Sample Filters

This sample does not actually do anything, it just illustrates the structure of the filter approach. This example shows an appropriate way to process the output stream as it is being written by the FCS server to the original stream.

public class TestFilter implements FCSStreamFilter {

    private Element _params;

    class MyFilteredOutputStream extends FilterOutputStream

    {

        private int _bytesWritten;

        public MyFilteredOutputStream(OutputStream out) {

            super(out);

        }

        public void write(byte[] b, int off, int len) throws 
IOException {

            super.write(b, off, len);

            _bytesWritten+= len;

        }

    }

    public OutputStream getCheckinStream(Item item, LocationInfo 
info, FcsContext context, OutputStream underlyingStream) throws 
FcsException {

        return new MyFilteredOutputStream(underlyingStream);

    }

    public InputStream getCheckoutStream(Item item, LocationInfo 
info, FcsContext context, InputStream underlyingStream) throws 
Exception {

        return underlyingStream;

    }

    public void init(Element params) {

        _params = params;

    }

}

This filter performs compression:

package main;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import com.matrixone.fcs.common.FcsException;
import com.matrixone.fcs.fcs.FCSStreamFilter;
import com.matrixone.fcs.fcs.FcsContext;
import com.matrixone.fcs.fcs.Location;
import com.matrixone.jdom.Element;

public class ZipFilter implements FCSStreamFilter {

	
	@Override
	public OutputStream getCheckinStream(FcsContext arg0, Location arg1,
			OutputStream arg2) throws FcsException {
		ZipOutputStream z = new ZipOutputStream(arg2);
		ZipEntry e = new ZipEntry("a");
		try {
			z.putNextEntry(e);
		} catch (IOException e1) {
			throw new FcsException(e1);
		}
		return z;
	}

	@Override
	public InputStream getCheckoutStream(FcsContext arg0, Location arg1,
			InputStream arg2) throws Exception {
		ZipInputStream z = new ZipInputStream(new MyZipInputStream(arg2));
		z.getNextEntry();
		return z;
	}
	
	class MyZipInputStream extends FilterInputStream {

		protected MyZipInputStream(InputStream arg0) {
			super(arg0);
		}
		
		@Override
		public void close() throws IOException {
			byte[] b = new byte [8192];
			while (read(b) > 0){				
			}
			super.close();
		}
	}

	@Override
	public void init(Location arg0, Element arg1) {
	}
}

Deprecation notice

Deprecation of the com.matrixone.util.MxXMLUtils java class is under preparation (due to its signature depending on mxjdom, which is being migrated out.) IT will be removed in R2020x.

The deprecation of mxjdom for FCS implies the deprecation of a part of the public file stream filters that use mxjdom.

If you want to use file stream filters, you must no longer implement the init method with the com.matrixone.jdom.Element but instead implement the signature with the org.w3c.dom.Element.

For the zip sample, just replace import com.matrixone.jdom.Element; by import org.w3c.dom.Element;