected options

Throws:

NullPointerException - if the argument is null

TailArguments

public TailArguments(String... args)

Constructor string arguments encoding options and arguments, possibly also containing variable expressions.

Parameters:

args - string arguments for the command

Throws:

NullPointerException - if args is null

Method Detail

getOptions

public TailOptions getOptions()

Returns the options set containing the selected command options. Returns an empty options set if no option has been selected.

Returns:

set with the selected options

getForContext

public TailArguments getForContext(ExecutionContext context)

Description copied from interface: Arguments

Returns an arguments object for the given execution context with resolved variables if necessary and possible. If variables are defined in this arguments instance, a new arguments instance is created with values instead of variables for those variables that are defined in the specified context object. If this arguments instance uses no variables, this arguments instance is simply returned.

If variables are present, they are resolved if such a variable is defined in the VariableContext returned by context.getVariableContext(). Values are converted if necessary with the ValueConverters returned by context.getValueConverterFor(Class).

Specified by:

getForContext in interface Arguments<TailArguments>

Parameters:

context - the execution context providing access to variables and converters

Returns:

an arguments object with resolved variables where possible

getCount

public long getCount()

Returns the <count> operand value: The last count lines of each input file are copied to standard output, starting from 1 (characters instead of lines if the -c option is specified, and offset from start instead of end with -s option). Must be a non-negative integer or an exception is thrown. If count is greater than the number number of lines (characters) in the input, the application will not error and send the whole file to the output.

Returns:

the <count> operand value (variables are not resolved)

Throws:

IllegalStateException - if this operand has never been set

isCountSet

public boolean isCountSet()

Returns true if the <count> operand has been set.

Note that this method returns true even if null was passed to the setCount(long) method.

Returns:

true if the setter for the <count> operand has been called at least once

setCount

public void setCount(long count)

Sets <count>: The last count lines of each input file are copied to standard output, starting from 1 (characters instead of lines if the -c option is specified, and offset from start instead of end with -s option). Must be a non-negative integer or an exception is thrown. If count is greater than the number number of lines (characters) in the input, the application will not error and send the whole file to the output.

Parameters:

count - the value for the <count> operand

getPaths

public String[] getPaths()

Returns the <paths> operand value: Pathnames of the input files to be filtered; wildcards * and ? are supported; relative paths are resolved on the basis of the current working directory.

Returns:

the <paths> operand value (variables are not resolved)

Throws:

IllegalStateException - if this operand has never been set

isPathsSet

public boolean isPathsSet()

Returns true if the <paths> operand has been set.

Note that this method returns true even if null was passed to the setPaths(String[]) method.

Returns:

true if the setter for the <paths> operand has been called at least once

setPaths

public void setPaths(String... paths)

Sets <paths>: Pathnames of the input files to be filtered; wildcards * and ? are supported; relative paths are resolved on the basis of the current working directory.

Parameters:

paths - the value for the <paths> operand

getFiles

public File[] getFiles()

Returns the <files> operand value: The input files to be filtered; relative paths are not resolved (use the string paths argument to enable relative path resolving based on the current working directory).

Returns:

the <files> operand value (variables are not resolved)

Throws:

IllegalStateException - if this operand has never been set

isFilesSet

public boolean isFilesSet()

Returns true if the <files> operand has been set.

Note that this method returns true even if null was passed to the setFiles(java.io.File[]) method.

Returns:

true if the setter for the <files> operand has been called at least once

setFiles

public void setFiles(File... files)

Sets <files>: The input files to be filtered; relative paths are not resolved (use the string paths argument to enable relative path resolving based on the current working directory).

Parameters:

files - the value for the <files> operand

getArgs

public String[] getArgs()

Returns the <args> operand value: String arguments defining the options and operands for the command. Options can be specified by acronym (with a leading dash "-") or by long name (with two leading dashes "--"). Operands other than the default "--paths" operand have to be prefixed with the operand name (e.g. "--count" for a subsequent count operand value).

Returns:

the <args> operand value (variables are not resolved)

Throws:

IllegalStateException - if this operand has never been set

isArgsSet

public boolean isArgsSet()

Returns true if the <args> operand has been set.

Returns:

true if the setter for the <args> operand has been called at least once

isChars

public boolean isChars()

Returns true if the --chars option is set. The option is also known as -c option.

Description: The count argument is in units of characters instead of lines. Starts from 1 and includes line ending characters.

Returns:

true if the --chars or -c option is set

isSuppressHeaders

public boolean isSuppressHeaders()

Returns true if the --suppressHeaders option is set. The option is also known as -q option.

Description: Suppresses printing of headers when multiple files are being examined.

Returns:

true if the --suppressHeaders or -q option is set

isCountFromStart

public boolean isCountFromStart()

Returns true if the --countFromStart option is set. The option is also known as -s option.

Description: The count argument is relative to the beginning of the file instead of counting from the end of the file. For instance, tail -s 10 prints the lines starting from line 10; tail -s 1 prints the whole file.

Returns:

true if the --countFromStart or -s option is set

toString

public String toString()

Description copied from interface: Arguments

Returns a string representation of the command arguments and options.

Specified by:

toString in interface Arguments<TailArguments>

Overrides:

toString in class Object

Returns:

a string representation of the command arguments and options, such as "-matchString myString -ignoreCase"