com.mongodb.operation.CountOperation Maven / Gradle / Ivy
/*
* 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.operation;
import com.mongodb.ExplainVerbosity;
import com.mongodb.MongoNamespace;
import com.mongodb.async.AsyncBatchCursor;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.binding.AsyncConnectionSource;
import com.mongodb.binding.AsyncReadBinding;
import com.mongodb.binding.ConnectionSource;
import com.mongodb.binding.ReadBinding;
import com.mongodb.client.model.Collation;
import com.mongodb.connection.AsyncConnection;
import com.mongodb.connection.Connection;
import com.mongodb.connection.ConnectionDescription;
import com.mongodb.connection.ServerDescription;
import com.mongodb.internal.client.model.CountStrategy;
import com.mongodb.internal.connection.NoOpSessionContext;
import com.mongodb.operation.CommandOperationHelper.CommandReadTransformer;
import com.mongodb.operation.CommandOperationHelper.CommandReadTransformerAsync;
import com.mongodb.session.SessionContext;
import org.bson.BsonDocument;
import org.bson.BsonInt32;
import org.bson.BsonInt64;
import org.bson.BsonString;
import org.bson.BsonValue;
import org.bson.codecs.BsonDocumentCodec;
import org.bson.codecs.Decoder;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import static com.mongodb.assertions.Assertions.notNull;
import static com.mongodb.operation.CommandOperationHelper.CommandCreator;
import static com.mongodb.operation.CommandOperationHelper.executeCommandAsync;
import static com.mongodb.operation.CommandOperationHelper.executeCommand;
import static com.mongodb.operation.DocumentHelper.putIfNotNull;
import static com.mongodb.operation.DocumentHelper.putIfNotZero;
import static com.mongodb.operation.ExplainHelper.asExplainCommand;
import static com.mongodb.operation.OperationHelper.validateReadConcernAndCollation;
import static com.mongodb.operation.OperationReadConcernHelper.appendReadConcernToCommand;
/**
* An operation that executes a count.
*
* @since 3.0
*/
@Deprecated
public class CountOperation implements AsyncReadOperation, ReadOperation {
private static final Decoder DECODER = new BsonDocumentCodec();
private final MongoNamespace namespace;
private final CountStrategy countStrategy;
private boolean retryReads;
private BsonDocument filter;
private BsonValue hint;
private long skip;
private long limit;
private long maxTimeMS;
private Collation collation;
/**
* Construct a new instance.
*
* @param namespace the database and collection namespace for the operation.
*/
public CountOperation(final MongoNamespace namespace) {
this(namespace, CountStrategy.COMMAND);
}
/**
* Construct a new instance.
*
* @param namespace the database and collection namespace for the operation.
* @param countStrategy the strategy to use for calculating the count.
*/
public CountOperation(final MongoNamespace namespace, final CountStrategy countStrategy) {
this.namespace = notNull("namespace", namespace);
this.countStrategy = notNull("countStrategy", countStrategy);
}
/**
* Gets the query filter.
*
* @return the query filter
* @mongodb.driver.manual reference/method/db.collection.find/ filter
*/
public BsonDocument getFilter() {
return filter;
}
/**
* Sets the filter to apply to the query.
*
* @param filter the filter, which may be null.
* @return this
* @mongodb.driver.manual reference/method/db.collection.find/ Filter
*/
public CountOperation filter(final BsonDocument filter) {
this.filter = filter;
return this;
}
/**
* Enables retryable reads if a read fails due to a network error.
*
* @param retryReads true if reads should be retried
* @return this
* @since 3.11
*/
public CountOperation retryReads(final boolean retryReads) {
this.retryReads = retryReads;
return this;
}
/**
* Gets the value for retryable reads. The default is true.
*
* @return the retryable reads value
* @since 3.11
*/
public boolean getRetryReads() {
return retryReads;
}
/**
* Gets the hint to apply.
*
* @return the hint, which should describe an existing
*/
public BsonValue getHint() {
return hint;
}
/**
* Sets the hint to apply.
*
* @param hint a value describing the index which should be used for this operation.
* @return this
*/
public CountOperation hint(final BsonValue hint) {
this.hint = hint;
return this;
}
/**
* Gets the limit to apply. The default is 0, which means there is no limit.
*
* @return the limit
* @mongodb.driver.manual reference/method/cursor.limit/#cursor.limit Limit
*/
public long getLimit() {
return limit;
}
/**
* Sets the limit to apply.
*
* @param limit the limit
* @return this
* @mongodb.driver.manual reference/method/cursor.limit/#cursor.limit Limit
*/
public CountOperation limit(final long limit) {
this.limit = limit;
return this;
}
/**
* Gets the number of documents to skip. The default is 0.
*
* @return the number of documents to skip, which may be null
* @mongodb.driver.manual reference/method/cursor.skip/#cursor.skip Skip
*/
public long getSkip() {
return skip;
}
/**
* Sets the number of documents to skip.
*
* @param skip the number of documents to skip
* @return this
* @mongodb.driver.manual reference/method/cursor.skip/#cursor.skip Skip
*/
public CountOperation skip(final long skip) {
this.skip = skip;
return this;
}
/**
* Gets the maximum execution time on the server for this operation. The default is 0, which places no limit on the execution time.
*
* @param timeUnit the time unit to return the result in
* @return the maximum execution time in the given time unit
*/
public long getMaxTime(final TimeUnit timeUnit) {
notNull("timeUnit", timeUnit);
return timeUnit.convert(maxTimeMS, TimeUnit.MILLISECONDS);
}
/**
* Sets the maximum execution time on the server for this operation.
