Package org.apache.maven.index.reader

Class IndexReader

java.lang.Object

org.apache.maven.index.reader.IndexReader

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<ChunkReader>

public class IndexReader
extends Object
implements Iterable<ChunkReader>, Closeable

Maven Index reader that handles incremental updates, if possible, and provides one or more ChunkReaders, to read all the required records. Instances of this class MUST BE handled as resources (have them closed once done with them), it is user responsibility to close them, ideally in try-with-resource block.

Every involved instance, this IndexReader, provided ChunkReader, and used ResourceHandlers are Closeable, and all have to be explicitly closed, best in try-with-resource.

Since:

5.1.2

Constructor Summary

Constructors

Constructor	Description
IndexReader(WritableResourceHandler local, ResourceHandler remote)

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the underlying ResourceHandlers.
List<String>	getChunkNames()	Returns unmodifiable list of actual chunks that needs to be pulled from remote ResourceHandler.
String	getIndexId()	Returns the index context ID that published index has set.
Date	getPublishedTimestamp()	Returns the Date when remote index was last published.
boolean	isIncremental()	Returns true if incremental update is about to happen.
Iterator<ChunkReader>	iterator()	Returns an Iterator of ChunkReaders, that if read in sequence, provide all the (incremental) updates from the index.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Details

IndexReader

public IndexReader(WritableResourceHandler local,
 ResourceHandler remote)
            throws IOException

Throws:

IOException

Method Details

getIndexId

public String getIndexId()

Returns the index context ID that published index has set. Usually it is equal to "repository ID" used in Record.Type.DESCRIPTOR but does not have to be.

getPublishedTimestamp

public Date getPublishedTimestamp()

Returns the Date when remote index was last published.

isIncremental

public boolean isIncremental()

Returns true if incremental update is about to happen. If incremental update, the iterator() will return only the diff from the last update.

getChunkNames

public List<String> getChunkNames()

Returns unmodifiable list of actual chunks that needs to be pulled from remote ResourceHandler. Those are incremental chunks or the big main file, depending on result of isIncremental(). Empty list means local index is up to date, and iterator() will return empty iterator.

close

public void close()
           throws IOException

Closes the underlying ResourceHandlers. In case of incremental update use, it also assumes that user consumed all the iterator and integrated it, hence, it will update the WritableResourceHandler contents to prepare it for future incremental update. If this is not desired (ie. due to aborted update), then this method should NOT be invoked, but rather the ResourceHandlers that caller provided in constructor of this class should be closed manually.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

iterator

public Iterator<ChunkReader> iterator()

Returns an Iterator of ChunkReaders, that if read in sequence, provide all the (incremental) updates from the index. It is caller responsibility to either consume fully this iterator, or to close current ChunkReader if aborting.

Specified by:

iterator in interface Iterable<ChunkReader>