[webMethods] 如何安裝 Designer 工具

Installation Steps
1. 執行 installer，等待出現 installation window 以後，點選 Advanced Options


2. 點選 Images tab、勾選 Use installation image、選取要安裝的 image file，先點選 Validate Image 確定所選取的 image file 是否完整，確認 image file 是正確的才點選 OK


3. 選擇要安裝的 Installation directory，點選 Next


4. 選擇要安裝的 packages，點選 Next


5. 點選 checkbox，按下 Next



6. 選取 trial license file，按下 Next


7. 直接按下 Next


8. 直接按下 Next


9. 直接按下 Next


10. 此步驟需要等待數分鐘


11. 安裝完成畫面，按下 Close 即可完成安裝步驟



Designer Configuration Steps
1. 啟動 Designer 工具


2. Window => Preferences





3. 點選 Integration Servers 的選項


4. 輸入你要連線的 Integration Server 的 IP、Port、User name、Password，點選 Verify Server 可以檢查是否可以正常連上 Integration Server，按下 OK 即可完成設定


5. 完成設定後，若可以正常連上 Integration Server，Status 會顯示 Connected


Reference
[1] http://techcommunity.softwareag.com/pwiki/-/wiki/Main/Guide+to+Downloading+and+installing+the+webMethods+Free+Trial+Version

[Failsafe] Retry with backoff

Problem
I would like do retry if I fail to connect to database.  
My requirement is 

• retry 5 times at most and sleep 5 second then retry again
• Sets the delay between retries (i.e. 5 seconds), exponentially backing off to the maxDelay (i.e. 120 seconds) and multiplying successive delays by the delayFactor (i.e. 2).

How-to
Here has the sample code:

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package albert.practice.retry; import java.sql.Connection; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.TimeUnit; import lombok.extern.slf4j.Slf4j; import net.jodah.failsafe.Failsafe; import net.jodah.failsafe.RetryPolicy; @Slf4j public class RetryTest { private int count = 0; public static void main(String[] args) throws ConnectionException { new RetryTest().connectWithRetry(); } public Connection connectWithRetry() { // create a retry policy with 5 max retries and have 2 seconds delay among retries RetryPolicy retryPolicy = new RetryPolicy(); // create a retry policy and sets the delay 5 seconds between retries, exponentially backing off to the maxDelay 120 // seconds and multiplying successive delays by the delayFactor 2. retryPolicy.retryOn(ConnectionException.class).withMaxRetries(5).withBackoff(5, 120, TimeUnit.SECONDS, 2); // Using Fallbacks allow you to provide an alternative result for a failed execution. // In this example, it will retry again after 5 seconds. Connection conn = Failsafe.with(retryPolicy).withFallback(() -> retryIfFail()) .get(() -> connect()); return conn; } public void retryIfFail() throws InterruptedException { log.debug("GG at " + getCurrentTime()); Thread.sleep(5000); log.debug("retry....." + getCurrentTime()); connectWithRetry(); } public Connection connect() throws ConnectionException { log.debug(" time = " + getCurrentTime()); Connection conn = null; if (count < 9) { count++; throw new ConnectionException("connection fail!"); } else { log.debug("get connection successfuly..."); } return conn; } private String getCurrentTime() { SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS"); return dateFormat.format(new Date()); } }

Execution log:

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[main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:31:51.495 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:32:01.509 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:32:21.515 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:33:01.498 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:34:21.499 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:36:21.539 [main] DEBUG albert.practice.retry.RetryTest - GG at 2016/11/23 17:36:21.539 [main] DEBUG albert.practice.retry.RetryTest - retry.....2016/11/23 17:36:26.545 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:36:26.545 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:36:36.554 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:36:56.564 [main] DEBUG albert.practice.retry.RetryTest - time = 2016/11/23 17:37:36.571 [main] DEBUG albert.practice.retry.RetryTest - get connection successfuly...

[Failsafe] Retry with Fallback

Scenario
If we cannot get connection, then we will retry 5 times with 2 seconds delay.
If we fail to retry with 5 times, then we will pause X minutes then retry again.
How to implement it?


