/
CollectionGroup.java
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/
CollectionGroup.java
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/*
* Copyright 2020 Google LLC
*
* 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.google.cloud.firestore;
import com.google.api.core.ApiFunction;
import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutures;
import com.google.api.gax.rpc.ApiException;
import com.google.api.gax.rpc.ApiExceptions;
import com.google.api.gax.rpc.ApiStreamObserver;
import com.google.cloud.firestore.v1.FirestoreClient;
import com.google.cloud.firestore.v1.FirestoreClient.PartitionQueryPagedResponse;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.firestore.v1.Cursor;
import com.google.firestore.v1.PartitionQueryRequest;
import io.opencensus.common.Scope;
import io.opencensus.trace.Span;
import io.opencensus.trace.Status;
import java.util.Collections;
import java.util.List;
import javax.annotation.Nullable;
/**
* A Collection Group query matches all documents that are contained in a collection or
* subcollection with a specific collection ID.
*/
public class CollectionGroup extends Query {
final Query partitionQuery;
CollectionGroup(FirestoreRpcContext<?> rpcContext, String collectionId) {
super(
rpcContext,
QueryOptions.builder()
.setParentPath(rpcContext.getResourcePath())
.setCollectionId(collectionId)
.setAllDescendants(true)
.build());
// Partition queries require explicit ordering by __name__.
partitionQuery = orderBy(FieldPath.DOCUMENT_ID);
}
/**
* Partitions a query by returning partition cursors that can be used to run the query in
* parallel. The returned partition cursors are split points that can be used as starting/end
* points for the query results.
*
* @param desiredPartitionCount The desired maximum number of partition points. The number must be
* strictly positive. The actual number of partitions returned may be fewer.
* @param observer a stream observer that receives the result of the Partition request.
*/
public void getPartitions(
long desiredPartitionCount, final ApiStreamObserver<QueryPartition> observer) {
if (desiredPartitionCount == 1) {
// Short circuit if the user only requested a single partition.
observer.onNext(new QueryPartition(partitionQuery, null, null));
} else {
PartitionQueryRequest request = buildRequest(desiredPartitionCount);
final FirestoreClient.PartitionQueryPagedResponse response;
final TraceUtil traceUtil = TraceUtil.getInstance();
Span span = traceUtil.startSpan(TraceUtil.SPAN_NAME_PARTITIONQUERY);
try (Scope scope = traceUtil.getTracer().withSpan(span)) {
response =
ApiExceptions.callAndTranslateApiException(
rpcContext.sendRequest(
request, rpcContext.getClient().partitionQueryPagedCallable()));
consumePartitions(
response,
new Function<QueryPartition, Void>() {
@Override
public Void apply(QueryPartition queryPartition) {
observer.onNext(queryPartition);
return null;
}
});
observer.onCompleted();
} catch (ApiException exception) {
span.setStatus(Status.UNKNOWN.withDescription(exception.getMessage()));
throw FirestoreException.forApiException(exception);
} finally {
span.end(TraceUtil.END_SPAN_OPTIONS);
}
}
}
public ApiFuture<List<QueryPartition>> getPartitions(long desiredPartitionCount) {
if (desiredPartitionCount == 1) {
// Short circuit if the user only requested a single partition.
return ApiFutures.immediateFuture(
Collections.singletonList(new QueryPartition(partitionQuery, null, null)));
} else {
PartitionQueryRequest request = buildRequest(desiredPartitionCount);
final TraceUtil traceUtil = TraceUtil.getInstance();
Span span = traceUtil.startSpan(TraceUtil.SPAN_NAME_PARTITIONQUERY);
try (Scope scope = traceUtil.getTracer().withSpan(span)) {
return ApiFutures.transform(
rpcContext.sendRequest(request, rpcContext.getClient().partitionQueryPagedCallable()),
new ApiFunction<PartitionQueryPagedResponse, List<QueryPartition>>() {
@Override
public List<QueryPartition> apply(PartitionQueryPagedResponse response) {
final ImmutableList.Builder<QueryPartition> partitions = ImmutableList.builder();
consumePartitions(
response,
new Function<QueryPartition, Void>() {
@Override
public Void apply(QueryPartition queryPartition) {
partitions.add(queryPartition);
return null;
}
});
return partitions.build();
}
},
MoreExecutors.directExecutor());
} catch (ApiException exception) {
span.setStatus(Status.UNKNOWN.withDescription(exception.getMessage()));
throw FirestoreException.forApiException(exception);
} finally {
span.end(TraceUtil.END_SPAN_OPTIONS);
}
}
}
private PartitionQueryRequest buildRequest(long desiredPartitionCount) {
Preconditions.checkArgument(
desiredPartitionCount > 0, "Desired partition count must be one or greater");
PartitionQueryRequest.Builder request = PartitionQueryRequest.newBuilder();
request.setStructuredQuery(partitionQuery.buildQuery());
request.setParent(options.getParentPath().toString());
// Since we are always returning an extra partition (with en empty endBefore cursor), we
// reduce the desired partition count by one.
request.setPartitionCount(desiredPartitionCount - 1);
return request.build();
}
private void consumePartitions(
PartitionQueryPagedResponse response, Function<QueryPartition, Void> consumer) {
@Nullable Object[] lastCursor = null;
for (Cursor cursor : response.iterateAll()) {
Object[] decodedCursorValue = new Object[cursor.getValuesCount()];
for (int i = 0; i < cursor.getValuesCount(); ++i) {
decodedCursorValue[i] = UserDataConverter.decodeValue(rpcContext, cursor.getValues(i));
}
consumer.apply(new QueryPartition(partitionQuery, lastCursor, decodedCursorValue));
lastCursor = decodedCursorValue;
}
consumer.apply(new QueryPartition(partitionQuery, lastCursor, null));
}
}