1 /* 2 * Copyright 2017, OpenCensus Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.opencensus.trace.unsafe; 18 19 import io.grpc.Context; 20 import io.opencensus.internal.Utils; 21 import io.opencensus.trace.BlankSpan; 22 import io.opencensus.trace.Span; 23 24 /*>>> 25 import org.checkerframework.checker.nullness.qual.Nullable; 26 */ 27 28 /** 29 * Utilities for grabbing manipulating current context and grabbing current span. 30 * 31 * @deprecated Please use {@link io.opencensus.trace.unsafe.ContextHandleUtils} Util 32 * methods/functionality to interact with the {@link io.grpc.Context}. Users must interact with 33 * the current Context via the public APIs in {@link io.opencensus.trace.Tracer} and avoid 34 * usages of the {@link #CONTEXT_SPAN_KEY} directly. 35 * @since 0.5 36 */ 37 @Deprecated() 38 public final class ContextUtils { 39 // No instance of this class. ContextUtils()40 private ContextUtils() {} 41 42 /** The {@link io.grpc.Context.Key} used to interact with {@link io.grpc.Context}. */ 43 private static final Context.Key</*@Nullable*/ Span> CONTEXT_SPAN_KEY = 44 Context.<Span>key("opencensus-trace-span-key"); 45 46 /** 47 * Creates a new {@code Context} with the given value set. 48 * 49 * @param context the parent {@code Context}. 50 * @param span the value to be set. 51 * @return a new context with the given value set. 52 * @since 0.21 53 */ withValue(Context context, @javax.annotation.Nullable Span span)54 public static Context withValue(Context context, @javax.annotation.Nullable Span span) { 55 return Utils.checkNotNull(context, "context").withValue(CONTEXT_SPAN_KEY, span); 56 } 57 58 /** 59 * Returns the value from the specified {@code Context}. 60 * 61 * @param context the specified {@code Context}. 62 * @return the value from the specified {@code Context}. 63 * @since 0.21 64 */ getValue(Context context)65 public static Span getValue(Context context) { 66 @javax.annotation.Nullable 67 Span span = CONTEXT_SPAN_KEY.get(Utils.checkNotNull(context, "context")); 68 return span == null ? BlankSpan.INSTANCE : span; 69 } 70 } 71