com.bigzip.plugin.compression.io
Class AbstractStream

java.lang.Object
  |
  +--com.bigzip.plugin.compression.io.AbstractStream
Direct Known Subclasses:
ArchiveStream, CheckedStream, CompressionStream, IOStream

public abstract class AbstractStream
extends java.lang.Object

Instances of this class support both reading and writing to a random access file. An application can modify the position in the file at which the next read or write occurs. This class provides a sense of security by offering methods that allow specified mode accesses of read-only or read-write to files.

Since:
BiGZiP 0.3.25

Field Summary
protected  AbstractStream clientStream
          Should be set in the constructor and represents the underlying Randomly accessible Stream
 
Constructor Summary
AbstractStream()
           
 
Method Summary
 void close()
          Closes this random access file stream and releases any system resources associated with the stream.
 void ensureOpen()
          Check to make sure that this stream has not been closed
 void finish()
          Used as a means to flush any data before either closing or performing a new operation.
 long getFilePointer()
          Returns the current offset in this file.
 boolean isClosed()
           
 long length()
          Returns the length of this file.
 int read()
          Reads a byte of data from this file.
 int read(byte[] b)
          Reads up to b.length bytes of data from this file into an array of bytes.
abstract  int read(byte[] b, int off, int len)
          Reads up to len bytes of data from this file into an array of bytes.
 boolean readBoolean()
          Reads a boolean from this file.
 byte readByte()
          Reads a signed 8-bit value from this file.
 char readChar()
          Reads a Unicode character from this file.
 int readDirect(byte[] b)
           
 int readDirect(byte[] b, int off, int len)
           
 double readDouble()
          Reads a double from this file.
 float readFloat()
          Reads a float from this file.
 void readFully(byte[] b, int off, int len)
          Reads exactly len bytes from this file into the byte array.
 int readInt()
          Reads a signed 32 or 16-bit integer from this file.
 int readInt(byte[] b, int off)
          Reads a signed 32/16-bit integer from a buffer.
 java.lang.String readLine()
          Reads the next line of text from this file.
 long readLong()
          Reads a signed 64 or 32-bit integer from this file.
 long readLong(byte[] b, int off)
          Reads a signed 64/32-bit long from a buffer.
 short readShort()
          Reads a signed 16-bit number from this file.
 int readUnsignedByte()
          Reads an unsigned 8-bit number from this file.
 int readUnsignedShort()
          Reads an unsigned 16-bit number from this file.
 java.lang.String readUTF()
          Reads in a string from this file.
 void seek(long pos)
          Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.
 void setClientStream(AbstractStream clientStream)
          Assigns a new stream client
 void setClosed(boolean b)
          Sets the closed status of the file.
 int skipBytes(int n)
          Skips exactly n bytes of input.
 void write(byte[] b)
          Writes b.length bytes from the specified byte array starting at offset off to this file.
abstract  void write(byte[] b, int off, int len)
          Writes len bytes from the specified byte array starting at offset off to this file.
abstract  void write(int b)
          Writes the specified byte to this file.
 void writeBoolean(boolean v)
          Writes a boolean to the file as a 1-byte value.
 void writeByte(int v)
          Writes a byte to the file as a 1-byte value.
 void writeBytes(java.lang.String s)
          Writes the string to the file as a sequence of bytes.
 void writeChar(int v)
          Writes a char to the file as a 2-byte value, high byte first.
 void writeChars(java.lang.String s)
          Writes a string to the file as a sequence of characters.
 void writeDirect(byte[] b)
           
 void writeDirect(byte[] b, int off, int len)
           
 void writeDouble(double v)
          Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8 or 4-byte quantity, high byte first.
 void writeFloat(float v)
          Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4 or 2-byte quantity, high byte first.
 void writeFully(byte[] b, int off, int len)
          Writes len bytes from the specified byte array starting at offset off to this random access stream.
 void writeInt(int v)
          Writes an int to the file as four bytes, high byte first.
 void writeLong(long v)
          Writes a long to the file as eight bytes, high byte first.
 void writeShort(int v)
          Writes a short to the file as two bytes, high byte first.
 void writeUTF(java.lang.String str)
          Writes a string to the file using UTF-8 encoding in a machine-independent manner.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

clientStream

protected AbstractStream clientStream
Should be set in the constructor and represents the underlying Randomly accessible Stream
Constructor Detail

