org.jclouds.collect

Class PagedIterable<E>

java.lang.Object

com.google.common.collect.FluentIterable<IterableWithMarker<E>>

org.jclouds.collect.PagedIterable<E>

All Implemented Interfaces:

Iterable<IterableWithMarker<E>>

@Beta
public abstract class PagedIterable<E>
extends com.google.common.collect.FluentIterable<IterableWithMarker<E>>

Extends FluentIterable allowing you to lazily advance through sequence of pages in a resultset. Typically used in apis that return only a certain number of records at a time. Simplest usage is to employ the concat() convenience function, and one of the methods from FluentIterable.

    // pull in new pages until it we see something interesting.
     Optional firstInterestingBlob = blobstore
         .list(// options //)
         .concat()
         .firstMatch(isInterestingBlob());
 

For those seeking manual control of page advances, don't use concat, and instead look at the value of IterableWithMarker#nextToken.

 PagedIterator blobs = blobstore.list(...).iterator();
 while (blobs.hasNext()) {
     IterableWithMarker page = blobs.next();
     ProcessedResults results = process(page);
     if (results.shouldBeBookmarked() && page.nextMarker().isPresent()) {
         saveBookmark(page.nextMarker().get());
     }
 }
 

Author:

Adrian Cole

Constructor Summary

Constructors

Constructor and Description
PagedIterable()

Method Summary

Methods

Modifier and Type	Method and Description
com.google.common.collect.FluentIterable<E>	concat() Combines all the pages into a single unmodifiable iterable.

Methods inherited from class com.google.common.collect.FluentIterable

allMatch, anyMatch, contains, cycle, filter, filter, first, firstMatch, from, from, get, isEmpty, last, limit, size, skip, toArray, toImmutableList, toImmutableSet, toImmutableSortedSet, toSortedImmutableList, toString, transform, transformAndConcat

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

iterator

Constructor Detail

PagedIterable

public PagedIterable()

Method Detail

concat

public com.google.common.collect.FluentIterable<E> concat()

Combines all the pages into a single unmodifiable iterable. ex.

 FluentIterable blobs = blobstore.list(...).concat();
 for (StorageMetadata blob : blobs) {
     process(blob);
 }
 

See Also:

Iterators.concat(java.util.Iterator<? extends T>, java.util.Iterator<? extends T>)