eWON JTK

com.ewon.ewonitf
Class Exporter

java.lang.Object
  extended by java.io.InputStream
      extended by com.ewon.ewonitf.Exporter

public class Exporter
extends InputStream

This class implements an intput stream with data provided from an export block descriptor.


Constructor Summary
Exporter(String exportBlockDescriptor)
          Creates a new instance of Exporter.
 
Method Summary
 int available()
          Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
 void close()
          Closes this input stream and releases any system resources associated with the stream.
 void ExportTo(String fileName)
          Transfert the data from the export block descriptor to the given connector.
This function is typically used after the stream (the Exporter) has been created.
protected  void finalize()
           
 int read()
          Reads the next byte of data from the input stream.
 int read(byte[] b, int off, int len)
          Reads up to len bytes of data from the input stream into an array of bytes.
 
Methods inherited from class java.io.InputStream
mark, markSupported, read, reset, skip
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Exporter

public Exporter(String exportBlockDescriptor)
         throws IOException
Creates a new instance of Exporter. The Export bloc descriptor is validated and opened. Once the Exporter has been created, its stream can be read to fetch data from the export bloc descriptor.

Parameters:
exportBlockDescriptor - This is the Export Block Descriptor that describes the data to export. The Export Block Descriptor syntax is described in details in the eWON user manual. It allows to export almost any data from the eWON in different formats.
Throws:
IOException
Method Detail

ExportTo

public void ExportTo(String fileName)
              throws IOException
Transfert the data from the export block descriptor to the given connector.
This function is typically used after the stream (the Exporter) has been created.

Example:
Loader loader; //This will load the /usr/MyFile.txt file to the eWON config file. exporter = new Exporter("$dtEV"); exporter.ExportTo("file:////usr/events_data.txt"); exporter.close();

Parameters:
fileName - Name of connector where the export stream must transfert its data (example: file:////usr/MyFile.txt).
Throws:
IOException - if an error occurs.

read

public int read()
         throws IOException
Description copied from class: InputStream
Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

A subclass must provide an implementation of this method.

Specified by:
read in class InputStream
Returns:
the next byte of data, or -1 if the end of the stream is reached.
Throws:
IOException - if an I/O error occurs.

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException
Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If b is null, a NullPointerException is thrown.

If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected.

If the first byte cannot be read for any reason other than end of file, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

The read(b, off, len) method for class InputStream simply calls the method read() repeatedly. If the first such call results in an IOException, that exception is returned from the call to the read(b, off, len) method. If any subsequent call to read() results in a IOException, the exception is caught and treated as if it were end of file; the bytes read up to that point are stored into b and the number of bytes read before the exception occurred is returned.

Overrides:
read in class InputStream
Parameters:
b - the buffer into which the data is read.
off - the start offset in array b at which the data is written.
len - the maximum number of bytes to read.
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
Throws:
IOException - if an I/O error occurs.
See Also:
InputStream.read()

available

public int available()
              throws IOException
Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread.

The available method for class InputStream always returns 0.

Overrides:
available in class InputStream
Returns:
the number of bytes that can be read from this input stream without blocking.
Throws:
IOException - if an I/O error occurs.

close

public void close()
           throws IOException
Closes this input stream and releases any system resources associated with the stream.

Overrides:
close in class InputStream
Throws:
IOException - if an I/O error occurs.

finalize

protected void finalize()

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