home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Lucene example source code file (NumericRangeQuery.java)

This example Lucene source code file (NumericRangeQuery.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

double, double, float, indexreader, integer, io, ioexception, long, numericrangequery, numericrangequery, override, override, string, string, t, util

The Lucene NumericRangeQuery.java source code

package org.apache.lucene.search;

/**
 * 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.io.IOException;
import java.util.LinkedList;

import org.apache.lucene.analysis.NumericTokenStream; // for javadocs
import org.apache.lucene.document.NumericField; // for javadocs
import org.apache.lucene.util.NumericUtils;
import org.apache.lucene.util.ToStringUtils;
import org.apache.lucene.util.StringHelper;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;

/**
 * <p>A {@link Query} that matches numeric values within a
 * specified range.  To use this, you must first index the
 * numeric values using {@link NumericField} (expert: {@link
 * NumericTokenStream}).  If your terms are instead textual,
 * you should use {@link TermRangeQuery}.  {@link
 * NumericRangeFilter} is the filter equivalent of this
 * query.</p>
 *
 * <p>You create a new NumericRangeQuery with the static
 * factory methods, eg:
 *
 * <pre>
 * Query q = NumericRangeQuery.newFloatRange("weight", 0.03f, 0.10f, true, true);
 * </pre>
 *
 * matches all documents whose float valued "weight" field
 * ranges from 0.03 to 0.10, inclusive.
 *
 * <p>The performance of NumericRangeQuery is much better
 * than the corresponding {@link TermRangeQuery} because the
 * number of terms that must be searched is usually far
 * fewer, thanks to trie indexing, described below.</p>
 *
 * <p>You can optionally specify a precisionStep
 * when creating this query.  This is necessary if you've
 * changed this configuration from its default (4) during
 * indexing.  Lower values consume more disk space but speed
 * up searching.  Suitable values are between <b>1 and
 * <b>8. A good starting point to test is 4,
 * which is the default value for all <code>Numeric*
 * classes.  See <a href="#precisionStepDesc">below for
 * details.
 *
 * <p>This query defaults to {@linkplain
 * MultiTermQuery#CONSTANT_SCORE_AUTO_REWRITE_DEFAULT} for
 * 32 bit (int/float) ranges with precisionStep ≤8 and 64
 * bit (long/double) ranges with precisionStep ≤6.
 * Otherwise it uses {@linkplain
 * MultiTermQuery#CONSTANT_SCORE_FILTER_REWRITE} as the
 * number of terms is likely to be high.  With precision
 * steps of ≤4, this query can be run with one of the
 * BooleanQuery rewrite methods without changing
 * BooleanQuery's default max clause count.
 *
 * <br>

How it works

* * <p>See the publication about panFMP, * where this algorithm was described (referred to as <code>TrieRangeQuery): * * <blockquote>Schindler, U, Diepenbroek, M, 2008. * <em>Generic XML-based Framework for Metadata Portals. * Computers & Geosciences 34 (12), 1947-1955. * <a href="http://dx.doi.org/10.1016/j.cageo.2008.02.023" * target="_blank">doi:10.1016/j.cageo.2008.02.023</a> * * <p>A quote from this paper: Because Apache Lucene is a full-text * search engine and not a conventional database, it cannot handle numerical ranges * (e.g., field value is inside user defined bounds, even dates are numerical values). * We have developed an extension to Apache Lucene that stores * the numerical values in a special string-encoded format with variable precision * (all numerical values like doubles, longs, floats, and ints are converted to * lexicographic sortable string representations and stored with different precisions * (for a more detailed description of how the values are stored, * see {@link NumericUtils}). A range is then divided recursively into multiple intervals for searching: * The center of the range is searched only with the lowest possible precision in the <em>trie, * while the boundaries are matched more exactly. This reduces the number of terms dramatically.</p> * * <p>For the variant that stores long values in 8 different precisions (each reduced by 8 bits) that * uses a lowest precision of 1 byte, the index contains only a maximum of 256 distinct values in the * lowest precision. Overall, a range could consist of a theoretical maximum of * <code>7*255*2 + 255 = 3825 distinct terms (when there is a term for every distinct value of an * 8-byte-number in the index and the range covers almost all of them; a maximum of 255 distinct values is used * because it would always be possible to reduce the full 256 values to one term with degraded precision). * In practice, we have seen up to 300 terms in most cases (index with 500,000 metadata records * and a uniform value distribution).</p> * * <a name="precisionStepDesc">

