Example usage for com.google.common.collect Iterators transform

Introduction

In this page you can find the example usage for com.google.common.collect Iterators transform.

Prototype

public static <F, T> Iterator<T> transform(final Iterator<F> fromIterator,
        final Function<? super F, ? extends T> function) 

Source Link

Document

Returns an iterator that applies function to each element of fromIterator .

Usage

From source file:org.kiji.schema.impl.cassandra.CassandraKijiResultScanner.java

/**
 * Get an iterator of the entity IDs in a list of Cassandra Kiji tables that correspond to a
 * subset of cassandra tables in a Kiji table.
 *
 * @param tables The Cassandra tables to get Entity IDs from.
 * @param options The scan options. May specify start and stop tokens.
 * @param table The Kiji Cassandra table which the Cassandra tables belong to.
 * @param layout The layout of the Kiji Cassandra table.
 * @return An iterator of Entity IDs./* ww w  . j a  v a  2  s  .c o m*/
 */
public static Iterator<EntityId> getEntityIDs(final List<CassandraTableName> tables,
        final CassandraKijiScannerOptions options, final CassandraKijiTable table,
        final KijiTableLayout layout) {

    final List<ResultSetFuture> localityGroupFutures = FluentIterable.from(tables)
            .transform(new Function<CassandraTableName, Statement>() {
                /** {@inheritDoc} */
                @Override
                public Statement apply(final CassandraTableName tableName) {
                    return CQLUtils.getEntityIDScanStatement(layout, tableName, options);
                }
            }).transform(new Function<Statement, ResultSetFuture>() {
                /** {@inheritDoc} */
                @Override
                public ResultSetFuture apply(final Statement statement) {
                    return table.getAdmin().executeAsync(statement);
                }
            })
            // Force futures to execute by sending results to a list
            .toList();

    // We can use the DISTINCT optimization iff the entity ID contains only hashed components
    RowKeyFormat2 keyFormat = (RowKeyFormat2) layout.getDesc().getKeysFormat();
    final boolean deduplicateComponents = keyFormat.getRangeScanStartIndex() != keyFormat.getComponents()
            .size();

    if (deduplicateComponents) {
        LOG.warn(
                "Scanning a Cassandra Kiji table with non-hashed entity ID components is"
                        + " inefficient.  Consider hashing all entity ID components. Table: {}.",
                table.getURI());
    }

    final List<Iterator<TokenRowKeyComponents>> tokenRowKeyStreams = FluentIterable.from(localityGroupFutures)
            .transform(new Function<ResultSetFuture, Iterator<Row>>() {
                /** {@inheritDoc} */
                @Override
                public Iterator<Row> apply(final ResultSetFuture future) {
                    return CassandraKijiResult.unwrapFuture(future).iterator();
                }
            }).transform(new Function<Iterator<Row>, Iterator<TokenRowKeyComponents>>() {
                /** {@inheritDoc} */
                @Override
                public Iterator<TokenRowKeyComponents> apply(final Iterator<Row> rows) {
                    return Iterators.transform(rows, RowDecoders.getRowKeyDecoderFunction(layout));
                }
            }).transform(new Function<Iterator<TokenRowKeyComponents>, Iterator<TokenRowKeyComponents>>() {
                /** {@inheritDoc} */
                @Override
                public Iterator<TokenRowKeyComponents> apply(final Iterator<TokenRowKeyComponents> components) {
                    if (deduplicateComponents) {
                        return IteratorUtils.deduplicatingIterator(components);
                    } else {
                        return components;
                    }
                }
            }).toList();

    return Iterators.transform(
            IteratorUtils.deduplicatingIterator(
                    Iterators.mergeSorted(tokenRowKeyStreams, TokenRowKeyComponentsComparator.getInstance())),
            RowDecoders.getEntityIdFunction(table));
}

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From source file:org.hashtrees.manager.HashTreesManager.java

private void rebuildAllLocalTrees() {
    Iterator<Callable<Void>> rebuildTasks = Iterators.transform(treeIdProvider.getAllPrimaryTreeIds(),
            new Function<Long, Callable<Void>>() {

                @Override/* www  .  jav  a 2 s  .  c o  m*/
                public Callable<Void> apply(final Long treeId) {
                    return new Callable<Void>() {

                        @Override
                        public Void call() throws IOException {
                            sendRebuildRequestToRemoteTrees(treeId);
                            rebuildHashTree(treeId, fullRebuildPeriod);
                            return null;
                        }
                    };
                }
            });

