| #!/usr/bin/env python |
| # -*- encoding: utf-8 -*- |
| |
| # 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. |
| |
| '''builder.py: module for creating streamlets''' |
| |
| import sets |
| |
| from heronpy.streamlet.generator import Generator |
| from heronpy.streamlet.impl.supplierspout import SupplierStreamlet |
| from heronpy.streamlet.impl.generatorspout import GeneratorStreamlet |
| |
| class Builder(object): |
| """A Builder object is used to build the functional API DAG in Heron.""" |
| def __init__(self): |
| """ |
| """ |
| self._sources = [] |
| |
| def new_source(self, source): |
| """Adds a new source to the computation DAG""" |
| |
| source_streamlet = None |
| if callable(source): |
| source_streamlet = SupplierStreamlet(source) |
| elif isinstance(source, Generator): |
| source_streamlet = GeneratorStreamlet(source) |
| else: |
| raise RuntimeError("Builder's new source has to be either a Generator or a function") |
| |
| self._sources.append(source_streamlet) |
| return source_streamlet |
| |
| # pylint: disable=protected-access |
| def build(self, bldr): |
| """Builds the topology and returns the builder""" |
| stage_names = sets.Set() |
| for source in self._sources: |
| source._build(bldr, stage_names) |
| for source in self._sources: |
| if not source._all_built(): |
| raise RuntimeError("Topology cannot be fully built! Are all sources added?") |