AbstractStream

public AbstractStream()
Method Detail

isClosed

public boolean isClosed()
Returns:
the closed status of the file.

setClosed

public void setClosed(boolean b)
Sets the closed status of the file.
Parameters:
b - closed status.

ensureOpen

public void ensureOpen()
                throws java.io.IOException
Check to make sure that this stream has not been closed
Throws:
java.io.IOException - If the stream is no longer opened

setClientStream

public void setClientStream(AbstractStream clientStream)
Assigns a new stream client
Parameters:
AbstractStream - the new stream client inherited by Abstract stream

read

public int read()
         throws java.io.IOException
Reads a byte of data from this file. This method blocks if no input is yet available.
Returns:
the next byte of data, or -1 if the end of the file is reached.

read

public abstract int read(byte[] b,
                         int off,
                         int len)
                  throws java.io.IOException
Reads up to len bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the maximum number of bytes read.
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.

read

public int read(byte[] b)
         throws java.io.IOException
Reads up to b.length bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.
Parameters:
b - the buffer into which the data is read.
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of this file has been reached.

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException
Reads exactly len bytes from this file into the byte array. This method reads repeatedly from the file until all the bytes are read. This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the number of bytes to read.

readDirect

public int readDirect(byte[] b)
               throws java.io.IOException

readDirect

public int readDirect(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException

write

public abstract void write(int b)
                    throws java.io.IOException
Writes the specified byte to this file.
Parameters:
b - the byte to be written.

write

public void write(byte[] b)
           throws java.io.IOException
Writes b.length bytes from the specified byte array starting at offset off to this file.
Parameters:
b - the data.

write

public abstract void write(byte[] b,
                           int off,
                           int len)
                    throws java.io.IOException
Writes len bytes from the specified byte array starting at offset off to this file.
Parameters:
b - the data.
off - the start offset in the data.
len - the number of bytes to write.

writeFully

public void writeFully(byte[] b,
                       int off,
                       int len)
                throws java.io.IOException
Writes len bytes from the specified byte array starting at offset off to this random access stream.

The write method of IOStream calls the write method of one argument on each byte to output.

Note that this method does not call the write method of its underlying random access stream with the same arguments. Subclasses of IOStream should provide a more efficient implementation of this method.

Parameters:
b - the data.
off - the start offset in the data.
len - the number of bytes to write.
Throws:
java.io.IOException - if an I/O error occurs.

writeDirect

public void writeDirect(byte[] b)
                 throws java.io.IOException

writeDirect

public void writeDirect(byte[] b,
                        int off,
                        int len)
                 throws java.io.IOException

skipBytes

public int skipBytes(int n)
              throws java.io.IOException
Skips exactly n bytes of input.

This method blocks until all the bytes are skipped, the end of the stream is detected, or an exception is thrown.

Parameters:
n - the number of bytes to be skipped.
Returns:
the number of bytes skipped, which is always n.

getFilePointer

public long getFilePointer()
                    throws java.io.IOException
Returns the current offset in this file.
Returns:
the offset from the beginning of the file, in bytes, at which the next read or write occurs.

seek

public void seek(long pos)
          throws java.io.IOException
Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs. The offset may be set beyond the end of the file. Setting the offset beyond the end of the file does not change the file length. The file length will change only by writing after the offset has been set beyond the end of the file.
Parameters:
pos - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer.

length

public long length()
            throws java.io.IOException
Returns the length of this file.
Returns:
the length of this file.

close

public void close()
           throws java.io.IOException
Closes this random access file stream and releases any system resources associated with the stream.

finish

public void finish()
            throws java.io.IOException
Used as a means to flush any data before either closing or performing a new operation.

readBoolean

public boolean readBoolean()
                    throws java.io.IOException
Reads a boolean from this file. This method reads a single byte from the file. A value of 0 represents false. Any other value represents true. This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
Returns:
the boolean value read.

readByte

public byte readByte()
              throws java.io.IOException
Reads a signed 8-bit value from this file. This method reads a byte from the file.

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Returns:
the next byte of this file as a signed 8-bit byte.

readUnsignedByte

public int readUnsignedByte()
                     throws java.io.IOException
Reads an unsigned 8-bit number from this file. This method reads a byte from this file and returns that byte.

