/* =========================================================================================
* Copyright © 2013-2017 the kamon project <http://kamon.io/>
*
* 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 kamon
package context
import java.util.{Map => JavaMap}
import scala.collection.JavaConverters._
class Context private (private[context] val entries: Map[Context.Key[_], Any], val tags: Map[String, String]) {
def get[T](key: Context.Key[T]): T =
entries.getOrElse(key, key.emptyValue).asInstanceOf[T]
def getTag(tagKey: String): Option[String] =
tags.get(tagKey)
def withKey[T](key: Context.Key[T], value: T): Context =
new Context(entries.updated(key, value), tags)
def withTag(tagKey: String, tagValue: String): Context =
new Context(entries, tags.updated(tagKey, tagValue))
def withTags(tags: Map[String, String]): Context =
new Context(entries, this.tags ++ tags)
def withTags(tags: JavaMap[String, String]): Context =
new Context(entries, this.tags ++ tags.asScala.toMap)
}
object Context {
val Empty = new Context(Map.empty, Map.empty)
def of(tags: JavaMap[String, String]): Context =
new Context(Map.empty, tags.asScala.toMap)
def of(tags: Map[String, String]): Context =
new Context(Map.empty, tags)
def of[T](key: Context.Key[T], value: T): Context =
new Context(Map(key -> value), Map.empty)
def of[T](key: Context.Key[T], value: T, tags: JavaMap[String, String]): Context =
new Context(Map(key -> value), tags.asScala.toMap)
def of[T](key: Context.Key[T], value: T, tags: Map[String, String]): Context =
new Context(Map(key -> value), tags)
def of[T, U](keyOne: Context.Key[T], valueOne: T, keyTwo: Context.Key[U], valueTwo: U): Context =
new Context(Map(keyOne -> valueOne, keyTwo -> valueTwo), Map.empty)
def of[T, U](keyOne: Context.Key[T], valueOne: T, keyTwo: Context.Key[U], valueTwo: U, tags: JavaMap[String, String]): Context =
new Context(Map(keyOne -> valueOne, keyTwo -> valueTwo), tags.asScala.toMap)
def of[T, U](keyOne: Context.Key[T], valueOne: T, keyTwo: Context.Key[U], valueTwo: U, tags: Map[String, String]): Context =
new Context(Map(keyOne -> valueOne, keyTwo -> valueTwo), tags)
def key[T](name: String, emptyValue: T): Context.Key[T] =
new Context.Key(name, emptyValue)
/**
* Encapsulates the type, name and empty value for a context entry. All reads and writes from a context instance
* must be done using a context key, which will ensure the right type is used on both operations. The key's name
* is used when configuring mappings and incoming/outgoing/returning codecs for context propagation across channels.
*
* If you try to read an entry from a context and such entry is not present, the empty value for the key is returned
* instead.
*
* @param name Key name. Must be unique.
* @param emptyValue Value to be returned when reading from a context that doesn't have an entry with this key.
* @tparam ValueType Type of the value to be held on the context with this key.
*/
final class Key[ValueType](val name: String, val emptyValue: ValueType) {
override def hashCode(): Int =
name.hashCode
override def equals(that: Any): Boolean =
that.isInstanceOf[Context.Key[_]] && that.asInstanceOf[Context.Key[_]].name == this.name
}
}
