| package org.apache.lucene.expressions; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.apache.lucene.queries.function.ValueSource; |
| import org.apache.lucene.queries.function.valuesource.DoubleFieldSource; |
| import org.apache.lucene.queries.function.valuesource.FloatFieldSource; |
| import org.apache.lucene.queries.function.valuesource.IntFieldSource; |
| import org.apache.lucene.queries.function.valuesource.LongFieldSource; |
| import org.apache.lucene.search.FieldCache.DoubleParser; |
| import org.apache.lucene.search.FieldCache.FloatParser; |
| import org.apache.lucene.search.FieldCache.IntParser; |
| import org.apache.lucene.search.FieldCache.LongParser; |
| import org.apache.lucene.search.SortField; |
| |
| /** |
| * Simple class that binds expression variable names to {@link SortField}s |
| * or other {@link Expression}s. |
| * <p> |
| * Example usage: |
| * <pre class="prettyprint"> |
| * SimpleBindings bindings = new SimpleBindings(); |
| * // document's text relevance score |
| * bindings.add(new SortField("_score", SortField.Type.SCORE)); |
| * // integer NumericDocValues field (or from FieldCache) |
| * bindings.add(new SortField("popularity", SortField.Type.INT)); |
| * // another expression |
| * bindings.add("recency", myRecencyExpression); |
| * |
| * // create a sort field in reverse order |
| * Sort sort = new Sort(expr.getSortField(bindings, true)); |
| * </pre> |
| * |
| * @lucene.experimental |
| */ |
| public final class SimpleBindings extends Bindings { |
| final Map<String,Object> map = new HashMap<>(); |
| |
| /** Creates a new empty Bindings */ |
| public SimpleBindings() {} |
| |
| /** |
| * Adds a SortField to the bindings. |
| * <p> |
| * This can be used to reference a DocValuesField, a field from |
| * FieldCache, the document's score, etc. |
| */ |
| public void add(SortField sortField) { |
| map.put(sortField.getField(), sortField); |
| } |
| |
| /** |
| * Adds an Expression to the bindings. |
| * <p> |
| * This can be used to reference expressions from other expressions. |
| */ |
| public void add(String name, Expression expression) { |
| map.put(name, expression); |
| } |
| |
| @Override |
| public ValueSource getValueSource(String name) { |
| Object o = map.get(name); |
| if (o == null) { |
| throw new IllegalArgumentException("Invalid reference '" + name + "'"); |
| } else if (o instanceof Expression) { |
| return ((Expression)o).getValueSource(this); |
| } |
| SortField field = (SortField) o; |
| switch(field.getType()) { |
| case INT: |
| return new IntFieldSource(field.getField(), (IntParser) field.getParser()); |
| case LONG: |
| return new LongFieldSource(field.getField(), (LongParser) field.getParser()); |
| case FLOAT: |
| return new FloatFieldSource(field.getField(), (FloatParser) field.getParser()); |
| case DOUBLE: |
| return new DoubleFieldSource(field.getField(), (DoubleParser) field.getParser()); |
| case SCORE: |
| return getScoreValueSource(); |
| default: |
| throw new UnsupportedOperationException(); |
| } |
| } |
| |
| /** |
| * Traverses the graph of bindings, checking there are no cycles or missing references |
| * @throws IllegalArgumentException if the bindings is inconsistent |
| */ |
| public void validate() { |
| for (Object o : map.values()) { |
| if (o instanceof Expression) { |
| Expression expr = (Expression) o; |
| try { |
| expr.getValueSource(this); |
| } catch (StackOverflowError e) { |
| throw new IllegalArgumentException("Recursion Error: Cycle detected originating in (" + expr.sourceText + ")"); |
| } |
| } |
| } |
| } |
| } |