    LOG.info("Building locally managed trees.");
    TaskQueue<Void> taskQueue = new TaskQueue<Void>(threadPool, rebuildTasks, noOfThreads);
    while (taskQueue.hasNext()) {
        try {
            taskQueue.next().get();
        } catch (ExecutionException | InterruptedException e) {
            LOG.info("Failure occurred in build task.", e);
        }
        if (hasStopRequested()) {
            taskQueue.stopAsync();
        }
    }
    LOG.info("No of successful/failed rebuild tasks : " + taskQueue.getPasseTasksCount() + "/"
            + taskQueue.getFailedTasksCount());
    LOG.info("Building locally managed trees - Done");
}

---

From source file:kn.uni.gis.dataimport.util.GeoUtil.java

public static CPolygon polygonAt(ResultSet object, int index) throws SQLException {
    PGgeometry geo = (PGgeometry) object.getObject(index);
    CPolygon cPolygon = new CPolygon(ImmutableList
            .copyOf((Iterators.transform(pointIterator(geo.getGeometry()), new Function<Point, CPoint>() {
                @Override/*  www . java2s  . com*/
                public CPoint apply(Point input) {
                    return new CPoint(input.getX(), input.getY());
                }
            }))));
    return cPolygon;
}

---

From source file:org.jglue.totorom.GlobalVertexTraversal.java

public Iterator iterator() {
    return Iterators.transform(simpleIterator(), new Function() {

        public Object apply(Object e) {
            return graph.frameElement((Element) e, FramedVertex.class);
        }//from  w ww .  jav a2 s  . co  m
    });
}

---

From source file:com.google.cloud.genomics.localrepo.vcf.VCFReader.java

/**
 * Read the VCF data and pass the data to the provided {@code Callback}.
 *//*w  ww  . ja v a  2s .  c  om*/
public <X> X read(Callback<X> callback) throws Exception {
    final PeekingIterator<String> iterator = Iterators.peekingIterator(new AbstractIterator<String>() {
        @Override
        protected String computeNext() {
            try {
                String line = in.readLine();
                return null == line ? endOfData() : line;
            } catch (IOException e) {
                throw Throwables.propagate(e);
            }
        }
    });
    return callback.readVcf(parseMetaInfo(iterator), parseHeader(iterator), new FluentIterable<VCFRecord>() {
        @Override
        public Iterator<VCFRecord> iterator() {
            return Iterators.transform(Iterators.filter(iterator, IS_NOT_EMPTY), PARSE_RECORD);
        }
    });
}

---

From source file:org.locationtech.geogig.porcelain.RemoveOp.java

private void stageDeletes(Iterator<NodeRef> trees, Iterator<String> features) {
    final StagingArea index = stagingArea();

    Iterator<DiffEntry> treeDeletes = Iterators.transform(trees, (treeRef) -> new DiffEntry(treeRef, null));

    Iterator<DiffEntry> featureDeletes = Iterators.transform(features, (featurePath) -> {
        Node node = Node.create(NodeRef.nodeFromPath(featurePath), ObjectId.NULL, ObjectId.NULL, TYPE.FEATURE,
                null);/*from   www.ja  v  a2  s.  c o m*/
        String parentPath = NodeRef.parentPath(featurePath);
        NodeRef oldFeature = new NodeRef(node, parentPath, ObjectId.NULL);
        return new DiffEntry(oldFeature, null);
    });

    ProgressListener progress = DefaultProgressListener.NULL;
    index.stage(progress, Iterators.concat(treeDeletes, featureDeletes), -1);
}

