/* Copyright (c) 2014 Boundless and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Distribution License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/org/documents/edl-v10.html
*
* Contributors:
* Victor Olaya (Boundless) - initial implementation
*/
package org.locationtech.geogig.geotools.plumbing;
import static com.google.common.base.Preconditions.checkArgument;
import java.io.IOException;
import java.util.Iterator;
import javax.annotation.Nullable;
import org.geotools.data.DefaultTransaction;
import org.geotools.data.Transaction;
import org.geotools.data.simple.SimpleFeatureStore;
import org.geotools.factory.Hints;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureIterator;
import org.geotools.feature.collection.BaseFeatureCollection;
import org.geotools.feature.collection.DelegateFeatureIterator;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.locationtech.geogig.api.AbstractGeoGigOp;
import org.locationtech.geogig.api.NodeRef;
import org.locationtech.geogig.api.ObjectId;
import org.locationtech.geogig.api.ProgressListener;
import org.locationtech.geogig.api.RevFeature;
import org.locationtech.geogig.api.RevFeatureType;
import org.locationtech.geogig.api.RevFeatureTypeImpl;
import org.locationtech.geogig.api.RevObject.TYPE;
import org.locationtech.geogig.api.RevTree;
import org.locationtech.geogig.api.plumbing.FindTreeChild;
import org.locationtech.geogig.api.plumbing.ResolveTreeish;
import org.locationtech.geogig.api.plumbing.diff.DiffEntry;
import org.locationtech.geogig.api.porcelain.DiffOp;
import org.locationtech.geogig.geotools.plumbing.GeoToolsOpException.StatusCode;
import org.locationtech.geogig.storage.ObjectDatabase;
import org.opengis.feature.Feature;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.base.Predicates;
import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import com.google.common.collect.UnmodifiableIterator;
/**
* Internal operation for creating a FeatureCollection from a tree content.
*
*/
public class ExportDiffOp extends AbstractGeoGigOp<SimpleFeatureStore> {
private static final Function<Feature, Optional<Feature>> IDENTITY = new Function<Feature, Optional<Feature>>() {
@Override
@Nullable
public Optional<Feature> apply(@Nullable Feature feature) {
return Optional.fromNullable(feature);
}
};
private String path;
private Supplier<SimpleFeatureStore> targetStoreProvider;
private Function<Feature, Optional<Feature>> function = IDENTITY;
private boolean transactional;
private boolean old;
private String newRef;
private String oldRef;
/**
* Executes the export operation using the parameters that have been specified.
*
* @return a FeatureCollection with the specified features
*/
@Override
protected SimpleFeatureStore _call() {
final SimpleFeatureStore targetStore = getTargetStore();
final String refspec = old ? oldRef : newRef;
final RevTree rootTree = resolveRootTree(refspec);
final NodeRef typeTreeRef = resolTypeTreeRef(refspec, path, rootTree);
final ObjectId defaultMetadataId = typeTreeRef.getMetadataId();
final ProgressListener progressListener = getProgressListener();
progressListener.started();
progressListener.setDescription("Exporting diffs for path '" + path + "'... ");
FeatureCollection<SimpleFeatureType, SimpleFeature> asFeatureCollection = new BaseFeatureCollection<SimpleFeatureType, SimpleFeature>() {
@Override
public FeatureIterator<SimpleFeature> features() {
Iterator<DiffEntry> diffs = command(DiffOp.class).setOldVersion(oldRef)
.setNewVersion(newRef).setFilter(path).call();
final Iterator<SimpleFeature> plainFeatures = getFeatures(diffs, old, stagingDatabase(),
defaultMetadataId, progressListener);
Iterator<Optional<Feature>> transformed = Iterators.transform(plainFeatures,
ExportDiffOp.this.function);
Iterator<SimpleFeature> filtered = Iterators.filter(Iterators.transform(
transformed, new Function<Optional<Feature>, SimpleFeature>() {
@Override
public SimpleFeature apply(Optional<Feature> input) {
return (SimpleFeature) (input.isPresent() ? input.get() : null);
}
}), Predicates.notNull());
return new DelegateFeatureIterator<SimpleFeature>(filtered);
}
};
// add the feature collection to the feature store
final Transaction transaction;
if (transactional) {
transaction = new DefaultTransaction("create");
} else {
transaction = Transaction.AUTO_COMMIT;
}
try {
targetStore.setTransaction(transaction);
try {
targetStore.addFeatures(asFeatureCollection);
transaction.commit();
} catch (final Exception e) {
if (transactional) {
transaction.rollback();
}
Throwables.propagateIfInstanceOf(e, GeoToolsOpException.class);
throw new GeoToolsOpException(e, StatusCode.UNABLE_TO_ADD);
} finally {
transaction.close();
}
} catch (IOException e) {
throw new GeoToolsOpException(e, StatusCode.UNABLE_TO_ADD);
}
progressListener.complete();
return targetStore;
}
private static Iterator<SimpleFeature> getFeatures(Iterator<DiffEntry> diffs,
final boolean old, final ObjectDatabase database, final ObjectId metadataId,
final ProgressListener progressListener) {
final SimpleFeatureType featureType = addFidAttribute(database.getFeatureType(metadataId));
