com.marklogic.xcc.examples
Class DynamicContentStream

java.lang.Object
  java.io.InputStream
      com.marklogic.xcc.examples.DynamicContentStream

public class DynamicContentStream

extends InputStream

This class, which extends InputStream, is an example of producing dynamic, on-the-fly content that can be used with ContentFactory.newUnBufferedContent(String, java.io.InputStream, com.marklogic.xcc.ContentCreateOptions).

Click here for the source code for this class

Like OutputStreamInserter, this is an example of inserting dynamically generated or transformed on-the-fly content. The OutputStreamInserter example uses OutputStreamContent and spawns a thread which then loops and writes to an OutputStream.

By contrast, this example illustrates how to insert dynamic content without creating a new thread. Here, a custom InputStream is passed to the standard factory ContentFactory.newUnBufferedContent(String, java.io.InputStream, com.marklogic.xcc.ContentCreateOptions). When Session.insertContent(com.marklogic.xcc.Content) is invoked, it will repeatedly call back into this class to obtain chunks of data to send to the server.

If your data generation can be expressed this way, multiple calls to obtain the data in chunks, it is preferrable to spawning a new thread.

Note that if your content is potentially large, you should use the above unbuffered factory method. If you call ContentFactory.newContent(String, java.io.InputStream, com.marklogic.xcc.ContentCreateOptions), XCC will first consume and buffer the entire stream before attempting the insert. If the content is unbuffered, then automatic error recovery cannot be performed.

Constructor Summary

DynamicContentStream(int lines)
Constructor for the example, which takes the number of lines to generate in the dummy document.

Method Summary

int	fillBuffer(byte[] buffer) This method will be called repeatedly as XCC reads data from the InputStream (this object).
static void	main(String[] args) Example invocation that uses an instance of this class to insert dynamically-generated content, without spawning a separate thread.
int	read() Read a single byte.
int	read(byte[] userBuffer, int off, int len) Read "len" bytes into "userBuffer", starting at "off".

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DynamicContentStream

public DynamicContentStream(int lines)

Constructor for the example, which takes the number of lines to generate in the dummy document.

Parameters:

lines - Number of lines to put in the programmatically generated document.

Method Detail

read

public int read()
         throws IOException

Read a single byte. This method passes through to the byte-array read().

Returns:

A byte value, as an integer, or -1 on EOF.

Throws:

IOException - If there is a problem.

read

public int read(byte[] userBuffer,
                int off,
                int len)
         throws IOException

Read "len" bytes into "userBuffer", starting at "off". This method copies bytes from an internal holding buffer out to the provided buffer. On underflow, when the internal buffer is exhausted, the fillBuffer() method is called to obtain more data. Your logic, which may be fetching data from an SQL source or a web service and transforming it on the fly, would placed in fillBUffer().

Parameters:

userBuffer - The buffer to place data in.

off - Index into userBuffer where data should be placed.

len - The maximum number of bytes to transfer.

Returns:

The number of bytes actually transferred, or -1 on EOS.

Throws:

IOException - Will not happen in this sample implementation but could conceivably be thrown by fillBUffer().

fillBuffer

public int fillBuffer(byte[] buffer)

This method will be called repeatedly as XCC reads data from the InputStream (this object). In a real app, this method would do something more useful, such as reading data from some other source and transforming it. This dummy implementation uses a simple state machine to produce the beginning of a document, then the variable length body, then the end and finally indicates EOS.

Parameters:

buffer - The byte array to which data should be copied.

Returns:

The number of bytes transferred, or -1 if there are no more bytes available.

main

public static void main(String[] args)
                 throws Exception

Example invocation that uses an instance of this class to insert dynamically-generated content, without spawning a separate thread.

Parameters:

args - Server URI: xcc://user:password@host:port/contentbase, Doc URI: any valid URI string to assign to the new content.

Throws:

Exception - If anything bad happens.