Lifecycle.java

package org.fastcatsearch.common;

public class Lifecycle {
	public static enum State {
        INITIALIZED,
        STOPPED,
        STARTED,
        CLOSED
    }

    private volatile State state = State.INITIALIZED;

    public State state() {
        return this.state;
    }

    /**
     * Returns <tt>true</tt> if the state is initialized.
     */
    public boolean initialized() {
        return state == State.INITIALIZED;
    }

    /**
     * Returns <tt>true</tt> if the state is started.
     */
    public boolean started() {
        return state == State.STARTED;
    }

    /**
     * Returns <tt>true</tt> if the state is stopped.
     */
    public boolean stopped() {
        return state == State.STOPPED;
    }

    /**
     * Returns <tt>true</tt> if the state is closed.
     */
    public boolean closed() {
        return state == State.CLOSED;
    }

    public boolean stoppedOrClosed() {
        Lifecycle.State state = this.state;
        return state == State.STOPPED || state == State.CLOSED;
    }
    
    public boolean canMoveToStarted() {
        State localState = this.state;
        if (localState == State.INITIALIZED || localState == State.STOPPED) {
            return true;
        }
        if (localState == State.STARTED) {
            return false;
        }
        if (localState == State.CLOSED) {
        	return false;
        }
        return false;
    }


    public boolean moveToStarted() {
        State localState = this.state;
        if (localState == State.INITIALIZED || localState == State.STOPPED) {
            state = State.STARTED;
            return true;
        }
        if (localState == State.STARTED) {
            return false;
        }
        if (localState == State.CLOSED) {
        	return false;
        }
        return false;
    }

    public boolean canMoveToStopped() {
        State localState = state;
        if (localState == State.STARTED) {
            return true;
        }
        if (localState == State.INITIALIZED || localState == State.STOPPED) {
            return false;
        }
        if (localState == State.CLOSED) {
        	return false;
        }
        return false;
    }

    public boolean moveToStopped() {
        State localState = state;
        if (localState == State.STARTED) {
            state = State.STOPPED;
            return true;
        }
        if (localState == State.INITIALIZED || localState == State.STOPPED) {
            return false;
        }
        if (localState == State.CLOSED) {
        	return false;
        }
        return false;
    }

    public boolean canMoveToClosed() {
        State localState = state;
        if (localState == State.CLOSED) {
            return false;
        }
        if (localState == State.STARTED) {
        	return false;
        }
        return true;
    }


    public boolean moveToClosed() {
        State localState = state;
        if (localState == State.CLOSED) {
            return false;
        }
        if (localState == State.STARTED) {
        	return false;
        }
        state = State.CLOSED;
        return true;
    }

    @Override
    public String toString() {
        return state.toString();
    }
}