Class ManagedProperties


  • public class ManagedProperties
    extends java.lang.Object

    This class may disappear in the future, or be moved to another project..

    Extend the concept of System properties to a hierarchical scheme based around class loaders. System properties are global in nature, so using them easily violates sound architectural and design principles for maintaining separation between components and runtime environments. Nevertheless, there is a need for properties broader in scope than class or class instance scope.

    This class is one solution.

    Manage properties according to a secure scheme similar to that used by classloaders:

    • ClassLoaders are organized in a tree hierarchy.
    • each ClassLoader has a reference to a parent ClassLoader.
    • the root of the tree is the bootstrap ClassLoaderer.
    • the youngest decendent is the thread context class loader.
    • properties are bound to a ClassLoader instance
      • non-default properties bound to a parent ClassLoader instance take precedence over all properties of the same name bound to any decendent. Just to confuse the issue, this is the default case.
      • default properties bound to a parent ClassLoader instance may be overriden by (default or non-default) properties of the same name bound to any decendent.
    • System properties take precedence over all other properties

    This is not a perfect solution, as it is possible that different ClassLoaders load different instances of ScopedProperties. The 'higher' this class is loaded within the ClassLoader hierarchy, the more usefull it will be.

    Author:
    Richard A. Sitze
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.util.Properties getProperties()
      This is an expensive operation.
      static java.lang.String getProperty​(java.lang.ClassLoader classLoader, java.lang.String propertyName)
      Get value for property bound to the class loader.
      static java.lang.String getProperty​(java.lang.ClassLoader classLoader, java.lang.String propertyName, java.lang.String dephault)
      Get value for property bound to the class loader.
      static java.lang.String getProperty​(java.lang.String propertyName)
      Get value for property bound to the current thread context class loader.
      static java.lang.String getProperty​(java.lang.String propertyName, java.lang.String dephault)
      Get value for property bound to the current thread context class loader.
      static java.util.Enumeration propertyNames()
      Return list of all property names.
      static void setLog​(org.apache.commons.logging.Log _log)  
      static void setProperties​(java.util.Map newProperties)
      Set property values for Properties bound to the current thread context class loader.
      static void setProperties​(java.util.Map newProperties, boolean isDefault)
      Set property values for Properties bound to the current thread context class loader.
      static void setProperty​(java.lang.String propertyName, java.lang.String value)
      Set value for property bound to the current thread context class loader.
      static void setProperty​(java.lang.String propertyName, java.lang.String value, boolean isDefault)
      Set value for property bound to the current thread context class loader.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ManagedProperties

        public ManagedProperties()
    • Method Detail

      • setLog

        public static void setLog​(org.apache.commons.logging.Log _log)
      • getProperty

        public static java.lang.String getProperty​(java.lang.String propertyName)
        Get value for property bound to the current thread context class loader.
        Parameters:
        propertyName - property name.
        Returns:
        property value if found, otherwise default.
      • getProperty

        public static java.lang.String getProperty​(java.lang.String propertyName,
                                                   java.lang.String dephault)
        Get value for property bound to the current thread context class loader. If not found, then return default.
        Parameters:
        propertyName - property name.
        dephault - default value.
        Returns:
        property value if found, otherwise default.
      • getProperty

        public static java.lang.String getProperty​(java.lang.ClassLoader classLoader,
                                                   java.lang.String propertyName)
        Get value for property bound to the class loader.
        Parameters:
        classLoader -
        propertyName - property name.
        Returns:
        property value if found, otherwise default.
      • getProperty

        public static java.lang.String getProperty​(java.lang.ClassLoader classLoader,
                                                   java.lang.String propertyName,
                                                   java.lang.String dephault)
        Get value for property bound to the class loader. If not found, then return default.
        Parameters:
        classLoader -
        propertyName - property name.
        dephault - default value.
        Returns:
        property value if found, otherwise default.
      • setProperty

        public static void setProperty​(java.lang.String propertyName,
                                       java.lang.String value)
        Set value for property bound to the current thread context class loader.
        Parameters:
        propertyName - property name
        value - property value (non-default) If null, remove the property.
      • setProperty

        public static void setProperty​(java.lang.String propertyName,
                                       java.lang.String value,
                                       boolean isDefault)
        Set value for property bound to the current thread context class loader.
        Parameters:
        propertyName - property name
        value - property value. If null, remove the property.
        isDefault - determines if property is default or not. A non-default property cannot be overriden. A default property can be overriden by a property (default or non-default) of the same name bound to a decendent class loader.
      • setProperties

        public static void setProperties​(java.util.Map newProperties)
        Set property values for Properties bound to the current thread context class loader.
        Parameters:
        newProperties - name/value pairs to be bound
      • setProperties

        public static void setProperties​(java.util.Map newProperties,
                                         boolean isDefault)
        Set property values for Properties bound to the current thread context class loader.
        Parameters:
        newProperties - name/value pairs to be bound
        isDefault - determines if properties are default or not. A non-default property cannot be overriden. A default property can be overriden by a property (default or non-default) of the same name bound to a decendent class loader.
      • propertyNames

        public static java.util.Enumeration propertyNames()
        Return list of all property names. This is an expensive operation: ON EACH CALL it walks through all property lists associated with the current context class loader upto and including the bootstrap class loader.
      • getProperties

        public static java.util.Properties getProperties()
        This is an expensive operation. ON EACH CALL it walks through all property lists associated with the current context class loader upto and including the bootstrap class loader.
        Returns:
        Returns a java.util.Properties instance that is equivalent to the current state of the scoped properties, in that getProperty() will return the same value. However, this is a copy, so setProperty on the returned value will not effect the scoped properties.