BasicInput (Starlink-UK API)

All Known Implementing Classes:

BlockInput, BlockMappedInput, BufferedRandomInput, ByteBufferInput, MultiByteBufferInput, SimpleMappedInput
```
public interface BasicInput
```
Interface defining the basic data input operations required for the FITS reading classes. All the read operations operate at the current position of the assumed stream and advance the current position past the item they just read. Storage is FITS-like, which, happily, matches ByteBuffer conventions. Random access may or may not be supported.
This interface has some similarities to DataInput, and that interface could have been used instead, but this one is explicitly used for the hand-coded FITS reader implementation to make clear which operations need to be efficient. At present no multi-byte (or multi-other-primitive-type) read operations are included, since it's not clear that these are required in practice for efficient table input, though for (uncommon?) tables that have columns with large array values that might not be true. If that turns out to be an important use case, such methods can be added to this interface, implemented in its implementations, and used in the clients of this interface.
Instances of this are not expected to be safe for use from multiple threads. Depending on the implementation, ignoring that fact may be a very bad idea indeed.

Since:

1 Dec 2014

Author:

Mark Taylor

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`close()` Releases resources belonging to this object.
`long`	`getOffset()` Returns the curent position in this stream (optional operation).
`boolean`	`isRandom()` Indicates whether this object supports random access.
`byte`	`readByte()` Reads a byte from the stream.
`void`	`readBytes(byte[] buf)` Reads bytes into an array from the stream.
`double`	`readDouble()` Reads an 8-byte floating point value from the stream.
`float`	`readFloat()` Reads a 4-byte floating point value from the stream.
`int`	`readInt()` Reads a 4-byte integer from the stream.
`long`	`readLong()` Reads an 8-byte integer from the stream.
`short`	`readShort()` Reads a 2-byte integer from the stream.
`void`	`seek(long offset)` Moves the current position of this stream to a given byte offset (optional operation).
`void`	`skip(long nbyte)` Skips a given number of bytes forwards through the stream.

- Method Detail
  - readByte
```
byte readByte()
       throws IOException
```
    Reads a byte from the stream. The current position is advanced.
    
    Returns:
    
    byte value
    
    Throws:
    
    IOException
  - readShort
```
short readShort()
         throws IOException
```
    Reads a 2-byte integer from the stream. The current position is advanced.
    
    Returns:
    
    short value
    
    Throws:
    
    IOException
  - readInt
```
int readInt()
     throws IOException
```
    Reads a 4-byte integer from the stream. The current position is advanced.
    
    Returns:
    
    int value
    
    Throws:
    
    IOException
  - readLong
```
long readLong()
       throws IOException
```
    Reads an 8-byte integer from the stream. The current position is advanced.
    
    Returns:
    
    long value
    
    Throws:
    
    IOException
  - readFloat
```
float readFloat()
         throws IOException
```
    Reads a 4-byte floating point value from the stream. The current position is advanced.
    
    Returns:
    
    float value
    
    Throws:
    
    IOException
  - readDouble
```
double readDouble()
           throws IOException
```
    Reads an 8-byte floating point value from the stream. The current position is advanced.
    
    Returns:
    
    double value
    
    Throws:
    
    IOException
  - readBytes
```
void readBytes(byte[] buf)
        throws IOException
```
    Reads bytes into an array from the stream. The current position is advanced.
    
    Parameters:
    
    buf - array into which the bytes are read; the number of bytes read is the length of the array
    
    Throws:
    
    IOException
  - skip
```
void skip(long nbyte)
   throws IOException
```
    Skips a given number of bytes forwards through the stream. An exception is thrown if there are not enough bytes left.
    
    Parameters:
    
    nbyte - number of bytes to skip
    
    Throws:
    
    IOException
  - close
```
void close()
    throws IOException
```
    Releases resources belonging to this object. Attempts to use it after a call to this method result in undefined behaviour.
    
    Throws:
    
    IOException
  - isRandom
```
boolean isRandom()
```
    Indicates whether this object supports random access. The seek and getOffset methods may only be called if this method returns true.
    
    Returns:
    
    true iff random access is supported
  - seek
```
void seek(long offset)
   throws IOException
```
    Moves the current position of this stream to a given byte offset (optional operation).
    
    Throws:
    
    UnsupportedOperationException - if not random-access
    
    IOException
  - getOffset
```
long getOffset()
```
    Returns the curent position in this stream (optional operation).
    
    Throws:
    
    UnsupportedOperationException - if not random-access

Interface BasicInput

Method Summary

Method Detail

readByte

readShort

readInt

readLong

readFloat

readDouble

readBytes

skip

close

isRandom

seek

getOffset