| // Copyright 2014 The Bazel Authors. 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.analysis.starlark; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.devtools.build.lib.analysis.ProviderCollection; |
| |
| /** |
| * An abstract class for adding a Starlark API for the built-in providers. Derived classes should |
| * declare functions to be used from Starlark. |
| */ |
| public abstract class StarlarkApiProvider { |
| private ProviderCollection info; |
| |
| protected ProviderCollection getInfo() { |
| return info; |
| } |
| |
| public final void init(ProviderCollection info) { |
| if (this.info != null) { |
| // todo(dslomov): nuke this weird initialization mechanism. |
| |
| // Allow multiple calls. |
| // It is possible for the Starlark rule to get a StarlarkApiProvider such as `target.java` |
| // from its dependency and pass it on. It does not make a whole lot of sense, but we |
| // shouldn't crash. |
| return; |
| } |
| this.info = Preconditions.checkNotNull(info); |
| } |
| } |