package require java
java::import AirPurifier
pack [button .b -text "Start purifier" -command action]
pack [label .l]
proc action {} {
    switch [.b cget -text] {
        "Start purifier" {
           set ::purifier [java::new AirPurifier]
           .b configure -text "Emit pulse"
           set label "Purifier started."
        }
        "Emit pulse" {
           ::purifier standard
           set label "Pulse emitted."
        }
        default {
           set label ""
        }
    }
    .l configure -text $label
}

Example 1: TclBlend example.