diff options
Diffstat (limited to 'impl_core/src/main/java/io/opencensus/implcore/tags/CurrentTagContextUtils.java')
-rw-r--r-- | impl_core/src/main/java/io/opencensus/implcore/tags/CurrentTagContextUtils.java | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/impl_core/src/main/java/io/opencensus/implcore/tags/CurrentTagContextUtils.java b/impl_core/src/main/java/io/opencensus/implcore/tags/CurrentTagContextUtils.java new file mode 100644 index 00000000..e6bb12f5 --- /dev/null +++ b/impl_core/src/main/java/io/opencensus/implcore/tags/CurrentTagContextUtils.java @@ -0,0 +1,71 @@ +/* + * Copyright 2017, OpenCensus Authors + * + * 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 io.opencensus.implcore.tags; + +import io.grpc.Context; +import io.opencensus.common.Scope; +import io.opencensus.tags.TagContext; +import io.opencensus.tags.unsafe.ContextUtils; + +/** + * Utility methods for accessing the {@link TagContext} contained in the {@link io.grpc.Context}. + */ +final class CurrentTagContextUtils { + + private CurrentTagContextUtils() {} + + /** + * Returns the {@link TagContext} from the current context. + * + * @return the {@code TagContext} from the current context. + */ + static TagContext getCurrentTagContext() { + return ContextUtils.TAG_CONTEXT_KEY.get(); + } + + /** + * Enters the scope of code where the given {@link TagContext} is in the current context and + * returns an object that represents that scope. The scope is exited when the returned object is + * closed. + * + * @param tags the {@code TagContext} to be set to the current context. + * @return an object that defines a scope where the given {@code TagContext} is set to the current + * context. + */ + static Scope withTagContext(TagContext tags) { + return new WithTagContext(tags); + } + + private static final class WithTagContext implements Scope { + + private final Context orig; + + /** + * Constructs a new {@link WithTagContext}. + * + * @param tags the {@code TagContext} to be added to the current {@code Context}. + */ + private WithTagContext(TagContext tags) { + orig = Context.current().withValue(ContextUtils.TAG_CONTEXT_KEY, tags).attach(); + } + + @Override + public void close() { + Context.current().detach(orig); + } + } +} |