How-to
You can make good use of failsafe to fulfill this implement.
In this exampe, it will demonstrate:
1. create a retry policy with 5 max retries and have 2 seconds delay among retries
2. If you got failed execution, it will retry again after 5 seconds.

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package albert.practice.retry; import java.sql.Connection; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.TimeUnit; import lombok.extern.slf4j.Slf4j; import net.jodah.failsafe.Failsafe; import net.jodah.failsafe.RetryPolicy; @Slf4j public class RetryTest { private int count = 0; public static void main(String[] args) throws ConnectionException { new RetryTest().connectWithRetry(); } public Connection connectWithRetry() { // create a retry policy with 5 max retries and have 2 seconds delay among retries RetryPolicy retryPolicy = new RetryPolicy(); retryPolicy.retryOn(ConnectionException.class).withDelay(2, TimeUnit.SECONDS) .withMaxRetries(5); // Using Fallbacks allow you to provide an alternative result for a failed execution. // In this example, it will retry again after 5 seconds. Connection conn = Failsafe.with(retryPolicy).withFallback(() -> retryIfFail()) .get(() -> connect()); return conn; } public void retryIfFail() throws InterruptedException { log.debug("GG at " + getCurrentTime()); Thread.sleep(5000); log.debug("retry....." + getCurrentTime()); connectWithRetry(); } public Connection connect() throws ConnectionException { log.debug(" time = " + getCurrentTime()); Connection conn = null; if (count < 9) { count++; throw new ConnectionException("connection fail!"); } else { log.debug("get connection successfuly..."); } return conn; } private String getCurrentTime() { SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS"); return dateFormat.format(new Date()); } }

Console log:

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DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:13.832 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:15.837 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:17.837 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:19.837 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:21.838 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:23.839 DEBUG albert.practice.retry.RetryTest - GG at 2016/11/05 11:42:23.839 DEBUG albert.practice.retry.RetryTest - retry.....2016/11/05 11:42:28.839 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:28.839 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:30.839 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:32.839 DEBUG albert.practice.retry.RetryTest - time = 2016/11/05 11:42:34.840 DEBUG albert.practice.retry.RetryTest - get connection successfuly...

Reference
[1] https://github.com/jhalterman/failsafe#fallbacks

[Angular2] fail to load data items in ng2-select component

Problem
I am using ng2-select to implement a dropdown list function.
But my dropdown list cannot be showed just like the example:


Here is my code snippet:

   <div class="row">
    <div class="col-sm-12">
        <div class="form-group">
           <label> 負責人員 </label>
           <div style="width: 300px; margin-bottom: 20px;">
              <ng-select [allowClear]="true" 
                         [items]="items" 
                         [data]="selectedItem"
                         (data)="refreshValue($event)" 
                         (selected)="selected($event)"
                         (removed)="removed($event)" 
                         placeholder="請選擇負責人員">
              </ng-select>
           </div>
        </div>
    </div>
   </div>

How-to
Owning to the data items in ng2-select example is static:

The data items in my function which will retrieve them from database, so we need to wait until data items had been finished then create the DOM element.

Owing to I do not know how long I need to wait, so I add *ngIf in the first div tag.

   <div class="row" *ngIf="items && items.length > 0">
    <div class="col-sm-12">
        <div class="form-group">
           <label> 負責人員 </label>
           <div style="width: 300px; margin-bottom: 20px;">
              <ng-select [allowClear]="true" 
                         [items]="items" 
                         [data]="selectedItem"
                         (data)="refreshValue($event)" 
                         (selected)="selected($event)"
                         (removed)="removed($event)" 
                         placeholder="請選擇負責人員">
              </ng-select>
           </div>
        </div>
    </div>
   </div>

Reference
[1] https://valor-software.com/ng2-select/

[UML] How to Draw a Scheduler Service in Sequence Diagram

Problem
Assume I have a HeartBeatService and HeartbeatProducerService.
HeartBeatService will call HeartbeatProducerService every 5 seconds to check system is alive or not. 

