| /* |
| * 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.accumulo; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static java.util.Objects.requireNonNull; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.rya.api.domain.RyaType; |
| import org.apache.rya.api.resolver.RdfToRyaConversions; |
| import org.eclipse.rdf4j.model.IRI; |
| import org.eclipse.rdf4j.model.Value; |
| import org.eclipse.rdf4j.model.ValueFactory; |
| import org.eclipse.rdf4j.model.impl.SimpleValueFactory; |
| import org.eclipse.rdf4j.model.vocabulary.XMLSchema; |
| import org.eclipse.rdf4j.query.BindingSet; |
| import org.eclipse.rdf4j.query.algebra.evaluation.QueryBindingSet; |
| import org.eclipse.rdf4j.query.impl.MapBindingSet; |
| |
| import com.google.common.base.Joiner; |
| |
| import edu.umd.cs.findbugs.annotations.DefaultAnnotation; |
| import edu.umd.cs.findbugs.annotations.NonNull; |
| |
| /** |
| * Converts {@link BindingSet}s to Strings and back again. The Strings do not |
| * include the binding names and are ordered with a {@link VariableOrder}. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public class BindingSetStringConverter implements BindingSetConverter<String> { |
| |
| public static final String BINDING_DELIM = ":::"; |
| public static final String TYPE_DELIM = "<<~>>"; |
| public static final String NULL_VALUE_STRING = Character.toString( '\0' ); |
| |
| private static final ValueFactory VF = SimpleValueFactory.getInstance(); |
| |
| @Override |
| public String convert(final BindingSet bindingSet, final VariableOrder varOrder) { |
| requireNonNull(bindingSet); |
| requireNonNull(varOrder); |
| |
| // Convert each Binding to a String. |
| final List<String> bindingStrings = new ArrayList<>(); |
| for(final String varName : varOrder) { |
| if(bindingSet.hasBinding(varName)) { |
| // Add a value to the binding set. |
| final Value value = bindingSet.getBinding(varName).getValue(); |
| final RyaType ryaValue = RdfToRyaConversions.convertValue(value); |
| final String bindingString = ryaValue.getData() + TYPE_DELIM + ryaValue.getDataType(); |
| bindingStrings.add(bindingString); |
| } else { |
| // Add a null value to the binding set. |
| bindingStrings.add(NULL_VALUE_STRING); |
| } |
| } |
| |
| // Join the bindings using the binding delim. |
| return Joiner.on(BINDING_DELIM).join(bindingStrings); |
| } |
| |
| @Override |
| public BindingSet convert(final String bindingSetString, final VariableOrder varOrder) { |
| requireNonNull(bindingSetString); |
| requireNonNull(varOrder); |
| |
| // If both are empty, return an empty binding set. |
| if(bindingSetString.isEmpty() && varOrder.toString().isEmpty()) { |
| return new MapBindingSet(); |
| } |
| |
| // Otherwise parse it. |
| final String[] bindingStrings = bindingSetString.split(BINDING_DELIM); |
| final String[] varOrderArr = varOrder.toArray(); |
| checkArgument(varOrderArr.length == bindingStrings.length, "The number of Bindings must match the length of the VariableOrder."); |
| |
| final QueryBindingSet bindingSet = new QueryBindingSet(); |
| for(int i = 0; i < bindingStrings.length; i++) { |
| final String bindingString = bindingStrings[i]; |
| if(!NULL_VALUE_STRING.equals(bindingString)) { |
| final String name = varOrderArr[i]; |
| final Value value = toValue(bindingStrings[i]); |
| bindingSet.addBinding(name, value); |
| } |
| } |
| return bindingSet; |
| } |
| |
| /** |
| * Creates a {@link Value} from a String representation of it. |
| * |
| * @param valueString - The String representation of the value. (not null) |
| * @return The {@link Value} representation of the String. |
| */ |
| protected static Value toValue(final String valueString) { |
| requireNonNull(valueString); |
| |
| // Split the String that was stored in Fluo into its Value and Type parts. |
| final String[] valueAndType = valueString.split(TYPE_DELIM); |
| if(valueAndType.length != 2) { |
| throw new IllegalArgumentException("Array must contain data and type info!"); |
| } |
| |
| final String dataString = valueAndType[0]; |
| final String typeString = valueAndType[1]; |
| |
| // Convert the String Type into a IRI that describes the type. |
| final IRI typeIRI = VF.createIRI(typeString); |
| |
| // Convert the String Value into a Value. |
| final Value value = typeIRI.equals(XMLSchema.ANYURI) ? |
| VF.createIRI(dataString) : |
| VF.createLiteral(dataString, VF.createIRI(typeString)); |
| |
| return value; |
| } |
| } |