org.unix4j.util

Class Variables

java.lang.Object

org.unix4j.util.Variables

public class Variables
extends Object

Variables contains static utility methods related to variables or place holders used as Command arguments. Variables are represented as string of the form "{varname}", where varname refers to the name of the variable.

Method Summary

Modifier and Type	Method and Description
static String	encode(String varname) Returns the string encoding for a variable with the given name.
static String	encode(String varname, int index) Returns the string encoding for an indexed variable with the given name and index.
static boolean	isVariable(String expression) Returns true if the given expression represents an encoded variable.
static String	resolve(String expression, Map<String,String> variables) If expression represents an encoded variable, it is resolved using the values in the given map.

Methods inherited from class java.lang.Object

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

Method Detail

encode

public static String encode(String varname)

Returns the string encoding for a variable with the given name. The returned string has the form "{varname}". For instance, a variable named "hostname" would result in a string "{hostname}".

Parameters:

varname - the name of the variable

Returns:

the encoded variable, a string of the form "{varname}"

encode

public static String encode(String varname,
                            int index)

Returns the string encoding for an indexed variable with the given name and index. The returned string has the form "{varname[index]}". For instance, the second element of a variable named "args" would result in a string "{args[1]}".

Parameters:

varname - the name of the variable

index - the zero-based variable index

Returns:

the encoded variable, a string of the form "{varname[index]}"

isVariable

public static boolean isVariable(String expression)

Returns true if the given expression represents an encoded variable. A variable expression starts with "{" and ends with "}" as described for encode(String) and encode(String, int).

Parameters:

expression - the expression to be checked

Returns:

true if the expression represents a variable, that is, if it has the form "{varname}"

resolve

public static String resolve(String expression,
                             Map<String,String> variables)

If expression represents an encoded variable, it is resolved using the values in the given map. The key in the map must exactly match the encoded expression to be successfully resolved. If no value is found for the variable expression, an expression is thrown.

If the given expression does not represent a variable, it is returned unchanged.

Parameters:

expression - the expression to resolve

variables - the variable values with the encoded variable name as key

Returns:

the resolved variable if expression represents a variable, and the unchanged expression otherwise

Throws:

IllegalArgumentException - if expression represents a variable but no value for this variable is found in the given variables map