How to show this kind of scheduler job in sequence diagram.


How-to
You can add a loop combined fragment in sequence diagram, it looks like:

[Failsafe] Simple, sophisticated failure handling

Scenario
We have a Java application to connect to OPC server, if it fail to connect to OPC server it will retry 5 times.


How-to
You can make good use of Failsafe to fulfill this requirement. 
Failsafe is a lightweight, zero-dependency library for handling failures. It was designed to be as easy to use as possible, with a concise API for handling everyday use cases and the flexibility to handle everything else.

Maven dependency:

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<dependencies> <dependency> <groupId>net.jodah</groupId> <artifactId>failsafe</artifactId> <version>0.9.5</version> </dependency> </dependencies>

If I catch ConnectionException, it will do retry, the retry policy is as bellows:

• it will delay 2 seconds between retries
• it will retry 5 times at most

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package albert.practice.retry; import java.util.Calendar; import java.util.Date; import java.util.concurrent.TimeUnit; import lombok.extern.slf4j.Slf4j; import net.jodah.failsafe.Failsafe; import net.jodah.failsafe.RetryPolicy; @Slf4j public class RetryTest { public static void main(String[] args) throws ConnectionException { @SuppressWarnings("unchecked") RetryPolicy retryPolicy = new RetryPolicy().retryOn(ConnectionException.class) .withDelay(2, TimeUnit.SECONDS).withMaxRetries(5); Failsafe.with(retryPolicy).run(() -> new RetryTest().connect()); } public void connect() throws ConnectionException { log.debug("time=" + new Date(Calendar.getInstance().getTimeInMillis())); if (true) { throw new ConnectionException("connection fail!"); } } }

Reference
[1] https://github.com/jhalterman/failsafe

[閱讀筆記] Waltzing with Bears (1/2)

1. 經營管理是企業體的成長與永續之道，投資理財是個人的安身之道，而經濟趨勢則是會影響這兩者的變數
2. 風險管理的事務，著重於成因風險（cause risk)的管理，亦即你能管理的部分
3. 風險就是還沒發生的問題，問題是已經發生的風險
4. 風險管理是在問題發生之前，預先思考應變措施的過程；危機管理則是在問題發生之後，嘗試處理善後
5. 軟體工程規範原地踏步了許多年，他始終缺乏跟上資訊時代並滿足資訊社會所需要的成熟工程規範
6. 很多軟體專案會失敗，並非風險管理方法不好，而是他根本就沒花任何功夫在風險管理上，反而在祈禱風險不會發生
7. 風險管理就是把不確定性侷限在一個範圍內，或許你害怕僅憑少量資訊就要把問題解決掉。但是，若連這點資訊都沒有，情況會更糟糕。無窮無盡的不確定性，結果不是讓人過分保守，就是讓人變得莽撞，兩者都不是好事
8. 進行風險管理不會使問題消失，只能保證不會讓你遭受突如其來的衝擊，殺的你措手不及
9. 當你在祈禱所有的好運都降臨在你身上，當運氣其成為你整體策略的一部分時，小心，你的麻煩要來了
10. 風險管理往往能提供你想要的更多事實真相
11. 有些組織一廂情願的相信可以控制一切，即使心知肚明這並非事實，還是慣用控制的假象來蒙蔽現實。最常見的特徵，就是一開始弄出一個精確到令人可笑的預估結果，事後卻證明他跟事實差了十萬八千里
12. 你可以管理風險，但不可能使風險消失
13. 在最糟糕的組織中，報壞消息的人會被懲罰，但壞結果卻不會被檢討。當你提出風險時，就會有另外一位同儕會搶著說包在他身上，他一定可以如期完成。在這種文化中，大家都會先把牛吹大，因為這遠比按時交貨來得重要。如果再這種公司上班，把風險評估收起來，自己私底下用就好
14. 組織不允許不確定性存在，風險管理就不用做了。這樣的組織，成員不可以對「一切如期完成」表現出一丁點的疑慮。事情做錯沒關係，就是不可以不確定
15. 組織常常缺少能發出「災難」訊號的自主神經系統，常常自以為掌握了所有風險（潛在問題），其實只掌握了一部份而已（已有解決方案的潛在問題）
16. 當你決定忽略某個風險時，就等於要賭運氣，賭這個風險不會發生
17. 當專案包裝成一項挑戰時，就相當於強迫你去賭運氣。例如，你是全公司最後的希望，希望你能在這個月底完成這個專案
18. 專案一開始就以個人挑戰的形式出發，便很難有明智的風險管理，這種專案就是在賭運氣
19. 做軟體專案，你一定要把失敗的可能性限制在一定範圍內
20. 我們在做預估的時候，記得把預估背後依賴的假設統統列舉出來
21. 專案偏離時程，陷入泥沼，很少是因為工作比預期的更花時間，多半是為了處理原本沒有規劃到的事情
22. 越棘手的風險，高層主管想弄走他的壓力就越大。根據經驗，高層主管若抓狂到某種地步，就比較不會想去了解為什麼風險會消失，反正只要它不見了就好
23. 在軟體專案中，你不知道的問題，那通常就是風險所在。無論是什麼事情不知道，只要會造成不利的負面影響，就是風險。蒐集各種「我不知道」的問題，把不知道的根本原因找出來，你就可以得到一份完整的風險列表

