| #!/usr/bin/env python |
| # -*- encoding: utf-8 -*- |
| |
| # Copyright 2016 - Twitter, Inc. |
| # |
| # 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. |
| '''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?") |