com.townleyenterprises.filter
Class QueryFilter

java.lang.Object
  com.townleyenterprises.common.PropertyProxy
      com.townleyenterprises.filter.QueryFilter

All Implemented Interfaces:

Filter, java.io.Serializable

Direct Known Subclasses:

StringFilter

public class QueryFilter

extends PropertyProxy

implements Filter, java.io.Serializable

This class provides an implementation of the Query Object design pattern for the filtering mechanism which may be used for lazy evaluation of the filter criteria. This class is the basis for using Filters with database systems as they can be easily translated into SQL.

Since:

2.0

Version:

$Id: QueryFilter.java,v 1.7 2004/11/28 20:12:52 atownley Exp $

Author:

Andrew S. Townley

See Also:

Serialized Form

Constructor Summary

QueryFilter(java.lang.Class klass, java.lang.String property, QueryOperator op, java.lang.Comparable val)
The constructor initializes the query filter.

Method Summary

boolean	doFilter(java.lang.Object o) This method actually performs the operation that will determine if the parameter object should be included in the "result" or not.
QueryOperator	getOperator()
protected java.lang.String	getOperatorString() This method may be overridden by custom query filter instances to return a string which describes the test they are performing if it is not one of the standard operators.
java.lang.String	getProperty()
java.lang.Comparable	getValue()
java.lang.String	toString()

Methods inherited from class com.townleyenterprises.common.PropertyProxy

getPropertyValue, getSubjectClass

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryFilter

public QueryFilter(java.lang.Class klass,
                   java.lang.String property,
                   QueryOperator op,
                   java.lang.Comparable val)

The constructor initializes the query filter. Each QueryFilter is fixed once it is constructed.

Parameters:

klass - the class of the object to be filtered

property - the property name based on the object being queried

op - the QueryOperator to be used

val - the Comparable to be used for comparison (must

Method Detail

doFilter

public boolean doFilter(java.lang.Object o)

Description copied from interface: Filter

This method actually performs the operation that will determine if the parameter object should be included in the "result" or not.

Specified by:

doFilter in interface Filter

Parameters:

o - the object to be tested

Returns:

true if the object should be included in the result; false if the object should not

getProperty

public java.lang.String getProperty()

getOperator

public QueryOperator getOperator()

getValue

public java.lang.Comparable getValue()

toString

public java.lang.String toString()

getOperatorString

protected java.lang.String getOperatorString()

This method may be overridden by custom query filter instances to return a string which describes the test they are performing if it is not one of the standard operators.

Returns:

the operator string