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Returns:
the next byte of this file, interpreted as an unsigned 8-bit number.

readShort

public short readShort()
                throws java.io.IOException
Reads a signed 16-bit number from this file. The method reads 2 bytes from this file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next two bytes of this file, interpreted as a signed 16-bit number.

readUnsignedShort

public int readUnsignedShort()
                      throws java.io.IOException
Reads an unsigned 16-bit number from this file. This method reads two bytes from the file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next two bytes of this file, interpreted as an unsigned 16-bit integer.

readChar

public char readChar()
              throws java.io.IOException
Reads a Unicode character from this file. This method reads two bytes from the file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next two bytes of this file as a Unicode character.

readInt

public int readInt()
            throws java.io.IOException
Reads a signed 32 or 16-bit integer from this file. This method reads 4 or 2 bytes from the file.

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next four/two bytes of this file, interpreted as an int.

readInt

public int readInt(byte[] b,
                   int off)
Reads a signed 32/16-bit integer from a buffer. This method reads 4/2 bytes from the buffer.
Parameters:
b - The byte array containing the value
off - The starting position of the value in the array
Returns:
the next four bytes of this file, interpreted as an int.

readLong

public long readLong()
              throws java.io.IOException
Reads a signed 64 or 32-bit integer from this file. This method reads eight or four bytes from the file.

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next eight/four bytes of this file, interpreted as a long.

readLong

public long readLong(byte[] b,
                     int off)
Reads a signed 64/32-bit long from a buffer. This method reads eight/four bytes from the buffer.
Parameters:
b - The byte array containing the value
off - The starting position of the value in the array
Returns:
the next eight bytes of this file, interpreted as a long.

readFloat

public float readFloat()
                throws java.io.IOException
Reads a float from this file. This method reads an int value as if by the readInt method and then converts that int to a float using the intBitsToFloat method in class Float.

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next four/two bytes of this file, interpreted as a float.

readDouble

public double readDouble()
                  throws java.io.IOException
Reads a double from this file. This method reads a long value as if by the readLong method and then converts that long to a double using the longBitsToDouble method in class Double.

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Returns:
the next eight/four bytes of this file, interpreted as a double.

readLine

public java.lang.String readLine()
                          throws java.io.IOException
Reads the next line of text from this file. This method successively reads bytes from the file until it reaches the end of a line of text.

This method blocks until a newline character is read, a carriage return and the byte following it are read (to see if it is a newline), the end of the stream is detected, or an exception is thrown.

Returns:
the next line of text from this file.

readUTF

public java.lang.String readUTF()
                         throws java.io.IOException
Reads in a string from this file. The string has been encoded using a modified UTF-8 format.
Returns:
a Unicode string.

writeBoolean

public void writeBoolean(boolean v)
                  throws java.io.IOException
Writes a boolean to the file as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.
Parameters:
v - a boolean value to be written.

writeByte

public void writeByte(int v)
               throws java.io.IOException
Writes a byte to the file as a 1-byte value.
Parameters:
v - a byte value to be written.

writeShort

public void writeShort(int v)
                throws java.io.IOException
Writes a short to the file as two bytes, high byte first.
Parameters:
v - a short to be written.

writeChar

public void writeChar(int v)
               throws java.io.IOException
Writes a char to the file as a 2-byte value, high byte first.
Parameters:
v - a char value to be written.

writeInt

public void writeInt(int v)
              throws java.io.IOException
Writes an int to the file as four bytes, high byte first.
Parameters:
v - an int to be written.

writeLong

public void writeLong(long v)
               throws java.io.IOException
Writes a long to the file as eight bytes, high byte first.
Parameters:
v - a long to be written.

writeFloat

public void writeFloat(float v)
                throws java.io.IOException
Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4 or 2-byte quantity, high byte first.
Parameters:
v - a float value to be written.

writeDouble

public void writeDouble(double v)
                 throws java.io.IOException
Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8 or 4-byte quantity, high byte first.
Parameters:
v - a double value to be written.

writeBytes

public void writeBytes(java.lang.String s)
                throws java.io.IOException
Writes the string to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits.
Parameters:
s - a string of bytes to be written.

writeChars

public void writeChars(java.lang.String s)
                throws java.io.IOException
Writes a string to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method.
Parameters:
s - a String value to be written.

writeUTF

public void writeUTF(java.lang.String str)
              throws java.io.IOException
Writes a string to the file using UTF-8 encoding in a machine-independent manner.
Parameters:
str - a string to be written.