Class ManagedProperties
- java.lang.Object
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- org.apache.commons.discovery.tools.ManagedProperties
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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 parentClassLoader
. - 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.
- non-default properties bound to a parent
- 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 ofScopedProperties
. The 'higher' this class is loaded within theClassLoader
hierarchy, the more usefull it will be.- Author:
- Richard A. Sitze
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Constructor Summary
Constructors Constructor Description ManagedProperties()
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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 forProperties
bound to the current thread context class loader.static void
setProperties(java.util.Map newProperties, boolean isDefault)
Set property values forProperties
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.
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Method Detail
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setLog
public static void setLog(org.apache.commons.logging.Log _log)
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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.
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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.
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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.
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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.
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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 namevalue
- property value (non-default) If null, remove the property.
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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 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.
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setProperties
public static void setProperties(java.util.Map newProperties)
Set property values forProperties
bound to the current thread context class loader.- Parameters:
newProperties
- name/value pairs to be bound
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setProperties
public static void setProperties(java.util.Map newProperties, boolean isDefault)
Set property values forProperties
bound to the current thread context class loader.- Parameters:
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.
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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.
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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.
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