sunlabs.brazil.properties
Class PropertiesList

java.lang.Object
  java.util.Dictionary
      java.util.Hashtable
          java.util.Properties
              sunlabs.brazil.properties.PropertiesList (view source)

All Implemented Interfaces:

Serializable, Cloneable, Map

public class PropertiesList
extends Properties

A PropertiesList instance is intended to be an element of a doubly linked list consisting of other PropertiesList instances. Each PropertiesList instance "wraps" a Dictionary object. A PropertiesList is a subclass of Properties and therefore provides the same API, including the methods and fields of Dictionary and Hashtable. The PropertiesList class overrides all methods of the Properties API and delegates the method evaluation to the wrapped Properties object.

The linked list of PropertiesList objects is constructed by Request for each incoming request. That is, there is a unique PropertiesList linked list for each request. The head of the initial list constructed by request is Request.props and the tail of the two element list is Request.serverProps. The former wraps an empty Properties object, while the latter wraps Server.props. Other PropertiesList objects can be added, and removed, from this initial list as required.

Given a reference to a PropertiesList object on the linked list (e.g. request.props), one typically "looks up" the value associated with a name using the getProperty method, which delegates to the wrapped Properties.getProperty method. If the result is null, meaning the name/value pair is not stored in the wrapped Properties object, the request is "forwarded" to the next object on the linked list, and so on until either the name/value pair is found (and the value is returned) or the end of the list is reached (and null is returned).

It may be desirable for the name/value lookup to be delayed until after the lookup request has been passed on to subsequent objects on the list. This can be done by using the two parameter constructor and setting the second, boolean, parameter to true. Then the getProperty request is forwarded to the next object in the list rather than delegated to the wrapped Properties object. If the result of the forwarded request is null, the request is then passed to the wrapped Properties object and it's result is returned.

See Also:

Dictionary, Hashtable, Properties, Serialized Form

Field Summary

static boolean

debug Set true to turn on debug output.

Constructor Summary

PropertiesList()
Constructs a new PropertiesList object that wraps an empty new Properties object.

PropertiesList(Dictionary dict)
Constructs a new PropertiesList object that wraps the input Dictionary.

PropertiesList(Dictionary dict, boolean searchNextFirst)
Constructs a new PropertiesList object that wraps the input Dictionary.

Method Summary

void	addAfter(PropertiesList cursor) Adds this PropertiesList object into a linked list following the object referenced by the cursor parameter.
void	addBefore(PropertiesList cursor) Adds this PropertiesList object into a linked list preceding the object referenced by the cursor parameter.
void	clear() Invokes the same method on the wrapped Hashtable object.
Object	clone() Invokes the same method on the wrapped Hashtable object.
boolean	contains(Object value) Invokes the same method on the wrapped Hashtable object.
boolean	containsKey(Object key) Invokes the same method on the wrapped Hashtable object.
void	dump(boolean full, String msg) Starting with this object, print the contents of this and succeeding objects that are on the same list as this object is.
Enumeration	elements() Invokes the same method on the wrapped Dictionary object.
Set	entrySet() Invokes the same method on the wrapped Hashtable object.
boolean	equals(Object o) Invokes the same method on the wrapped Hashtable object.
Object	get(Object key) Invokes the same method on the wrapped Dictionary object.
PropertiesList	getHead() Returns the PropertiesList object that is the first object on the list of which this object is a member.
PropertiesList	getNext() Returns the PropertiesList object that succedes this object on the list of which this object is a member.
PropertiesList	getPrior() Returns the PropertiesList object that precedes this object on the list of which this object is a member.
String	getProperty(String key) Looks up key in the wrapped object.
String	getProperty(String key, String defaultValue) Uses getProperty(String) to look up the value associated with the key.
Dictionary	getWrapped() Returns the Dictionary object wrapped by this PropertiesList.
int	hashCode() Invokes the same method on the wrapped Hashtable object.
boolean	isEmpty() Invokes the same method on the wrapped Dictionary object.
boolean	isTransient() Sub-classes of PropertiesList can override this to mark themselves "transient", in which case addAfter will skip this list.
Enumeration	keys() Invokes the same method on the wrapped Dictionary object.
Set	keySet() Invokes the same method on the wrapped Hashtable object.
void	list(PrintStream out) Invokes the same method on the wrapped Properties object.
void	list(PrintWriter out) Invokes the same method on the wrapped Properties object.
void	load(InputStream in) Invokes the same method on the wrapped Properties object.
Enumeration	propertyNames() Invokes the same method on the wrapped Properties object.
Enumeration	propertyNames(String pattern) Returns an Enumeration of property names that match a glob pattern.
Object	put(Object key, Object value) Invokes the same method on the wrapped Dictionary object.
void	putAll(Map t) Invokes the same method on the wrapped Hashtable object.
boolean	remove() Remove this object from the list in which it's a member.
Object	remove(Object key) Invokes the same method on the wrapped Dictionary object.
boolean	removeProperty(String key) Remove the key and its associated value from the first properties object in the chain that contains this key.
boolean	removeProperty(String key, boolean all) Remove a property from a a chain of properties lists.
void	save(OutputStream out, String header) Invokes the same method on the wrapped Properties object.
Object	setProperty(String key, String value) Invokes the same method on the wrapped Properties object if it exists.
int	size() Invokes the same method on the wrapped Dictionary object.
void	store(OutputStream out, String header) Invokes the same method on the wrapped Properties object.
String	toString() Returns a String containing the System.identityHashCodes of this object, the wrapped object, and the preceding and succeding objects on the list of which this object is a member.
Collection	values() Invokes the same method on the wrapped Hashtable object.
PropertiesList	wraps(Dictionary d) Find the first PropertiesList object on the list of which this object is a member that wraps the Dictionary parameter.