---

From source file:org.geogig.osm.cli.commands.OSMExport.java

private Iterator<EntityContainer> getFeatures(String ref) {
    Optional<ObjectId> id = geogig.command(RevParse.class).setRefSpec(ref).call();
    if (!id.isPresent()) {
        return Collections.emptyIterator();
    }//  w ww . j a  va2  s .c  om
    LsTreeOp op = geogig.command(LsTreeOp.class).setStrategy(Strategy.DEPTHFIRST_ONLY_FEATURES)
            .setReference(ref);
    if (bbox != null) {
        final Envelope env;
        try {
            env = new Envelope(Double.parseDouble(bbox.get(0)), Double.parseDouble(bbox.get(2)),
                    Double.parseDouble(bbox.get(1)), Double.parseDouble(bbox.get(3)));
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Wrong bbox definition");
        }
        Predicate<Bounded> filter = new Predicate<Bounded>() {
            @Override
            public boolean apply(final Bounded bounded) {
                boolean intersects = bounded.intersects(env);
                return intersects;
            }
        };
        op.setBoundsFilter(filter);
    }
    Iterator<NodeRef> iterator = op.call();
    final EntityConverter converter = new EntityConverter();
    final Function<NodeRef, EntityContainer> function = (nr) -> {
        RevFeature revFeature = geogig.command(RevObjectParse.class).setObjectId(nr.getObjectId())
                .call(RevFeature.class).get();
        SimpleFeatureType featureType;
        if (nr.path().startsWith(OSMUtils.NODE_TYPE_NAME)) {
            featureType = OSMUtils.nodeType();
        } else {
            featureType = OSMUtils.wayType();
        }
        SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(featureType);
        RevFeatureType revFeatureType = RevFeatureTypeBuilder.build(featureType);
        List<PropertyDescriptor> descriptors = revFeatureType.descriptors();
        for (int i = 0; i < descriptors.size(); i++) {
            PropertyDescriptor descriptor = descriptors.get(i);
            Optional<Object> value = revFeature.get(i);
            featureBuilder.set(descriptor.getName(), value.orNull());
        }
        SimpleFeature feature = featureBuilder.buildFeature(nr.name());
        Entity entity = converter.toEntity(feature, null);
        EntityContainer container;
        if (entity instanceof Node) {
            container = new NodeContainer((Node) entity);
        } else {
            container = new WayContainer((Way) entity);
        }

        return container;
    };
    return Iterators.transform(iterator, function);
}

---

From source file:qdg.StaticMixedIdGraph.java

@Override
public Iterator<Edge> getIncidentArcIterator(Node node) {
    return Iterators.transform(new ConcatIterator<Integer>(arcLace.getOutArcIterator(((N) node).getId()),
            arcLace.getInArcIterator(((N) node).getId())), constructArc);
}

---

From source file:org.geogit.osm.out.cli.OSMExport.java

private Iterator<EntityContainer> getFeatures(String ref) {
    Optional<ObjectId> id = geogit.command(RevParse.class).setRefSpec(ref).call();
    if (!id.isPresent()) {
        return Iterators.emptyIterator();
    }//from   w  w w  .j  ava  2s .  c om
    LsTreeOp op = geogit.command(LsTreeOp.class).setStrategy(Strategy.DEPTHFIRST_ONLY_FEATURES)
            .setReference(ref);
    if (bbox != null) {
        final Envelope env;
        try {
            env = new Envelope(Double.parseDouble(bbox.get(0)), Double.parseDouble(bbox.get(2)),
                    Double.parseDouble(bbox.get(1)), Double.parseDouble(bbox.get(3)));
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Wrong bbox definition");
        }
        Predicate<Bounded> filter = new Predicate<Bounded>() {
            @Override
            public boolean apply(final Bounded bounded) {
                boolean intersects = bounded.intersects(env);
                return intersects;
            }
        };
        op.setBoundsFilter(filter);
    }
    Iterator<NodeRef> iterator = op.call();
    final EntityConverter converter = new EntityConverter();
    Function<NodeRef, EntityContainer> function = new Function<NodeRef, EntityContainer>() {

        @Override
        @Nullable
        public EntityContainer apply(@Nullable NodeRef ref) {
            RevFeature revFeature = geogit.command(RevObjectParse.class).setObjectId(ref.objectId())
                    .call(RevFeature.class).get();
            SimpleFeatureType featureType;
            if (ref.path().startsWith(OSMUtils.NODE_TYPE_NAME)) {
                featureType = OSMUtils.nodeType();
            } else {
                featureType = OSMUtils.wayType();
            }
            SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(featureType);
            RevFeatureType revFeatureType = RevFeatureType.build(featureType);
            List<PropertyDescriptor> descriptors = revFeatureType.sortedDescriptors();
            ImmutableList<Optional<Object>> values = revFeature.getValues();
            for (int i = 0; i < descriptors.size(); i++) {
                PropertyDescriptor descriptor = descriptors.get(i);
                Optional<Object> value = values.get(i);
                featureBuilder.set(descriptor.getName(), value.orNull());
            }
            SimpleFeature feature = featureBuilder.buildFeature(ref.name());
            Entity entity = converter.toEntity(feature);
            EntityContainer container;
            if (entity instanceof Node) {
                container = new NodeContainer((Node) entity);
            } else {
                container = new WayContainer((Way) entity);
            }

            return container;

        }

    };
    return Iterators.transform(iterator, function);
}

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