tutorial/batch-processing008.html at gh-pages · javaee/tutorial

This repository was archived by the owner on Jan 28, 2019. It is now read-only.

History

665 lines (648 loc) · 23 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

<!DOCTYPE html>

<head>

<title>The webserverlog Example Application</title>

</head>

<body>

<tr>

<b>Java Platform, Enterprise Edition (Java EE) 8</b><br />

<b>The Java EE Tutorial</b>

</td>

</tr>

</table>

<hr />

</colgroup>

<tr>

<span style="position:relative;top:-2px;">Previous</span>

</a>

</td>

</a>

</td>

<span style="position:relative;top:-2px;">Contents</span>

</a>

</td>

</tr>

</table>

</div>

<h2 id="_the_webserverlog_example_application">The webserverlog Example Application</h2>

<p>The <code>webserverlog</code> example application, located in the

tut-install`/examples/batch/webserverlog/` directory, demonstrates how

to use the batch framework in Java EE to analyze the log file from a web

server. This example application reads a log file and finds what

percentage of page views from tablet devices are product sales.</p>

</div>

<p>The following topics are addressed here:</p>

</div>

<ul>

<li>

<p><a href="#BABCHDFB">Architecture of the webserverlog Example Application</a></p>

</li>

<li>

<p><a href="#BABFIHJA">Running the webserverlog Example Application</a></p>

</li>

</ul>

</div>

</div>

<h3 id="_architecture_of_the_webserverlog_example_application">Architecture of the webserverlog Example Application</h3>

<p>The <code>webserverlog</code> example application consists of the following

elements:</p>

</div>

<ul>

<li>

<p>A job definition file (<code>webserverlog.xml</code>) that uses the Job

Specification Language (JSL) to define a batch job with a chunk step and

a task step. The chunk step acts as a filter, and the task step

calculates statistics on the remaining entries.</p>

</li>

<li>

<p>A log file (<code>log1.txt</code>) that serves as input data to the batch job.</p>

</li>

<li>

<p>Two Java classes (<code>LogLine</code> and <code>LogFilteredLine</code>) that represent

input items and output items for the chunk step.</p>

</li>

<li>

<p>Three batch artifacts (<code>LogLineReader</code>, <code>LogLineProcessor</code>, and

<code>LogFilteredLineWriter</code>) that implement the chunk step of the

application. This step reads items from the web server log file, filters

them by the web browser used by the client, and writes the results to a

text file.</p>

</li>

<li>

<p>Two batch artifacts (<code>InfoJobListener</code> and <code>InfoItemProcessListener</code>)

that implement two simple listeners.</p>

</li>

<li>

<p>A batch artifact (<code>MobileBatchlet.java</code>) that calculates statistics on

the filtered items.</p>

</li>

<li>

<p>Two Facelets pages (<code>index.xhtml</code> and <code>jobstarted.xhtml</code>) that provide

the front end of the batch application. The first page shows the log

file that will be processed by the batch job, and the second page

enables the user to check on the status of the job and shows the

results.</p>

</li>

<li>

<p>A managed bean (<code>JsfBean</code>) that is accessed from the Facelets pages.

The bean submits the job to the batch runtime, checks on the status of

the job, and reads the results from a text file.</p>

</li>

</ul>

</div>

</div>

<h4 id="_the_job_definition_file">The Job Definition File</h4>

<p>The <code>webserverlog.xml</code> job definition file is located in the

<code>WEB-INF/classes/META-INF/batch-jobs/</code> directory. The file specifies

seven job-level properties and two steps:</p>

</div>

<job id="webserverlog" xmlns="http://xmlns.jcp.org/xml/ns/javaee"

version="1.0">

</properties>

</listeners>

</job></code></pre>

</div>

<p>The first step is defined as follows:</p>

</div>

</listeners>

</chunk>

</step></code></pre>

</div>

<p>This step is a normal chunk step that specifies the batch artifacts that

implement each phase of the step. The batch artifact names are not fully

qualified class names, so the batch artifacts are CDI beans annotated

with <code>@Named</code>.</p>

</div>

<p>The second step is defined as follows:</p>

</div>

</step></code></pre>

</div>

<p>This step is a task step that specifies the batch artifact that

implements it. This is the last step of the job.</p>

</div>

</div>

<h4 id="_the_logline_and_logfilteredline_items">The LogLine and LogFilteredLine Items</h4>

<p>The <code>LogLine</code> class represents entries in the web server log file and it

is defined as follows:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">public class LogLine {

private final String datetime;

private final String ipaddr;

private final String browser;

private final String url;

