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// distributed with this work for additional information

// regarding copyright ownership. The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// 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

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package com.cloud.utils.db;

import static java.lang.annotation.ElementType.METHOD;

import static java.lang.annotation.ElementType.TYPE;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Retention;

import java.lang.annotation.Target;

/**

* Running with assertions on, will find all classes that are

*

* 1. Annotate method that starts and commits DB transactions.

* Transaction txn = Transaction.currentTxn();

* txn.start();

* ...

* txn.commit();

*

* 2. Annotate methods that uses a DAO's acquire method.

* _dao.acquireInLockTable(id);

* ...

* _dao.releaseFromLockTable(id);

*

* 3. Annotate methods that are inside a DAO but doesn't use

* the Transaction class. Generally, these are methods

* that are utility methods for setting up searches. In

* this case use @DB(txn=false) to annotate the method.

* While this is not required, it helps when you're debugging

* the code and it saves on method calls during runtime.

*

*/

@Target({TYPE, METHOD})

@Retention(RUNTIME)

public @interface DB {

/**

* (Optional) Specifies that the method

* does not use transaction. This is useful for

* utility methods within DAO classes which are

* automatically marked with @DB. By marking txn=false,

* the method is not surrounded with transaction code.

*/

boolean txn() default true;

}