// Copyright 2014 Google Inc. All rights reserved. // // Licensed 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.google.devtools.build.lib.query2.engine; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableSet; import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Argument; import com.google.devtools.build.lib.query2.engine.QueryEnvironment.ArgumentType; import com.google.devtools.build.lib.query2.engine.QueryEnvironment.QueryFunction; import java.util.List; import java.util.Set; /** * A some(x) filter expression, which returns an arbitrary node in set x, or * fails if x is empty. * *
expr ::= SOME '(' expr ')'
*/ class SomeFunction implements QueryFunction { SomeFunction() { } @Override public String getName() { return "some"; } @Override public int getMandatoryArguments() { return 1; } @Override public List getArgumentTypes() { return ImmutableList.of(ArgumentType.EXPRESSION); } @Override public Set eval(QueryEnvironment env, QueryExpression expression, List args) throws QueryException, InterruptedException { Set argumentValue = args.get(0).getExpression().eval(env); if (argumentValue.isEmpty()) { throw new QueryException(expression, "argument set is empty"); } return ImmutableSet.of(argumentValue.iterator().next()); } }