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.lucene.document; import java.util.Arrays; import java.util.Collection; import org.apache.lucene.index.PointValues; import org.apache.lucene.search.BooleanQuery; import org.apache.lucene.search.BoostQuery; import org.apache.lucene.search.PointInSetQuery; import org.apache.lucene.search.PointRangeQuery; import org.apache.lucene.search.Query; import org.apache.lucene.search.BooleanClause.Occur; import org.apache.lucene.util.BytesRef; import org.apache.lucene.util.NumericUtils; /** * An indexed {@code long} field for fast range filters. If you also * need to store the value, you should add a separate {@link StoredField} instance. * <p> * Finding all documents within an N-dimensional shape or range at search time is * efficient. Multiple values for the same field in one document * is allowed. * <p> * This field defines static factory methods for creating common queries: * <ul> * <li>{@link #newExactQuery(String, long)} for matching an exact 1D point. * <li>{@link #newSetQuery(String, long...)} for matching a set of 1D values. * <li>{@link #newRangeQuery(String, long, long)} for matching a 1D range. * <li>{@link #newRangeQuery(String, long[], long[])} for matching points/ranges in n-dimensional space. * </ul> * @see PointValues */ public final class LongPoint extends Field { private static FieldType getType(int numDims) { FieldType type = new FieldType(); type.setDimensions(numDims, Long.BYTES); type.freeze(); return type; } @Override public void setLongValue(long value) { setLongValues(value); } /** Change the values of this field */ public void setLongValues(long... point) { if (type.pointDataDimensionCount() != point.length) { throw new IllegalArgumentException( "this field (name=" + name + ") uses " + type.pointDataDimensionCount() + " dimensions; cannot change to (incoming) " + point.length + " dimensions"); } fieldsData = pack(point); } @Override public void setBytesValue(BytesRef bytes) { throw new IllegalArgumentException("cannot change value type from long to BytesRef"); } @Override public Number numericValue() { if (type.pointDataDimensionCount() != 1) { throw new IllegalStateException("this field (name=" + name + ") uses " + type.pointDataDimensionCount() + " dimensions; cannot convert to a single numeric value"); } BytesRef bytes = (BytesRef) fieldsData; assert bytes.length == Long.BYTES; return decodeDimension(bytes.bytes, bytes.offset); } /** * Pack a long point into a BytesRef * * @param point long[] value * @throws IllegalArgumentException is the value is null or of zero length */ public static BytesRef pack(long... point) { if (point == null) { throw new IllegalArgumentException("point must not be null"); } if (point.length == 0) { throw new IllegalArgumentException("point must not be 0 dimensions"); } byte[] packed = new byte[point.length * Long.BYTES]; for (int dim = 0; dim < point.length; dim++) { encodeDimension(point[dim], packed, dim * Long.BYTES); } return new BytesRef(packed); } /** Creates a new LongPoint, indexing the * provided N-dimensional long point. * * @param name field name * @param point long[] value * @throws IllegalArgumentException if the field name or value is null. */ public LongPoint(String name, long... point) { super(name, pack(point), getType(point.length)); } @Override public String toString() { StringBuilder result = new StringBuilder(); result.append(getClass().getSimpleName()); result.append(" <"); result.append(name); result.append(':'); BytesRef bytes = (BytesRef) fieldsData; for (int dim = 0; dim < type.pointDataDimensionCount(); dim++) { if (dim > 0) { result.append(','); } result.append(decodeDimension(bytes.bytes, bytes.offset + dim * Long.BYTES)); } result.append('>'); return result.toString(); } // public helper methods (e.g. for queries) /** Encode single long dimension */ public static void encodeDimension(long value, byte dest[], int offset) { NumericUtils.longToSortableBytes(value, dest, offset); } /** Decode single long dimension */ public static long decodeDimension(byte value[], int offset) { return NumericUtils.sortableBytesToLong(value, offset); } // static methods for generating queries /** * Create a query for matching an exact long value. * <p> * This is for simple one-dimension points, for multidimensional points use * {@link #newRangeQuery(String, long[], long[])} instead. * * @param field field name. must not be {@code null}. * @param value exact value * @throws IllegalArgumentException if {@code field} is null. * @return a query matching documents with this exact value */ public static Query newExactQuery(String