org.apache.druid.data.input.impl.prefetch

Class Fetcher<T>

java.lang.Object

org.apache.druid.data.input.impl.prefetch.Fetcher<T>

All Implemented Interfaces:

Iterator<org.apache.druid.data.input.impl.prefetch.OpenedObject<T>>

Direct Known Subclasses:

FileFetcher, SqlFetcher

public abstract class Fetcher<T>
extends Object
implements Iterator<org.apache.druid.data.input.impl.prefetch.OpenedObject<T>>

A file fetcher used by PrefetchableTextFilesFirehoseFactory and PrefetchSqlFirehoseFactory. See the javadoc of PrefetchableTextFilesFirehoseFactory for more details.

Method Summary

Modifier and Type	Method and Description
protected abstract long	download(T object, File outFile) Downloads an object into a file.
protected abstract org.apache.druid.data.input.impl.prefetch.OpenedObject<T>	generateOpenObject(T object) Generates an instance of OpenedObject for the given object.
boolean	hasNext()
org.apache.druid.data.input.impl.prefetch.OpenedObject<T>	next()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Method Detail

download

protected abstract long download(T object,
                                 File outFile)
                          throws IOException

Downloads an object into a file. The download process could be retried depending on the object source.

Parameters:

object - an object to be downloaded

outFile - a file which the object data is stored

Returns:

number of downloaded bytes

Throws:

IOException

generateOpenObject

protected abstract org.apache.druid.data.input.impl.prefetch.OpenedObject<T> generateOpenObject(T object)
                                                                                         throws IOException

Generates an instance of OpenedObject for the given object.

Throws:

IOException

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<org.apache.druid.data.input.impl.prefetch.OpenedObject<T>>

next

public org.apache.druid.data.input.impl.prefetch.OpenedObject<T> next()

Specified by:

next in interface Iterator<org.apache.druid.data.input.impl.prefetch.OpenedObject<T>>