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Lucene example source code file (OrdFieldSource.java)
The Lucene OrdFieldSource.java source code/** * 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.search.function; import org.apache.lucene.index.IndexReader; import org.apache.lucene.search.FieldCache; import java.io.IOException; /** * Expert: obtains the ordinal of the field value from the default Lucene * {@link org.apache.lucene.search.FieldCache Fieldcache} using getStringIndex(). * <p> * The native lucene index order is used to assign an ordinal value for each field value. * <p * Field values (terms) are lexicographically ordered by unicode value, and numbered starting at 1. * <p> * Example: * <br>If there were only three field values: "apple","banana","pear" * <br>then ord("apple")=1, ord("banana")=2, ord("pear")=3 * <p> * WARNING: * ord() depends on the position in an index and can thus change * when other documents are inserted or deleted, * or if a MultiSearcher is used. * * @lucene.experimental * * <p>NOTE: with the switch in 2.9 to segment-based * searching, if {@link #getValues} is invoked with a * composite (multi-segment) reader, this can easily cause * double RAM usage for the values in the FieldCache. It's * best to switch your application to pass only atomic * (single segment) readers to this API.</p> */ public class OrdFieldSource extends ValueSource { protected String field; /** * Constructor for a certain field. * @param field field whose values order is used. */ public OrdFieldSource(String field) { this.field = field; } /*(non-Javadoc) @see org.apache.lucene.search.function.ValueSource#description() */ @Override public String description() { return "ord(" + field + ')'; } /*(non-Javadoc) @see org.apache.lucene.search.function.ValueSource#getValues(org.apache.lucene.index.IndexReader) */ @Override public DocValues getValues(IndexReader reader) throws IOException { final int[] arr = FieldCache.DEFAULT.getStringIndex(reader, field).order; return new DocValues() { /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#floatVal(int) */ @Override public float floatVal(int doc) { return arr[doc]; } /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#strVal(int) */ @Override public String strVal(int doc) { // the string value of the ordinal, not the string itself return Integer.toString(arr[doc]); } /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#toString(int) */ @Override public String toString(int doc) { return description() + '=' + intVal(doc); } /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#getInnerArray() */ @Override Object getInnerArray() { return arr; } }; } /*(non-Javadoc) @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object o) { if (o == this) return true; if (o == null) return false; if (o.getClass() != OrdFieldSource.class) return false; OrdFieldSource other = (OrdFieldSource)o; return this.field.equals(other.field); } private static final int hcode = OrdFieldSource.class.hashCode(); /*(non-Javadoc) @see java.lang.Object#hashCode() */ @Override public int hashCode() { return hcode + field.hashCode(); } } Other Lucene examples (source code examples)Here is a short list of links related to this Lucene OrdFieldSource.java source code file: |
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