Precision Step

* <p>You can choose any precisionStep when encoding values. * Lower step values mean more precisions and so more terms in index (and index gets larger). * On the other hand, the maximum number of terms to match reduces, which optimized query speed. * The formula to calculate the maximum term count is: * <pre> * n = [ (bitsPerValue/precisionStep - 1) * (2^precisionStep - 1 ) * 2 ] + (2^precisionStep - 1 ) * </pre> * <p>(this formula is only correct, when bitsPerValue/precisionStep is an integer; * in other cases, the value must be rounded up and the last summand must contain the modulo of the division as * precision step)</em>. * For longs stored using a precision step of 4, <code>n = 15*15*2 + 15 = 465, and for a precision * step of 2, <code>n = 31*3*2 + 3 = 189. But the faster search speed is reduced by more seeking * in the term enum of the index. Because of this, the ideal <code>precisionStep value can only * be found out by testing. <b>Important: You can index with a lower precision step value and test search speed * using a multiple of the original step value.</p> * * <p>Good values for precisionStep are depending on usage and data type: * <ul> * <li>The default for all data types is 4, which is used, when no precisionStep is given. * <li>Ideal value in most cases for 64 bit data types (long, double) is 6 or 8. * <li>Ideal value in most cases for 32 bit data types (int, float) is 4. * <li>For low cardinality fields larger precision steps are good. If the cardinality is < 100, it is * fair to use {@link Integer#MAX_VALUE} (see below). * <li>Steps ≥64 for long/double and ≥32 for int/float produces one token * per value in the index and querying is as slow as a conventional {@link TermRangeQuery}. But it can be used * to produce fields, that are solely used for sorting (in this case simply use {@link Integer#MAX_VALUE} as * <code>precisionStep). Using {@link NumericField NumericFields} for sorting * is ideal, because building the field cache is much faster than with text-only numbers. * These fields have one term per value and therefore also work with term enumeration for building distinct lists * (e.g. facets / preselected values to search for). * Sorting is also possible with range query optimized fields using one of the above <code>precisionSteps. * </ul> * * <p>Comparisons of the different types of RangeQueries on an index with about 500,000 docs showed * that {@link TermRangeQuery} in boolean rewrite mode (with raised {@link BooleanQuery} clause count) * took about 30-40 secs to complete, {@link TermRangeQuery} in constant score filter rewrite mode took 5 secs * and executing this class took <100ms to complete (on an Opteron64 machine, Java 1.5, 8 bit * precision step). This query type was developed for a geographic portal, where the performance for * e.g. bounding boxes or exact date/time stamps is important.</p> * * @since 2.9 **/ public final class NumericRangeQuery<T extends Number> extends MultiTermQuery { private NumericRangeQuery(final String field, final int precisionStep, final int valSize, T min, T max, final boolean minInclusive, final boolean maxInclusive ) { assert (valSize == 32 || valSize == 64); if (precisionStep < 1) throw new IllegalArgumentException("precisionStep must be >=1"); this.field = StringHelper.intern(field); this.precisionStep = precisionStep; this.valSize = valSize; this.min = min; this.max = max; this.minInclusive = minInclusive; this.maxInclusive = maxInclusive; // For bigger precisionSteps this query likely // hits too many terms, so set to CONSTANT_SCORE_FILTER right off // (especially as the FilteredTermEnum is costly if wasted only for AUTO tests because it // creates new enums from IndexReader for each sub-range) switch (valSize) { case 64: setRewriteMethod( (precisionStep > 6) ? CONSTANT_SCORE_FILTER_REWRITE : CONSTANT_SCORE_AUTO_REWRITE_DEFAULT ); break; case 32: setRewriteMethod( (precisionStep > 8) ? CONSTANT_SCORE_FILTER_REWRITE : CONSTANT_SCORE_AUTO_REWRITE_DEFAULT ); break; default: // should never happen throw new IllegalArgumentException("valSize must be 32 or 64"); } // shortcut if upper bound == lower bound if (min != null && min.equals(max)) { setRewriteMethod(CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE); } } /** * Factory that creates a <code>NumericRangeQuery, that queries a long * range using the given <a href="#precisionStepDesc">precisionStep. * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Long> newLongRange(final String field, final int precisionStep, Long min, Long max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Long>(field, precisionStep, 64, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a long * range using the default <code>precisionStep {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Long> newLongRange(final String field, Long min, Long