/*
 * 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.hadoop.hive.ql.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.Text;


/**
 * UDFReplace replaces all substrings that are matched with a replacement substring.
 *
 */
@Description(name = "replace",
    value = "_FUNC_(str, search, rep) - replace all substrings of 'str' that "
    + "match 'search' with 'rep'", extended = "Example:\n"
    + "  > SELECT _FUNC_('Hack and Hue', 'H', 'BL') FROM src LIMIT 1;\n"
    + "  'BLack and BLue'")
public class UDFReplace extends UDF {

  private Text result = new Text();

  public UDFReplace() {
  }

  public Text evaluate(Text s, Text search, Text replacement) {
    if (s == null || search == null || replacement == null) {
      return null;
    }
    String r = s.toString().replace(search.toString(), replacement.toString());
    result.set(r);
    return result;
  }
}
