Examples of com.google.appengine.tools.mapreduce.DatastoreMutationPool

com.google.appengine.tools.mapreduce.DatastoreMutationPool

DatastoreMutationPool allows you to pool datastore operations such that they are applied in batches, requiring fewer datastore API calls. Mutations are accumulated until they reach a count limit on the number of unflushed mutations, until they reach a size limit on the byte count of unflushed mutations, or until a manual flush is requested. A typical use would be:

    {@code}class Example extends Mapper<...>  ... private transient DatastoreMutationPool pool; ... public void beginSlice() { pool = DatastoreMutationPool.create(); } public void endSlice() { pool.flush(); } public void map(... value) { ... Entity entity = ... pool.put(entity); ... } } }

      
      Entity city = new Entity("City", cityName);
      city.setProperty("state", state);
      city.setUnindexedProperty("zip", zipcode);
      
      DatastoreMutationPool mutationPool = this.getAppEngineContext(context)
          .getMutationPool();
      mutationPool.put(zip);
      mutationPool.put(city);
    }


  }

      .getName());


  @Override
  public void map(Key key, Entity value, Context context) {
    log.info("Adding key to deletion pool: " + key);
    DatastoreMutationPool mutationPool = this.getAppEngineContext(context)
        .getMutationPool();
    mutationPool.delete(value.getKey());
  }

      String comment = (String) value.getProperty("comment");
      comment = comment.toLowerCase();
      value.setProperty("comment", comment);
      value.setProperty("updatedAt", new Date());


      DatastoreMutationPool mutationPool = this.getAppEngineContext(
          context).getMutationPool();
      mutationPool.put(value);
    }
  }

Examples of com.google.appengine.tools.mapreduce.DatastoreMutationPool

Related Classes of com.google.appengine.tools.mapreduce.DatastoreMutationPool