def verify_signature
      if @local_path
        if RUBY_PLATFORM =~ /java/
          begin
            jarfile = java.util.jar.JarInputStream.new(FileInputStream.new(@local_path), true)
            @signature_verified = true
          rescue NativeException
            @signature_verified = false
          end
        else
          # Use IO.popen instead of system() to absorb
          # jarsigners messages to $stdout
          response = IO.popen("jarsigner -verify #{@local_path}"){|io| io.gets}
          @signature_verified = ($?.exitstatus == 0)
        end
      else
        nil
      end
    end
def verify_signature
      if @local_path
        if RUBY_PLATFORM =~ /java/
          begin
            jarfile = java.util.jar.JarInputStream.new(FileInputStream.new(@local_path), true)
            @signature_verified = true
          rescue NativeException
            @signature_verified = false
          end
        else
          # Use IO.popen instead of system() to absorb
          # jarsigners messages to $stdout
          response = IO.popen("jarsigner -verify #{@local_path}"){|io| io.gets}
          @signature_verified = ($?.exitstatus == 0)
        end
      else
        nil
      end
    end
Verifies signature of locallly cached resource

 Returns boolean value indicating whether the signature of the
 cached local copy of the resource verified successfully

 The value return is nil if no local cache has been created.

 Example:

   true || false || nil