nom.tam.util

Class BufferedDataOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.io.BufferedOutputStream

nom.tam.util.BufferedDataOutputStream

All Implemented Interfaces:

Closeable, DataOutput, Flushable, AutoCloseable, ArrayDataOutput

public class BufferedDataOutputStream
extends BufferedOutputStream
implements ArrayDataOutput

This class is intended for high performance I/O in scientific applications. It combines the functionality of the BufferedOutputStream and the DataOutputStream as well as more efficient handling of arrays. This minimizes the number of method calls that are required to write data. Informal tests of this method show that it can be as much as 10 times faster than using a DataOutputStream layered on a BufferedOutputStream for writing large arrays. The performance gain on scalars or small arrays will be less but there should probably never be substantial degradation of performance.

Note that there is substantial duplication of code to minimize method invocations. However simple output methods were used where empirical tests seemed to indicate that the simpler method did not cost any time. It seems likely that most of these variations will be washed out across different compilers and users who wish to tune the method for their particular system may wish to compare the the implementation of write(int[], int, int) with write(float[], int, int).

Testing and timing for this class is peformed in the nom.tam.util.test.BufferedFileTester class.

Field Summary

Fields inherited from class java.io.BufferedOutputStream

buf, count

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor and Description
BufferedDataOutputStream(OutputStream o) Use the BufferedOutputStream constructor
BufferedDataOutputStream(OutputStream o, int bufLength) Use the BufferedOutputStream constructor

Method Summary

Modifier and Type	Method and Description
protected void	checkBuf(int need)
void	write(boolean[] b) Write an array of booleans.
void	write(boolean[] b, int start, int len) Write a segment of an array of booleans.
void	write(char[] c) Write an array of char's.
void	write(char[] c, int start, int len) Write a segment of an array of char's.
void	write(double[] d) Write an array of doubles.
void	write(double[] d, int start, int len)
void	write(float[] f) Write an array of floats.
void	write(float[] f, int start, int len)
void	write(int[] i) Write an array of int's.
void	write(int[] i, int start, int len) Write a segment of an array of int's.
void	write(long[] l) Write an array of longs.
void	write(long[] l, int start, int len) Write a segement of an array of longs.
void	write(short[] s) Write an array of shorts.
void	write(short[] s, int start, int len) Write a segment of an array of shorts.
void	write(String[] s) Write an array of Strings -- equivalent to calling writeBytes for each string.
void	write(String[] s, int start, int len) Write a segment of an array of Strings.
void	writeArray(Object o) This routine provides efficient writing of arrays of any primitive type.
void	writeBoolean(boolean b) Write a boolean value
void	writeByte(int b) Write a byte value.
void	writeBytes(String s) Write a string using the local protocol to convert char's to bytes.
void	writeChar(int c) Write a char value.
void	writeChars(String s) Write a string as an array of chars.
void	writeDouble(double d) Write a double value.
void	writeFloat(float f) Write a float value.
void	writeInt(int i) Write an integer value.
void	writeLong(long l) Write a long value.
void	writePrimitiveArray(Object o) This routine provides efficient writing of arrays of any primitive type.
void	writeShort(int s) Write a short value.
void	writeUTF(String s) Write a string as a UTF.

Methods inherited from class java.io.BufferedOutputStream

flush, write, write

Methods inherited from class java.io.FilterOutputStream

close, write

Methods inherited from class java.lang.Object

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

Methods inherited from interface nom.tam.util.ArrayDataOutput

close, flush, write, write

Methods inherited from interface java.io.DataOutput

write

Constructor Detail

BufferedDataOutputStream

public BufferedDataOutputStream(OutputStream o)

Use the BufferedOutputStream constructor

Parameters:

o - An open output stream.

BufferedDataOutputStream

public BufferedDataOutputStream(OutputStream o,
                                int bufLength)

Use the BufferedOutputStream constructor

Parameters:

o - An open output stream.

bufLength - The buffer size.

Method Detail

writeBoolean

public void writeBoolean(boolean b)
                  throws IOException

Write a boolean value

Specified by:

writeBoolean in interface DataOutput

Parameters:

b - The value to be written. Externally true is represented as a byte of 1 and false as a byte value of 0.

Throws:

IOException

writeByte

public void writeByte(int b)
               throws IOException

Write a byte value.

