// GPars (formerly GParallelizer)
//
// Copyright © 2008-10  The original author or authors
//
// 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 c20;

import org.jcsp.lang.*

class StateManager implements CSProcess {

    def ChannelInput fromQueue
    def ChannelOutput toElement
    def int queueSlots

    void run() {
        def limit = queueSlots / 2
        def state = "NORMAL"
        while (true) {
            def usedSlots = fromQueue.read()
            def aboveLimit = (usedSlots >= limit)
            if ((state == "NORMAL") && (aboveLimit)) {
                state = "ABOVE_LIMIT"
                toElement.write("STOP")
                println "SM: stopping"
            }
            if ((state == "ABOVE_LIMIT") && (!aboveLimit)) {
                state = "NORMAL"
                toElement.write("RESTART")
                println "SM: restarting"
            }
        }
    }

}