Github user isper3at commented on a diff in the pull request:
https://github.com/apache/incubator-rya/pull/172#discussion_r160810774
--- Diff:
extras/rya.indexing.pcj/src/main/java/org/apache/rya/indexing/pcj/storage/mongo/MongoPcjDocuments.java
---
@@ -0,0 +1,438 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.rya.indexing.pcj.storage.mongo;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.accumulo.core.security.Authorizations;
+import org.apache.rya.api.domain.RyaType;
+import org.apache.rya.api.resolver.RdfToRyaConversions;
+import org.apache.rya.api.resolver.RyaToRdfConversions;
+import org.apache.rya.indexing.pcj.storage.PcjMetadata;
+import
org.apache.rya.indexing.pcj.storage.PrecomputedJoinStorage.CloseableIterator;
+import
org.apache.rya.indexing.pcj.storage.PrecomputedJoinStorage.PCJStorageException;
+import org.apache.rya.indexing.pcj.storage.accumulo.PcjVarOrderFactory;
+import org.apache.rya.indexing.pcj.storage.accumulo.ShiftVarOrderFactory;
+import org.apache.rya.indexing.pcj.storage.accumulo.VariableOrder;
+import org.apache.rya.indexing.pcj.storage.accumulo.VisibilityBindingSet;
+import org.bson.Document;
+import org.bson.conversions.Bson;
+import org.openrdf.model.URI;
+import org.openrdf.model.Value;
+import org.openrdf.model.impl.URIImpl;
+import org.openrdf.query.BindingSet;
+import org.openrdf.query.MalformedQueryException;
+import org.openrdf.query.QueryEvaluationException;
+import org.openrdf.query.QueryLanguage;
+import org.openrdf.query.TupleQuery;
+import org.openrdf.query.TupleQueryResult;
+import org.openrdf.query.impl.MapBindingSet;
+import org.openrdf.repository.RepositoryConnection;
+import org.openrdf.repository.RepositoryException;
+
+import com.mongodb.MongoClient;
+import com.mongodb.client.FindIterable;
+import com.mongodb.client.MongoCollection;
+import com.mongodb.util.JSON;
+
+/**
+ * Creates and modifies PCJs in MongoDB. PCJ's are stored as follows:
+ *
+ * <pre>
+ * <code>
+ * ----- PCJ Metadata Doc -----
+ * {
+ * _id: [table_name]_METADATA,
+ * sparql: [sparql query to match results],
+ * cardinality: [number of results]
+ * }
+ *
+ * ----- PCJ Results Doc -----
+ * {
+ * pcjName: [table_name],
+ * auths: [auths]
+ * [binding_var1]: {
+ * uri: [type_uri],
+ * value: value
+ * }
+ * .
+ * .
+ * .
+ * [binding_varn]: {
+ * uri: [type_uri],
+ * value: value
+ * }
+ * }
+ * </code>
+ * </pre>
+ */
+public class MongoPcjDocuments {
+ public static final String PCJ_COLLECTION_NAME = "pcjs";
+
+ // metadata fields
+ public static final String CARDINALITY_FIELD = "cardinality";
+ public static final String SPARQL_FIELD = "sparql";
+ public static final String PCJ_ID = "_id";
+ public static final String VAR_ORDER_ID = "varOrders";
+
+ // pcj results fields
+ private static final String BINDING_VALUE = "value";
+ private static final String BINDING_TYPE = "uri";
+ private static final String AUTHS_FIELD = "auths";
+ private static final String PCJ_NAME = "pcjName";
+
+ private final MongoCollection<Document> pcjCollection;
+ private static final PcjVarOrderFactory pcjVarOrderFactory = new
ShiftVarOrderFactory();
+
+ /**
+ * Creates a new {@link MongoPcjDocuments}.
+ * @param client - The {@link MongoClient} to use to connect to mongo.
+ * @param ryaInstanceName - The rya instance to connect to.
+ */
+ public MongoPcjDocuments(final MongoClient client, final String
ryaInstanceName) {
+ requireNonNull(client);
+ requireNonNull(ryaInstanceName);
+ pcjCollection =
client.getDatabase(ryaInstanceName).getCollection(PCJ_COLLECTION_NAME);
+ }
+
+ private String getMetadataID(final String pcjName) {
+ return pcjName + "_METADATA";
+ }
+
+ /**
+ * Creates a {@link Document} containing the metadata defining the PCj.
+ * @param pcjName - The name of the PCJ. (not null)
--- End diff --
the pcjName is generated by the PCJIdFactory. the reason I tack the
metadata at the end is for easy lookups, so when listing PCJ's I can just grab
every document that ends in METADATA.
---
