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/*
 * Copyright 2001-2013 Artima, 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.
 */
package org.scalatest.enablers

import org.scalactic.Requirements._
import scala.collection.JavaConverters._
import org.scalactic.Equality
import org.scalatest.FailureMessages
import scala.annotation.tailrec
import scala.collection.GenTraversable

/**
 * Supertrait for typeclasses that enable contain key matcher syntax.
 *
 * 
 * A KeyMapping[M] provides access to the "key mapping nature" of type M in such
 * a way that contain key matcher syntax can be used with type M. A M
 * can be any type for which contain key syntax makes sense. ScalaTest provides implicit implementations
 * for scala.collection.GenMap and java.util.Map. You can enable the contain key
 * matcher syntax on your own type U by defining a KeyMapping[U] for the type and making it
 * available implicitly.
 * 
 * 

 * ScalaTest provides implicit KeyMapping instances for scala.collection.GenMap,
 * and java.util.Map in the KeyMapping companion object.
 * 
 */
trait KeyMapping[-M] {

  /**
   * Check if the passed map contains the passed key.
   *
   * @param map a map about which an assertion is being made
   * @param key key of which should be contained in the passed map
   * @return true if the passed map contains the passed key
   */
  def containsKey(map: M, key: Any): Boolean
}

/**
 * Companion object for KeyMapping that provides implicit implementations for scala.collection.GenMap and java.util.Map.
 */
object KeyMapping {

  import scala.language.higherKinds

  /**
   * Enable KeyMapping implementation for scala.collection.GenMap.
   *
   * @param equality Equality type class that is used to check equality of key in the scala.collection.GenMap
   * @tparam K the type of the key in the scala.collection.GenMap
   * @tparam V the type of the value in the scala.collection.GenMap
   * @tparam MAP any subtype of scala.collection.GenMap
   * @return KeyMapping[MAP[K, V]] that supports scala.collection.GenMap in contain key syntax
   */
  implicit def keyMappingNatureOfGenMap[K, V, MAP[k, v] <: scala.collection.GenMap[k, v]](implicit equality: Equality[K]): KeyMapping[MAP[K, V]] = 
    new KeyMapping[MAP[K, V]] {
      def containsKey(map: MAP[K, V], key: Any): Boolean = {
        requireNonNull(map)
        map.keySet.exists((k: K) => equality.areEqual(k, key))
      }
    }

  import scala.language.implicitConversions

  /**
   * Implicit conversion that converts an Equality of type K
   * into KeyMapping of type MAP[K, V], where MAP is a subtype of scala.collection.GenMap.
   * This is required to support the explicit Equality syntax, for example:
   *
   *    * (Map("one" -> 1) should contain key "ONE") (after being lowerCased)
   * 
   *
   * (after being lowerCased) will returns an Equality[String]
   * and this implicit conversion will convert it into KeyMapping[Map[String, Int]].
   *
   * @param equality Equality of type K
   * @tparam K the type of the key in the scala.collection.GenMap
   * @tparam V the type of the value in the scala.collection.GenMap
   * @tparam MAP any subtype of scala.collection.GenMap
   * @return KeyMapping of type MAP[K, V]
   */
  implicit def convertEqualityToGenMapKeyMapping[K, V, MAP[k, v] <: scala.collection.GenMap[k, v]](equality: Equality[K]): KeyMapping[MAP[K, V]] = 
    keyMappingNatureOfGenMap(equality)

  /**
   * Enable KeyMapping implementation for java.util.Map.
   *
   * @param equality Equality type class that is used to check equality of key in the java.util.Map
   * @tparam K the type of the key in the java.util.Map
   * @tparam V the type of the value in the java.util.Map
   * @tparam JMAP any subtype of java.util.Map
   * @return KeyMapping[JMAP[K, V]] that supports java.util.Map in contain key syntax
   */
  implicit def keyMappingNatureOfJavaMap[K, V, JMAP[k, v] <: java.util.Map[k, v]](implicit equality: Equality[K]): KeyMapping[JMAP[K, V]] = 
    new KeyMapping[JMAP[K, V]] {
      def containsKey(jMap: JMAP[K, V], key: Any): Boolean = {
        jMap.asScala.keySet.exists((k: K) => equality.areEqual(k, key))
      }
    }

  /**
   * Implicit conversion that converts an Equality of type K
   * into KeyMapping of type JMAP[K, V], where JMAP is a subtype of java.util.Map.
   * This is required to support the explicit Equality syntax, for example:
   *
   *    * val javaMap = new java.util.HashMap[String, Int]()
   * javaMap.put("one", 1)
   * (javaMap should contain key "ONE") (after being lowerCased)
   * 
   *
   * (after being lowerCased) will returns an Equality[String]
   * and this implicit conversion will convert it into KeyMapping[java.util.HashMap[String, Int]].
   *
   * @param equality Equality of type K
   * @tparam K the type of the key in the java.util.Map
   * @tparam V the type of the value in the java.util.Map
   * @tparam JMAP any subtype of java.util.Map
   * @return KeyMapping of type JMAP[K, V]
   */
  implicit def convertEqualityToJavaMapKeyMapping[K, V, JMAP[k, v] <: java.util.Map[k, v]](equality: Equality[K]): KeyMapping[JMAP[K, V]] = 
    keyMappingNatureOfJavaMap(equality)
}