/gemfire-core/src/main/java/com/gemstone/gemfire/cache/client/internal/QueryOp.java

/*=========================================================================
 * Copyright (c) 2002-2014 Pivotal Software, Inc. All Rights Reserved.
 * This product is protected by U.S. and international copyright
 * and intellectual property laws. Pivotal products are covered by
 * more patents listed at http://www.pivotal.io/patents.
 *=========================================================================
 */
package com.gemstone.gemfire.cache.client.internal;

import java.util.Arrays;
import com.gemstone.gemfire.internal.Version;
import com.gemstone.gemfire.internal.cache.tier.MessageType;
import com.gemstone.gemfire.internal.cache.tier.sockets.Message;
import com.gemstone.gemfire.internal.cache.tier.sockets.ChunkedMessage;
import com.gemstone.gemfire.internal.cache.tier.sockets.ObjectPartList;
import com.gemstone.gemfire.internal.cache.tier.sockets.Part;
import com.gemstone.gemfire.cache.query.SelectResults;
import com.gemstone.gemfire.cache.query.types.CollectionType;
import com.gemstone.gemfire.cache.query.types.ObjectType;
import com.gemstone.gemfire.cache.query.internal.QueryUtils;
import com.gemstone.gemfire.cache.query.internal.StructImpl;
import com.gemstone.gemfire.cache.query.internal.types.StructTypeImpl;
import com.gemstone.gemfire.cache.query.internal.types.TypeUtils;
import com.gemstone.gemfire.SerializationException;
import com.gemstone.gemfire.cache.client.ServerOperationException;

/**
 * Does a region query on a server
 * @author darrel
 * @since 5.7
 */
public class QueryOp {
  /**
   * Does a region query on a server using connections from the given pool
   * to communicate with the server.
   * @param pool the pool to use to communicate with the server.
   * @param queryPredicate A query language boolean query predicate
   * @return  A <code>SelectResults</code> containing the values
   *            that match the <code>queryPredicate</code>.
   */
  public static SelectResults execute(ExecutablePool pool, String queryPredicate,
                                      Object[] queryParams)
  {
    AbstractOp op = null;
    
    if (queryParams != null && queryParams.length > 0) {
      op = new QueryOpImpl(queryPredicate, queryParams);
    } else {
      op = new QueryOpImpl(queryPredicate);      
    }
    return (SelectResults)pool.execute(op);
  }
                                                               
  private QueryOp() {
    // no instances allowed
  }

  /**
   * Note: this class is extended by CreateCQWithIROpImpl.
   */
  protected static class QueryOpImpl extends AbstractOp {
    /**
     * @throws com.gemstone.gemfire.SerializationException if serialization fails
     */
    public QueryOpImpl(String queryPredicate) {
      super(MessageType.QUERY, 1);
      getMessage().addStringPart(queryPredicate);
    }

    /**
     * @throws com.gemstone.gemfire.SerializationException if serialization fails
     */
    public QueryOpImpl(String queryPredicate, Object[] queryParams) {
      super(MessageType.QUERY_WITH_PARAMETERS, 2 + queryParams.length);
      getMessage().addStringPart(queryPredicate);
      getMessage().addIntPart(queryParams.length);
      for (Object param : queryParams){
        getMessage().addObjPart(param);
      }
    }

    /**
     * This constructor is used by our subclass CreateCQWithIROpImpl
     * @throws com.gemstone.gemfire.SerializationException if serialization fails
     */
    protected QueryOpImpl(int msgType, int numParts) {
      super(msgType, numParts);
    }
    @Override  
    protected Message createResponseMessage() {
      return new ChunkedMessage(2, Version.CURRENT);
    }
    @Override  
    protected Object processResponse(Message msg) throws Exception {
      final SelectResults[] resultRef = new SelectResults[1];
      final Exception[] exceptionRef = new Exception[1];
      ChunkHandler ch = new ChunkHandler() {
          public void handle(ChunkedMessage cm) throws Exception {
            Part collectionTypePart = cm.getPart(0);
            Object o = collectionTypePart.getObject();
            if (o instanceof Throwable) {
              String s = "While performing a remote " + getOpName();
              exceptionRef[0] = new ServerOperationException(s, (Throwable)o);
              return;
            }
            CollectionType collectionType = (CollectionType)o;
            Part resultPart = cm.getPart(1);
            Object queryResult = null;
            try {
              queryResult = resultPart.getObject();
            } catch (Exception e) {
              String s = "While deserializing " + getOpName() + " result";
              exceptionRef[0] = new SerializationException(s, e);
              return;
            }
            if (queryResult instanceof Throwable) {
              String s = "While performing a remote " + getOpName();
              exceptionRef[0] = new ServerOperationException(s, (Throwable)queryResult);
              return;
            } else if (queryResult instanceof Integer) {
              // Create the appropriate SelectResults instance if necessary
              if (resultRef[0] == null) {
                resultRef[0] = QueryUtils.
                               getEmptySelectResults(TypeUtils.OBJECT_TYPE,
                                                     null);
              }
              resultRef[0].add(queryResult);
            } else { // typical query result
              // Create the appropriate SelectResults instance if necessary
              if (resultRef[0] == null) {
                resultRef[0] = QueryUtils.getEmptySelectResults(collectionType,
                                                                null);
              }
              SelectResults selectResults = resultRef[0];
              ObjectType objectType = collectionType.getElementType();
              Object[] resultArray;
             // for select * queries, the serialized object byte arrays are
             // returned as part of ObjectPartList
              boolean isObjectPartList = false;
              if (queryResult instanceof ObjectPartList) {
                isObjectPartList = true;
                resultArray = ((ObjectPartList) queryResult).getObjects().toArray();
              } else{ 
                // Add the results to the SelectResults
                resultArray = (Object[]) queryResult;
              }
              if (objectType.isStructType()) {
                for (int i = 0; i < resultArray.length; i++) {
                  if (isObjectPartList) {
                    selectResults
                        .add(new StructImpl((StructTypeImpl) objectType,
                            ((ObjectPartList) resultArray[i]).getObjects()
                                .toArray()));
                  } else {
                    selectResults.add(new StructImpl((StructTypeImpl) objectType,
                        (Object[]) resultArray[i]));
                  }
                }
              } else {
                selectResults.addAll(Arrays.asList(resultArray));
              }
            }
          }
        };
      processChunkedResponse((ChunkedMessage)msg, getOpName(), ch);
      if (exceptionRef[0] != null) {
        throw exceptionRef[0];
      } else {
        return resultRef[0];
      }
    }
    protected String getOpName() {
      return "query";
    }
    @Override  
    protected boolean isErrorResponse(int msgType) {
      return msgType == MessageType.QUERY_DATA_ERROR
        || msgType == MessageType.CQDATAERROR_MSG_TYPE
        || msgType == MessageType.CQ_EXCEPTION_TYPE;
    }
    @Override  
    protected long startAttempt(ConnectionStats stats) {
      return stats.startQuery();
    }
    @Override  
    protected void endSendAttempt(ConnectionStats stats, long start) {
      stats.endQuerySend(start, hasFailed());
    }
    @Override  
    protected void endAttempt(ConnectionStats stats, long start) {
      stats.endQuery(start, hasTimedOut(), hasFailed());
    }
  }
}