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/*
 * 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;

import com.hazelcast.org.apache.calcite.adapter.java.JavaTypeFactory;
import com.hazelcast.org.apache.calcite.linq4j.QueryProvider;
import com.hazelcast.org.apache.calcite.linq4j.tree.Expressions;
import com.hazelcast.org.apache.calcite.linq4j.tree.ParameterExpression;
import com.hazelcast.org.apache.calcite.schema.SchemaPlus;
import com.hazelcast.org.apache.calcite.sql.advise.SqlAdvisor;

import com.hazelcast.com.google.common.base.CaseFormat;

import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;

import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Modifier;
import java.util.Locale;
import java.util.TimeZone;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Runtime context allowing access to the tables in a database.
 *
 * @see DataContexts
 */
public interface DataContext {
  ParameterExpression ROOT =
      Expressions.parameter(Modifier.FINAL, DataContext.class, "root");

  /**
   * Returns a sub-schema with a given name, or null.
   */
  @Nullable SchemaPlus getRootSchema();

  /**
   * Returns the type factory.
   */
  JavaTypeFactory getTypeFactory();

  /**
   * Returns the query provider.
   */
  QueryProvider getQueryProvider();

  /**
   * Returns a context variable.
   *
   * 

Supported variables include: "sparkContext", "currentTimestamp", * "localTimestamp".

* * @param name Name of variable */ @Nullable Object get(String name); /** Variable that may be asked for in a call to {@link DataContext#get}. */ enum Variable { UTC_TIMESTAMP("utcTimestamp", Long.class), /** The time at which the current statement started executing. In * milliseconds after 1970-01-01 00:00:00, UTC. Required. */ CURRENT_TIMESTAMP("currentTimestamp", Long.class), /** The time at which the current statement started executing. In * milliseconds after 1970-01-01 00:00:00, in the time zone of the current * statement. Required. */ LOCAL_TIMESTAMP("localTimestamp", Long.class), /** The Spark engine. Available if Spark is on the class path. */ SPARK_CONTEXT("sparkContext", Object.class), /** A mutable flag that indicates whether user has requested that the * current statement be canceled. Cancellation may not be immediate, but * implementations of relational operators should check the flag fairly * frequently and cease execution (e.g. by returning end of data). */ CANCEL_FLAG("cancelFlag", AtomicBoolean.class), /** Query timeout in milliseconds. * When no timeout is set, the value is 0 or not present. */ TIMEOUT("timeout", Long.class), /** Advisor that suggests completion hints for SQL statements. */ SQL_ADVISOR("sqlAdvisor", SqlAdvisor.class), /** Writer to the standard error (stderr). */ STDERR("stderr", OutputStream.class), /** Reader on the standard input (stdin). */ STDIN("stdin", InputStream.class), /** Writer to the standard output (stdout). */ STDOUT("stdout", OutputStream.class), /** Locale in which the current statement is executing. * Affects the behavior of functions such as {@code DAYNAME} and * {@code MONTHNAME}. Required; defaults to the root locale if the * connection does not specify a locale. */ LOCALE("locale", Locale.class), /** Time zone in which the current statement is executing. Required; * defaults to the time zone of the JVM if the connection does not specify a * time zone. */ TIME_ZONE("timeZone", TimeZone.class), /** The query user. * *

Default value is "sa". */ USER("user", String.class), /** The system user. * *

Default value is "user.name" from * {@link System#getProperty(String)}. */ SYSTEM_USER("systemUser", String.class); public final String camelName; public final Class clazz; Variable(String camelName, Class clazz) { this.camelName = camelName; this.clazz = clazz; assert camelName.equals( CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, name())); } /** Returns the value of this variable in a given data context. */ public T get(DataContext dataContext) { //noinspection unchecked return (T) clazz.cast(dataContext.get(camelName)); } } }





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