content: /*
   * 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.cassandra.cql3.selection;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.stream.Collectors;
  
  import com.google.common.base.Objects;
  
  import org.apache.cassandra.cql3.ColumnSpecification;
  import org.apache.cassandra.cql3.terms.Maps;
  import org.apache.cassandra.cql3.QueryOptions;
  import org.apache.cassandra.cql3.functions.Function;
  import org.apache.cassandra.db.TypeSizes;
  import org.apache.cassandra.db.filter.ColumnFilter.Builder;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.MapType;
  import org.apache.cassandra.io.util.DataInputPlus;
  import org.apache.cassandra.io.util.DataOutputPlus;
  import org.apache.cassandra.schema.ColumnMetadata;
  import org.apache.cassandra.schema.TableMetadata;
  import org.apache.cassandra.transport.ProtocolVersion;
  import org.apache.cassandra.utils.Pair;
  
  /**
   * <code>Selector</code> for literal map (e.g. {'min' : min(value), 'max' : max(value), 'count' : count(value)}).
   *
   */
  final class MapSelector extends Selector
  {
      protected static final SelectorDeserializer deserializer = new SelectorDeserializer()
      {
          protected Selector deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
          {
              MapType<?, ?> type = (MapType<?, ?>) readType(metadata, in);
              int size = in.readUnsignedVInt32();
              List<Pair<Selector, Selector>> entries = new ArrayList<>(size);
              for (int i = 0; i < size; i++)
              {
                  Pair<Selector, Selector> entry = Pair.create(serializer.deserialize(in, version, metadata),
                                                               serializer.deserialize(in, version, metadata));
                  entries.add(entry);
              }
              return new MapSelector(type, entries);
          }
      };
  
      /**
       * The map type.
       */
      private final MapType<?, ?> type;
  
      /**
       * The map elements
       */
      private final List<Pair<Selector, Selector>> elements;
  
      public static Factory newFactory(final AbstractType<?> type, final List<Pair<Factory, Factory>> factories)
      {
          return new Factory()
          {
              protected String getColumnName()
              {
                  return Maps.mapToString(factories, Factory::getColumnName);
              }
  
              protected AbstractType<?> getReturnType()
              {
                  return type;
              }
  
              protected final void addColumnMapping(SelectionColumnMapping mapping, ColumnSpecification resultsColumn)
              {
                  SelectionColumnMapping tmpMapping = SelectionColumnMapping.newMapping();
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      entry.left.addColumnMapping(tmpMapping, resultsColumn);
                      entry.right.addColumnMapping(tmpMapping, resultsColumn);
                  }
  
                  if (tmpMapping.getMappings().get(resultsColumn).isEmpty())
                      // add a null mapping for cases where the collection is empty
                      mapping.addMapping(resultsColumn, (ColumnMetadata)null);
                  else
                      // collate the mapped columns from the child factories & add those
                      mapping.addMapping(resultsColumn, tmpMapping.getMappings().values());
              }
  
              public Selector newInstance(final QueryOptions options)
              {
                  return new MapSelector(type,
                                          factories.stream()
                                                   .map(p -> Pair.create(p.left.newInstance(options),
                                                                         p.right.newInstance(options)))
                                                   .collect(Collectors.toList()));
              }
  
              @Override
              public boolean isAggregateSelectorFactory()
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      if (entry.left.isAggregateSelectorFactory() || entry.right.isAggregateSelectorFactory())
                          return true;
                  }
                  return false;
              }
  
              @Override
              public void addFunctionsTo(List<Function> functions)
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      entry.left.addFunctionsTo(functions);
                      entry.right.addFunctionsTo(functions);
                  }
              }
  
              @Override
              public boolean isWritetimeSelectorFactory()
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      if (entry.left.isWritetimeSelectorFactory() || entry.right.isWritetimeSelectorFactory())
                          return true;
                  }
                  return false;
              }
  
              @Override
              public boolean isTTLSelectorFactory()
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      if (entry.left.isTTLSelectorFactory() || entry.right.isTTLSelectorFactory())
                          return true;
                  }
                  return false;
              }
  
              @Override
              boolean areAllFetchedColumnsKnown()
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      if (!entry.left.areAllFetchedColumnsKnown() || !entry.right.areAllFetchedColumnsKnown())
                          return false;
                  }
                  return true;
              }
  
              @Override
              void addFetchedColumns(Builder builder)
              {
                  for (Pair<Factory, Factory> entry : factories)
                  {
                      entry.left.addFetchedColumns(builder);
                      entry.right.addFetchedColumns(builder);
                  }
              }
          };
      }
  
      @Override
      public void addFetchedColumns(Builder builder)
      {
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> pair = elements.get(i);
              pair.left.addFetchedColumns(builder);
              pair.right.addFetchedColumns(builder);
          }
      }
  
      public void addInput(InputRow input)
      {
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> pair = elements.get(i);
              pair.left.addInput(input);
              pair.right.addInput(input);
          }
      }
  
      public ByteBuffer getOutput(ProtocolVersion protocolVersion)
      {
          Map<ByteBuffer, ByteBuffer> map = new TreeMap<>(type.getKeysType());
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> pair = elements.get(i);
              map.put(pair.left.getOutput(protocolVersion), pair.right.getOutput(protocolVersion));
          }
  
          List<ByteBuffer> buffers = new ArrayList<>(elements.size() * 2);
          for (Map.Entry<ByteBuffer, ByteBuffer> entry : map.entrySet())
          {
              buffers.add(entry.getKey());
              buffers.add(entry.getValue());
          }
          return type.pack(buffers);
      }
  
      public void reset()
      {
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> pair = elements.get(i);
              pair.left.reset();
              pair.right.reset();
          }
      }
  
      @Override
      public boolean isTerminal()
      {
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> pair = elements.get(i);
              if (!pair.left.isTerminal() || !pair.right.isTerminal())
                  return false;
          }
          return true;
      }
  
      public AbstractType<?> getType()
      {
          return type;
      }
  
      @Override
      public String toString()
      {
          return Maps.mapToString(elements);
      }
  
      private MapSelector(AbstractType<?> type, List<Pair<Selector, Selector>> elements)
      {
          super(Kind.MAP_SELECTOR);
          this.type = (MapType<?, ?>) type;
          this.elements = elements;
      }
      
  
      @Override
      public boolean equals(Object o)
      {
          if (this == o)
              return true;
  
          if (!(o instanceof MapSelector))
              return false;
  
          MapSelector s = (MapSelector) o;
  
          return Objects.equal(type, s.type)
              && Objects.equal(elements, s.elements);
      }
  
      @Override
      public int hashCode()
      {
          return Objects.hashCode(type, elements);
      }
  
      @Override
      protected int serializedSize(int version)
      {
          int size = sizeOf(type) + TypeSizes.sizeofUnsignedVInt(elements.size());
  
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> entry = elements.get(i);
              size += serializer.serializedSize(entry.left, version) + serializer.serializedSize(entry.right, version);
          }
  
          return size;
      }
  
      @Override
      protected void serialize(DataOutputPlus out, int version) throws IOException
      {
          writeType(out, type);
          out.writeUnsignedVInt32(elements.size());
  
          for (int i = 0, m = elements.size(); i < m; i++)
          {
              Pair<Selector, Selector> entry = elements.get(i);
              serializer.serialize(entry.left, out, version);
              serializer.serialize(entry.right, out, version);
          }
      }
  }
  