org.apache.commons.discovery.tools
Class ManagedProperties
java.lang.Object
org.apache.commons.discovery.tools.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:
ClassLoader
s are organized in a tree hierarchy.- each
ClassLoader
has a reference
to a parent ClassLoader
. - the root of the tree is the bootstrap
ClassLoader
er. - 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
ClassLoader
s load different instances of
ScopedProperties
. The 'higher' this class is loaded
within the
ClassLoader
hierarchy, the more usefull
it will be.
static Properties | getProperties() - This is an expensive operation.
|
static String | getProperty(ClassLoader classLoader, String propertyName) - Get value for property bound to the class loader.
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static String | getProperty(ClassLoader classLoader, String propertyName, String dephault) - Get value for property bound to the class loader.
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static String | getProperty(String propertyName) - Get value for property bound to the current thread context class loader.
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static String | getProperty(String propertyName, String dephault) - Get value for property bound to the current thread context class loader.
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static Enumeration | propertyNames() - Return list of all property names.
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static void | setLog(Log _log)
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static void | setProperties(Map newProperties) - Set property values for
Properties bound to the
current thread context class loader.
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static void | setProperties(Map newProperties, boolean isDefault) - Set property values for
Properties bound to the
current thread context class loader.
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static void | setProperty(String propertyName, String value) - Set value for property bound to the current thread context class loader.
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static void | setProperty(String propertyName, String value, boolean isDefault) - Set value for property bound to the current thread context class loader.
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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 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.
classLoader
- propertyName
- property name.
- 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.
classLoader
- propertyName
- property name.dephault
- default value.
- 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.
propertyName
- property name.
- 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.
propertyName
- property name.dephault
- default value.
- 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.
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.
newProperties
- name/value pairs to be boundisDefault
- 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.
propertyName
- property namevalue
- 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.
propertyName
- property namevalue
- 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