package org.apache.lucene.document;
/*
* 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 org.apache.lucene.analysis.NumericTokenStream; // javadocs
import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.search.FieldCache; // javadocs
import org.apache.lucene.search.NumericRangeFilter; // javadocs
import org.apache.lucene.search.NumericRangeQuery; // javadocs
import org.apache.lucene.util.NumericUtils;
/**
* <p>
* Field that indexes <code>double</code> values
* for efficient range filtering and sorting. Here's an example usage:
*
* <pre class="prettyprint">
* document.add(new DoubleField(name, 6.0, Field.Store.NO));
* </pre>
*
* For optimal performance, re-use the <code>DoubleField</code> and
* {@link Document} instance for more than one document:
*
* <pre class="prettyprint">
* DoubleField field = new DoubleField(name, 0.0, Field.Store.NO);
* Document document = new Document();
* document.add(field);
*
* for(all documents) {
* ...
* field.setDoubleValue(value)
* writer.addDocument(document);
* ...
* }
* </pre>
*
* See also {@link IntField}, {@link LongField}, {@link
* FloatField}.
*
* <p>To perform range querying or filtering against a
* <code>DoubleField</code>, use {@link NumericRangeQuery} or {@link
* NumericRangeFilter}. To sort according to a
* <code>DoubleField</code>, use the normal numeric sort types, eg
* {@link org.apache.lucene.search.SortField.Type#DOUBLE}. <code>DoubleField</code>
* values can also be loaded directly from {@link FieldCache}.</p>
*
* <p>You may add the same field name as an <code>DoubleField</code> to
* the same document more than once. Range querying and
* filtering will be the logical OR of all values; so a range query
* will hit all documents that have at least one value in
* the range. However sort behavior is not defined. If you need to sort,
* you should separately index a single-valued <code>DoubleField</code>.</p>
*
* <p>A <code>DoubleField</code> will consume somewhat more disk space
* in the index than an ordinary single-valued field.
* However, for a typical index that includes substantial
* textual content per document, this increase will likely
* be in the noise. </p>
*
* <p>Within Lucene, each numeric value is indexed as a
* <em>trie</em> structure, where each term is logically
* assigned to larger and larger pre-defined brackets (which
* are simply lower-precision representations of the value).
* The step size between each successive bracket is called the
* <code>precisionStep</code>, measured in bits. Smaller
* <code>precisionStep</code> values result in larger number
* of brackets, which consumes more disk space in the index
* but may result in faster range search performance. The
* default value, 4, was selected for a reasonable tradeoff
* of disk space consumption versus performance. You can
* create a custom {@link FieldType} and invoke the {@link
* FieldType#setNumericPrecisionStep} method if you'd
* like to change the value. Note that you must also
* specify a congruent value when creating {@link
* NumericRangeQuery} or {@link NumericRangeFilter}.
* For low cardinality fields larger precision steps are good.
* If the cardinality is < 100, it is fair
* to use {@link Integer#MAX_VALUE}, which produces one
* term per value.
*
* <p>For more information on the internals of numeric trie
* indexing, including the <a
* href="../search/NumericRangeQuery.html#precisionStepDesc"><code>precisionStep</code></a>
* configuration, see {@link NumericRangeQuery}. The format of
* indexed values is described in {@link NumericUtils}.
*
* <p>If you only need to sort by numeric value, and never
* run range querying/filtering, you can index using a
* <code>precisionStep</code> of {@link Integer#MAX_VALUE}.
* This will minimize disk space consumed. </p>
*
* <p>More advanced users can instead use {@link
* NumericTokenStream} directly, when indexing numbers. This
* class is a wrapper around this token stream type for
* easier, more intuitive usage.</p>
*
* @since 2.9
*/
public final class DoubleField extends Field {
/**
* Type for a DoubleField that is not stored:
* normalization factors, frequencies, and positions are omitted.
*/
public static final FieldType TYPE_NOT_STORED = new FieldType();
static {
TYPE_NOT_STORED.setIndexed(true);
TYPE_NOT_STORED.setTokenized(true);
TYPE_NOT_STORED.setOmitNorms(true);
TYPE_NOT_STORED.setIndexOptions(IndexOptions.DOCS_ONLY);
TYPE_NOT_STORED.setNumericType(FieldType.NumericType.DOUBLE);
TYPE_NOT_STORED.freeze();
}
/**
* Type for a stored DoubleField:
* normalization factors, frequencies, and positions are omitted.
*/
public static final FieldType TYPE_STORED = new FieldType();
static {
TYPE_STORED.setIndexed(true);
TYPE_STORED.setTokenized(true);
TYPE_STORED.setOmitNorms(true);
TYPE_STORED.setIndexOptions(IndexOptions.DOCS_ONLY);
TYPE_STORED.setNumericType(FieldType.NumericType.DOUBLE);
TYPE_STORED.setStored(true);
TYPE_STORED.freeze();
}
/** Creates a stored or un-stored DoubleField with the provided value
* and default <code>precisionStep</code> {@link
* NumericUtils#PRECISION_STEP_DEFAULT} (4).
* @param name field name
* @param value 64-bit double value
* @param stored Store.YES if the content should also be stored
* @throws IllegalArgumentException if the field name is null.
*/
public DoubleField(String name, double value, Store stored) {
super(name, stored == Store.YES ? TYPE_STORED : TYPE_NOT_STORED);
fieldsData = Double.valueOf(value);
}
/** Expert: allows you to customize the {@link
* FieldType}.
* @param name field name
* @param value 64-bit double value
* @param type customized field type: must have {@link FieldType#numericType()}
* of {@link FieldType.NumericType#DOUBLE}.
* @throws IllegalArgumentException if the field name or type is null, or
* if the field type does not have a DOUBLE numericType()
*/
public DoubleField(String name, double value, FieldType type) {
super(name, type);
if (type.numericType() != FieldType.NumericType.DOUBLE) {
throw new IllegalArgumentException("type.numericType() must be DOUBLE but got " + type.numericType());
}
fieldsData = Double.valueOf(value);
}
}