/*
 * Copyright 2013 Orient Technologies.
 * Copyright 2013 Geomatys.
 *
 * Licensed 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 com.orientechnologies.orient.core.sql.method;

import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.sql.method.misc.OAbstractSQLMethod;

/**
 * Returns a character in a string.
 * 
 * @author Johann Sorel (Geomatys)
 * @author Luca Garulli
 */
public class OSQLMethodCharAt extends OAbstractSQLMethod {

  public static final String NAME = "charat";

  public OSQLMethodCharAt() {
    super(NAME, 1, 1);
  }

  @Override
  public String getSyntax() {
    return "charAt(<position>)";
  }

  @Override
  public Object execute(Object iThis, OIdentifiable iCurrentRecord, OCommandContext iContext, Object ioResult,
      Object[] iParams) {
    if (iParams[0] == null) {
      return null;
    }

    int index = Integer.parseInt(iParams[0].toString());
    return "" + iThis.toString().charAt(index);
  }
}