2017/03 Travel

奮起湖









台大杜鵑節


台北北門

[Agnular2] Notifying parent Components that something has happened via events

Scenario

If we would like to tell the parent Component that the child component has added or deleted subtask. How to implement in Angualr2 ?


How-to
To create a custom event, we can use the new @Output decorator. So let's start by creating a new instance of an Event Emitter and decorate the property with the @Output decorator.

Then we've got an event emitter in place, let's call its emit method, callParent(), to raise the event and pass to parent component. 

The child component's code snippet looks like:

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@Component({ selector: 'sub-task', directives: [MODAL_DIRECTIVES, SELECT_DIRECTIVES, NgClass], providers: [SubtaskService, UserService, IssueService, ProjectService], templateUrl: 'sub.task.html' }) export class SubTaskComponent implements OnInit { @Input() issue: Issue; @Input() watchers: Watcher[]; @Output() refreshIssueEvent = new EventEmitter(); callParent() { this.refreshIssueEvent.emit(this.issue.id); } //... }

The parent component receives that event and its payload. We use event binding to bind to this notify event and call a method.

Our final step is to provide the refreshIssue method to execute when the notify event occurs. 

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<div class="container" *ngIf="issue.id"> <sub-task [issue]="issue" [watchers]="issue.watchers" (refreshIssueEvent)="refreshIssue($event)"></sub-task> </div>

We have to pass the $event to parent component's handler because that variable holds the event payload.

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@Component({ selector: 'issue-detail', templateUrl: 'issue.detail.html', providers: [IssueService] }) export class IssueDetailComponent implements OnInit, OnDestroy { refreshIssue(issueId: number){ this.issueService.getIssue(issueId.toString()).subscribe( data => { this.issue = data; } ); } //... }

[Angular2] Pass data from parent to child with input binding

Scenario


If we had two html pages which has parent and child relationship. If we would like to pass parameters from parent to child, how to implement in Agnular2?

How-to
Step 1. Define the input parameter names in child component which typically adorned with @Input decorations., the code snippet is as bellows:

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@Component({ selector: 'sub-task', directives: [MODAL_DIRECTIVES, SELECT_DIRECTIVES, NgClass], providers: [SubtaskService, UserService, IssueService, ProjectService], templateUrl: 'sub.task.html' }) export class SubTaskComponent implements OnInit { @Input() issue: Issue; @Input() watchers: Watcher[]; // ... }

Step 2. The Parent page, issue.detail.html, is binding its master string property to the child's property. The code snippet is as follows:

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<div class="container" *ngIf="issue.id"> <sub-task [issue]="issue" [watchers]="issue.watchers"></sub-task> </div>