File	Doc	Category	Size	Date	Package
DeferredFileOutputStream.java	API Doc	Android 1.5 API	8592	Wed May 06 22:42:46 BST 2009	org.apache.commons.io.output

DeferredFileOutputStream

• java.lang.Object
  • java.io.OutputStream
    • org.apache.commons.io.output.ThresholdingOutputStream

Fields Summary
private ByteArrayOutputStream	memoryOutputStream The output stream to which data will be written prior to the theshold being reached.
private OutputStream	currentOutputStream The output stream to which data will be written at any given time. This will always be one of memoryOutputStream or diskOutputStream.
private File	outputFile The file to which output will be directed if the threshold is exceeded.
private String	prefix The temporary file prefix.
private String	suffix The temporary file suffix.
private File	directory The directory to use for temporary files.
private boolean	closed True when close() has been called successfully.

Constructors Summary
public DeferredFileOutputStream(int threshold, File outputFile) Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point. param threshold The number of bytes at which to trigger an event. param outputFile The file to which data is saved beyond the threshold. // ----------------------------------------------------------- Constructors super(threshold); this.outputFile = outputFile; memoryOutputStream = new ByteArrayOutputStream(); currentOutputStream = memoryOutputStream;
public DeferredFileOutputStream(int threshold, String prefix, String suffix, File directory) Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a temporary file beyond that point. param threshold The number of bytes at which to trigger an event. param prefix Prefix to use for the temporary file. param suffix Suffix to use for the temporary file. param directory Temporary file directory. since Commons IO 1.4 this(threshold, (File)null); if (prefix == null) { throw new IllegalArgumentException("Temporary file prefix is missing"); } this.prefix = prefix; this.suffix = suffix; this.directory = directory;

Methods Summary
public void	close() Closes underlying output stream, and mark this as closed exception IOException if an error occurs. super.close(); closed = true;
public byte[]	getData() Returns the data for this output stream as an array of bytes, assuming that the data has been retained in memory. If the data was written to disk, this method returns null. return The data for this output stream, or null if no such data is available. if (memoryOutputStream != null) { return memoryOutputStream.toByteArray(); } return null;
public java.io.File	getFile() Returns either the output file specified in the constructor or the temporary file created or null. If the constructor specifying the file is used then it returns that same output file, even when threashold has not been reached. If constructor specifying a temporary file prefix/suffix is used then the temporary file created once the threashold is reached is returned If the threshold was not reached then null is returned. return The file for this output stream, or null if no such file exists. return outputFile;
protected java.io.OutputStream	getStream() Returns the current output stream. This may be memory based or disk based, depending on the current state with respect to the threshold. return The underlying output stream. exception IOException if an error occurs. return currentOutputStream;
public boolean	isInMemory() Determines whether or not the data for this output stream has been retained in memory. return true if the data is available in memory; false otherwise. return (!isThresholdExceeded());
protected void	thresholdReached() Switches the underlying output stream from a memory based stream to one that is backed by disk. This is the point at which we realise that too much data is being written to keep in memory, so we elect to switch to disk-based storage. exception IOException if an error occurs. if (prefix != null) { outputFile = File.createTempFile(prefix, suffix, directory); } FileOutputStream fos = new FileOutputStream(outputFile); memoryOutputStream.writeTo(fos); currentOutputStream = fos; memoryOutputStream = null;
public void	writeTo(java.io.OutputStream out) Writes the data from this output stream to the specified output stream, after it has been closed. param out output stream to write to. exception IOException if this stream is not yet closed or an error occurs. // we may only need to check if this is closed if we are working with a file // but we should force the habit of closing wether we are working with // a file or memory. if (!closed) { throw new IOException("Stream not closed"); } if(isInMemory()) { memoryOutputStream.writeTo(out); } else { FileInputStream fis = new FileInputStream(outputFile); try { IOUtils.copy(fis, out); } finally { IOUtils.closeQuietly(fis); } }