uk.ac.ed.epcc.safe.accounting.policy

Class AliasPropertyPolicy

java.lang.Object

uk.ac.ed.epcc.safe.accounting.update.AbstractPropertyContainerUpdater

uk.ac.ed.epcc.safe.accounting.policy.BasePolicy

uk.ac.ed.epcc.safe.accounting.policy.AliasPropertyPolicy

All Implemented Interfaces:

PropertyContainerPolicy, PropertyContainerUpdater

public class AliasPropertyPolicy
extends BasePolicy

This policy establishes aliases for properties already in scope. The alias can be as simple as one property is equal to another, or can involve complicated property expressions . This is under the control of java properties of the form

alias.table-name. name=prop-expression

Where name must be the name of a property currently in scope. The scope is defined as the properties that can be found in the PropertyFinder provided during initialisation (in the initFinder(uk.ac.ed.epcc.webapp.AppContext, uk.ac.ed.epcc.safe.accounting.properties.PropertyFinder, java.lang.String) method) as well as all properties present in the base and batch property registers located in BaseParser and BatchParser respectively.

Note that this allows the definition to be different for different accounting tables. Care needs to be taken to ensure that these different definitions are compatible if a UsageManager is going to be used.

Author:

jgreen4

Constructor Summary

Constructors

Constructor and Description
AliasPropertyPolicy()

Method Summary

Methods

Modifier and Type	Method and Description
PropExpressionMap	getDerivedProperties(PropExpressionMap previous) return a set of derived property definitions.
PropertyFinder	initFinder(uk.ac.ed.epcc.webapp.AppContext ctx, PropertyFinder origFinder, java.lang.String table) Generate a PropertyFinder that will find any PropertyTag generated by this class.

Methods inherited from class uk.ac.ed.epcc.safe.accounting.policy.BasePolicy

parse

Methods inherited from class uk.ac.ed.epcc.safe.accounting.update.AbstractPropertyContainerUpdater

endParse, modifyDefaultTableSpecification, startParse, unique

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface uk.ac.ed.epcc.safe.accounting.update.PropertyContainerUpdater

endParse, modifyDefaultTableSpecification, startParse

Constructor Detail

AliasPropertyPolicy

public AliasPropertyPolicy()

Method Detail

initFinder

public PropertyFinder initFinder(uk.ac.ed.epcc.webapp.AppContext ctx,
                        PropertyFinder origFinder,
                        java.lang.String table)

Description copied from interface: PropertyContainerUpdater

Generate a PropertyFinder that will find any PropertyTag generated by this class. This call should be treated as a secondary constructor and should be called before any other method from this interface.

All properties defined at run-time should have their PropertyTag objects constructed by the time the first call to this method returns. As some parsers properties will generate different things depending on the other properties already in scope this method is passed a PropertyFinder for any properties that may already be in scope. This will include any default parameters specified when the data was uploaded and any properties generated from the database meta-data. Though it is perfectly legal to return a PropertyFinder that returns a superset of the generated properties the only requirement is that the returned finder can find any property that this classes parse method may actually generate values for. So Normally the contents of the super-finder are not included in the result unless these values are actually generated by the parse. If values are generated then a MultiFinder can be populated with the PropertyRegistrys from the generated properties

origFinder - PropertyFinder for the higher levels in the call chain.

table - String name of the destination table in case per-table customisation is needed

Returns:

PropertyFinder or null

getDerivedProperties

public PropExpressionMap getDerivedProperties(PropExpressionMap previous)

Description copied from interface: PropertyContainerUpdater

return a set of derived property definitions. Each derived property is defined in terms of a simple expression over other properties (that may themselves be derived properties).

Definitions are allowed for properties that are also generated directly in the parse phase. In this case the parse value should always be used by preference and the derived definition only provides a fall-back implementation if the parse value is unavailable. For example if not persisted in the database layer. This allows one parser/policy to specify a default implementation as a derived property definition which is then overridden by having the same property generated in a parse method of a different policy/parser

Specified by:

getDerivedProperties in interface PropertyContainerUpdater

Overrides:

getDerivedProperties in class AbstractPropertyContainerUpdater

Parameters:

previous - Previous definitions

Returns:

Map modified map