com.facebook.presto.spi.block

Interface BlockCursor

All Known Implementing Classes:

FixedWidthBlockCursor, VariableWidthCursor

public interface BlockCursor

Iterate as:

Cursor cursor = ...;
 <p/>
  while (cursor.advanceNextPosition()) {
     long value = cursor.getLong(...);
     ...
  }
 

Method Summary

Methods

Modifier and Type	Method and Description
boolean	advanceNextPosition() Attempts to advance to the next position in this stream.
boolean	advanceToPosition(int position) Attempts to advance to the requested position.
void	appendTo(BlockBuilder blockBuilder) Appends the value at the current position to the block builder.
int	compareTo(io.airlift.slice.Slice otherSlice, int otherOffset) Compares the value at the current position to the value at the other offset in the other slice.
BlockCursor	duplicate() Creates a new cursor at the same position of as this cursor.
boolean	getBoolean() Gets the current value as a boolean.
double	getDouble() Gets the current value as a double.
long	getLong() Gets the current value as a long.
Object	getObjectValue(ConnectorSession session) Gets the current value as an Object.
int	getPosition() Returns the current position of this cursor.
Block	getRegionAndAdvance(int length) Creates a block view port starting at the next position and extending the specified length.
int	getRemainingPositions() Gets the number of positions remaining in this cursor.
Block	getSingleValueBlock() Gets the current value as a single element block.
io.airlift.slice.Slice	getSlice() Gets the current value as a Slice.
Type	getType() Gets the type of this cursor
int	hash() Calculates the hash code of the value at the current position.
boolean	isFinished() Returns true if the cursor has advanced beyond its last position.
boolean	isNull() Is the current value null?
boolean	isValid() Returns true if the current position of the cursor is valid; false if the cursor has not been advanced yet, or if the cursor has advanced beyond the last position.

Method Detail

duplicate

BlockCursor duplicate()

Creates a new cursor at the same position of as this cursor.

getType

Type getType()

Gets the type of this cursor

getRemainingPositions

int getRemainingPositions()

Gets the number of positions remaining in this cursor.

isValid

boolean isValid()

Returns true if the current position of the cursor is valid; false if the cursor has not been advanced yet, or if the cursor has advanced beyond the last position. INVARIANT 1: isValid is false if isFinished is true INVARIANT 2: all get* and data access methods will throw java.util.IllegalStateException while isValid is false

isFinished

boolean isFinished()

Returns true if the cursor has advanced beyond its last position. INVARIANT 1: isFinished will only return true once advance* has returned false. INVARIANT 2: all get* and data access methods will throw java.util.IllegalStateException once isFinished is true

advanceNextPosition

boolean advanceNextPosition()

Attempts to advance to the next position in this stream.

advanceToPosition

boolean advanceToPosition(int position)

Attempts to advance to the requested position.

getRegionAndAdvance

Block getRegionAndAdvance(int length)

Creates a block view port starting at the next position and extending the specified length. If the length is greater than the remaining positions, the length wil be reduced. This method advances the cursor to the last position in the view port, so repeated calls to this method will result in distinct chunks covering all positions of the cursor.

For example, to get a sequence of regions with 1024 positions, use the following code:

Cursor cursor = ...;
 <p/>
  while (cursor.getRemainingPositions() > 0) {
     Block block = cursor.getRegionAndAdvance(1024);
     ...
  }
 

getSingleValueBlock

Block getSingleValueBlock()

Gets the current value as a single element block.

Throws:

IllegalStateException - if this cursor is not at a valid position

getBoolean

boolean getBoolean()

Gets the current value as a boolean.

Throws:

IllegalStateException - if this cursor is not at a valid position

getLong

long getLong()

Gets the current value as a long.

Throws:

IllegalStateException - if this cursor is not at a valid position

getDouble

double getDouble()

Gets the current value as a double.

Throws:

IllegalStateException - if this cursor is not at a valid position

getSlice

io.airlift.slice.Slice getSlice()

Gets the current value as a Slice.

Throws:

IllegalStateException - if this cursor is not at a valid position

getObjectValue

Object getObjectValue(ConnectorSession session)

Gets the current value as an Object.

Parameters:

session -

Throws:

IllegalStateException - if this cursor is not at a valid position

isNull

boolean isNull()

Is the current value null?

Throws:

IllegalStateException - if this cursor is not at a valid position

getPosition

int getPosition()

Returns the current position of this cursor.

Throws:

IllegalStateException - if this cursor is not at a valid position

compareTo

int compareTo(io.airlift.slice.Slice otherSlice,
            int otherOffset)

Compares the value at the current position to the value at the other offset in the other slice.

hash

int hash()

Calculates the hash code of the value at the current position.

appendTo

void appendTo(BlockBuilder blockBuilder)

Appends the value at the current position to the block builder.