/**
 * Copyright 2013-2014 Recruit Technologies Co., Ltd. and contributors
 * (see CONTRIBUTORS.md)
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.  A copy of the
 * License is distributed with this work in the LICENSE.md file.  You may
 * also obtain a copy of the License from
 *
 *     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.gennai.gungnir.topology.udf;

import static org.gennai.gungnir.GungnirConst.*;

import java.util.List;
import java.util.Map;

import org.gennai.gungnir.tuple.Field;
import org.gennai.gungnir.tuple.GungnirTuple;

@BaseFunction.Description(name = "size")
public class Size extends BaseFunction<Integer> {

  private static final long serialVersionUID = SERIAL_VERSION_UID;

  public Size() {
  }

  private Size(Size c) {
    super(c);
  }

  @Override
  public Size create(Object... parameters) throws ArgumentException {
    if (parameters.length > 0) {
      if (parameters.length == 1) {
        if (parameters[0] instanceof Field) {
          setParameters(parameters);
        } else {
          throw new ArgumentException("Incorrect type of argument");
        }
      } else {
        throw new ArgumentException("Incorrect number of arguments");
      }
    }
    return this;
  }

  @Override
  protected void prepare() {
  }

  @Override
  public Integer evaluate(GungnirTuple tuple) {
    Object value = ((Field) getParameter(0)).getValue(tuple);
    if (value instanceof List) {
      return ((List<?>) value).size();
    } else if (value instanceof Map) {
      return ((Map<?, ?>) value).size();
    }
    return 0;
  }

  @Override
  public Size clone() {
    return new Size(this);
  }
}