net.markenwerk.utils.data.fetcher

Class AbstractBufferedDataFetcher

java.lang.Object

net.markenwerk.utils.data.fetcher.AbstractDataFetcher

net.markenwerk.utils.data.fetcher.AbstractBufferedDataFetcher

All Implemented Interfaces:

DataFetcher

Direct Known Subclasses:

BufferedDataFetcher

public abstract class AbstractBufferedDataFetcher
extends AbstractDataFetcher

AbstractBufferedDataFetcher is a sensible base implementation of DataFetcher that uses a byte[] as buffer, to while copying all bytes from an InputStream to an OutputStream by sequentially reading from the InputStream into the buffer and then writing from the buffer to the OutputStream.

Implementers must only implement the methods obtainBuffer() and returnBuffer(byte[]) that manage a byte[] to be used as a buffer in doCopy(InputStream, OutputStream, DataFetchProgressListener).

Implementers may also override returnBuffer(byte[]), which is called after doCopy(InputStream, OutputStream, DataFetchProgressListener) has finished using it.

Since:

4.0.0

Author:

Torsten Krause (tk at markenwerk dot net)

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	DEFAULT_BUFEFR_SIZE The default buffer size of 1024 bytes.

Constructor Summary

Constructors

Constructor and Description
AbstractBufferedDataFetcher()

Method Summary

Modifier and Type	Method and Description
protected static byte[]	createBuffer(int bufferSize) Safely creates a new byte[] to be used as a buffer.
protected void	doCopy(InputStream in, OutputStream out, DataFetchProgressListener listener) Copies the content of a given InputStream into a given OutputStream.
protected abstract byte[]	obtainBuffer() Called by doCopy(InputStream, OutputStream, DataFetchProgressListener) to obtain a byte[] to be used as a buffer.
protected abstract void	returnBuffer(byte[] buffer) Called by doCopy(InputStream, OutputStream, DataFetchProgressListener) to return a byte[] that has previously been obtained from obtainBuffer().

Methods inherited from class net.markenwerk.utils.data.fetcher.AbstractDataFetcher

copy, copy, copy, copy, fetch, fetch, fetch, fetch

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFEFR_SIZE

protected static final int DEFAULT_BUFEFR_SIZE

The default buffer size of 1024 bytes.

See Also:

Constant Field Values

Constructor Detail

AbstractBufferedDataFetcher

public AbstractBufferedDataFetcher()

Method Detail

createBuffer

protected static final byte[] createBuffer(int bufferSize)

Safely creates a new byte[] to be used as a buffer.

Parameters:

bufferSize - The size of the byte[] to be created. Defaults to the default buffer size, if the given buffer size is not positive.

Returns:

The new byte[].

doCopy

protected final void doCopy(InputStream in,
                            OutputStream out,
                            DataFetchProgressListener listener)
                     throws DataFetchException

Description copied from class: AbstractDataFetcher

Copies the content of a given InputStream into a given OutputStream.

It is guaranteed that neither the given InputStream nor the given OutputStream nor the given DataFetchProgressListener is null.

Implementers must not close either of the given streams.

Specified by:

doCopy in class AbstractDataFetcher

Parameters:

in - The InputStream to read from.

out - The OutputStream to write to.

listener - The DataFetchProgressListener to report to.

Throws:

DataFetchException - If anything went wrong while reading from the given InputStream or writing to the given OutputStream.

obtainBuffer

protected abstract byte[] obtainBuffer()

Called by doCopy(InputStream, OutputStream, DataFetchProgressListener) to obtain a byte[] to be used as a buffer.

Every byte[] that is returned by this method will be passed as an argument of returnBuffer(byte[]) after doCopy(InputStream, OutputStream, DataFetchProgressListener) has finished using it.

Returns:

The a byte[] to be used as a buffer.

returnBuffer

protected abstract void returnBuffer(byte[] buffer)

Called by doCopy(InputStream, OutputStream, DataFetchProgressListener) to return a byte[] that has previously been obtained from obtainBuffer().

Parameters:

buffer - The byte[] to be returned.