org.hd.d.pg2k.webSvr.exhibit
Class FilterBean

java.lang.Object
  org.hd.d.pg2k.webSvr.exhibit.AbstractFilterBean
      org.hd.d.pg2k.webSvr.exhibit.FilterBean

All Implemented Interfaces:

java.io.Serializable

public class FilterBean
extends AbstractFilterBean

Version of the filter/sorter (cache) JavaBean that returns selected/sorted items as a List. Other classes may find the simple select() methods useful and thus this is not final.

See Also:

Serialized Form

serialVersionUID

private static final long serialVersionUID

Unique Serialisation class ID generated by http://random.hd.org/.

See Also:

Constant Field Values

FilterBean

public FilterBean()

select

public java.util.List<Name.ExhibitFull> select(javax.servlet.ServletContext ctxt)
                                        throws java.io.IOException,
                                               java.lang.IllegalStateException

Get the results of applying this to the whole exhibit set given the context (the data source is found automagically); never null. The data source must already have been initialised for this to work.

The result is a set of full exhibit names as a private unsorted array.

This will only (re)compute its results if:

• there are no cached results, or,
• the exhibit hash has changed, or,
• this is a memory-sensitive cache that has been automatically cleared.

This never returns null.

Throws:

java.lang.IllegalStateException - if the filter has not been set

java.io.IOException

select

public java.util.List<Name.ExhibitFull> select(javax.servlet.ServletContext ctxt,
                                               java.util.List<Name.ExhibitFull> inputSet)
                                        throws java.io.IOException,
                                               java.lang.IllegalStateException

Get the results of applying this to the given exhibit set given the context (the data source is found automagically); never null. The data source must already have been initialised for this to work.

The result is a set of full exhibit names as an immutable RandomAccess List of Name.ExhibitFull values.

If the inputSet argument is null then the whole set of exhibits is used, else the supplied set is used.

This will only (re)compute its results if:

• there are no cached results, or,
• the exhibit hash has changed, or,
• the argument List is not the same one presented before (its hash has changed), or,
• this is a memory-sensitive cache that has been automatically cleared.

This never returns null.

Null names and names that do not represent items currently in the exhibit set are silently dropped.

Parameters:

inputSet - null, or a list of full exhibit names

Throws:

java.lang.IllegalStateException - if the filter has not been set

java.io.IOException

peek

public java.util.List<Name.ExhibitFull> peek(javax.servlet.ServletContext ctxt,
                                             java.util.List<Name.ExhibitFull> inputSet)
                                      throws java.io.IOException,
                                             java.lang.IllegalStateException

Returns the (immutable) exhibit list result of select() if the underlying data seems to be computed and cached and still valid, else null. Matches select(ctxt, inputSet) and filters from the provided exhibit set.

Does not force recomputation.

Throws:

java.io.IOException

java.lang.IllegalStateException

peek

public java.util.List<Name.ExhibitFull> peek(javax.servlet.ServletContext ctxt)
                                      throws java.io.IOException,
                                             java.lang.IllegalStateException

Returns the (immutable) exhibit list result of select() if the underlying data seems to be computed and cached and still valid, else null. Matches select(ctxt) and works on the entire exhibit set.

Does not force recomputation.

Throws:

java.io.IOException

java.lang.IllegalStateException