| /* |
| * 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.lucene.document; |
| |
| import java.io.IOException; |
| import java.util.Objects; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.PostingsEnum; |
| import org.apache.lucene.index.Terms; |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.search.FieldComparator; |
| import org.apache.lucene.search.SimpleFieldComparator; |
| import org.apache.lucene.search.SortField; |
| import org.apache.lucene.util.BytesRef; |
| |
| /** |
| * Sorts using the value of a specified feature name from a {@link FeatureField}. |
| */ |
| final class FeatureSortField extends SortField { |
| |
| private final String featureName; |
| |
| /** |
| * Creates a {@link FeatureSortField} that can be used to sort hits by |
| * the value of a particular feature in a {@link FeatureField}. |
| * |
| * @param featureName The name of the feature to use for the sort value |
| */ |
| public FeatureSortField(String field, String featureName) { |
| super(Objects.requireNonNull(field), SortField.Type.CUSTOM, true); |
| this.featureName = Objects.requireNonNull(featureName); |
| } |
| |
| @Override |
| public FieldComparator<?> getComparator(int numHits, int sortPos) { |
| return new FeatureComparator(numHits, getField(), featureName); |
| } |
| |
| @Override |
| public void setMissingValue(Object missingValue) { |
| throw new IllegalArgumentException("Missing value not supported for FeatureSortField"); |
| } |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = super.hashCode(); |
| result = prime * result + featureName.hashCode(); |
| return result; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) return true; |
| if (!super.equals(obj)) return false; |
| if (getClass() != obj.getClass()) return false; |
| FeatureSortField other = (FeatureSortField) obj; |
| return Objects.equals(featureName, other.featureName); |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder builder = new StringBuilder(); |
| builder.append("<feature:"); |
| builder.append('"'); |
| builder.append(getField()); |
| builder.append('"'); |
| builder.append(" featureName="); |
| builder.append(featureName); |
| builder.append('>'); |
| return builder.toString(); |
| } |
| |
| /** Parses a feature field's values as float and sorts by descending value */ |
| class FeatureComparator extends SimpleFieldComparator<Float> { |
| private final String field; |
| private final BytesRef featureName; |
| private final float[] values; |
| private float bottom; |
| private float topValue; |
| private PostingsEnum currentReaderPostingsValues; |
| |
| /** Creates a new comparator based on relevance for {@code numHits}. */ |
| public FeatureComparator(int numHits, String field, String featureName) { |
| this.values = new float[numHits]; |
| this.field = field; |
| this.featureName = new BytesRef(featureName); |
| } |
| |
| @Override |
| protected void doSetNextReader(LeafReaderContext context) throws IOException { |
| Terms terms = context.reader().terms(field); |
| if (terms == null) { |
| currentReaderPostingsValues = null; |
| } else { |
| TermsEnum termsEnum = terms.iterator(); |
| if (termsEnum.seekExact(featureName) == false) { |
| currentReaderPostingsValues = null; |
| } else { |
| currentReaderPostingsValues = termsEnum.postings(currentReaderPostingsValues, PostingsEnum.FREQS); |
| } |
| } |
| } |
| |
| private float getValueForDoc(int doc) throws IOException { |
| if (currentReaderPostingsValues != null && doc >= currentReaderPostingsValues.docID() |
| && (currentReaderPostingsValues.docID() == doc || currentReaderPostingsValues.advance(doc) == doc)) { |
| return FeatureField.decodeFeatureValue(currentReaderPostingsValues.freq()); |
| } else { |
| return 0.0f; |
| } |
| } |
| |
| @Override |
| public int compare(int slot1, int slot2) { |
| return Float.compare(values[slot1], values[slot2]); |
| } |
| |
| @Override |
| public int compareBottom(int doc) throws IOException { |
| return Float.compare(bottom, getValueForDoc(doc)); |
| } |
| |
| @Override |
| public void copy(int slot, int doc) throws IOException { |
| values[slot] = getValueForDoc(doc); |
| } |
| |
| @Override |
| public void setBottom(final int bottom) { |
| this.bottom = values[bottom]; |
| } |
| |
| @Override |
| public void setTopValue(Float value) { |
| topValue = value; |
| } |
| |
| @Override |
| public Float value(int slot) { |
| return Float.valueOf(values[slot]); |
| } |
| |
| @Override |
| public int compareTop(int doc) throws IOException { |
| return Float.compare(topValue, getValueForDoc(doc)); |
| } |
| } |
| } |