org.apache.lucene.collation.CollationDocValuesField Maven / Gradle / Ivy
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* 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.collation;
import java.text.Collator;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.SortedDocValuesField;
import org.apache.lucene.util.BytesRef;
/**
* Indexes collation keys as a single-valued {@link SortedDocValuesField}.
*
* This is more efficient that {@link CollationKeyAnalyzer} if the field
* only has one value: no uninversion is necessary to sort on the field,
* locale-sensitive range queries can still work via {@code DocValuesRangeQuery},
* and the underlying data structures built at index-time are likely more efficient
* and use less memory than FieldCache.
*/
public final class CollationDocValuesField extends Field {
private final String name;
private final Collator collator;
private final BytesRef bytes = new BytesRef();
/**
* Create a new ICUCollationDocValuesField.
*
* NOTE: you should not create a new one for each document, instead
* just make one and reuse it during your indexing process, setting
* the value via {@link #setStringValue(String)}.
* @param name field name
* @param collator Collator for generating collation keys.
*/
// TODO: can we make this trap-free? maybe just synchronize on the collator
// instead?
public CollationDocValuesField(String name, Collator collator) {
super(name, SortedDocValuesField.TYPE);
this.name = name;
this.collator = (Collator) collator.clone();
fieldsData = bytes; // so wrong setters cannot be called
}
@Override
public String name() {
return name;
}
@Override
public void setStringValue(String value) {
bytes.bytes = collator.getCollationKey(value).toByteArray();
bytes.offset = 0;
bytes.length = bytes.bytes.length;
}
}