Interface BlobReader


public interface BlobReader
Extension interface for XMLStreamReader implementations that expose base64 encoded binary content as Blob objects.

All the requirements specified in org.apache.axiom.ext.stax apply to this extension interface. In particular, a consumer MUST use XMLStreamReader.getProperty(String) with the property name defined by PROPERTY to get a reference to this extension interface.

If the XMLStreamReader wishes to expose base64 encoded content using this extension interface, it MUST do so using a single XMLStreamConstants.CHARACTERS event. To maintain compatibility with consumers that are unaware of the extension, the implementation SHOULD make sure that XMLStreamReader.getText(), XMLStreamReader.getTextStart(), XMLStreamReader.getTextLength(), XMLStreamReader.getTextCharacters(), XMLStreamReader.getTextCharacters(int, char[], int, int) and XMLStreamReader.getElementText() behave as expected for this type of event, i.e. return the base64 representation of the binary content.

The extension described by this interface will typically be implemented by XMLStreamReader instances provided by databinding frameworks or XMLStreamReader proxies that enrich a stream of StAX events with binary data existing outside of the XML document (e.g. an XOP/MTOM decoder).

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    The name of the property used to look up this extension interface from a XMLStreamReader implementation.
  • Method Summary

    Modifier and Type
    Method
    Description
    Get the Blob with the binary content for the current event.
    Get a BlobProvider instance for deferred loading of the binary content for the current event.
    Get the content ID of the binary content for the current event, if available.
    boolean
    Check whether the current event is a XMLStreamConstants.CHARACTERS event representing base64 encoded binary content and for which a Blob is available.
    boolean
    Check whether the XMLStreamReader supports deferred loading of the binary content for the current event.
    boolean
    Check if the binary content is eligible for optimization (e.g. using XOP) or if it should be serialized as base64.
  • Field Details

    • PROPERTY

      static final String PROPERTY
      The name of the property used to look up this extension interface from a XMLStreamReader implementation.
  • Method Details

    • isBinary

      boolean isBinary()
      Check whether the current event is a XMLStreamConstants.CHARACTERS event representing base64 encoded binary content and for which a Blob is available.
      Returns:
      true if the current event is a XMLStreamConstants.CHARACTERS event representing base64 encoded binary content and for which a Blob is available; false for all other types of events.
    • isOptimized

      boolean isOptimized()
      Check if the binary content is eligible for optimization (e.g. using XOP) or if it should be serialized as base64. Calling this method is only meaningful if isBinary() returns true for the current event. The behavior of this method is undefined if this is not the case.
      Returns:
      true if the binary content is eligible for optimization; false otherwise
    • isDeferred

      boolean isDeferred()
      Check whether the XMLStreamReader supports deferred loading of the binary content for the current event. If this method returns true then a consumer MAY call getBlobProvider() and retrieve the Blob later using BlobProvider.getBlob(). Calling this method is only meaningful if isBinary() returns true for the current event. The behavior of this method is undefined if this is not the case.
      Returns:
      true if deferred loading is supported; false otherwise
    • getContentID

      String getContentID()
      Get the content ID of the binary content for the current event, if available. The result of this method is defined if and only if isBinary() returns true for the current event.

      The implementation SHOULD only return a non null value if the content ID has been used previously in an interaction with another component or system. The implementation SHOULD NOT generate a new content ID solely for the purpose of this method.

      If available, the returned value MUST be a raw content ID. In particular:

      • If the content ID has been extracted from an href attribute, it MUST NOT contain the cid: prefix.
      • If it has been extracted from a Content-ID MIME header, it MUST NOT be enclosed in angles (<>).

      A consumer MAY use the return value of this method in contexts where it is desirable to preserve the original content ID used by another system or component to identify the binary content. However, the consumer MUST NOT make any assumption about the uniqueness or validity of the content ID (with respect to relevant standards such as RFC822) and SHOULD make provision to sanitize the value if necessary.

      Returns:
      any content ID used previously to identify the binary content, or null if no content ID is known
    • getBlob

      Blob getBlob() throws XMLStreamException
      Get the Blob with the binary content for the current event. The behavior of this method is only defined for events for which isBinary() returns true. For events of this type the method MUST return a valid Blob, regardless of the return value of isDeferred(). If isDeferred() returns true, then the consumer may use this method to force the implementation to load the binary content immediately.
      Returns:
      the binary content for the current event
      Throws:
      XMLStreamException - if an error occurs while loading the Blob
    • getBlobProvider

      BlobProvider getBlobProvider()
      Get a BlobProvider instance for deferred loading of the binary content for the current event. The behavior of this method is defined if and only if isDeferred() returns true for the current event. The returned reference MUST remain valid after the current event has been consumed. It is up to the implementation to specify the exact lifecycle of the returned instance, in particular until when the binary content can be retrieved.
      Returns:
      the BlobProvider instance the consumer can use to load the binary content at a later time