org.mmbase.storage.util
Class Scheme

java.lang.Object
  java.text.Format
      java.text.MessageFormat
          org.mmbase.storage.util.Scheme

All Implemented Interfaces:

java.lang.Cloneable, java.io.Serializable

public final class Scheme

extends java.text.MessageFormat

This is a specialised version of the MessageFormat class, with some awareness of MMBase objects. You can pass MMBase objects to Scheme when formatting a pattern. The Scheme automatically resolves the object to a value it can use in the pattern. Schemes are used by the storage to create configurable storage instructions (specifically database SQL code).

Version:

$Id: Scheme.java,v 1.2 2003/08/29 12:12:26 keesj Exp $

Author:

Pierre van Rooden

See Also:

Serialized Form

Nested Class Summary

Nested classes inherited from class java.text.MessageFormat

java.text.MessageFormat.Field

Constructor Summary

Scheme(StorageManagerFactory factory, java.lang.String pattern)
Instantiate the Scheme

Method Summary

java.lang.String	format(java.lang.Object[] params) Applies the parameters to the scheme's pattern.
protected java.lang.Object	resolveParameter(java.lang.Object param) Resolves an object (passed as a parameter) to a value that can be applied in a pattern.
java.lang.String	toString()

Methods inherited from class java.text.MessageFormat

applyPattern, clone, equals, format, format, format, formatToCharacterIterator, getFormats, getFormatsByArgumentIndex, getLocale, hashCode, parse, parse, parseObject, setFormat, setFormatByArgumentIndex, setFormats, setFormatsByArgumentIndex, setLocale, toPattern

Methods inherited from class java.text.Format

format, parseObject

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Scheme

public Scheme(StorageManagerFactory factory,
              java.lang.String pattern)

Instantiate the Scheme

Parameters:

factory - The factory this scheme belongs to.

pattern - The pattern to use for the scheme

Method Detail

resolveParameter

protected java.lang.Object resolveParameter(java.lang.Object param)
                                     throws StorageException

Resolves an object (passed as a parameter) to a value that can be applied in a pattern. It returns:

• For MMBase: the object storage element identifier as a String (fully expanded table name)
• For MMObjectBuilder: the builder storage element identifier as a String (fully expanded table name)
• For MMObjectNode: the object number as an Integer
• For FieldDefs: a storage-compatible field name as a String (if no such name exists a StorageException is thrown)

Other object types are returned as is, leaving them to be handled by MessageFormat's formatting code.

Parameters:

param - the object to resolve

Returns:

the resolved value

Throws:

StorageException - if the object cannot be resolved

To Do:

MMBase, FieldDefs, MMObjectNode, and MMObjectBuilder should be enriched with a Storable interface, which can be used instead

format

public java.lang.String format(java.lang.Object[] params)
                        throws StorageException

Applies the parameters to the scheme's pattern.

Parameters:

params - an array of parameters to apply to the pattern

Returns:

the result scheme as a String

Throws:

StorageException - if one of the passed parameters cannot be resolved

toString

public java.lang.String toString()