activity.json

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "required": [
    "time",
    "user",
    "type"
  ],
  "properties": {
    "time": {
      "type": "string",
      "format": "date-time"
    },
    "user": {
      "$ref": "user.json"
    },
    "type": {
      "type": "string"
    }
  },
  "oneOf": [
    {
      "$ref": "#/definitions/self-activity"
    },
    {
      "$ref": "#/definitions/group-activity"
    },
    {
      "$ref": "#/definitions/track-activity"
    },
    {
      "$ref": "#/definitions/user-activity"
    }
  ],
  "definitions": {
    "group-activity": {
      "properties": {
        "group": {
          "$ref": "group.json#"
        },
        "type": {
          "enum": [
            "CREATED_GROUP",
            "CHANGED_GROUP",
            "JOINED_GROUP",
            "LEFT_GROUP",
            "DELETED_GROUP"
          ]
        }
      }
    },
    "track-activity": {
      "properties": {
        "track": {
          "$ref": "track-reference.json"
        },
        "type": {
          "enum": [
            "CREATED_TRACK"
          ]
        }
      }
    },
    "user-activity": {
      "properties": {
        "other": {
          "$ref": "user.json#"
        },
        "type": {
          "enum": [
            "FRIENDED_USER",
            "UNFRIENDED_USER"
          ]
        }
      }
    },
    "self-activity": {
      "properties": {
        "type": {
          "enum": [
            "CHANGED_PROFILE"
          ]
        }
      }
    }
  }
}