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", 0.3f, 0.10f, true, true);
* </pre>
*
* matches all documents whose float valued "weight" field
* ranges from 0.3 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 <a
* href="#precisionStepDesc"><code>precisionStep</code></a>
* 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</b> and
* <b>8</b>. A good starting point to test is <b>4</b>,
* which is the default value for all <code>Numeric*</code>
* classes. See <a href="#precisionStepDesc">below</a> 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.
*
* <p><font color="red"><b>NOTE:</b> This API is experimental and
* might change in incompatible ways in the next release.</font>
*
* <br><h3>How it works</h3>
*
* <p>See the publication about <a target="_blank" href="http://www.panfmp.org">panFMP</a>,
* where this algorithm was described (referred to as <code>TrieRangeQuery</code>):
*
* <blockquote><strong>Schindler, U, Diepenbroek, M</strong>, 2008.
* <em>Generic XML-based Framework for Metadata Portals.</em>
* 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></blockquote>
*
* <p><em>A quote from this paper:</em> 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</em>,
* 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</code> 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"><h3>Precision Step</h3>
* <p>You can choose any <code>precisionStep</code> 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><em>(this formula is only correct, when <code>bitsPerValue/precisionStep</code> 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</code>, and for a precision
* step of 2, <code>n = 31*3*2 + 3 = 189</code>. But the faster search speed is reduced by more seeking
* in the term enum of the index. Because of this, the ideal <code>precisionStep</code> value can only
* be found out by testing. <b>Important:</b> 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 <code>precisionStep</code> are depending on usage and data type:
* <ul>
* <li>The default for all data types is <b>4</b>, which is used, when no <code>precisionStep</code> is given.
* <li>Ideal value in most cases for <em>64 bit</em> data types <em>(long, double)</em> is <b>6</b> or <b>8</b>.
* <li>Ideal value in most cases for <em>32 bit</em> data types <em>(int, float)</em> is <b>4</b>.
* <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 <b>≥64</b> for <em>long/double</em> and <b>≥32</b> for <em>int/float</em> 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</code>). 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</code>.
* </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</code>, that queries a <code>long</code>
* range using the given <a href="#precisionStepDesc"><code>precisionStep</code></a>.
* You can have half-open ranges (which are in fact </≤ or >/≥ queries)
* by setting the min or max value to <code>null</code>. 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</code>, that queries a <code>long</code>
* range using the default <code>precisionStep</code> {@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</code>. 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</code>, that queries a <code>int</code>
* range using the given <a href="#precisionStepDesc"><code>precisionStep</code></a>.
* You can have half-open ranges (which are in fact </≤ or >/≥ queries)
* by setting the min or max value to <code>null</code>. 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</code>, that queries a <code>int</code>
* range using the default <code>precisionStep</code> {@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</code>. 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</code>, that queries a <code>double</code>
* range using the given <a href="#precisionStepDesc"><code>precisionStep</code></a>.
* You can have half-open ranges (which are in fact </≤ or >/≥ queries)
* by setting the min or max value to <code>null</code>. 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</code>, that queries a <code>double</code>
* range using the default <code>precisionStep</code> {@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</code>. 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</code>, that queries a <code>float</code>
* range using the given <a href="#precisionStepDesc"><code>precisionStep</code></a>.
* You can have half-open ranges (which are in fact </≤ or >/≥ queries)
* by setting the min or max value to <code>null</code>. 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</code>, that queries a <code>float</code>
* range using the default <code>precisionStep</code> {@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</code>. 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</code> if the lower endpoint is inclusive */
public boolean includesMin() { return minInclusive; }
/** Returns <code>true</code> 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; }
@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<String>();
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,
* this also updates the term count for statistics.
* In contrast to {@link FilteredTermEnum}, a return value
* of <code>false</code> 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();
}
}
}