| /* |
| * 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.eval; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.solr.client.solrj.io.Tuple; |
| import org.apache.solr.client.solrj.io.stream.StreamContext; |
| 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.StreamExpressionParameter; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| public class FieldValueEvaluator extends SourceEvaluator { |
| private static final long serialVersionUID = 1L; |
| |
| private String fieldName; |
| |
| public FieldValueEvaluator(String fieldName) { |
| if(fieldName.startsWith("'") && fieldName.endsWith("'") && fieldName.length() > 1){ |
| fieldName = fieldName.substring(1, fieldName.length() - 1); |
| } |
| |
| this.fieldName = fieldName; |
| } |
| |
| @Override |
| @SuppressWarnings({"unchecked"}) |
| public Object evaluate(Tuple tuple) throws IOException { |
| Object value = tuple.get(fieldName); |
| |
| // This is somewhat radical. |
| // Here, we allow for the use of the context to provide alternative values |
| // when they are not available in the provided tuple. This means that all |
| // evaluators can evaluate over both a stream's tuple and the context, and |
| // can even evaluate over fields from both of them in the same evaluation |
| if(null == value && null != getStreamContext()){ |
| value = getStreamContext().getLets().get(fieldName); |
| |
| // If what's contained in the context is itself an evaluator then |
| // we need to evaluate it |
| if(value instanceof StreamEvaluator){ |
| value = ((StreamEvaluator)value).evaluate(tuple); |
| } |
| } |
| |
| // if we have an array then convert to an ArrayList |
| // if we have an iterable that is not a list then convert to ArrayList |
| // lists are good to go |
| if(null != value){ |
| if(value instanceof Object[]){ |
| Object[] array = (Object[])value; |
| List<Object> list = new ArrayList<Object>(array.length); |
| for(Object obj : array){ |
| list.add(obj); |
| } |
| return list; |
| } else if(value instanceof Matrix) { |
| return value; |
| } else if(value instanceof VectorFunction) { |
| return value; |
| } else if(value instanceof Iterable && !(value instanceof List<?>)){ |
| Iterable<?> iter = (Iterable<?>)value; |
| List<Object> list = new ArrayList<Object>(); |
| for(Object obj : iter){ |
| list.add(obj); |
| } |
| return list; |
| } |
| } |
| |
| StreamContext sc = getStreamContext(); |
| |
| if(sc != null) {sc.getTupleContext().remove("null");} |
| |
| if(value == null) { |
| if(sc != null) {sc.getTupleContext().put("null", fieldName);} |
| if(fieldName.startsWith("\"") && fieldName.endsWith("\"")) { |
| return fieldName.substring(1, fieldName.length()-1); |
| } else { |
| return null; |
| } |
| } |
| |
| return value; |
| } |
| |
| @Override |
| public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException { |
| return new StreamExpressionValue(fieldName); |
| } |
| |
| @Override |
| public Explanation toExplanation(StreamFactory factory) throws IOException { |
| return new Explanation(nodeId.toString()) |
| .withExpressionType(ExpressionType.EVALUATOR) |
| .withImplementingClass(getClass().getName()) |
| .withExpression(toExpression(factory).toString()); |
| } |
| |
| } |