Class ReferenceResolver


  • public class ReferenceResolver
    extends Object
    Resolves Module references. They can be
    • Module configuration property to Rule Configuration property
    • Module configuration property to Composite Module configuration property
    • Module inputs to Composite Module inputs
    • Module inputs to Composite Module Configuration
    Module 'A' Configuration properties can have references to either CompositeModule Configuration properties or Rule Configuration properties depending where Module 'A' is placed.
    Note. If Module 'A' is child of CompositeModule - it cannot have direct configuration references to the Rule that is holding the CompositeModule.
    • Single reference configuration value where whole configuration property value is replaced(if found) with the referenced value
      'configurationProperty': '${singleReference}'
    • Complex reference configuration value where only reference parts are replaced in the whole configuration property value.
      'configurationProperty': '{key1: ${complexReference1}, key2: ${complexReference2}'
    Given Module 'A' is child of CompositeModule then its inputs can have '${singleReferences}' to CompositeModule.
    • Single reference to CompositeModule inputs where whole input value is replaced with the referenced value
      'childInput' : '${compositeModuleInput}'
    • Single reference to CompositeModule configuration where whole input value is replaced with the referenced value
      'childInput' : '${compositeModuleConfiguration}'
    Author:
    Vasil Ilchev - Initial contribution, Ana Dimova - new reference syntax: list[index], map["key"], bean.field
    • Constructor Detail

      • ReferenceResolver

        public ReferenceResolver()
    • Method Detail

      • updateConfiguration

        public static void updateConfiguration​(Configuration config,
                                               Map<String,​?> context,
                                               org.slf4j.Logger logger)
        Updates (changes) configuration properties of module base on given context (it can be CompositeModule Configuration or Rule Configuration). For example: 1) If a module configuration property has a value '${name}' the method looks for such key in context and if found - replace the module's configuration value as it is. 2) If a module configuration property has complex value 'Hello ${firstName} ${lastName}' the method tries to parse it and replace (if values are found) referenced parts in module's configuration value. Will try to find values for ${firstName} and ${lastName} in the given context and replace them. References that are not found in the context - are not replaced.
        Parameters:
        module - module that is directly part of Rule or part of CompositeModule
        context - containing Rule configuration or Composite configuration values.
      • getCompositeChildContext

        public static Map<String,​Object> getCompositeChildContext​(Module module,
                                                                        Map<String,​?> compositeContext)
        Resolves Composite child module's references to CompositeModule context (inputs and configuration).
        Parameters:
        module - Composite Module's child module.
        compositeContext - Composite Module's context
        Returns:
        context for given module ready for execution.
      • resolveReference

        public static Object resolveReference​(String reference,
                                              Map<String,​?> context)
        Resolves single reference '${singleReference}' from given context.
        Parameters:
        reference - single reference expression for resolving
        context - contains the values that will be used for reference resolving
        Returns:
        resolved value.
      • getNextRefToken

        public static int getNextRefToken​(String ref,
                                          int startIndex)
        Gets the end of current token of reference path.
        Parameters:
        ref - reference path used to access value in bean or map objects
        startIndex - starting point to check for next tokens
        Returns:
        end of current token.
      • splitReferenceToTokens

        public static String[] splitReferenceToTokens​(String reference)
                                               throws IllegalArgumentException
        Splits a given reference to tokens.
        The reference must have the following syntax: list[index], map["key"], bean.field.
        It is possible to chain references in one bigger expression. For example: list[1].name.values.
        Parameters:
        reference - the reference that should be split
        Returns:
        array of the tokens in the reference
        Throws:
        IllegalArgumentException
      • resolveComplexDataReference

        public static Object resolveComplexDataReference​(Object object,
                                                         String... tokens)
                                                  throws IllegalArgumentException,
                                                         SecurityException
        Gets an object by given hierarchical path of tokens.
        Parameters:
        object - bean, map or list
        tokens - a sequence of field names, indexes, or keys that represent the hierarchical path to the required object
        Returns:
        the value of the object to witch the hierarchical path is pointing.
        Throws:
        IllegalArgumentException - if one of the tokens point to field that is not existing or the object is null
        SecurityException - If a security manager, s, is present and any of the following conditions is met:
        • the caller's class loader is not the same as the class loader of this class and invocation of s.checkPermission method with RuntimePermission("accessDeclaredMembers") denies access to the declared field
        • the caller's class loader is not the same as or an ancestor of the class loader for the current class and invocation of s.checkPackageAccess() denies access to the package of this class
        ArrayIndexOutOfBoundsException - if one of the tokens represent a invalid index in the list.
        NullPointerException - if the path references something in a non existing map entry.
        NumberFormatException - if one of the tokens is accessing a list and the token that represent the index can't be converted to integer.