sunlabs.brazil.properties

Class PropertiesList

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.

Version: 2.8

Author: Steve Drach <drach@sun.com>

See Also: java.util.Dictionary java.util.Hashtable java.util.Properties

Field Summary
static booleandebug
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
voidaddAfter(PropertiesList cursor)
Adds this PropertiesList object into a linked list following the object referenced by the cursor parameter.
voidaddBefore(PropertiesList cursor)
Adds this PropertiesList object into a linked list preceding the object referenced by the cursor parameter.
voidclear()
Invokes the same method on the wrapped Hashtable object.
Objectclone()
Invokes the same method on the wrapped Hashtable object.
booleancontains(Object value)
Invokes the same method on the wrapped Hashtable object.
booleancontainsKey(Object key)
Invokes the same method on the wrapped Hashtable object.
voiddump(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.
Enumerationelements()
Invokes the same method on the wrapped Dictionary object.
SetentrySet()
Invokes the same method on the wrapped Hashtable object.
booleanequals(Object o)
Invokes the same method on the wrapped Hashtable object.
Objectget(Object key)
Invokes the same method on the wrapped Dictionary object.
PropertiesListgetHead()
Returns the PropertiesList object that is the first object on the list of which this object is a member.
PropertiesListgetNext()
Returns the PropertiesList object that succedes this object on the list of which this object is a member.
PropertiesListgetPrior()
Returns the PropertiesList object that precedes this object on the list of which this object is a member.
StringgetProperty(String key)
Looks up key in the wrapped object.
StringgetProperty(String key, String defaultValue)
Uses getProperty(String) to look up the value associated with the key.
DictionarygetWrapped()
Returns the Dictionary object wrapped by this PropertiesList.
inthashCode()
Invokes the same method on the wrapped Hashtable object.
booleanisEmpty()
Invokes the same method on the wrapped Dictionary object.
booleanisTransient()
Sub-classes of PropertiesList can override this to mark themselves "transient", in which case addAfter will skip this list.
Enumerationkeys()
Invokes the same method on the wrapped Dictionary object.
SetkeySet()
Invokes the same method on the wrapped Hashtable object.
voidlist(PrintStream out)
Invokes the same method on the wrapped Properties object.
voidlist(PrintWriter out)
Invokes the same method on the wrapped Properties object.
voidload(InputStream in)
Invokes the same method on the wrapped Properties object.
EnumerationpropertyNames()
Invokes the same method on the wrapped Properties object.
EnumerationpropertyNames(String pattern)
Returns an Enumeration of property names that match a glob pattern.
Objectput(Object key, Object value)
Invokes the same method on the wrapped Dictionary object.
voidputAll(Map t)
Invokes the same method on the wrapped Hashtable object.
booleanremove()
Remove this object from the list in which it's a member.
Objectremove(Object key)
Invokes the same method on the wrapped Dictionary object.
booleanremoveProperty(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.
booleanremoveProperty(String key)
Remove the key and its associated value from the first properties object in the chain that contains this key.
voidsave(OutputStream out, String header)
Invokes the same method on the wrapped Properties object.
ObjectsetProperty(String key, String value)
Invokes the same method on the wrapped Properties object if it exists.
intsize()
Invokes the same method on the wrapped Dictionary object.
voidstore(OutputStream out, String header)
Invokes the same method on the wrapped Properties object.
StringtoString()
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.
Collectionvalues()
Invokes the same method on the wrapped Hashtable object.
PropertiesListwraps(Dictionary d)
Find the first PropertiesList object on the list of which this object is a member that wraps the Dictionary parameter.

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

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.

clear

public void clear()
Invokes the same method on the wrapped Hashtable object.

clone

public Object clone()
Invokes the same method on the wrapped Hashtable object.

contains

public boolean contains(Object value)
Invokes the same method on the wrapped Hashtable object.

containsKey

public boolean containsKey(Object key)
Invokes the same method on the wrapped Hashtable object.

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.

entrySet

public Set entrySet()
Invokes the same method on the wrapped Hashtable object.

equals

public boolean equals(Object o)
Invokes the same method on the wrapped Hashtable object.

get

public Object get(Object key)
Invokes the same method on the wrapped Dictionary object.

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.

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.

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.

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.

Parameters: key The key whose value is sought. defaultValue The default value.

Returns: The value or null.

getWrapped

public Dictionary getWrapped()
Returns the Dictionary object wrapped by this PropertiesList.

hashCode

public int hashCode()
Invokes the same method on the wrapped Hashtable object.

isEmpty

public boolean isEmpty()
Invokes the same method on the wrapped Dictionary object.

isTransient

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

keys

public Enumeration keys()
Invokes the same method on the wrapped Dictionary object.

keySet

public Set keySet()
Invokes the same method on the wrapped Hashtable object.

list

public void list(PrintStream out)
Invokes the same method on the wrapped Properties object.

list

public void list(PrintWriter out)
Invokes the same method on the wrapped Properties object.

load

public void load(InputStream in)
Invokes the same method on the wrapped Properties object.

propertyNames

public Enumeration propertyNames()
Invokes the same method on the wrapped Properties object.

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.

put

public Object put(Object key, Object value)
Invokes the same method on the wrapped Dictionary object.

putAll

public void putAll(Map t)
Invokes the same method on the wrapped Hashtable object.

remove

public boolean remove()
Remove this object from the list in which it's a member.

Returns: true.

remove

public Object remove(Object key)
Invokes the same method on the wrapped Dictionary object.

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.

save

public void save(OutputStream out, String header)
Invokes the same method on the wrapped Properties object.

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.

size

public int size()
Invokes the same method on the wrapped Dictionary object.

store

public void store(OutputStream out, String header)
Invokes the same method on the wrapped Properties object.

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.

Returns: String representation of this object.

values

public Collection values()
Invokes the same method on the wrapped Hashtable 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.