field, long value) { return newRangeQuery(field, value, value); } /** * Create a range query for long values. * <p> * This is for simple one-dimension ranges, for multidimensional ranges use * {@link #newRangeQuery(String, long[], long[])} instead. * <p> * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting {@code lowerValue = Long.MIN_VALUE} or {@code upperValue = Long.MAX_VALUE}. * <p> * Ranges are inclusive. For exclusive ranges, pass {@code Math.addExact(lowerValue, 1)} * or {@code Math.addExact(upperValue, -1)}. * * @param field field name. must not be {@code null}. * @param lowerValue lower portion of the range (inclusive). * @param upperValue upper portion of the range (inclusive). * @throws IllegalArgumentException if {@code field} is null. * @return a query matching documents within this range. */ public static Query newRangeQuery(String field, long lowerValue, long upperValue) { return newRangeQuery(field, new long[] { lowerValue }, new long[] { upperValue }); } /** * Create a range query for n-dimensional long values. * <p> * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting {@code lowerValue[i] = Long.MIN_VALUE} or {@code upperValue[i] = Long.MAX_VALUE}. * <p> * Ranges are inclusive. For exclusive ranges, pass {@code Math.addExact(lowerValue[i], 1)} * or {@code Math.addExact(upperValue[i], -1)}. * * @param field field name. must not be {@code null}. * @param lowerValue lower portion of the range (inclusive). must not be {@code null}. * @param upperValue upper portion of the range (inclusive). must not be {@code null}. * @throws IllegalArgumentException if {@code field} is null, if {@code lowerValue} is null, if {@code upperValue} is null, * or if {@code lowerValue.length != upperValue.length} * @return a query matching documents within this range. */ public static Query newRangeQuery(String field, long[] lowerValue, long[] upperValue) { PointRangeQuery.checkArgs(field, lowerValue, upperValue); return new PointRangeQuery(field, pack(lowerValue).bytes, pack(upperValue).bytes, lowerValue.length) { @Override protected String toString(int dimension, byte[] value) { return Long.toString(decodeDimension(value, 0)); } }; } /** * Create a query matching any of the specified 1D values. This is the points equivalent of {@code TermsQuery}. * * @param field field name. must not be {@code null}. * @param values all values to match */ public static Query newSetQuery(String field, long... values) { // Don't unexpectedly change the user's incoming values array: long[] sortedValues = values.clone(); Arrays.sort(sortedValues); final BytesRef encoded = new BytesRef(new byte[Long.BYTES]); return new PointInSetQuery(field, 1, Long.BYTES, new PointInSetQuery.Stream() { int upto; @Override public BytesRef next() { if (upto == sortedValues.length) { return null; } else { encodeDimension(sortedValues[upto], encoded.bytes, 0); upto++; return encoded; } } }) { @Override protected String toString(byte[] value) { assert value.length == Long.BYTES; return Long.toString(decodeDimension(value, 0)); } }; } /** * Create a query matching any of the specified 1D values. This is the points equivalent of {@code TermsQuery}. * * @param field field name. must not be {@code null}. * @param values all values to match */ public static Query newSetQuery(String field, Collection<Long> values) { Long[] boxed = values.toArray(new Long[0]); long[] unboxed = new long[boxed.length]; for (int i = 0; i < boxed.length; i++) { unboxed[i] = boxed[i]; } return newSetQuery(field, unboxed); } /** * Given a field that indexes the same long values into a {@link LongPoint} * and doc values (either {@link NumericDocValuesField} or * {@link SortedNumericDocValuesField}), this returns a query that scores * documents based on their distance to {@code origin}: * {@code score = weight * pivotDistance / (pivotDistance + distance)}, ie. * score is in the {@code [0, weight]} range, is equal to {@code weight} when * the document's value is equal to {@code origin} and is equal to * {@code weight/2} when the document's value is distant of * {@code pivotDistance} from {@code origin}. * In case of multi-valued fields, only the closest point to {@code origin} * will be considered. * This query is typically useful to boost results based on recency by adding * this query to a {@link Occur#SHOULD} clause of a {@link BooleanQuery}. */ public static Query newDistanceFeatureQuery(String field, float weight, long origin, long pivotDistance) { Query query = new LongDistanceFeatureQuery(field, origin, pivotDistance); if (weight != 1f) { query = new BoostQuery(query, weight); } return query; } }