org.apache.ambari.server.state.kerberos

Class VariableReplacementHelper

java.lang.Object

org.apache.ambari.server.state.kerberos.VariableReplacementHelper

public class VariableReplacementHelper
extends Object

Helper class to provide variable replacement services

Constructor Summary

Constructors

Constructor and Description
VariableReplacementHelper()

Method Summary

Modifier and Type	Method and Description
String	replaceVariables(String value, Map<String,Map<String,String>> replacementsMap) Performs variable replacement on the supplied String value using values from the replacementsMap.

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableReplacementHelper

public VariableReplacementHelper()

Method Detail

replaceVariables

public String replaceVariables(String value,
                               Map<String,Map<String,String>> replacementsMap)
                        throws org.apache.ambari.server.AmbariException

Performs variable replacement on the supplied String value using values from the replacementsMap.

The value is a String containing one or more "variables" in the form of ${variable_name}, such that "variable_name" may indicate a group identifier; else "" is used as the group. For example:

variable_name: group: ""; property: "variable_name" group1/variable_name: group: "group1"; property: "variable_name" root/group1/variable_name: Not Supported

The replacementsMap is a Map of Maps creating a (small) hierarchy of data to traverse in order to resolve the variable.

If a variable resolves to one or more variables, that new variable(s) will be processed and replaced. If variable exists after a set number of iterations it is assumed that a cycle has been created and the process will abort returning a String in a possibly unexpected state.

Parameters:

value - a String containing zero or more variables to be replaced

replacementsMap - a Map of data used to perform the variable replacements

Returns:

a new String

Throws:

org.apache.ambari.server.AmbariException