final RevFeatureType revFeatureType = RevFeatureTypeImpl.build(featureType);
final SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(featureType);
Function<DiffEntry, SimpleFeature> asFeature = new Function<DiffEntry, SimpleFeature>() {
@Override
@Nullable
public SimpleFeature apply(final DiffEntry input) {
NodeRef nodeRef = old ? input.getOldObject() : input.getNewObject();
if (nodeRef == null) {
return null;
}
final RevFeature revFeature = database.getFeature(nodeRef.objectId());
ImmutableList<Optional<Object>> values = revFeature.getValues();
for (int i = 0; i < values.size(); i++) {
String name = featureType.getDescriptor(i + 1).getLocalName();
Object value = values.get(i).orNull();
featureBuilder.set(name, value);
}
featureBuilder.set("geogig_fid", nodeRef.name());
Feature feature = featureBuilder.buildFeature(nodeRef.name());
feature.getUserData().put(Hints.USE_PROVIDED_FID, true);
feature.getUserData().put(RevFeature.class, revFeature);
feature.getUserData().put(RevFeatureType.class, revFeatureType);
if (feature instanceof SimpleFeature) {
return (SimpleFeature) feature;
}
return null;
}
};
Iterator<SimpleFeature> asFeatures = Iterators.transform(diffs, asFeature);
UnmodifiableIterator<SimpleFeature> filterNulls = Iterators.filter(asFeatures,
Predicates.notNull());
return filterNulls;
}
private static SimpleFeatureType addFidAttribute(RevFeatureType revFType) {
SimpleFeatureType featureType = (SimpleFeatureType) revFType.type();
SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
builder.add("geogig_fid", String.class);
for (AttributeDescriptor descriptor : featureType.getAttributeDescriptors()) {
builder.add(descriptor);
}
builder.setName(featureType.getName());
builder.setCRS(featureType.getCoordinateReferenceSystem());
featureType = builder.buildFeatureType();
return featureType;
}
private NodeRef resolTypeTreeRef(final String refspec, final String treePath,
final RevTree rootTree) {
Optional<NodeRef> typeTreeRef = command(FindTreeChild.class).setIndex(true)
.setParent(rootTree).setChildPath(treePath).call();
checkArgument(typeTreeRef.isPresent(), "Type tree %s does not exist", refspec);
checkArgument(TYPE.TREE.equals(typeTreeRef.get().getType()),
"%s did not resolve to a tree", refspec);
return typeTreeRef.get();
}
private RevTree resolveRootTree(final String refspec) {
Optional<ObjectId> rootTreeId = command(ResolveTreeish.class).setTreeish(refspec).call();
checkArgument(rootTreeId.isPresent(), "Invalid tree spec: %s", refspec);
RevTree rootTree = stagingDatabase().getTree(rootTreeId.get());
return rootTree;
}
private SimpleFeatureStore getTargetStore() {
SimpleFeatureStore targetStore;
try {
targetStore = targetStoreProvider.get();
} catch (Exception e) {
throw new GeoToolsOpException(StatusCode.CANNOT_CREATE_FEATURESTORE);
}
if (targetStore == null) {
throw new GeoToolsOpException(StatusCode.CANNOT_CREATE_FEATURESTORE);
}
return targetStore;
}
/**
*
* @param featureStore a supplier that resolves to the feature store to use for exporting
* @return
*/
public ExportDiffOp setFeatureStore(Supplier<SimpleFeatureStore> featureStore) {
this.targetStoreProvider = featureStore;
return this;
}
/**
*
* @param featureStore the feature store to use for exporting The schema of the feature store
* must be equal to the one of the layer whose diffs are to be exported, plus an
* additional "geogig_fid" field of type String, which is used to include the id of each
* feature.
*
* @return
*/
public ExportDiffOp setFeatureStore(SimpleFeatureStore featureStore) {
this.targetStoreProvider = Suppliers.ofInstance(featureStore);
return this;
}
/**
* @param path the path to export
* @return {@code this}
*/
public ExportDiffOp setPath(String path) {
this.path = path;
return this;
}
/**
* Sets the function to use for creating a valid Feature that has the FeatureType of the output
* FeatureStore, based on the actual FeatureType of the Features to export.
*
* The Export operation assumes that the feature returned by this function are valid to be added
* to the current FeatureSource, and, therefore, performs no checking of FeatureType matching.
* It is up to the user performing the export to ensure that the function actually generates
* valid features for the current FeatureStore.
*
* If no function is explicitly set, an identity function is used, and Features are not
* converted.
*
* This function can be used as a filter as well. If the returned object is Optional.absent, no
* feature will be added
*
* @param function
* @return {@code this}
*/
public ExportDiffOp setFeatureTypeConversionFunction(
Function<Feature, Optional<Feature>> function) {
this.function = function == null ? IDENTITY : function;
return this;
}
/**
* @param transactional whether to use a geotools transaction for the operation, defaults to
* {@code true}
*/
public ExportDiffOp setTransactional(boolean transactional) {
this.transactional = transactional;
return this;
}
public ExportDiffOp setNewRef(String newRef) {
this.newRef = newRef;
return this;
}
public ExportDiffOp setOldRef(String oldRef) {
this.oldRef = oldRef;
return this;
}
public ExportDiffOp setUseOld(boolean old) {
this.old = old;
return this;
}
}