content: /*
   * 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.SqlCallBinding;
  import org.apache.calcite.sql.SqlFunction;
  import org.apache.calcite.sql.SqlFunctionCategory;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  import org.apache.calcite.sql.type.SqlOperandTypeChecker;
  
  /**
   * The <code>POSITION</code> function.
   */
  public class SqlPositionFunction extends SqlFunction {
    //~ Constructors -----------------------------------------------------------
  
    // FIXME jvs 25-Jan-2009:  POSITION should verify that
    // params are all same character set, like OVERLAY does implicitly
    // as part of rtiDyadicStringSumPrecision
  
    private static final SqlOperandTypeChecker OTC_CUSTOM =
        OperandTypes.STRING_SAME_SAME
            .or(OperandTypes.STRING_SAME_SAME_INTEGER)
            .or(
                OperandTypes.sequence("INSTR(<STRING>, <STRING>, <INTEGER>, <INTEGER>)",
                OperandTypes.STRING, OperandTypes.STRING, OperandTypes.INTEGER,
                OperandTypes.INTEGER));
  
    public SqlPositionFunction(String name) {
      super(name, SqlKind.POSITION, ReturnTypes.INTEGER_NULLABLE, null,
          OTC_CUSTOM, SqlFunctionCategory.NUMERIC);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void unparse(
        SqlWriter writer,
        SqlCall call,
        int leftPrec,
        int rightPrec) {
      final SqlWriter.Frame frame = writer.startFunCall(getName());
      if (call.operandCount() == 2 || call.operandCount() == 3) {
        call.operand(0).unparse(writer, leftPrec, rightPrec);
        writer.sep("IN");
        call.operand(1).unparse(writer, leftPrec, rightPrec);
        if (call.operandCount() == 3) {
          writer.sep("FROM");
          call.operand(2).unparse(writer, leftPrec, rightPrec);
        }
      }
      if (call.operandCount() == 4) {
        call.operand(0).unparse(writer, leftPrec, rightPrec);
        writer.sep(",");
        call.operand(1).unparse(writer, leftPrec, rightPrec);
        writer.sep(",");
        call.operand(2).unparse(writer, leftPrec, rightPrec);
        writer.sep(",");
        call.operand(3).unparse(writer, leftPrec, rightPrec);
      }
      writer.endFunCall(frame);
    }
  
    @Override public String getSignatureTemplate(final int operandsCount) {
      switch (operandsCount) {
      case 2:
        return "{0}({1} IN {2})";
      case 3:
        return "{0}({1} IN {2} FROM {3})";
      case 4:
        return "{0}({1}, {2}, {3}, {4})";
      default:
        throw new AssertionError();
      }
    }
  
    @Override public boolean checkOperandTypes(
        SqlCallBinding callBinding,
        boolean throwOnFailure) {
      // check that the two operands are of same type.
      switch (callBinding.getOperandCount()) {
      case 2:
        return OperandTypes.SAME_SAME.checkOperandTypes(
            callBinding, throwOnFailure)
            && super.checkOperandTypes(callBinding, throwOnFailure);
  
      case 3:
        return OperandTypes.SAME_SAME_INTEGER.checkOperandTypes(
            callBinding, throwOnFailure)
            && super.checkOperandTypes(callBinding, throwOnFailure);
      case 4:
        return OperandTypes.sequence("INSTR(<STRING>, <STRING>, <INTEGER>, <INTEGER>)",
            OperandTypes.STRING, OperandTypes.STRING, OperandTypes.INTEGER,
            OperandTypes.INTEGER).checkOperandTypes(
            callBinding, throwOnFailure)
            && super.checkOperandTypes(callBinding, throwOnFailure);
      default:
        throw new AssertionError();
      }
    }
  }
  