AbstractBackupStorage.java example

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zstack-master
package org.zstack.storage.backup;

import org.zstack.core.Platform;
import org.zstack.core.statemachine.StateMachine;
import org.zstack.header.storage.backup.*;
import org.zstack.utils.message.OperationChecker;

public abstract class AbstractBackupStorage implements BackupStorage {
	protected final static StateMachine<BackupStorageState, BackupStorageStateEvent> states;
    protected final static OperationChecker statusChecker = new OperationChecker();
    protected final static OperationChecker stateChecker = new OperationChecker();

	static {
		states = Platform.<BackupStorageState, BackupStorageStateEvent>createStateMachine();
		states.addTranscation(BackupStorageState.Enabled, BackupStorageStateEvent.disable, BackupStorageState.Disabled);
		states.addTranscation(BackupStorageState.Enabled, BackupStorageStateEvent.enable, BackupStorageState.Enabled);
		states.addTranscation(BackupStorageState.Disabled, BackupStorageStateEvent.disable, BackupStorageState.Disabled);
		states.addTranscation(BackupStorageState.Disabled, BackupStorageStateEvent.enable, BackupStorageState.Enabled);

        statusChecker.addState(BackupStorageStatus.Connected.toString(),
                DeleteBitsOnBackupStorageMsg.class.getName(),
                DownloadImageMsg.class.getName(),
                DownloadVolumeMsg.class.getName()
        );

        statusChecker.addState(BackupStorageStatus.Connecting.toString());
        statusChecker.addState(BackupStorageStatus.Disconnected.toString());

        stateChecker.addState(BackupStorageState.Enabled.toString(),
                DeleteBitsOnBackupStorageMsg.class.getName(),
                DownloadImageMsg.class.getName(),
                DownloadVolumeMsg.class.getName()
        );

        stateChecker.addState(BackupStorageState.Disabled.toString());
	}
	
	public static BackupStorageState getNextState(BackupStorageState curr, BackupStorageStateEvent evt) {
		return states.getNextState(curr, evt);
	}
}