[GitHub] tomee pull request #219: Avoid String in a loop

[otaviojava <gi...@git.apache.org>]

GitHub user otaviojava opened a pull request:

    https://github.com/apache/tomee/pull/219

    Avoid String in a loop

    The reason to prefer StringBuilder is that both + and concat create a new object every time you call them (provided the right-hand side argument is not empty). This can quickly add up to a lot of objects, almost all of which are completely unnecessary.
    
    ```java
    public class Main
    {
        public static void main(String[] args)
        {
            long now = System.currentTimeMillis();
            slow();
            System.out.println("slow elapsed " + (System.currentTimeMillis() - now) + " ms");
    
            now = System.currentTimeMillis();
            fast();
            System.out.println("fast elapsed " + (System.currentTimeMillis() - now) + " ms");
        }
    
        private static void fast()
        {
            StringBuilder s = new StringBuilder();
            for(int i=0;i<100000;i++)
                s.append("*");      
        }
    
        private static void slow()
        {
            String s = "";
            for(int i=0;i<100000;i++)
                s+="*";
        }
    }
    ```
    
    * slow elapsed 11741 ms
    * fast elapsed 7 ms
    
    Also, this PR avoids unnecessary call in StringBuilder

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/otaviojava/tomee use_string_builder_instad_string_loop

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/tomee/pull/219.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #219
    
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commit 442a81b3e78b7700f0420573927872bedbec30a4
Author: Otavio Santana <ot...@...>
Date:   2018-11-22T15:23:49Z

    removes String concatenation loop in Assembler

commit afec54d2204e6e5b8814cddc7eef427a35b54dd5
Author: Otavio Santana <ot...@...>
Date:   2018-11-22T15:24:04Z

    removes String concatenation loop in AnnotationDeployer

commit 20b08f5093e2c562886d6221e5f2a6322bd158e1
Author: Otavio Santana <ot...@...>
Date:   2018-11-22T15:24:17Z

    removes String concatenation loop in SunConvertion

commit e859469a996d4581a971869f685dea5bf9b06b8d
Author: Otavio Santana <ot...@...>
Date:   2018-11-22T15:24:41Z

    removes String concatenation loop in LoggingPreparedSqlStatement

commit 806df6dc4095d0d444357b242560d182544fa69f
Author: Otavio Santana <ot...@...>
Date:   2018-11-22T18:26:57Z

    removes redudant toString

----


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[GitHub] tomee pull request #219: Avoid String in a loop

[asfgit <gi...@git.apache.org>]

Github user asfgit closed the pull request at:

    https://github.com/apache/tomee/pull/219


---

[GitHub] tomee pull request #219: Avoid String in a loop

[danielsoro <gi...@git.apache.org>]

Github user danielsoro commented on a diff in the pull request:

    https://github.com/apache/tomee/pull/219#discussion_r236279011
  
    --- Diff: container/openejb-core/src/main/java/org/apache/openejb/config/AnnotationDeployer.java ---
    @@ -2939,12 +2939,14 @@ public EjbModule deploy(final EjbModule ejbModule) throws OpenEJBException {
                             }
     
                             if (interfaces.size() != 1) {
    -                            String msg = "When annotating a bean class as @MessageDriven without declaring messageListenerInterface, the bean must implement exactly one interface, no more and no less. beanClass=" + clazz.getName() + " interfaces=";
    +                            StringBuilder msg = new StringBuilder("When annotating a bean class as @MessageDriven without" +
    --- End diff --
    
    What do you think to use String.format in cases like that?


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