Class: Hatchet::Message

Inherits:
Object
  • Object
show all
Defined in:
lib/hatchet/message.rb

Overview

Public: Class for wrapping message strings and blocks in a way that means they can be treated identically.

If an error is associated with the message this will be available via the #error attribute.

The nested diagnostic context of the message will be availble via the #ndc attribute.

Blocks will be lazily evaluated once for all appenders when required.

Defined Under Namespace

Classes: ErrorDecorator

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}, error = nil, &block) ⇒ Message

Public: Creates a new message.

args - The Hash used to provide context for the message (default: {}):

:ndc     - An Array of nested diagnostic context values
           (default: []).
:message - An already evaluated message, usually a String
           (default: nil).
:error   - An error that is associated with the message
           (default: nil).

block - An optional block which will provide a message when invoked.

Examples

Message.new(ndc: [], message: "Evaluated message", error: e)
Message.new(ndc: %w{Foo Bar}) { "Lazily evaluated message" }

The signature of the constructor was originally:

message - An already evaluated message, usually a String (default: nil). error - An error that is associated with the message (default: nil). block - An optional block which will provide a message when invoked.

This format is also supported for compatibility to version 0.1.0 and below and will be deprecated in the future.

Examples

Message.new("Evaluated message", e)
Message.new { "Lazily evaluated message" }

One of message or block must be provided. If both are provided then the block is preferred as it is assumed to provide more detail.



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# File 'lib/hatchet/message.rb', line 83

def initialize(args = {}, error = nil, &block)
  @message = nil

  if args.kind_of? Hash
    # If args is a Hash then using new constructor format or no parameters
    # specified. Either way, use the new format.
    @ndc     = args[:ndc] || []
    @error   = args[:error]
    @message = args[:message] unless block
  else
    # Otherwise assume the old format and coerce args accordingly.
    @ndc     = []
    @error   = error
    @message = args unless block
  end

  @error = ErrorDecorator.new(@error, args[:backtrace_filters]) if @error && args[:backtrace_filters]
  @block = block
end

Instance Attribute Details

#error ⇒ Object (readonly)

Public: Gets the error associated with this message, if given.



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# File 'lib/hatchet/message.rb', line 44

def error
  @error
end

#ndc ⇒ Object (readonly)

Public: Gets the nested diagnostic context values.



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# File 'lib/hatchet/message.rb', line 48

def ndc
  @ndc
end

Instance Method Details

#evaluated_message ⇒ Object

Public: Returns the evaluated message.



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# File 'lib/hatchet/message.rb', line 111

def evaluated_message
  @evaluated_message ||= (@message || @block.call)
end

#to_s ⇒ Object

Public: Returns the String representation of the message.



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# File 'lib/hatchet/message.rb', line 105

def to_s
  evaluated_message.to_s
end