org.apache.commons.discovery.tools

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:

  • 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

    static Properties
    getProperties()
    This is an expensive operation.
    static String
    getProperty(ClassLoader classLoader, String propertyName)
    Get value for property bound to the class loader.
    static String
    getProperty(ClassLoader classLoader, String propertyName, String dephault)
    Get value for property bound to the class loader.
    static String
    getProperty(String propertyName)
    Get value for property bound to the current thread context class loader.
    static String
    getProperty(String propertyName, String dephault)
    Get value for property bound to the current thread context class loader.
    static Enumeration
    propertyNames()
    Return list of all property names.
    static void
    setLog(Log _log)
    static void
    setProperties(Map newProperties)
    Set property values for Properties bound to the current thread context class loader.
    static void
    setProperties(Map newProperties, boolean isDefault)
    Set property values for Properties bound to the current thread context class loader.
    static void
    setProperty(String propertyName, String value)
    Set value for property bound to the current thread context class loader.
    static void
    setProperty(String propertyName, String value, boolean isDefault)
    Set value for property bound to the current thread context class loader.

    Method Details

    getProperties

    public static 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.

    getProperty

    public static String getProperty(ClassLoader classLoader,
                                     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 String getProperty(ClassLoader classLoader,
                                     String propertyName,
                                     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.

    getProperty

    public static String getProperty(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 String getProperty(String propertyName,
                                     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.

    propertyNames

    public static 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.

    setLog

    public static void setLog(Log _log)

    setProperties

    public static void setProperties(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(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.

    setProperty

    public static void setProperty(String propertyName,
                                   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(String propertyName,
                                   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.

    Copyright (c) 2002 - Apache Software Foundation