Java tutorial
/* * Copyright 2008-present MongoDB, Inc. * * Licensed 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 com.mongodb.client.model; import org.bson.BsonDocument; import org.bson.BsonInt32; import org.bson.BsonString; import org.bson.BsonValue; import org.bson.codecs.configuration.CodecRegistry; import org.bson.conversions.Bson; import java.util.List; import static com.mongodb.assertions.Assertions.notNull; import static java.util.Arrays.asList; /** * A factory for defining index keys. A convenient way to use this class is to statically import all of its methods, which allows usage * like: * <blockquote><pre> * collection.createIndex(compoundIndex(ascending("x"), descending("y"))); * </pre></blockquote> * @since 3.1 */ public final class Indexes { private Indexes() { } /** * Create an index key for an ascending index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/indexes indexes */ public static Bson ascending(final String... fieldNames) { return ascending(asList(fieldNames)); } /** * Create an index key for an ascending index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/indexes indexes */ public static Bson ascending(final List<String> fieldNames) { notNull("fieldNames", fieldNames); return compoundIndex(fieldNames, new BsonInt32(1)); } /** * Create an index key for an ascending index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/indexes indexes */ public static Bson descending(final String... fieldNames) { return descending(asList(fieldNames)); } /** * Create an index key for an ascending index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/indexes indexes */ public static Bson descending(final List<String> fieldNames) { notNull("fieldNames", fieldNames); return compoundIndex(fieldNames, new BsonInt32(-1)); } /** * Create an index key for an 2dsphere index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/2dsphere 2dsphere Index */ public static Bson geo2dsphere(final String... fieldNames) { return geo2dsphere(asList(fieldNames)); } /** * Create an index key for an ascending index on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the index specification * @mongodb.driver.manual core/indexes indexes */ public static Bson geo2dsphere(final List<String> fieldNames) { notNull("fieldNames", fieldNames); return compoundIndex(fieldNames, new BsonString("2dsphere")); } /** * Create an index key for a 2d index on the given field. * * <p> * <strong>Note: </strong>A 2d index is for data stored as points on a two-dimensional plane. * The 2d index is intended for legacy coordinate pairs used in MongoDB 2.2 and earlier. * </p> * * @param fieldName the field to create a 2d index on * @return the index specification * @mongodb.driver.manual core/2d 2d index */ public static Bson geo2d(final String fieldName) { notNull("fieldName", fieldName); return new BsonDocument(fieldName, new BsonString("2d")); } /** * Create an index key for a geohaystack index on the given field. * * <p> * <strong>Note: </strong>For queries that use spherical geometry, a 2dsphere index is a better option than a haystack index. * 2dsphere indexes allow field reordering; geoHaystack indexes require the first field to be the location field. Also, geoHaystack * indexes are only usable via commands and so always return all results at once.. * </p> * * @param fieldName the field to create a geoHaystack index on * @param additional the additional field that forms the geoHaystack index key * @return the index specification * @mongodb.driver.manual core/geohaystack geoHaystack index */ public static Bson geoHaystack(final String fieldName, final Bson additional) { notNull("fieldName", fieldName); return compoundIndex(new BsonDocument(fieldName, new BsonString("geoHaystack")), additional); } /** * Create an index key for a text index on the given field. * * @param fieldName the field to create a text index on * @return the index specification * @mongodb.driver.manual core/text text index */ public static Bson text(final String fieldName) { notNull("fieldName", fieldName); return new BsonDocument(fieldName, new BsonString("text")); } /** * Create an index key for a text index on every field that contains string data. * * @return the index specification * @mongodb.driver.manual core/text text index */ public static Bson text() { return text("$**"); } /** * Create an index key for a hashed index on the given field. * * @param fieldName the field to create a hashed index on * @return the index specification * @mongodb.driver.manual core/hashed hashed index */ public static Bson hashed(final String fieldName) { notNull("fieldName", fieldName); return new BsonDocument(fieldName, new BsonString("hashed")); } /** * create a compound index specifications. If any field names are repeated, the last one takes precedence. * * @param indexes the index specifications * @return the compound index specification * @mongodb.driver.manual core/index-compound compoundIndex */ public static Bson compoundIndex(final Bson... indexes) { return compoundIndex(asList(indexes)); } /** * compound multiple index specifications. If any field names are repeated, the last one takes precedence. * * @param indexes the index specifications * @return the compound index specification * @mongodb.driver.manual core/index-compound compoundIndex */ public static Bson compoundIndex(final List<? extends Bson> indexes) { return new CompoundIndex(indexes); } private static Bson compoundIndex(final List<String> fieldNames, final BsonValue value) { BsonDocument document = new BsonDocument(); for (String fieldName : fieldNames) { document.append(fieldName, value); } return document; } private static class CompoundIndex implements Bson { private final List<? extends Bson> indexes; CompoundIndex(final List<? extends Bson> indexes) { notNull("indexes", indexes); this.indexes = indexes; } @Override public <TDocument> BsonDocument toBsonDocument(final Class<TDocument> documentClass, final CodecRegistry codecRegistry) { BsonDocument compoundIndex = new BsonDocument(); for (Bson index : indexes) { BsonDocument indexDocument = index.toBsonDocument(documentClass, codecRegistry); for (String key : indexDocument.keySet()) { compoundIndex.append(key, indexDocument.get(key)); } } return compoundIndex; } @Override public boolean equals(final Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } CompoundIndex that = (CompoundIndex) o; return indexes.equals(that.indexes); } @Override public int hashCode() { return indexes.hashCode(); } } }