com.hazelcast.org.apache.calcite.sql.SqlHopTableFunction Maven / Gradle / Ivy

/*
 * 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 com.hazelcast.org.apache.calcite.sql;

import com.hazelcast.com.google.common.collect.ImmutableList;

/**
 * SqlHopTableFunction implements an operator for hopping.
 *
 * It allows four parameters:
 *
 * 

 *   a table
 *   a descriptor to provide a watermarked column name from the input table
 *   an interval parameter to specify the length of window shifting
 *   an interval parameter to specify the length of window size
 * 
 */
public class SqlHopTableFunction extends SqlWindowTableFunction {
  public SqlHopTableFunction() {
    super(SqlKind.HOP.name(), new OperandMetadataImpl());
  }

  /** Operand type checker for HOP. */
  private static class OperandMetadataImpl extends AbstractOperandMetadata {
    OperandMetadataImpl() {
      super(
          ImmutableList.of(PARAM_DATA, PARAM_TIMECOL, PARAM_SLIDE,
              PARAM_SIZE, PARAM_OFFSET), 4);
    }

    @Override public boolean checkOperandTypes(SqlCallBinding callBinding,
        boolean throwOnFailure) {
      if (!checkTableAndDescriptorOperands(callBinding, 1)) {
        return throwValidationSignatureErrorOrReturnFalse(callBinding, throwOnFailure);
      }
      if (!checkTimeColumnDescriptorOperand(callBinding, 1)) {
        return throwValidationSignatureErrorOrReturnFalse(callBinding, throwOnFailure);
      }
      if (!checkIntervalOperands(callBinding, 2)) {
        return throwValidationSignatureErrorOrReturnFalse(callBinding, throwOnFailure);
      }
      return true;
    }

    @Override public String getAllowedSignatures(SqlOperator op, String opName) {
      return opName + "(TABLE table_name, DESCRIPTOR(timecol), "
          + "datetime interval, datetime interval[, datetime interval])";
    }
  }
}