org.apache.hadoop.io: public class: DataOutputBuffer

org.apache.hadoop.io
public class: DataOutputBuffer [javadoc | source]

java.lang.Object
   java.io.OutputStream
      java.io.FilterOutputStream
         java.io.DataOutputStream
            org.apache.hadoop.io.DataOutputBuffer

All Implemented Interfaces:
DataOutput, Closeable, Flushable

A reusable DataOutput implementation that writes to an in-memory buffer.

This saves memory over creating a new DataOutputStream and ByteArrayOutputStream each time data is written.

Typical usage is something like the following:


DataOutputBuffer buffer = new DataOutputBuffer();
while (... loop condition ...) {
buffer.reset();
... write buffer using DataOutput methods ...
byte[] data = buffer.getData();
int dataLength = buffer.getLength();
... write data to its ultimate destination ...
}

Constructor:
public DataOutputBuffer() { this(new Buffer()); } Constructs a new empty buffer.

Constructor:

 public DataOutputBuffer() {
    this(new Buffer());
}

Constructs a new empty buffer.

Method from org.apache.hadoop.io.DataOutputBuffer Summary:
getData, getLength, reset, write

Methods from java.io.DataOutputStream:
flush, size, write, write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods from java.io.FilterOutputStream:
close, flush, write, write, write

Methods from java.io.OutputStream:
close, flush, write, write, write

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.hadoop.io.DataOutputBuffer Detail:
public byte[] getData() { return buffer.getData(); } Returns the current contents of the buffer. Data is only valid to #getLength() .
public int getLength() { return buffer.getLength(); } Returns the length of the valid data currently in the buffer.
public DataOutputBuffer reset() { this.written = 0; buffer.reset(); return this; } Resets the buffer to empty.
public void write(DataInput in, int length) throws IOException { buffer.write(in, length); } Writes bytes from a DataInput directly into the buffer.

Method from org.apache.hadoop.io.DataOutputBuffer Detail:

 public byte[] getData() {
 return buffer.getData();
}

#getLength()

 public int getLength() {
 return buffer.getLength();
}

Returns the length of the valid data currently in the buffer.

 public DataOutputBuffer reset() {
    this.written = 0;
    buffer.reset();
    return this;
}

Resets the buffer to empty.

 public  void write(DataInput in,
    int length) throws IOException {
    buffer.write(in, length);
}

Writes bytes from a DataInput directly into the buffer.