com.google.cloud.dataflow.sdk.io

Class CompressedSource.CompressedReader<T>

java.lang.Object

com.google.cloud.dataflow.sdk.io.Source.Reader<T>

com.google.cloud.dataflow.sdk.io.BoundedSource.BoundedReader<T>

com.google.cloud.dataflow.sdk.io.OffsetBasedSource.OffsetBasedReader<T>

com.google.cloud.dataflow.sdk.io.FileBasedSource.FileBasedReader<T>

com.google.cloud.dataflow.sdk.io.CompressedSource.CompressedReader<T>

Type Parameters:

T - The type of records read from the source.

All Implemented Interfaces:

AutoCloseable

Enclosing class:

CompressedSource<T>

public static class CompressedSource.CompressedReader<T>
extends FileBasedSource.FileBasedReader<T>

Reader for a CompressedSource. Decompresses its input and uses a delegate reader to read elements from the decompressed input.

Constructor Summary

Constructors

Constructor and Description
CompressedReader(CompressedSource<T> source, FileBasedSource.FileBasedReader<T> readerDelegate) Create a CompressedReader from a CompressedSource and delegate reader.

Method Summary

Modifier and Type	Method and Description
T	getCurrent() Gets the current record from the delegate reader.
protected long	getCurrentOffset() Returns the delegate reader's current offset in the decompressed input.
protected boolean	isAtSplitPoint() Returns true only for the first record; compressed sources cannot be split.
protected boolean	readNextRecord() Reads the next record via the delegate reader.
protected void	startReading(ReadableByteChannel channel) Creates a decompressing channel from the input channel and passes it to its delegate reader's FileBasedReader#startReading(ReadableByteChannel).

Methods inherited from class com.google.cloud.dataflow.sdk.io.FileBasedSource.FileBasedReader

advanceImpl, close, getCurrentSource, startImpl

Methods inherited from class com.google.cloud.dataflow.sdk.io.OffsetBasedSource.OffsetBasedReader

advance, getFractionConsumed, splitAtFraction, start

Methods inherited from class com.google.cloud.dataflow.sdk.io.BoundedSource.BoundedReader

getCurrentTimestamp

Methods inherited from class java.lang.Object

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

Constructor Detail

CompressedReader

public CompressedReader(CompressedSource<T> source,
                        FileBasedSource.FileBasedReader<T> readerDelegate)

Create a CompressedReader from a CompressedSource and delegate reader.

Method Detail

getCurrent

public T getCurrent()
             throws NoSuchElementException

Gets the current record from the delegate reader.

Specified by:

getCurrent in class Source.Reader<T>

Throws:

NoSuchElementException - if Source.Reader.start() was never called, or if the last Source.Reader.start() or Source.Reader.advance() returned false.

isAtSplitPoint

protected final boolean isAtSplitPoint()

Returns true only for the first record; compressed sources cannot be split.

Overrides:

isAtSplitPoint in class OffsetBasedSource.OffsetBasedReader<T>

startReading

protected final void startReading(ReadableByteChannel channel)
                           throws IOException

Creates a decompressing channel from the input channel and passes it to its delegate reader's FileBasedReader#startReading(ReadableByteChannel).

Specified by:

startReading in class FileBasedSource.FileBasedReader<T>

Parameters:

channel - a byte channel representing the file backing the reader.

Throws:

IOException

readNextRecord

protected final boolean readNextRecord()
                                throws IOException

Reads the next record via the delegate reader.

Specified by:

readNextRecord in class FileBasedSource.FileBasedReader<T>

Returns:

true if a record was successfully read, false if the end of the channel was reached before successfully reading a new record.

Throws:

IOException

getCurrentOffset

protected final long getCurrentOffset()

Returns the delegate reader's current offset in the decompressed input.

Specified by:

getCurrentOffset in class OffsetBasedSource.OffsetBasedReader<T>