atg.process.filter
Class Filter

java.lang.Object
  atg.process.filter.Filter

Direct Known Subclasses:

ExpressionFilter

public abstract class Filter
extends java.lang.Object

An abstract base class for all process filters.

Field Summary

static java.lang.String	CLASS_VERSION Class version string
static Filter	FALSE Filter which represents false
static Filter	TRUE Filter which represents true

Constructor Summary

Filter()
Construct a new Filter.

Method Summary

static Filter	andFilters(Filter[] pFilters) Returns a filter which is obtained by ANDing the filters in the given array.
static Filter	andFilters(Filter pFilter1, Filter pFilter2) Returns a filter which is obtained by ANDing the two given filters.
Filter	assumeFalse(Filter pFalseFilter) Assumes that the given filter evaluates to FALSE, and tries to simplify this filter.
Filter	assumeTrue(Filter pTrueFilter) Assumes that the given filter evaluates to TRUE, and tries to simplify this filter.
Query	createProcessInstanceQuery(QueryBuilder pSubjectQueryBuilder, QueryBuilder pProcessInstanceQueryBuilder) Creates a repository query which can be used to find all the individual process instances that satisfy the filter.
Query	createSubjectQuery(QueryBuilder pSubjectQueryBuilder) Creates a repository query which can be used to find all the subjects that satisfy the filter.
protected abstract Filter	evaluate(ProcessExecutionContext pContext) Evaluates this filter in the given process execution context.
protected static java.util.ResourceBundle	getResourceBundle() Returns our resource bundle.
java.lang.String	getSubjectType() If this filter has subject-related conditions any of which assume a particular subject type, returns that type.
int	hashCode() Returns the hash code.
boolean	implies(Filter pFilter) Returns true if this filter implies the given filter - that is, if this filter evaluates to TRUE, the given filter must also evaluate to TRUE.
boolean	isCacheable() Returns true if the result of evaluating this filter should be cached, false otherwise.
Filter	negate() Returns a filter which is obtained by negating this filter.
static Filter	orFilters(Filter[] pFilters) Returns a filter which is obtained by ORing the filters in the given array.
static Filter	orFilters(Filter pFilter1, Filter pFilter2) Returns a filter which is obtained by ORing the two given filters.
void	setCacheable(boolean pCacheable) Sets the flag indicating whether the result of evaluating this filter should be cached.
Filter	test(ProcessExecutionContext pContext) Calls evaluate on this filter, and returns one of the following values: Filter.TRUE - if evaluate returned Filter.TRUE Filter.FALSE - if evaluate returned Filter.FALSE or null this or another, simplified, Filter - in all other cases

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_VERSION

public static java.lang.String CLASS_VERSION

Class version string

TRUE

public static final Filter TRUE

Filter which represents true

FALSE

public static final Filter FALSE

Filter which represents false

Constructor Detail

Filter

public Filter()

Construct a new Filter.

Method Detail

getResourceBundle

protected static java.util.ResourceBundle getResourceBundle()

Returns our resource bundle.

isCacheable

public boolean isCacheable()

Returns true if the result of evaluating this filter should be cached, false otherwise.

setCacheable

public void setCacheable(boolean pCacheable)

Sets the flag indicating whether the result of evaluating this filter should be cached. The default is false.

evaluate

protected abstract Filter evaluate(ProcessExecutionContext pContext)
                            throws ProcessException

Evaluates this filter in the given process execution context. The context may not yet contain all of the information necessary to evaluate the filter - specifically, it may be missing the particular process instance and/or subject that the process is being executed on. If that is the case, the filter is evaluated as much as possible, and the simplified filter is returned.

The possible return values of this method are as follows:

• Filter.TRUE - if the filter can be fully evaluated, and is satisfied in the given context
• Filter.FALSE - if the filter can be fully evaluated, and is not satisfied in the given context
• this or another, simplified, Filter - if the filter cannot be fully evaluated because of the missing information in the context
• null - if the filter cannot be evaluated because of a null expression encountered during evaluation (e.g., filter refers to a subject property which evaluates to null)

Throws:

ProcessException - if there is a problem evaluating the filter (other than information missing from the context)

test

public Filter test(ProcessExecutionContext pContext)
            throws ProcessException

Calls evaluate on this filter, and returns one of the following values:

• Filter.TRUE - if evaluate returned Filter.TRUE
• Filter.FALSE - if evaluate returned Filter.FALSE or null
• this or another, simplified, Filter - in all other cases

In other words, this method is different from evaluate only in that null values are treated instead as Filter.FALSE.

Throws:

ProcessException - if there is a problem evaluating the filter (other than information missing from the context)

getSubjectType

public java.lang.String getSubjectType()
                                throws ProcessException

If this filter has subject-related conditions any of which assume a particular subject type, returns that type. If the filter has no subject-related conditions, or if all such conditions apply to the base subject type, returns null.

The default implementation returns null.

Throws:

ProcessException - if there is a problem determining the subject type

createSubjectQuery

public Query createSubjectQuery(QueryBuilder pSubjectQueryBuilder)
                         throws RepositoryException,
                                ProcessException

Creates a repository query which can be used to find all the subjects that satisfy the filter. Returns null if no subjects can satisfy this filter.

This method will only be called on filters which have already been evaluated (by calling evaluate). Thus, the only subclasses which need to override this method are those which have conditions that contribute to the repository query (i.e., subject-related conditions). The default implementation throws a ProcessException.

Throws:

RepositoryException - if there is a repository problem constructing the query

ProcessException - if there is any other problem creating the query

createProcessInstanceQuery

public Query createProcessInstanceQuery(QueryBuilder pSubjectQueryBuilder,
                                        QueryBuilder pProcessInstanceQueryBuilder)
                                 throws RepositoryException,
                                        ProcessException

Creates a repository query which can be used to find all the individual process instances that satisfy the filter. Returns null if no process instances can satisfy this filter.

This method will only be called on filters which have already been evaluated (by calling evaluate). Thus, the only subclasses which need to override this method are those which have conditions that contribute to the repository query (i.e., subject- or process instance-related conditions). The default implementation throws a ProcessException.

Throws:

RepositoryException - if there is a repository problem constructing the query

ProcessException - if there is any other problem creating the query

andFilters

public static Filter andFilters(Filter pFilter1,
                                Filter pFilter2)

Returns a filter which is obtained by ANDing the two given filters.

andFilters

public static Filter andFilters(Filter[] pFilters)

Returns a filter which is obtained by ANDing the filters in the given array.

orFilters

public static Filter orFilters(Filter pFilter1,
                               Filter pFilter2)

Returns a filter which is obtained by ORing the two given filters.

orFilters

public static Filter orFilters(Filter[] pFilters)

Returns a filter which is obtained by ORing the filters in the given array.

negate

public Filter negate()

Returns a filter which is obtained by negating this filter.

assumeTrue

public Filter assumeTrue(Filter pTrueFilter)

Assumes that the given filter evaluates to TRUE, and tries to simplify this filter.

assumeFalse

public Filter assumeFalse(Filter pFalseFilter)

Assumes that the given filter evaluates to FALSE, and tries to simplify this filter.

implies

public boolean implies(Filter pFilter)

Returns true if this filter implies the given filter - that is, if this filter evaluates to TRUE, the given filter must also evaluate to TRUE. For example, this returns true if this filter is "(gender=Male)&(age=Young)" and the given filter is "age=Young."

hashCode

public int hashCode()

Returns the hash code.

Overrides:

hashCode in class java.lang.Object