| /* |
| * 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.solr.client.solrj.io.stream; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Locale; |
| |
| import org.apache.solr.client.solrj.io.Tuple; |
| import org.apache.solr.client.solrj.io.comp.StreamComparator; |
| import org.apache.solr.client.solrj.io.eq.FieldEqualitor; |
| import org.apache.solr.client.solrj.io.eq.StreamEqualitor; |
| import org.apache.solr.client.solrj.io.ops.DistinctOperation; |
| import org.apache.solr.client.solrj.io.stream.expr.Explanation; |
| import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType; |
| import org.apache.solr.client.solrj.io.stream.expr.Expressible; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExplanation; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionNamedParameter; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| |
| /** |
| * The UniqueStream emits a unique stream of Tuples based on a Comparator. |
| * |
| * Note: The sort order of the underlying stream must match the Comparator. |
| * @since 5.1.0 |
| **/ |
| |
| public class UniqueStream extends TupleStream implements Expressible { |
| |
| private static final long serialVersionUID = 1; |
| |
| private TupleStream originalStream; |
| private StreamEqualitor originalEqualitor; |
| |
| private ReducerStream reducerStream; |
| |
| public UniqueStream(TupleStream stream, StreamEqualitor eq) throws IOException { |
| init(stream,eq); |
| } |
| |
| public UniqueStream(StreamExpression expression,StreamFactory factory) throws IOException { |
| // grab all parameters out |
| List<StreamExpression> streamExpressions = factory.getExpressionOperandsRepresentingTypes(expression, Expressible.class, TupleStream.class); |
| StreamExpressionNamedParameter overExpression = factory.getNamedOperand(expression, "over"); |
| |
| // validate expression contains only what we want. |
| if(expression.getParameters().size() != streamExpressions.size() + 1){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - unknown operands found", expression)); |
| } |
| |
| if(1 != streamExpressions.size()){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single stream but found %d",expression, streamExpressions.size())); |
| } |
| |
| if(null == overExpression || !(overExpression.getParameter() instanceof StreamExpressionValue)){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting single 'over' parameter listing fields to unique over but didn't find one",expression)); |
| } |
| |
| init(factory.constructStream(streamExpressions.get(0)), factory.constructEqualitor(((StreamExpressionValue)overExpression.getParameter()).getValue(), FieldEqualitor.class)); |
| } |
| |
| private void init(TupleStream stream, StreamEqualitor eq) throws IOException{ |
| this.originalStream = stream; |
| this.originalEqualitor = eq; |
| |
| this.reducerStream = new ReducerStream(stream, eq, new DistinctOperation()); |
| |
| if(!eq.isDerivedFrom(stream.getStreamSort())){ |
| throw new IOException("Invalid UniqueStream - substream comparator (sort) must be a superset of this stream's equalitor."); |
| } |
| } |
| |
| @Override |
| public StreamExpression toExpression(StreamFactory factory) throws IOException{ |
| return toExpression(factory, true); |
| } |
| |
| private StreamExpression toExpression(StreamFactory factory, boolean includeStreams) throws IOException { |
| // function name |
| StreamExpression expression = new StreamExpression(factory.getFunctionName(this.getClass())); |
| |
| if(includeStreams){ |
| // streams |
| if(originalStream instanceof Expressible){ |
| expression.addParameter(((Expressible)originalStream).toExpression(factory)); |
| } |
| else{ |
| throw new IOException("This UniqueStream contains a non-expressible TupleStream - it cannot be converted to an expression"); |
| } |
| } |
| else{ |
| expression.addParameter("<stream>"); |
| } |
| |
| // over |
| if(originalEqualitor instanceof Expressible){ |
| expression.addParameter(new StreamExpressionNamedParameter("over",((Expressible)originalEqualitor).toExpression(factory))); |
| } |
| else{ |
| throw new IOException("This UniqueStream contains a non-expressible equalitor - it cannot be converted to an expression"); |
| } |
| |
| return expression; |
| } |
| |
| @Override |
| public Explanation toExplanation(StreamFactory factory) throws IOException { |
| |
| return new StreamExplanation(getStreamNodeId().toString()) |
| .withChildren(new Explanation[] { |
| originalStream.toExplanation(factory) |
| // we're not including that this is wrapped with a ReducerStream stream because that's just an implementation detail |
| }) |
| .withFunctionName(factory.getFunctionName(this.getClass())) |
| .withImplementingClass(this.getClass().getName()) |
| .withExpressionType(ExpressionType.STREAM_DECORATOR) |
| .withExpression(toExpression(factory, false).toString()) |
| .withHelper(originalEqualitor.toExplanation(factory)); |
| } |
| |
| public void setStreamContext(StreamContext context) { |
| this.originalStream.setStreamContext(context); |
| this.reducerStream.setStreamContext(context); |
| } |
| |
| public List<TupleStream> children() { |
| List<TupleStream> l = new ArrayList<TupleStream>(); |
| l.add(originalStream); |
| return l; |
| } |
| |
| public void open() throws IOException { |
| reducerStream.open(); |
| // opens originalStream as well |
| } |
| |
| public void close() throws IOException { |
| reducerStream.close(); |
| // closes originalStream as well |
| } |
| |
| public Tuple read() throws IOException { |
| return reducerStream.read(); |
| } |
| |
| /** Return the stream sort - ie, the order in which records are returned */ |
| public StreamComparator getStreamSort(){ |
| return reducerStream.getStreamSort(); |
| } |
| |
| public int getCost() { |
| return 0; |
| } |
| |
| } |