Java tutorial
/* * 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; import java.io.IOException; import java.util.Map; import org.apache.lucene.index.Fields; 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.queries.function.FunctionValues; import org.apache.lucene.queries.function.ValueSource; import org.apache.lucene.queries.function.docvalues.FloatDocValues; import org.apache.lucene.queries.payloads.PayloadFunction; import org.apache.lucene.search.DocIdSetIterator; import org.apache.lucene.util.BytesRef; import org.apache.solr.util.PayloadDecoder; public class FloatPayloadValueSource extends ValueSource { protected final String field; protected final String val; protected final String indexedField; protected final BytesRef indexedBytes; protected final PayloadDecoder decoder; protected final PayloadFunction payloadFunction; protected final ValueSource defaultValueSource; public FloatPayloadValueSource(String field, String val, String indexedField, BytesRef indexedBytes, PayloadDecoder decoder, PayloadFunction payloadFunction, ValueSource defaultValueSource) { this.field = field; this.val = val; this.indexedField = indexedField; this.indexedBytes = indexedBytes; this.decoder = decoder; this.payloadFunction = payloadFunction; this.defaultValueSource = defaultValueSource; } @Override public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException { Fields fields = readerContext.reader().fields(); final Terms terms = fields.terms(indexedField); FunctionValues defaultValues = defaultValueSource.getValues(context, readerContext); // copied the bulk of this from TFValueSource - TODO: this is a very repeated pattern - base-class this advance logic stuff? return new FloatDocValues(this) { PostingsEnum docs; int atDoc; int lastDocRequested = -1; { reset(); } public void reset() throws IOException { // no one should call us for deleted docs? if (terms != null) { final TermsEnum termsEnum = terms.iterator(); if (termsEnum.seekExact(indexedBytes)) { docs = termsEnum.postings(null, PostingsEnum.ALL); } else { docs = null; } } else { docs = null; } if (docs == null) { // dummy PostingsEnum so floatVal() can work // when would this be called? if field/val did not match? this is called for every doc? create once and cache? docs = new PostingsEnum() { @Override public int freq() { return 0; } @Override public int nextPosition() throws IOException { return -1; } @Override public int startOffset() throws IOException { return -1; } @Override public int endOffset() throws IOException { return -1; } @Override public BytesRef getPayload() throws IOException { return null; } @Override public int docID() { return DocIdSetIterator.NO_MORE_DOCS; } @Override public int nextDoc() { return DocIdSetIterator.NO_MORE_DOCS; } @Override public int advance(int target) { return DocIdSetIterator.NO_MORE_DOCS; } @Override public long cost() { return 0; } }; } atDoc = -1; } @Override public float floatVal(int doc) { try { if (doc < lastDocRequested) { // out-of-order access.... reset reset(); } lastDocRequested = doc; if (atDoc < doc) { atDoc = docs.advance(doc); } if (atDoc > doc) { // term doesn't match this document... either because we hit the // end, or because the next doc is after this doc. return defaultValues.floatVal(doc); } // a match! int freq = docs.freq(); int numPayloadsSeen = 0; float currentScore = 0; for (int i = 0; i < freq; i++) { docs.nextPosition(); BytesRef payload = docs.getPayload(); if (payload != null) { float payloadVal = decoder.decode(atDoc, docs.startOffset(), docs.endOffset(), payload); // payloadFunction = null represents "first" if (payloadFunction == null) return payloadVal; currentScore = payloadFunction.currentScore(doc, indexedField, docs.startOffset(), docs.endOffset(), numPayloadsSeen, currentScore, payloadVal); numPayloadsSeen++; } } return (numPayloadsSeen > 0) ? payloadFunction.docScore(doc, indexedField, numPayloadsSeen, currentScore) : defaultValues.floatVal(doc); } catch (IOException e) { throw new RuntimeException("caught exception in function " + description() + " : doc=" + doc, e); } } }; } // TODO: should this be formalized at the ValueSource level? Seems to be the convention public String name() { return "payload"; } @Override public String description() { return name() + '(' + field + ',' + val + ',' + defaultValueSource.toString() + ')'; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; FloatPayloadValueSource that = (FloatPayloadValueSource) o; if (!indexedField.equals(that.indexedField)) return false; if (indexedBytes != null ? !indexedBytes.equals(that.indexedBytes) : that.indexedBytes != null) return false; if (!decoder.equals(that.decoder)) return false; if (payloadFunction != null ? !payloadFunction.equals(that.payloadFunction) : that.payloadFunction != null) return false; return defaultValueSource.equals(that.defaultValueSource); } @Override public int hashCode() { int result = indexedField.hashCode(); result = 31 * result + (indexedBytes != null ? indexedBytes.hashCode() : 0); result = 31 * result + decoder.hashCode(); result = 31 * result + (payloadFunction != null ? payloadFunction.hashCode() : 0); result = 31 * result + defaultValueSource.hashCode(); return result; } }