Specified by:

writeByte in interface DataOutput

Throws:

IOException

writeInt

public void writeInt(int i)
              throws IOException

Write an integer value.

Specified by:

writeInt in interface DataOutput

Throws:

IOException

writeShort

public void writeShort(int s)
                throws IOException

Write a short value.

Specified by:

writeShort in interface DataOutput

Throws:

IOException

writeChar

public void writeChar(int c)
               throws IOException

Write a char value.

Specified by:

writeChar in interface DataOutput

Throws:

IOException

writeLong

public void writeLong(long l)
               throws IOException

Write a long value.

Specified by:

writeLong in interface DataOutput

Throws:

IOException

writeFloat

public void writeFloat(float f)
                throws IOException

Write a float value.

Specified by:

writeFloat in interface DataOutput

Throws:

IOException

writeDouble

public void writeDouble(double d)
                 throws IOException

Write a double value.

Specified by:

writeDouble in interface DataOutput

Throws:

IOException

writeBytes

public void writeBytes(String s)
                throws IOException

Write a string using the local protocol to convert char's to bytes.

Specified by:

writeBytes in interface DataOutput

Parameters:

s - The string to be written.

Throws:

IOException

writeChars

public void writeChars(String s)
                throws IOException

Write a string as an array of chars.

Specified by:

writeChars in interface DataOutput

Throws:

IOException

writeUTF

public void writeUTF(String s)
              throws IOException

Write a string as a UTF. Note that this class does not handle this situation efficiently since it creates new DataOutputStream to handle each call.

Specified by:

writeUTF in interface DataOutput

Throws:

IOException

writePrimitiveArray

public void writePrimitiveArray(Object o)
                         throws IOException

This routine provides efficient writing of arrays of any primitive type. The String class is also handled but it is an error to invoke this method with an object that is not an array of these types. If the array is multidimensional, then it calls itself recursively to write the entire array. Strings are written using the standard 1 byte format (i.e., as in writeBytes). If the array is an array of objects, then writePrimitiveArray will be called for each element of the array.

Parameters:

o - The object to be written. It must be an array of a primitive type, Object, or String.

Throws:

IOException

writeArray

public void writeArray(Object o)
                throws IOException

This routine provides efficient writing of arrays of any primitive type. The String class is also handled but it is an error to invoke this method with an object that is not an array of these types. If the array is multidimensional, then it calls itself recursively to write the entire array. Strings are written using the standard 1 byte format (i.e., as in writeBytes). If the array is an array of objects, then writePrimitiveArray will be called for each element of the array.

Specified by:

writeArray in interface ArrayDataOutput

Parameters:

o - The object to be written. It must be an array of a primitive type, Object, or String.

Throws:

IOException - if the argument is not of the proper type

write

public void write(boolean[] b)
           throws IOException

Write an array of booleans.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(boolean[] b,
                  int start,
                  int len)
           throws IOException

Write a segment of an array of booleans.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(short[] s)
           throws IOException

Write an array of shorts.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(short[] s,
                  int start,
                  int len)
           throws IOException

Write a segment of an array of shorts.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(char[] c)
           throws IOException

Write an array of char's.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(char[] c,
                  int start,
                  int len)
           throws IOException

Write a segment of an array of char's.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(int[] i)
           throws IOException

Write an array of int's.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(int[] i,
                  int start,
                  int len)
           throws IOException

Write a segment of an array of int's.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(long[] l)
           throws IOException

Write an array of longs.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(long[] l,
                  int start,
                  int len)
           throws IOException

Write a segement of an array of longs.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(float[] f)
           throws IOException

Write an array of floats.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(float[] f,
                  int start,
                  int len)
           throws IOException

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(double[] d)
           throws IOException

Write an array of doubles.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(double[] d,
                  int start,
                  int len)
           throws IOException

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(String[] s)
           throws IOException

Write an array of Strings -- equivalent to calling writeBytes for each string.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

write

public void write(String[] s,
                  int start,
                  int len)
           throws IOException

Write a segment of an array of Strings. Equivalent to calling writeBytes for the selected elements.

Specified by:

write in interface ArrayDataOutput

Throws:

IOException

checkBuf

protected void checkBuf(int need)
                 throws IOException

Throws:

IOException