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/*
 * The MIT License
 *
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package com.influxdb.query.dsl.functions;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import javax.annotation.Nonnull;

import com.influxdb.query.dsl.Flux;
import com.influxdb.query.dsl.VariableAssignment;
import com.influxdb.utils.Arguments;

/**
 * Join two time series together on time and the list of on keys.
 * See SPEC.
 *
 * 

* Options *

    *
  • tables - Map of tables to join. Currently only two tables are allowed. [map of tables]
  • *
  • on - List of tag keys that when equal produces a result set. [array of strings]
  • *
  • * method - An optional parameter that specifies the type of join to be performed.
  • *
* *

* Example *

 * Flux cpu = Flux.from("telegraf")
 *     .filter(Restrictions.and(Restrictions.measurement().equal("cpu"), Restrictions.field().equal("usage_user")))
 *     .range(-30L, ChronoUnit.MINUTES);
 *
 * Flux mem = Flux.from("telegraf")
 *     .filter(Restrictions.and(Restrictions.measurement().equal("mem"), Restrictions.field().equal("used_percent")))
 *     .range(-30L, ChronoUnit.MINUTES);
 *
 * Flux flux = Flux.join()
 *     .withTable("cpu", cpu)
 *     .withTable("mem", mem)
 *     .withOn("host")
 *     .withMethod("outer");
 * 
* * @author Jakub Bednar (bednar@github) (17/07/2018 14:47) */ public final class JoinFlux extends AbstractParametrizedFlux { private final Map tables = new LinkedHashMap<>(); private String assignToVariable; public JoinFlux() { super(); // add tables: property withPropertyValue("tables", (Supplier) () -> tables .entrySet().stream().map(e -> { String var = e.getValue() instanceof VariableAssignment ? ((VariableAssignment) e.getValue()).getVariableName() : e.getKey(); return e.getKey() + ":" + var; }) .collect(Collectors.joining(", ", "{", "}"))); } public enum MethodType { /** * inner join. */ INNER, /** * cross product. */ CROSS, /** * left outer join. */ LEFT, /** * right outer join. */ RIGHT, /** * full outer join. */ OUTER } @Nonnull @Override protected String operatorName() { return "join"; } @Override protected void beforeAppendOperatorName(@Nonnull final StringBuilder operator, @Nonnull final Map parameters) { // add tables Flux scripts tables.forEach((key, flux) -> { if (flux instanceof JoinFlux) { operator.append(flux.toString(parameters)).append("\n"); } else if (!(flux instanceof VariableAssignment)) { operator.append(key).append(" = ").append(flux.toString(parameters)).append("\n"); } }); if (assignToVariable != null) { operator.append(assignToVariable).append(" = "); } } /** * Map of table to join. Currently, only two tables are allowed. * * @param name table name * @param table Flux script to map table * @return this */ @Nonnull public JoinFlux withTable(@Nonnull final String name, @Nonnull final Flux table) { Arguments.checkNonEmpty(name, "FluxTable name"); Arguments.checkNotNull(table, "Flux script to map table"); tables.put(name, table); if (table instanceof JoinFlux) { ((JoinFlux) table).assignToVariable = name; } return this; } /** * @param tag Tag key that when equal produces a result set. * @return this */ @Nonnull public JoinFlux withOn(@Nonnull final String tag) { Arguments.checkNonEmpty(tag, "Tag name"); return withOn(new String[]{tag}); } /** * @param tags List of tag keys that when equal produces a result set. * @return this */ @Nonnull public JoinFlux withOn(@Nonnull final String[] tags) { Arguments.checkNotNull(tags, "Tags are required"); withPropertyValue("on", tags); return this; } /** * @param tags List of tag keys that when equal produces a result set. * @return this */ @Nonnull public JoinFlux withOn(@Nonnull final Collection tags) { Arguments.checkNotNull(tags, "Tags are required"); withPropertyValue("on", tags); return this; } /** * @param method the type of join to be performed * @return this */ @Nonnull public JoinFlux withMethod(@Nonnull final String method) { Arguments.checkNonEmpty(method, "Method"); this.withPropertyValueEscaped("method", method); return this; } /** * @param method the type of join to be performed * @return this */ @Nonnull public JoinFlux withMethod(@Nonnull final MethodType method) { Arguments.checkNotNull(method, "Method"); this.withPropertyValueEscaped("method", method.toString().toLowerCase()); return this; } }




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