Methods inherited from class java.util.Properties

load, loadFromXML, store, storeToXML, storeToXML, stringPropertyNames

Methods inherited from class java.util.Hashtable

containsValue

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

debug

public static boolean debug

Set true to turn on debug output. It's alot of output and probably of use only to the author. Note, if server.props contains the name debugProps this variable will be set true by Server.

Constructor Detail

PropertiesList

public PropertiesList()

Constructs a new PropertiesList object that wraps an empty new Properties object.

PropertiesList

public PropertiesList(Dictionary dict)

Constructs a new PropertiesList object that wraps the input Dictionary.

Parameters:

dict - The Dictionary object wrapped by this PropertiesList.

PropertiesList

public PropertiesList(Dictionary dict,
                      boolean searchNextFirst)

Constructs a new PropertiesList object that wraps the input Dictionary. If the boolean parameter is set true, the wrapped Dictionary is searched after subsequent PropertiesList objects in the linked list are searched, and only if the result of that search was null.

Parameters:

dict - The Dictionary object wrapped by this PropertiesList.

searchNextFirst - If true all the following objects in the list are searched before this one.

Method Detail

getWrapped

public Dictionary getWrapped()

Returns the Dictionary object wrapped by this PropertiesList.

addAfter

public void addAfter(PropertiesList cursor)

Adds this PropertiesList object into a linked list following the object referenced by the cursor parameter. The result is a list that could look like: request.props -> cursor -> this -> serverProps

Any transient properties lists's are skipped over before this one is inserted into the list

Parameters:

cursor - The list object that will precede this object.

addBefore

public void addBefore(PropertiesList cursor)

Adds this PropertiesList object into a linked list preceding the object referenced by the cursor parameter. The result is a list that could look like: request.props -> this -> cursor -> serverProps

Parameters:

cursor - The list object that will succede this object.

remove

public boolean remove()

Remove this object from the list in which it's a member.

Returns:

true.

getNext

public PropertiesList getNext()

Returns the PropertiesList object that succedes this object on the list of which this object is a member.

Returns:

A PropertiesList object or null.

getPrior

public PropertiesList getPrior()

Returns the PropertiesList object that precedes this object on the list of which this object is a member.

Returns:

A PropertiesList object or null.

getHead

public PropertiesList getHead()

Returns the PropertiesList object that is the first object on the list of which this object is a member. Note that the first object may be this object.

Returns:

A PropertiesList object.

wraps

public PropertiesList wraps(Dictionary d)

Find the first PropertiesList object on the list of which this object is a member that wraps the Dictionary parameter.

Parameters:

d - The Dictionary that is compared with the wrapped Dictionary's for a match.

Returns:

PropertiesList object that wraps the input parameter, otherwise null.

dump

public void dump(boolean full,
                 String msg)

Starting with this object, print the contents of this and succeeding objects that are on the same list as this object is.

Parameters:

full - If true also print the contents of the wrapped Dictionary object.

msg - If not null, add this message to the header line.

elements

public Enumeration elements()

Invokes the same method on the wrapped Dictionary object.

Overrides:

elements in class Hashtable

get

public Object get(Object key)

Invokes the same method on the wrapped Dictionary object.

Specified by:

get in interface Map

Overrides:

get in class Hashtable

isEmpty

public boolean isEmpty()

Invokes the same method on the wrapped Dictionary object.

Specified by:

isEmpty in interface Map

Overrides:

isEmpty in class Hashtable

keys

public Enumeration keys()

Invokes the same method on the wrapped Dictionary object.

Overrides:

keys in class Hashtable

put

public Object put(Object key,
                  Object value)

Invokes the same method on the wrapped Dictionary object.

Specified by:

put in interface Map

Overrides:

put in class Hashtable

remove

public Object remove(Object key)

Invokes the same method on the wrapped Dictionary object.

