Package org.apache.poi.hpsf
Processes streams in the Horrible Property Set Format (HPSF) in POI filesystems. Microsoft Office documents, i.e. POI filesystems, usually contain meta data like author, title, last saving time etc. These items are called properties and stored in property set streams along with the document itself. These streams are commonly named \005SummaryInformation and \005DocumentSummaryInformation. However, a POI filesystem may contain further property sets of other names or types.
In order to extract the properties from a POI filesystem, a property set
stream's contents must be parsed into a PropertySet
instance. Its subclasses SummaryInformation
and DocumentSummaryInformation
deal with the well-known
property set streams \005SummaryInformation and
\005DocumentSummaryInformation. (However, the streams' names are
irrelevant. What counts is the property set's first section's format ID -
see below.)
The factory method PropertySetFactory.create(org.apache.poi.poifs.filesystem.DirectoryEntry, java.lang.String)
creates a PropertySet
instance. This method
always returns the most specific property set: If it
identifies the stream data as a Summary Information or as a Document
Summary Information it returns an instance of the corresponding class, else
the general PropertySet
.
A PropertySet
contains a list of Section
s which can be retrieved with PropertySet.getSections()
. Each Section
contains a Property
array which can be retrieved with Section.getProperties()
. Since the vast majority of
PropertySet
s contains only a single Section
, the convenience method PropertySet.getProperties()
returns the properties of a
PropertySet
's Section
(throwing a NoSingleSectionException
if the PropertySet
contains more (or less) than exactly one
Section
).
Each Property
has an ID, a
type, and a value which can be retrieved
with Property.getID()
, Property.getType()
, and Property.getValue()
, respectively. The value's class
depends on the property's type. The current implementation
does not yet support all property types and restricts the values' classes
to String
, Integer
and Date
. A value of a yet unknown type is returned as a byte array
containing the value's origin bytes from the property set stream.
To retrieve the value of a specific Property
,
use Section.getProperty(long)
or Section.getPropertyIntValue(long)
.
The SummaryInformation
and DocumentSummaryInformation
classes provide convenience
methods for retrieving well-known properties. For example, an application
that wants to retrieve a document's title string just calls SummaryInformation.getTitle()
instead of going through
the hassle of first finding out what the title's property ID is and then
using this ID to get the property's value.
Public documentation from Microsoft can be found in the appropriate section of the MSDN Library.
History
- 2003-09-11:
-
PropertySetFactory.create(InputStream)
no longer throws anUnexpectedPropertySetTypeException
.
To Do
The following is still left to be implemented. Sponsering could foster these issues considerably.
-
Convenience methods for setting summary information and document summary information properties
-
Better codepage support
-
Support for more property (variant) types
- Author:
- Rainer Klute (klute@rainer-klute.de)
-
ClassDescriptionRepresents a class ID (16 bytes).Maintains the instances of
CustomProperty
that belong to aDocumentSummaryInformation
.This class represents custom properties in the document summary information stream.Convenience class representing a DocumentSummary Information stream in a Microsoft Office document.The Windows FILETIME structure holds a date and time associated with a file.This exception is the superclass of all other checked exceptions thrown in this package.A version ofPOIDocument
which allows access to the HPSF Properties, but no other document contents.This exception is the superclass of all other unchecked exceptions thrown in this package.This exception is thrown when there is an illegal value set in aPropertySet
.This exception is thrown if HPSF encounters a variant type that is illegal in the current context.This exception is thrown if anInputStream
does not support theInputStream.mark(int)
operation.This exception is thrown if one of thePropertySet
's convenience methods does not find a requiredSection
.This exception is thrown if aPropertySet
is to be written but does not have a formatID set (seeSection.setFormatID(ClassID)
orSection.setFormatID(byte[])
.This exception is thrown if a format error in a property set stream is detected or when the input data do not constitute a property set stream.This exception is thrown if one of thePropertySet
's convenience methods that require a singleSection
is called and thePropertySet
does not contain exactly oneSection
.A property in aSection
of aPropertySet
.Represents a property set in the Horrible Property Set Format (HPSF).Factory class to create instances ofSummaryInformation
,DocumentSummaryInformation
andPropertySet
.This exception is thrown when HPSF tries to read a (yet) unsupported variant type.Represents a section in aPropertySet
.Convenience class representing a Summary Information stream in a Microsoft Office document.Class to manipulate data in the Clipboard Variant (VT_CF
) format.This exception is thrown if a certain type of property set is expected (e.g.This exception is thrown if HPSF encounters a variant type that isn't supported yet.TheVariant
types as defined by Microsoft's COM.Supports reading and writing of variant data.This exception is thrown if HPSF encounters a problem with a variant type.Holder for vector-type propertiesThis exception is thrown when trying to write a (yet) unsupported variant type.