java/src/main/com/google/appengine/api/datastore/QueryResultsSourceV3.java

   1 package com.google.appengine.api.datastore;
   2
   3 import static com.google.appengine.api.datastore.DatastoreApiHelper.makeAsyncCall;
   4
   5 import com.google.apphosting.api.ApiProxy.ApiConfig;
   6 import com.google.apphosting.datastore.DatastoreV3Pb;
   7 import com.google.apphosting.datastore.DatastoreV3Pb.CompiledCursor;
   8 import com.google.apphosting.datastore.DatastoreV3Pb.DatastoreService_3.Method;
   9 import com.google.apphosting.datastore.DatastoreV3Pb.NextRequest;
  10 import com.google.apphosting.datastore.DatastoreV3Pb.QueryResult;
  11 import com.google.common.collect.Lists;
  12 import com.google.storage.onestore.v3.OnestoreEntity.CompositeIndex;
  13 import com.google.storage.onestore.v3.OnestoreEntity.EntityProto;
  14
  15 import java.util.Collection;
  16 import java.util.Collections;
  17 import java.util.List;
  18 import java.util.concurrent.Future;
  19
  20 /**
  21  * V3 service specific code for iterating query results and requesting more results.
  22  * Instances can be shared between queries using the same ApiConfig.
  23  */
  24 class QueryResultsSourceV3 extends BaseQueryResultsSource<QueryResult, NextRequest, QueryResult> {
  25
  26   private final ApiConfig apiConfig;
  27
  28   QueryResultsSourceV3(DatastoreCallbacks callbacks, FetchOptions fetchOptions, Transaction txn,
  29       Query query, Future<QueryResult> initialQueryResultFuture, ApiConfig apiConfig) {
  30     super(callbacks, fetchOptions, txn, query, initialQueryResultFuture);
  31     this.apiConfig = apiConfig;
  32   }
  33
  34   @Override
  35   public NextRequest buildNextCallPrototype(QueryResult initialResult) {
  36     DatastoreV3Pb.NextRequest req = new DatastoreV3Pb.NextRequest();
  37     req.setCursor(initialResult.getCursor());
  38     if (initialResult.hasCompiledCursor()) {
  39       req.setCompile(true);
  40     }
  41     req.freeze();
  42     return req;
  43   }
  44
  45   @Override
  46   public Future<QueryResult> makeNextCall(NextRequest reqPrototype, WrappedQueryResult unused, Integer fetchCount, Integer offsetOrNull) {
  47     DatastoreV3Pb.NextRequest req = reqPrototype.clone();
  48     if (fetchCount != null) {
  49       req.setCount(fetchCount);
  50     }
  51     if (offsetOrNull != null) {
  52       req.setOffset(offsetOrNull);
  53     }
  54     return makeAsyncCall(apiConfig, Method.Next, req, new DatastoreV3Pb.QueryResult());
  55   }
  56
  57   @Override
  58   public WrappedQueryResult wrapResult(QueryResult result) {
  59     return new WrappedQueryResultV3(result);
  60   }
  61
  62   @Override
  63   public WrappedQueryResult wrapInitialResult(QueryResult initialResult) {
  64     return new WrappedQueryResultV3(initialResult);
  65   }
  66
  67   private static class WrappedQueryResultV3 implements WrappedQueryResult {
  68     private final DatastoreV3Pb.QueryResult res;
  69
  70     WrappedQueryResultV3(DatastoreV3Pb.QueryResult res) {
  71       this.res = res;
  72     }
  73
  74     @Override
  75     public List<Entity> getEntities(Collection<Projection> projections) {
  76       List<Entity> entities = Lists.newArrayListWithCapacity(res.resultSize());
  77       if (projections.isEmpty()) {
  78         for (EntityProto entityProto : res.results()) {
  79           entities.add(EntityTranslator.createFromPb(entityProto));
  80         }
  81       } else {
  82         for (EntityProto entityProto : res.results()) {
  83           entities.add(EntityTranslator.createFromPb(entityProto, projections));
  84         }
  85       }
  86       return entities;
  87     }
  88
  89     @Override
  90     public List<Cursor> getResultCursors() {
  91       List<Cursor> cursors = Lists.newArrayListWithCapacity(res.resultSize());
  92
  93       for (CompiledCursor compiledCursor : res.resultCompiledCursors()) {
  94         cursors.add(new Cursor(compiledCursor.toByteString()));
  95       }
  96       cursors.addAll(Collections.<Cursor>nCopies(res.resultSize() - cursors.size(), null));
  97       return cursors;
  98     }
  99
 100     @Override
 101     public int numSkippedResults() {
 102       return res.getSkippedResults();
 103     }
 104
 105     @Override
 106     public Cursor getSkippedResultsCursor() {
 107       return res.hasSkippedResultsCompiledCursor()
 108           ? new Cursor(res.getSkippedResultsCompiledCursor().toByteString()) : null;
 109     }
 110
 111     @Override
 112     public boolean hasMoreResults() {
 113       return res.isMoreResults();
 114     }
 115
 116     @Override
 117     public Cursor getEndCursor() {
 118       return res.hasCompiledCursor() ? new Cursor(res.getCompiledCursor().toByteString()) : null;
 119     }
 120
 121     @Override
 122     public List<Index> getIndexInfo(Collection<Index> monitoredIndexBuffer) {
 123       List<Index> indexList = Lists.newArrayListWithCapacity(res.indexSize());
 124       for (CompositeIndex indexProtobuf : res.indexs()) {
 125         Index index = IndexTranslator.convertFromPb(indexProtobuf);
 126         indexList.add(index);
 127         if (indexProtobuf.isOnlyUseIfRequired()) {
 128           monitoredIndexBuffer.add(index);
 129         }
 130       }
 131       return indexList;
 132     }
 133   }
 134 }