*
* @param maxTime the max time
* @param timeUnit the time unit, which may not be null
* @return this
*/
public CountOperation maxTime(final long maxTime, final TimeUnit timeUnit) {
notNull("timeUnit", timeUnit);
this.maxTimeMS = TimeUnit.MILLISECONDS.convert(maxTime, timeUnit);
return this;
}
/**
* Returns the collation options
*
* @return the collation options
* @since 3.4
* @mongodb.server.release 3.4
*/
public Collation getCollation() {
return collation;
}
/**
* Sets the collation options
*
* A null value represents the server default.
* @param collation the collation options to use
* @return this
*/
public CountOperation collation(final Collation collation) {
this.collation = collation;
return this;
}
@Override
public Long execute(final ReadBinding binding) {
if (countStrategy.equals(CountStrategy.COMMAND)) {
return executeCommand(binding, namespace.getDatabaseName(),
getCommandCreator(binding.getSessionContext()), DECODER, transformer(), retryReads);
} else {
BatchCursor cursor = getAggregateOperation().execute(binding);
return cursor.hasNext() ? getCountFromAggregateResults(cursor.next()) : 0;
}
}
@Override
public void executeAsync(final AsyncReadBinding binding, final SingleResultCallback callback) {
if (countStrategy.equals(CountStrategy.COMMAND)) {
executeCommandAsync(binding, namespace.getDatabaseName(), getCommandCreator(binding.getSessionContext()),
DECODER, asyncTransformer(), retryReads, callback);
} else {
getAggregateOperation().executeAsync(binding, new SingleResultCallback>(){
@Override
public void onResult(final AsyncBatchCursor result, final Throwable t) {
if (t != null) {
callback.onResult(null, t);
} else {
result.next(new SingleResultCallback>() {
@Override
public void onResult(final List result, final Throwable t) {
if (t != null) {
callback.onResult(null, t);
} else {
callback.onResult(getCountFromAggregateResults(result), null);
}
}
});
}
}
});
}
}
/**
* Gets an operation whose execution explains this operation.
*
* @param explainVerbosity the explain verbosity
* @return a read operation that when executed will explain this operation
*/
public ReadOperation asExplainableOperation(final ExplainVerbosity explainVerbosity) {
if (countStrategy.equals(CountStrategy.COMMAND)) {
return createExplainableOperation(explainVerbosity);
} else {
return getAggregateOperation().asExplainableOperation(explainVerbosity);
}
}
/**
* Gets an operation whose execution explains this operation.
*
* @param explainVerbosity the explain verbosity
* @return a read operation that when executed will explain this operation
*/
public AsyncReadOperation asExplainableOperationAsync(final ExplainVerbosity explainVerbosity) {
if (countStrategy.equals(CountStrategy.COMMAND)) {
return createExplainableOperation(explainVerbosity);
} else {
return getAggregateOperation().asExplainableOperationAsync(explainVerbosity);
}
}
private CommandReadOperation createExplainableOperation(final ExplainVerbosity explainVerbosity) {
return new CommandReadOperation(namespace.getDatabaseName(),
asExplainCommand(getCommand(NoOpSessionContext.INSTANCE), explainVerbosity),
new BsonDocumentCodec());
}
private CommandReadTransformer transformer() {
return new CommandReadTransformer() {
@Override
public Long apply(final BsonDocument result, final ConnectionSource source, final Connection connection) {
return (result.getNumber("n")).longValue();
}
};
}
private CommandReadTransformerAsync asyncTransformer() {
return new CommandReadTransformerAsync() {
@Override
public Long apply(final BsonDocument result, final AsyncConnectionSource source, final AsyncConnection connection) {
return (result.getNumber("n")).longValue();
}
};
}
private CommandCreator getCommandCreator(final SessionContext sessionContext) {
return new CommandCreator() {
@Override
public BsonDocument create(final ServerDescription serverDescription, final ConnectionDescription connectionDescription) {
validateReadConcernAndCollation(connectionDescription, sessionContext.getReadConcern(), collation);
return getCommand(sessionContext);
}
};
}
private BsonDocument getCommand(final SessionContext sessionContext) {
BsonDocument document = new BsonDocument("count", new BsonString(namespace.getCollectionName()));
appendReadConcernToCommand(sessionContext, document);
putIfNotNull(document, "query", filter);
putIfNotZero(document, "limit", limit);
putIfNotZero(document, "skip", skip);
putIfNotNull(document, "hint", hint);
putIfNotZero(document, "maxTimeMS", maxTimeMS);
if (collation != null) {
document.put("collation", collation.asDocument());
}
return document;
}
private AggregateOperation getAggregateOperation() {
return new AggregateOperation(namespace, getPipeline(), DECODER)
.retryReads(retryReads)
.collation(collation)
.hint(hint)
.maxTime(maxTimeMS, TimeUnit.MILLISECONDS);
}
private List getPipeline() {
ArrayList pipeline = new ArrayList();
pipeline.add(new BsonDocument("$match", filter != null ? filter : new BsonDocument()));
if (skip > 0) {
pipeline.add(new BsonDocument("$skip", new BsonInt64(skip)));
}
if (limit > 0) {
pipeline.add(new BsonDocument("$limit", new BsonInt64(limit)));
}
pipeline.add(new BsonDocument("$group", new BsonDocument("_id", new BsonInt32(1))
.append("n", new BsonDocument("$sum", new BsonInt32(1)))));
return pipeline;
}
private Long getCountFromAggregateResults(final List results) {
if (results == null || results.isEmpty()) {
return 0L;
} else {
return results.get(0).getNumber("n").longValue();
}
}
}