| /* |
| * 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.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.StreamFactory; |
| |
| /** |
| * The priority function wraps two topics that represent high priority and low priority task queues. |
| * Each time the priority function is called it will check to see if there are any high priority tasks in the queue. If there |
| * are high priority tasks, then the high priority queue will be read until it returns the EOF Tuple. |
| * |
| * If there are no tasks in the high priority queue, then the lower priority task queue will be opened and read until the EOF Tuple is |
| * returned. |
| * |
| * The scheduler is designed to be wrapped by the executor function and a daemon function can be used to call the executor iteratively. |
| * @since 6.4.0 |
| **/ |
| |
| public class PriorityStream extends TupleStream implements Expressible { |
| |
| private PushBackStream highPriorityTasks; |
| private PushBackStream tasks; |
| private TupleStream currentStream; |
| |
| public PriorityStream(StreamExpression expression, StreamFactory factory) throws IOException { |
| // grab all parameters out |
| List<StreamExpression> streamExpressions = factory.getExpressionOperandsRepresentingTypes(expression, Expressible.class, TupleStream.class); |
| |
| |
| if(2 != streamExpressions.size()){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single stream but found %d",expression, streamExpressions.size())); |
| } |
| |
| TupleStream stream1 = factory.constructStream(streamExpressions.get(0)); |
| TupleStream stream2 = factory.constructStream(streamExpressions.get(1)); |
| |
| if(!(stream1 instanceof TopicStream) || !(stream2 instanceof TopicStream)) { |
| throw new IOException("The scheduler expects both stream parameters to be topics."); |
| } |
| |
| init(new PushBackStream(stream1), new PushBackStream(stream2)); |
| } |
| |
| private void init(PushBackStream stream1, PushBackStream stream2) throws IOException{ |
| this.highPriorityTasks = stream1; |
| this.tasks = stream2; |
| } |
| |
| @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())); |
| |
| // stream |
| if(includeStreams) { |
| if (highPriorityTasks instanceof Expressible) { |
| expression.addParameter(((Expressible) highPriorityTasks).toExpression(factory)); |
| } else { |
| throw new IOException("The SchedulerStream contains a non-expressible TupleStream - it cannot be converted to an expression"); |
| } |
| |
| if (tasks instanceof Expressible) { |
| expression.addParameter(((Expressible) tasks).toExpression(factory)); |
| } else { |
| throw new IOException("The SchedulerStream contains a non-expressible TupleStream - 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[]{ |
| highPriorityTasks.toExplanation(factory), tasks.toExplanation(factory) |
| }) |
| .withFunctionName(factory.getFunctionName(this.getClass())) |
| .withImplementingClass(this.getClass().getName()) |
| .withExpressionType(ExpressionType.STREAM_DECORATOR) |
| .withExpression(toExpression(factory, false).toString()); |
| } |
| |
| public void setStreamContext(StreamContext streamContext) { |
| this.highPriorityTasks.setStreamContext(streamContext); |
| tasks.setStreamContext(streamContext); |
| } |
| |
| public List<TupleStream> children() { |
| List<TupleStream> l = new ArrayList<>(); |
| l.add(highPriorityTasks); |
| l.add(tasks); |
| return l; |
| } |
| |
| public void open() throws IOException { |
| highPriorityTasks.open(); |
| Tuple tuple = highPriorityTasks.read(); |
| if(tuple.EOF) { |
| highPriorityTasks.close(); |
| tasks.open(); |
| currentStream = tasks; |
| } else { |
| highPriorityTasks.pushBack(tuple); |
| currentStream = highPriorityTasks; |
| } |
| } |
| |
| public void close() throws IOException { |
| currentStream.close(); |
| } |
| |
| public Tuple read() throws IOException { |
| return currentStream.read(); |
| } |
| |
| public StreamComparator getStreamSort(){ |
| return null; |
| } |
| |
| public int getCost() { |
| return 0; |
| } |
| } |