| /* |
| * 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.search.function; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.queries.function.FunctionValues; |
| import org.apache.lucene.queries.function.ValueSource; |
| import org.apache.lucene.queries.function.valuesource.SimpleFloatFunction; |
| import org.apache.solr.common.util.NamedList; |
| import org.apache.solr.search.FunctionQParser; |
| import org.apache.solr.search.SyntaxError; |
| import org.apache.solr.search.ValueSourceParser; |
| |
| /** |
| * A sample ValueSourceParser for testing. Approximates the oracle NVL function, |
| * letting you substitute a value when a "null" is encountered. In this case, |
| * null is approximated by a float value, since ValueSource always returns a |
| * float, even if the field is undefined for a document. |
| * |
| * Initialization parameters: |
| * - nvlFloatValue: float value to consider as "NULL" when seen in a field. defaults to 0.0f. |
| * |
| * Example: |
| * nvl(vs,2) will return 2 if the vs is NULL (as defined by nvlFloatValue above) or the doc value otherwise |
| * |
| */ |
| public class NvlValueSourceParser extends ValueSourceParser { |
| |
| /** |
| * Value to consider "null" when found in a ValueSource Defaults to 0.0 |
| */ |
| private float nvlFloatValue = 0.0f; |
| |
| @Override |
| public ValueSource parse(FunctionQParser fp) throws SyntaxError { |
| ValueSource source = fp.parseValueSource(); |
| final float nvl = fp.parseFloat(); |
| |
| return new SimpleFloatFunction(source) { |
| @Override |
| protected String name() { |
| return "nvl"; |
| } |
| |
| @Override |
| protected float func(int doc, FunctionValues vals) throws IOException { |
| float v = vals.floatVal(doc); |
| if (v == nvlFloatValue) { |
| return nvl; |
| } else { |
| return v; |
| } |
| } |
| }; |
| } |
| |
| @Override |
| public void init(@SuppressWarnings({"rawtypes"})NamedList args) { |
| /* initialize the value to consider as null */ |
| Float nvlFloatValueArg = (Float) args.get("nvlFloatValue"); |
| if (nvlFloatValueArg != null) { |
| this.nvlFloatValue = nvlFloatValueArg; |
| } |
| } |
| } |