org.apache.hadoop.io.file.tfile

Class TFile.Reader.Scanner.Entry

java.lang.Object

org.apache.hadoop.io.file.tfile.TFile.Reader.Scanner.Entry

All Implemented Interfaces:

Comparable<RawComparable>

Enclosing class:

TFile.Reader.Scanner

public class TFile.Reader.Scanner.Entry
extends Object
implements Comparable<RawComparable>

Entry to a <Key, Value> pair.

Constructor Summary

Constructors

Constructor and Description
Entry()

Method Summary

Modifier and Type	Method and Description
int	compareTo(byte[] buf) Compare the entry key to another key.
int	compareTo(byte[] buf, int offset, int length) Compare the entry key to another key.
int	compareTo(RawComparable key) Compare an entry with a RawComparable object.
boolean	equals(Object other) Compare whether this and other points to the same key value.
void	get(BytesWritable key, BytesWritable value) Copy the key and value in one shot into BytesWritables.
int	getKey(byte[] buf) Copy the key into user supplied buffer.
int	getKey(byte[] buf, int offset) Copy the key into user supplied buffer.
int	getKey(BytesWritable key) Copy the key into BytesWritable.
int	getKeyLength() Get the length of the key.
DataInputStream	getKeyStream() Streaming access to the key.
int	getValue(byte[] buf) Copy value into user-supplied buffer.
int	getValue(byte[] buf, int offset) Copy value into user-supplied buffer.
long	getValue(BytesWritable value) Copy the value into BytesWritable.
int	getValueLength() Get the length of the value.
DataInputStream	getValueStream() Stream access to value.
int	hashCode()
boolean	isValueLengthKnown() Check whether it is safe to call getValueLength().
int	writeKey(OutputStream out) Writing the key to the output stream.
long	writeValue(OutputStream out) Writing the value to the output stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

Entry

public Entry()

Method Detail

getKeyLength

public int getKeyLength()

Get the length of the key.

Returns:

the length of the key.

get

public void get(BytesWritable key,
                BytesWritable value)
         throws IOException

Copy the key and value in one shot into BytesWritables. This is equivalent to getKey(key); getValue(value);

Parameters:

key - BytesWritable to hold key.

value - BytesWritable to hold value

Throws:

IOException

getKey

public int getKey(BytesWritable key)
           throws IOException

Copy the key into BytesWritable. The input BytesWritable will be automatically resized to the actual key size.

Parameters:

key - BytesWritable to hold the key.

Throws:

IOException

getValue

public long getValue(BytesWritable value)
              throws IOException

Copy the value into BytesWritable. The input BytesWritable will be automatically resized to the actual value size. The implementation directly uses the buffer inside BytesWritable for storing the value. The call does not require the value length to be known.

Parameters:

value -

Throws:

IOException

writeKey

public int writeKey(OutputStream out)
             throws IOException

Writing the key to the output stream. This method avoids copying key buffer from Scanner into user buffer, then writing to the output stream.

Parameters:

out - The output stream

Returns:

the length of the key.

Throws:

IOException

writeValue

public long writeValue(OutputStream out)
                throws IOException

Writing the value to the output stream. This method avoids copying value data from Scanner into user buffer, then writing to the output stream. It does not require the value length to be known.

Parameters:

out - The output stream

Returns:

the length of the value

Throws:

IOException

getKey

public int getKey(byte[] buf)
           throws IOException

Copy the key into user supplied buffer.

Parameters:

buf - The buffer supplied by user. The length of the buffer must not be shorter than the key length.

Returns:

The length of the key.

Throws:

IOException

getKey

public int getKey(byte[] buf,
                  int offset)
           throws IOException

Copy the key into user supplied buffer.

Parameters:

buf - The buffer supplied by user.

offset - The starting offset of the user buffer where we should copy the key into. Requiring the key-length + offset no greater than the buffer length.

Returns:

The length of the key.

Throws:

IOException

getKeyStream

public DataInputStream getKeyStream()

Streaming access to the key. Useful for desrializing the key into user objects.

Returns:

The input stream.

getValueLength

public int getValueLength()

Get the length of the value. isValueLengthKnown() must be tested true.

Returns:

the length of the value.

getValue

public int getValue(byte[] buf)
             throws IOException

Copy value into user-supplied buffer. User supplied buffer must be large enough to hold the whole value. The value part of the key-value pair pointed by the current cursor is not cached and can only be examined once. Calling any of the following functions more than once without moving the cursor will result in exception: getValue(byte[]), getValue(byte[], int), getValueStream().

Returns:

the length of the value. Does not require isValueLengthKnown() to be true.

Throws:

IOException

getValue

public int getValue(byte[] buf,
                    int offset)
             throws IOException

Copy value into user-supplied buffer. User supplied buffer must be large enough to hold the whole value (starting from the offset). The value part of the key-value pair pointed by the current cursor is not cached and can only be examined once. Calling any of the following functions more than once without moving the cursor will result in exception: getValue(byte[]), getValue(byte[], int), getValueStream().

Returns:

the length of the value. Does not require isValueLengthKnown() to be true.

Throws:

IOException

getValueStream

public DataInputStream getValueStream()
                               throws IOException

Stream access to value. The value part of the key-value pair pointed by the current cursor is not cached and can only be examined once. Calling any of the following functions more than once without moving the cursor will result in exception: getValue(byte[]), getValue(byte[], int), getValueStream().

Returns:

The input stream for reading the value.

Throws:

IOException

isValueLengthKnown

public boolean isValueLengthKnown()

Check whether it is safe to call getValueLength().

Returns:

true if value length is known before hand. Values less than the chunk size will always have their lengths known before hand. Values that are written out as a whole (with advertised length up-front) will always have their lengths known in read.

compareTo

public int compareTo(byte[] buf)

Compare the entry key to another key. Synonymous to compareTo(key, 0, key.length).

Parameters:

buf - The key buffer.

Returns:

comparison result between the entry key with the input key.

compareTo

public int compareTo(byte[] buf,
                     int offset,
                     int length)

Compare the entry key to another key. Synonymous to compareTo(new ByteArray(buf, offset, length)

Parameters:

buf - The key buffer

offset - offset into the key buffer.

length - the length of the key.

Returns:

comparison result between the entry key with the input key.

compareTo

public int compareTo(RawComparable key)

Compare an entry with a RawComparable object. This is useful when Entries are stored in a collection, and we want to compare a user supplied key.

Specified by:

compareTo in interface Comparable<RawComparable>

equals

public boolean equals(Object other)

Compare whether this and other points to the same key value.

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object