public class MyAccountHandler implements Triggers.Handler, Triggers.BeforeUpdate {
    public Boolean criteria(Triggers.Context context) {
        return true;
    }

    public void beforeUpdate(Triggers.Context context) {
        // do stuff
    }
}

trigger AccountTrigger on Account (before update, after update) {
    Triggers.prepare()
        .beforeUpdate()
            .bind(new MyAccountHandler())
            .bind(new AnotherAccountHandler())
        .afterUpdate()
            .bind(new AnotherAccountHandler())
            .bind(new MyAccountHandler())
        .execute();
}

// 1. Use interfaces instead of a base class to extend a custom handler. With interface
// approach we can declare only the needed interfaces explicitly, which is much cleaner
// and clearer.
public class MyAccountHandler implements Triggers.Handler,
                                         Triggers.BeforeUpdate,
                                         Triggers.AfterUpdate {

    // 2. There is a "criteria" stage before any handler execution. This gives
    // developers chances to turn on and off the handlers according to
    // configurations at run time.
    public Boolean criteria(Triggers.Context context) {
        return Triggers.WHEN_ALWAYS;

        // 3. There are also helper methods to check if certain fields have changes
        // return context.props.isChangedAny(Account.Name, Account.Description);
        // return context.props.isChangedAll(Account.Name, Account.Description);
    }

    public void beforeUpdate(Triggers.Context context) {
        then(context);
    }

    public void afterUpdate(Triggers.Context context) {
        then(context);
    }

    private void then(Triggers.Context context) {
        // 4. All properties on Trigger have been exposed to context.props.
      	// Direct reference of Trigger.old and Trigger.new can be avoided,
        // instead use context.props.oldList and context.props.newList.
        if (context.props.isUpdate) {

            // 5. Use context.state to pass query or computation results down to all
            // following handlers within the current trigger context, i.e. before update.
            Integer counter = (Integer)context.state.get('counter');
            if (counter == null) {
                context.state.put('counter', 0);
            } else {
                context.state.put('counter', counter + 1);
            }

            // 6. Use context.skips or Triggers.skips to prevent specific handlers from
            // execution. Please do remember restore the handler when appropriate.
            context.skips.add(ContactHandler.class);
            List<Contact> contacts = ...;
            Database.insert(contacts);
            context.skips.remove(ContactHandler.class);

            // 7-1. Call context.next() to execute the next handler. It is optional to use,
            // unless some following up logics need to be performed after all following
            // handlers finished.
            context.next();

            // 7-2. If context.stop() is called instead of context.next(), any following
            // handlers won't be executed, just like the STOP in process builder.
            context.stop();
        }
    }
}

global class AccountUpdateBatch implements Database.Batchable<sObject> {
    ...
    global void execute(Database.BatchableContext BC, List<sObject> scope){
        Triggers.skips.add(MyAccountHandler.class);
        // Update accounts...
        Triggers.skips.remove(MyAccountHandler.class);
    }
    ...
}

public class MyAccountHandler implements Triggers.Handler, Triggers.BeforeUpdate {
    public Boolean criteria(Triggers.Context context) {
        return !System.isBatch();
    }
    ...
}

List<SObject> oldList = new List<SObject> {
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 1), Name = 'Old Name 1'),
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 2), Name = 'Old Name 2'),
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 3), Name = 'Old Name 3')}

List<SObject> newList = new List<SObject> {
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 1), Name = 'New Name 1'),
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 2), Name = 'New Name 2'),
    new Account(Id = TriggersTest.getFakeId(Account.SObjectType, 3), Name = 'New Name 3')}

Triggers.prepare(TriggerOperation.Before_Update, oldList, newList)
    .beforeUpdate()
        .bind(new MyAccountHandler())
    .execute();