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 JSRs: Java Specification Requests
JSR 173: Streaming API for XML
JCP version in use: 2.1 Java Specification Participation Agreement version in use: 1.0 Description: The Streaming API for XML (StAX) is a Java based API for pull-parsing XML. Please direct comments on this JSR to: jsr-173-public Team
Updates to the Original JSR The following information has been updated from the original request: 2006.09.29: The following Maintenance Lead was added: Maintenance Lead: Thorick Chow E-Mail Address: thorick.chow Telephone Number: +1 415 402 7677 Fax Number: +1 415 402 7250 2006.08.04:
Maintenance Lead: Larry Cable E-Mail Address: larry.cable Telephone Number: +1 415 402 7639 Fax Number: +1 415 402 7250 2005.11.09:
Specification Lead: Ron Benson E-Mail Address: rbenson Telephone Number: +1 415 402 7552 Fax Number: Original Java Specification Request (JSR) Identification
| Request | Contributions | Additional
Information
Section 1. Identification Submitting Member: BEA Systems Name of Contact Person: Christopher Fry E-Mail Address: christopher.fry@bea.com Telephone Number: 415 402 7426 Fax Number: 415 402 7250 Specification Lead: Christopher Fry E-Mail Address: christopher.fry@bea.com Telephone Number: 415 402 7426 Fax Number: 415 402 7250 NOTE that this information has been updated from this original request. Initial Expert Group Membership:
Section 2: Request
2.1 Please describe the proposed Specification:The Streaming API for XML (StAX) parsing will specify a Java-based, pull-parsing API for XML. The streaming API gives parsing control to the programmer by exposing a simple iterator based API. This allows the programmer to ask for the next event (pull the event) and allows state to be stored in a procedural fashion.Two recently proposed JSRs, JAXB and JAX-RPC, highlight the need for an XML Streaming API. Both data binding and remote procedure calling (RPC) require processing of XML as a stream of events, where the current context of the XML defines subsequent processing of the XML. A streaming API makes this type of code much more natural to write than SAX, and much more efficient than DOM. The goal of this API is to develop APIs and conventions that support processing XML as a stream. The specification will address three main areas:
Non-goals of this specification include:
2.2 What is the target Java platform? (i.e., desktop, server, personal, embedded, card, etc.)J2SE2.3 What need of the Java community will be addressed by the proposed specification?This specification will provide a standard, efficient, easy to use way to parse XML.2.4 Why isn't this need met by existing specifications?Two standard main approaches for processing XML exist: 1) the Simple API for XML processing (SAX) and 2) DOM (Document Object Model).SAX To use SAX one writes handlers (objects that implement the various SAX handler APIs) that receive callbacks during the processing of an XML document. The main benefits of this style of XML document processing are that it is efficient, flexible, and relatively low level. It is also possible to change handlers during the processing of an XML document allowing one to use different handlers for different sections of the document. One drawback to the SAX API is that the programmer must keep track of the current state of the document in the code each time one processes an XML document. This creates overhead for XML processing and may lead to convoluted document processing code. DOM DOM provides APIs to the programmer to manipulate the XML as a tree. At first glance this seems like a win for the application developer because it does not require writing specific parsing code. However this perceived simplicity comes at a very high cost: performance. Some implementations require the entire document to be read into memory, so for very large documents one must read the entire document into memory before taking appropriate actions based on the data. Another drawback is the programmer must use the DOM tree as the base for handling XML in the document. For many applications the tree model may not be the most natural representation for the data. 2.5 Please give a short description of the underlying technology or technologies:Standard XML parsing technology.2.6 Is there a proposed package name for the API Specification? (i.e., javapi.something, org.something, etc.)javax.xml.stream.*2.7 Does the proposed specification have any dependencies on specific operating systems, CPUs, or I/O devices that you know of?No.2.8 Are there any security issues that cannot be addressed by the current security model?No.2.9 Are there any internationalization or localization issues?Must handle standard character encodings.2.10 Are there any existing specifications that might be rendered obsolete, deprecated, or in need of revision as a result of this work?No, may need to revise JAXP, JAXB and JAX-RPC to take advantage of this work.2.11 Please describe the anticipated schedule for the development of this specification.The final schedule will need to be determined by the expert group. However, it is anticipated that a reasonably solid draft should be available in the Fall.2.12 Please describe the anticipated working model for the Expert Group working on developing this specification.It is anticipated there will be a face-to-face kick-off meeting. Subsequent work will be done by email. First we will define use cases, then we will focus on APIs.The goal will be to attempt to develop a consensus in the expert group
over the main APIs and technologies.
Section 3: Contributions
3.1 Please list any existing documents, specifications, or implementations that describe the technology. Please include links to the documents if they are publicly available.Java APIs for XML based RPChttp://www.jcp.org/jsr/detail/101.jsp XML Data Binding Specification
XML Pull Parser 2
XML Stream API
Xerces XNI Pull Parser Configuration
DOM Pull Parser for Python
Microsoft's XML Reader
3.2 Explanation of how these items might be used as a starting point for the work.The goal will be to analyze the current needs surrounding XML pull parsing, use this to develop a solid understanding of the use cases and then build agreement on the APIs of the JSR.Section 4: Additional Information (Optional)
4.1 This section contains any additional information that the submitting Member wishes to include in the JSR.None |
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