Adobe acrobat 7.0.5 sdk 用户手册

Working with Metadata

Many namespaces, keywords, and related names in this document are prefaced with 
the string “

XAP

”, which was an early internal code name for XMP metadata. These 

names are retained for compatibility. 

The XMP Toolkit consists of two parts:

●

MetaXAP manages the metadata for a managed resource such as an application 
document file. It defines the objects that act as containers for properties relating to a 
specific document, and is the primary interface to the XMP Toolkit. MetaXAP provides 
the top level abstraction for metadata about a document. Nodes are accessed via string 
pathnames which use a simplified form of XPath strings (XML Path Language: 

●

UtilityXAP provides a variety of special purpose utilities to simplify common uses of 
MetaXAP. For example, MetaXAP reads and writes property values as strings. UtilityXAP 
has services that include conversion between integers and other types. 

XMP metadata properties are organized by schemas. In RDF, the schema is defined by a 
namespace attribute. Within each schema, properties are named via a path string. This path 
string has a very simple syntax which is modelled on the XPath standard. 

The full XMP data model is supported, including values that are simple literals, nested 
descriptions, and structured containers. Applications should include only the 

XAPToolkit.h

 file, and optionally the 

UtilityXAP.h

 file.

You can search metadata both by using Acrobat JavaScript and from a plug-in. 

In Acrobat JavaScript, use the 

 and 

 properties of the 

 object.

In a plug-in, search metadata by setting the 

, 

, or 

 search option flags.

The PDF structure tree and marked content work in tandem to support object data. Object 
data is information associated with a particular object in a PDF document, such as a chair in 
an engineering drawing.