utils/src/com/cloud/utils/db/DB.java

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// to you under the Apache License, Version 2.0 (the
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//
// http://www.apache.org/licenses/LICENSE-2.0
//
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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;
}