max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Long>(field, NumericUtils.PRECISION_STEP_DEFAULT, 64, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a int * range using the given <a href="#precisionStepDesc">precisionStep. * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Integer> newIntRange(final String field, final int precisionStep, Integer min, Integer max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Integer>(field, precisionStep, 32, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a int * range using the default <code>precisionStep {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Integer> newIntRange(final String field, Integer min, Integer max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Integer>(field, NumericUtils.PRECISION_STEP_DEFAULT, 32, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a double * range using the given <a href="#precisionStepDesc">precisionStep. * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Double> newDoubleRange(final String field, final int precisionStep, Double min, Double max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Double>(field, precisionStep, 64, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a double * range using the default <code>precisionStep {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Double> newDoubleRange(final String field, Double min, Double max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Double>(field, NumericUtils.PRECISION_STEP_DEFAULT, 64, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a float * range using the given <a href="#precisionStepDesc">precisionStep. * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Float> newFloatRange(final String field, final int precisionStep, Float min, Float max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Float>(field, precisionStep, 32, min, max, minInclusive, maxInclusive); } /** * Factory that creates a <code>NumericRangeQuery, that queries a float * range using the default <code>precisionStep {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). * You can have half-open ranges (which are in fact </≤ or >/≥ queries) * by setting the min or max value to <code>null. By setting inclusive to false, it will * match all documents excluding the bounds, with inclusive on, the boundaries are hits, too. */ public static NumericRangeQuery<Float> newFloatRange(final String field, Float min, Float max, final boolean minInclusive, final boolean maxInclusive ) { return new NumericRangeQuery<Float>(field, NumericUtils.PRECISION_STEP_DEFAULT, 32, min, max, minInclusive, maxInclusive); } @Override protected FilteredTermEnum getEnum(final IndexReader reader) throws IOException { return new NumericRangeTermEnum(reader); } /** Returns the field name for this query */ public String getField() { return field; } /** Returns <code>true if the lower endpoint is inclusive */ public boolean includesMin() { return minInclusive; } /** Returns <code>true if the upper endpoint is inclusive */ public boolean includesMax() { return maxInclusive; } /** Returns the lower value of this range query */ public T getMin() { return min; } /** Returns the upper value of this range query */ public T getMax() { return max; } /** Returns the precision step. */ public int getPrecisionStep() { return precisionStep; } @Override public String toString(final String field) { final StringBuilder sb = new StringBuilder(); if (!this.field.equals(field)) sb.append(this.field).append(':'); return sb.append(minInclusive ? '[' : '{') .append((min == null) ? "*" : min.toString()) .append(" TO ") .append((max == null) ? "*" : max.toString()) .append(maxInclusive ? ']' : '}') .append(ToStringUtils.boost(getBoost())) .toString(); } @Override public final boolean equals(final Object o) { if (o==this) return true; if (!super.equals(o)) return false; if (o instanceof NumericRangeQuery) { final NumericRangeQuery q=(NumericRangeQuery)o; return ( field==q.field && (q.min == null ? min == null : q.min.equals(min)) && (q.max == null ? max == null : q.max.equals(max)) && minInclusive == q.minInclusive && maxInclusive == q.maxInclusive && precisionStep == q.precisionStep ); } return false; } @Override public final int hashCode() { int hash = super.hashCode(); hash += field.hashCode()^0x4565fd66 + precisionStep^0x64365465; if (min != null) hash += min.hashCode()^0x14fa55fb; if (max != null) hash += max.hashCode()^0x733fa5fe; return hash + (Boolean.valueOf(minInclusive).hashCode()^0x14fa55fb)+ (Boolean.valueOf(maxInclusive).hashCode()^0x733fa5fe); } // field must be interned after reading from stream private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException { in.defaultReadObject(); field = StringHelper.intern(field); } // members (package private, to be also fast accessible by NumericRangeTermEnum) String field; final int precisionStep, valSize; final T