/**
 * 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.tajo.catalog.function;

import com.google.common.base.Objects;
import com.google.gson.annotations.Expose;
import org.apache.tajo.catalog.proto.CatalogProtos;
import org.apache.tajo.json.GsonObject;
import org.apache.tajo.catalog.Column;
import org.apache.tajo.catalog.json.CatalogGsonHelper;
import org.apache.tajo.datum.Datum;
import org.apache.tajo.util.TUtil;

public abstract class Function<T extends Datum> implements Cloneable, GsonObject {
  @Expose protected Column[] definedParams;
  public final static Column [] NoArgs = new Column [] {};

  public Function(Column[] definedArgs) {
    this.definedParams = definedArgs;
  }

  @Override
  public boolean equals(Object obj) {
    if (obj instanceof Function) {
      Function other = (Function) obj;
      return TUtil.checkEquals(definedParams, other.definedParams);
    } else {
      return false;
    }
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(definedParams);
  }

  public Object clone() throws CloneNotSupportedException {
    Function func = (Function) super.clone();
    func.definedParams = definedParams != null ? definedParams.clone() : null;
    return func;
  }

  @Override
  public String toJson() {
    return CatalogGsonHelper.toJson(this, Function.class);
  }

  public abstract CatalogProtos.FunctionType getFunctionType();
}