SqlTranslate3Function.java

/*
 * 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.calcite.sql.fun;

import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlFunction;
import org.apache.calcite.sql.SqlFunctionCategory;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.SqlNode;
import org.apache.calcite.sql.SqlWriter;
import org.apache.calcite.sql.type.OperandTypes;
import org.apache.calcite.sql.type.ReturnTypes;

/**
 * Definition of the "TRANSLATE" built-in SQL function that takes 3 arguments.
 *
 * <p>Based on Oracle's {@code TRANSLATE} function, it is commonly called
 * "TRANSLATE3" to distinguish it from the standard SQL function
 * {@link SqlStdOperatorTable#TRANSLATE} that takes 2 arguments and has an
 * entirely different purpose.
 */
public class SqlTranslate3Function extends SqlFunction {
  //~ Constructors -----------------------------------------------------------

  /**
   * Creates the SqlTranslate3Function.
   */
  SqlTranslate3Function() {
    super("TRANSLATE3",
        SqlKind.OTHER_FUNCTION,
        ReturnTypes.ARG0_NULLABLE_VARYING,
        null,
        OperandTypes.STRING_STRING_STRING,
        SqlFunctionCategory.STRING);
  }

  //~ Methods ----------------------------------------------------------------

  @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
      int rightPrec) {
    final SqlWriter.Frame frame = writer.startFunCall("TRANSLATE");
    for (SqlNode sqlNode : call.getOperandList()) {
      writer.sep(",");
      sqlNode.unparse(writer, leftPrec, rightPrec);
    }
    writer.endFunCall(frame);
  }

  @Override public String getSignatureTemplate(final int operandsCount) {
    if (3 == operandsCount) {
      return "{0}({1}, {2}, {3})";
    }
    throw new AssertionError();
  }

}