min, max; final boolean minInclusive,maxInclusive; /** * Subclass of FilteredTermEnum for enumerating all terms that match the * sub-ranges for trie range queries. * <p> * WARNING: This term enumeration is not guaranteed to be always ordered by * {@link Term#compareTo}. * The ordering depends on how {@link NumericUtils#splitLongRange} and * {@link NumericUtils#splitIntRange} generates the sub-ranges. For * {@link MultiTermQuery} ordering is not relevant. */ private final class NumericRangeTermEnum extends FilteredTermEnum { private final IndexReader reader; private final LinkedList<String> rangeBounds = new LinkedList(); private final Term termTemplate = new Term(field); private String currentUpperBound = null; NumericRangeTermEnum(final IndexReader reader) throws IOException { this.reader = reader; switch (valSize) { case 64: { // lower long minBound = Long.MIN_VALUE; if (min instanceof Long) { minBound = min.longValue(); } else if (min instanceof Double) { minBound = NumericUtils.doubleToSortableLong(min.doubleValue()); } if (!minInclusive && min != null) { if (minBound == Long.MAX_VALUE) break; minBound++; } // upper long maxBound = Long.MAX_VALUE; if (max instanceof Long) { maxBound = max.longValue(); } else if (max instanceof Double) { maxBound = NumericUtils.doubleToSortableLong(max.doubleValue()); } if (!maxInclusive && max != null) { if (maxBound == Long.MIN_VALUE) break; maxBound--; } NumericUtils.splitLongRange(new NumericUtils.LongRangeBuilder() { @Override public final void addRange(String minPrefixCoded, String maxPrefixCoded) { rangeBounds.add(minPrefixCoded); rangeBounds.add(maxPrefixCoded); } }, precisionStep, minBound, maxBound); break; } case 32: { // lower int minBound = Integer.MIN_VALUE; if (min instanceof Integer) { minBound = min.intValue(); } else if (min instanceof Float) { minBound = NumericUtils.floatToSortableInt(min.floatValue()); } if (!minInclusive && min != null) { if (minBound == Integer.MAX_VALUE) break; minBound++; } // upper int maxBound = Integer.MAX_VALUE; if (max instanceof Integer) { maxBound = max.intValue(); } else if (max instanceof Float) { maxBound = NumericUtils.floatToSortableInt(max.floatValue()); } if (!maxInclusive && max != null) { if (maxBound == Integer.MIN_VALUE) break; maxBound--; } NumericUtils.splitIntRange(new NumericUtils.IntRangeBuilder() { @Override public final void addRange(String minPrefixCoded, String maxPrefixCoded) { rangeBounds.add(minPrefixCoded); rangeBounds.add(maxPrefixCoded); } }, precisionStep, minBound, maxBound); break; } default: // should never happen throw new IllegalArgumentException("valSize must be 32 or 64"); } // seek to first term next(); } @Override public float difference() { return 1.0f; } /** this is a dummy, it is not used by this class. */ @Override protected boolean endEnum() { throw new UnsupportedOperationException("not implemented"); } /** this is a dummy, it is not used by this class. */ @Override protected void setEnum(TermEnum tenum) { throw new UnsupportedOperationException("not implemented"); } /** * Compares if current upper bound is reached. * In contrast to {@link FilteredTermEnum}, a return value * of <code>false ends iterating the current enum * and forwards to the next sub-range. */ @Override protected boolean termCompare(Term term) { return (term.field() == field && term.text().compareTo(currentUpperBound) <= 0); } /** Increments the enumeration to the next element. True if one exists. */ @Override public boolean next() throws IOException { // if a current term exists, the actual enum is initialized: // try change to next term, if no such term exists, fall-through if (currentTerm != null) { assert actualEnum != null; if (actualEnum.next()) { currentTerm = actualEnum.term(); if (termCompare(currentTerm)) return true; } } // if all above fails, we go forward to the next enum, // if one is available currentTerm = null; while (rangeBounds.size() >= 2) { assert rangeBounds.size() % 2 == 0; // close the current enum and read next bounds if (actualEnum != null) { actualEnum.close(); actualEnum = null; } final String lowerBound = rangeBounds.removeFirst(); this.currentUpperBound = rangeBounds.removeFirst(); // create a new enum actualEnum = reader.terms(termTemplate.createTerm(lowerBound)); currentTerm = actualEnum.term(); if (currentTerm != null && termCompare(currentTerm)) return true; // clear the current term for next iteration currentTerm = null; } // no more sub-range enums available assert rangeBounds.size() == 0 && currentTerm == null; return false; } /** Closes the enumeration to further activity, freeing resources. */ @Override public void close() throws IOException { rangeBounds.clear(); currentUpperBound = null; super.close(); } } }

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene NumericRangeQuery.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.