| /* |
| * 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.cassandra.cql3.selection; |
| |
| import java.nio.ByteBuffer; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.commons.lang3.text.StrBuilder; |
| |
| import org.apache.cassandra.cql3.functions.AggregateFcts; |
| |
| import org.apache.cassandra.config.ColumnDefinition; |
| import org.apache.cassandra.cql3.ColumnSpecification; |
| import org.apache.cassandra.cql3.functions.Function; |
| import org.apache.cassandra.db.marshal.AbstractType; |
| import org.apache.cassandra.exceptions.InvalidRequestException; |
| |
| abstract class AbstractFunctionSelector<T extends Function> extends Selector |
| { |
| protected final T fun; |
| |
| /** |
| * The list used to pass the function arguments is recycled to avoid the cost of instantiating a new list |
| * with each function call. |
| */ |
| protected final List<ByteBuffer> args; |
| protected final List<Selector> argSelectors; |
| |
| public static Factory newFactory(final Function fun, final SelectorFactories factories) throws InvalidRequestException |
| { |
| if (fun.isAggregate()) |
| { |
| if (factories.doesAggregation()) |
| throw new InvalidRequestException("aggregate functions cannot be used as arguments of aggregate functions"); |
| } |
| |
| return new Factory() |
| { |
| protected String getColumnName() |
| { |
| if (AggregateFcts.isCountRows(fun)) |
| return "count"; |
| |
| return new StrBuilder(fun.name().toString()).append('(') |
| .appendWithSeparators(factories.getColumnNames(), ", ") |
| .append(')') |
| .toString(); |
| } |
| |
| protected AbstractType<?> getReturnType() |
| { |
| return fun.returnType(); |
| } |
| |
| protected void addColumnMapping(SelectionColumnMapping mapping, ColumnSpecification resultsColumn) |
| { |
| SelectionColumnMapping tmpMapping = SelectionColumnMapping.newMapping(); |
| for (Factory factory : factories) |
| factory.addColumnMapping(tmpMapping, resultsColumn); |
| |
| if (tmpMapping.getMappings().get(resultsColumn).isEmpty()) |
| // add a null mapping for cases where there are no |
| // further selectors, such as no-arg functions and count |
| mapping.addMapping(resultsColumn, (ColumnDefinition)null); |
| else |
| // collate the mapped columns from the child factories & add those |
| mapping.addMapping(resultsColumn, tmpMapping.getMappings().values()); |
| } |
| |
| public void addFunctionsTo(List<Function> functions) |
| { |
| fun.addFunctionsTo(functions); |
| factories.addFunctionsTo(functions); |
| } |
| |
| public Selector newInstance() throws InvalidRequestException |
| { |
| return fun.isAggregate() ? new AggregateFunctionSelector(fun, factories.newInstances()) |
| : new ScalarFunctionSelector(fun, factories.newInstances()); |
| } |
| |
| public boolean isWritetimeSelectorFactory() |
| { |
| return factories.containsWritetimeSelectorFactory(); |
| } |
| |
| public boolean isTTLSelectorFactory() |
| { |
| return factories.containsTTLSelectorFactory(); |
| } |
| |
| public boolean isAggregateSelectorFactory() |
| { |
| return fun.isAggregate() || factories.doesAggregation(); |
| } |
| }; |
| } |
| |
| protected AbstractFunctionSelector(T fun, List<Selector> argSelectors) |
| { |
| this.fun = fun; |
| this.argSelectors = argSelectors; |
| this.args = Arrays.asList(new ByteBuffer[argSelectors.size()]); |
| } |
| |
| public AbstractType<?> getType() |
| { |
| return fun.returnType(); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return new StrBuilder().append(fun.name()) |
| .append("(") |
| .appendWithSeparators(argSelectors, ", ") |
| .append(")") |
| .toString(); |
| } |
| } |