/*
* Licensed to Crate under one or more contributor license agreements.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership. Crate 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.
*
* However, if you have executed another commercial license agreement
* with Crate these terms will supersede the license and you may use the
* software solely pursuant to the terms of the relevant commercial
* agreement.
*/
package io.crate.analyze.relations;
import io.crate.analyze.symbol.Function;
import io.crate.analyze.symbol.Symbol;
import io.crate.analyze.symbol.SymbolVisitor;
import io.crate.operation.operator.AndOperator;
import io.crate.planner.consumer.ManyTableConsumer;
import io.crate.sql.tree.QualifiedName;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
public class QuerySplitter {
private static final SplitVisitor SPLIT_VISITOR = new SplitVisitor();
/**
* <p>
* Splits a (function) symbol on <code>AND</code> based on relation occurrences of {@link io.crate.analyze.symbol.Field}
* into multiple symbols.
* </p>
* <p>
* <h3>Examples:</h3>
* <p>
* Splittable down to single relation:
* <pre>
* t1.x = 30 and ty2.y = 20
*
* Output:
*
* set(t1) -> t1.x = 30
* set(t2) -> t2.y = 20
* </pre>
* <p>
* <p>
* Pairs of two relations:
* <pre>
* t1.x = t2.x and t2.x = t3.x
*
* Output:
*
* set(t1, t2) -> t1.x = t2.x
* set(t2, t3) -> t2.x = t3.x
* </pre>
* <p>
* <p>
* Mixed:
* <pre>
* t1.x = 30 and t2.x = t3.x
*
* Output:
*
* set(t1) -> t1.x = 30
* set(t2, t3) -> t2.x = t3.x
* </pre>
*/
public static Map<Set<QualifiedName>, Symbol> split(Symbol symbol) {
Map<Set<QualifiedName>, Symbol> splits = new HashMap<>();
SPLIT_VISITOR.process(symbol, splits);
return splits;
}
private static class SplitVisitor extends SymbolVisitor<Map<Set<QualifiedName>, Symbol>, Void> {
@Override
public Void visitFunction(Function function, Map<Set<QualifiedName>, Symbol> splits) {
if (!function.info().equals(AndOperator.INFO)) {
HashSet<QualifiedName> qualifiedNames = new HashSet<>();
ManyTableConsumer.QualifiedNameCounter.INSTANCE.process(function, qualifiedNames);
Symbol prevQuery = splits.put(qualifiedNames, function);
if (prevQuery != null) {
splits.put(qualifiedNames, AndOperator.of(prevQuery, function));
}
return null;
}
for (Symbol arg : function.arguments()) {
process(arg, splits);
}
return null;
}
}
}