Pdf Object Model
Pdf Object Model
The underlying, low-level PDF object model — what the PDF spec itself (ISO 32000-1:2008,
§7.3) calls the COS (Carousel Object System) layer — represents the raw PDF object types
that all high-level PDF structures are built on. Aspose.PDF FOSS for Java exposes this
layer through its own Pdf-prefixed classes (PdfDictionary, PdfArray, and so on
below), not a COS-prefixed family.
Core Types
| Class | PDF type |
|---|---|
PdfDictionary | Dictionary (<< >>) |
PdfArray | Array ([ ]) |
PdfStream | Stream with dictionary header |
PdfName | Name object (/Name) |
PdfString | String (literal or hex) |
PdfInteger | Integer |
PdfBoolean | Boolean |
PdfDictionary
PdfDictionary maps PdfName keys to Pdf object values. Use set(name, value) to add
entries and get(name) to retrieve them:
PdfDictionary dict = new PdfDictionary();
dict.set(PdfName.of("Author"), new PdfString("Jane Smith"));
PdfString author = (PdfString) dict.get(PdfName.of("Author"));PdfArray
PdfArray holds an ordered list of Pdf objects:
PdfArray array = new PdfArray();
array.add(PdfInteger.valueOf(1));
array.add(PdfInteger.valueOf(2));
int len = array.size(); // 2Accessing the Document Catalog
The PDF catalog is accessible via Document.getCatalog(), which returns a
PdfDictionary representing the root catalog object.