Specified by:

remove in interface Map

Overrides:

remove in class Hashtable

size

public int size()

Invokes the same method on the wrapped Dictionary object.

Specified by:

size in interface Map

Overrides:

size in class Hashtable

clear

public void clear()

Invokes the same method on the wrapped Hashtable object.

Specified by:

clear in interface Map

Overrides:

clear in class Hashtable

clone

public Object clone()

Invokes the same method on the wrapped Hashtable object.

Overrides:

clone in class Hashtable

contains

public boolean contains(Object value)

Invokes the same method on the wrapped Hashtable object.

Overrides:

contains in class Hashtable

containsKey

public boolean containsKey(Object key)

Invokes the same method on the wrapped Hashtable object.

Specified by:

containsKey in interface Map

Overrides:

containsKey in class Hashtable

entrySet

public Set entrySet()

Invokes the same method on the wrapped Hashtable object.

Specified by:

entrySet in interface Map

Overrides:

entrySet in class Hashtable

equals

public boolean equals(Object o)

Invokes the same method on the wrapped Hashtable object.

Specified by:

equals in interface Map

Overrides:

equals in class Hashtable

hashCode

public int hashCode()

Invokes the same method on the wrapped Hashtable object.

Specified by:

hashCode in interface Map

Overrides:

hashCode in class Hashtable

keySet

public Set keySet()

Invokes the same method on the wrapped Hashtable object.

Specified by:

keySet in interface Map

Overrides:

keySet in class Hashtable

putAll

public void putAll(Map t)

Invokes the same method on the wrapped Hashtable object.

Specified by:

putAll in interface Map

Overrides:

putAll in class Hashtable

values

public Collection values()

Invokes the same method on the wrapped Hashtable object.

Specified by:

values in interface Map

Overrides:

values in class Hashtable

toString

public String toString()

Returns a String containing the System.identityHashCodes of this object, the wrapped object, and the preceding and succeding objects on the list of which this object is a member. Additionally, if debug is true, the result of invoking toString on the wrapped Dictionary is appended.

Overrides:

toString in class Hashtable

Returns:

String representation of this object.

getProperty

public String getProperty(String key)

Looks up key in the wrapped object. If the result is null the request is forwarded to the succeeding object in the list of which this object is a member. If the search order was changed by constructing this object with the two parameter constructor, the request is first forwarded and then, if the result of the forwarded request is null, the key is looked up in the wrapped Properties object.

Overrides:

getProperty in class Properties

Parameters:

key - The key whose value is sought.

Returns:

The value or null.

getProperty

public String getProperty(String key,
                          String defaultValue)

Uses getProperty(String) to look up the value associated with the key. If the result is null, returns the default value.

Overrides:

getProperty in class Properties

Parameters:

key - The key whose value is sought.

defaultValue - The default value.

Returns:

The value or null.

removeProperty

public boolean removeProperty(String key,
                              boolean all)

Remove a property from a a chain of properties lists. if "all" is specified, then remove all the keys and values from all property lists in the chain instead of just the first one found.

Parameters:

key - The key whose value is to be removed

all - remove all matching keys.

Returns:

true, if at least one key/value pair was removed.

removeProperty

public boolean removeProperty(String key)

Remove the key and its associated value from the first properties object in the chain that contains this key.

Returns:

true, if the key was removed.

list

public void list(PrintStream out)

Invokes the same method on the wrapped Properties object.

Overrides:

list in class Properties

list

public void list(PrintWriter out)

Invokes the same method on the wrapped Properties object.

Overrides:

list in class Properties

load

public void load(InputStream in)
          throws IOException

Invokes the same method on the wrapped Properties object.

Overrides:

load in class Properties

Throws:

IOException

propertyNames

public Enumeration propertyNames()

Invokes the same method on the wrapped Properties object.

Overrides:

propertyNames in class Properties

save

public void save(OutputStream out,
                 String header)

Invokes the same method on the wrapped Properties object.

Overrides:

save in class Properties

setProperty

public Object setProperty(String key,
                          String value)

Invokes the same method on the wrapped Properties object if it exists. Otherwise invokes put on the wrapped Dictionary object.

Overrides:

setProperty in class Properties

store

public void store(OutputStream out,
                  String header)
           throws IOException

Invokes the same method on the wrapped Properties object.

Overrides:

store in class Properties

Throws:

IOException

propertyNames

public Enumeration propertyNames(String pattern)

Returns an Enumeration of property names that match a glob pattern.

Parameters:

pattern - The glob pattern to match.

Returns:

An Enumeration containing matching property names, if any.

isTransient

public boolean isTransient()

Sub-classes of PropertiesList can override this to mark themselves "transient", in which case addAfter will skip this list.