/* ... Constructor, getters, and setters ... */

}</code></pre>

</div>

<p>The <code>LogFileteredLine</code> class is similar to this class but only has two

fields: the IP address of the client and the URL.</p>

</div>

</div>

<h4 id="_the_chunk_step_batch_artifacts">The Chunk Step Batch Artifacts</h4>

<p>The first step is composed of the <code>LogLineReader</code>, <code>LogLineProcessor</code>,

and <code>LogFilteredLineWriter</code> batch artifacts.</p>

</div>

<p>The <code>LogLineReader</code> artifact reads records from the web server log file:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Dependent

@Named("LogLineReader")

public class LogLineReader implements ItemReader {

private ItemNumberCheckpoint checkpoint;

private String fileName;

private BufferedReader breader;

@Inject

private JobContext jobCtx;

public LogLineReader() { }

/* ... Override the open, close, readItem, and

* checkpointInfo methods ... */

}</code></pre>

</div>

<p>The <code>open</code> method reads the <code>log_file_name</code> property and opens the log

file with a buffered reader. In this example, the log file has been

included with the application under

<code>webserverlog/WEB-INF/classes/log1.txt</code>:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">fileName = jobCtx.getProperties().getProperty("log_file_name");

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();

InputStream iStream = classLoader.getResourceAsStream(fileName);

breader = new BufferedReader(new InputStreamReader(iStream));</code></pre>

</div>

<p>If a checkpoint object is provided, the <code>open</code> method advances the

reader up to the last checkpoint. Otherwise, this method creates a new

checkpoint object. The checkpoint object keeps track of the line number

from the last committed chunk.</p>

</div>

<p>The <code>readItem</code> method returns a new <code>LogLine</code> object or null at the end

of the log file:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Override

public Object readItem() throws Exception {

String entry = breader.readLine();

if (entry != null) {

checkpoint.nextLine();

return new LogLine(entry);

} else {

return null;

}

}</code></pre>

</div>

<p>The <code>LogLineProcessor</code> artifact obtains a list of browsers from the job

properties and filters the log entries according to the list:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Override

public Object processItem(Object item) {

/* Obtain a list of browsers we are interested in */

if (nbrowsers == 0) {

Properties props = jobCtx.getProperties();

nbrowsers = Integer.parseInt(props.getProperty("num_browsers"));

browsers = new String[nbrowsers];

for (int i = 1; i < nbrowsers + 1; i++)

browsers[i - 1] = props.getProperty("browser_" + i);

}

LogLine logline = (LogLine) item;

/* Filter for only the mobile/tablet browsers as specified */

for (int i = 0; i < nbrowsers; i++) {

if (logline.getBrowser().equals(browsers[i])) {

return new LogFilteredLine(logline);

}

return null;

}</code></pre>

</div>

<p>The <code>LogFilteredLineWriter</code> artifact reads the name of the output file

from the job properties. The <code>open</code> method opens the file for writing.

If a checkpoint object is provided, the artifact continues writing at

the end of the file; otherwise, it overwrites the file if it exists. The

<code>writeItems</code> method writes filtered items to the output file:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Override

public void writeItems(List<Object> items) throws Exception {

/* Write the filtered lines to the output file */

for (int i = 0; i < items.size(); i++) {

LogFilteredLine filtLine = (LogFilteredLine) items.get(i);

bwriter.write(filtLine.toString());

bwriter.newLine();

}

}</code></pre>

</div>

</div>

<h4 id="_the_listener_batch_artifacts">The Listener Batch Artifacts</h4>

<p>The <code>InfoJobListener</code> batch artifact implements a simple listener that

writes log messages when the job starts and when it ends:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Dependent

@Named("InfoJobListener")

public class InfoJobListener implements JobListener {

...

@Override

public void beforeJob() throws Exception {

logger.log(Level.INFO, "The job is starting");

}

@Override

public void afterJob() throws Exception { ... }

}</code></pre>

</div>

<p>The <code>InfoItemProcessListener</code> batch artifact implements the

<code>ItemProcessListener</code> interface for chunk steps:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Dependent

@Named("InfoItemProcessListener")

public class InfoItemProcessListener implements ItemProcessListener {

...

@Override

public void beforeProcess(Object o) throws Exception {

LogLine logline = (LogLine) o;

llogger.log(Level.INFO, "Processing entry {0}", logline);

}

...

}</code></pre>

</div>

</div>

<h4 id="_the_task_step_batch_artifact">The Task Step Batch Artifact</h4>

<p>The task step is implemented by the <code>MobileBatchlet</code> artifact, which

computes what percentage of the filtered log entries are purchases:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">@Override

public String process() throws Exception {

/* Get properties from the job definition file */

...

/* Count from the output of the previous chunk step */

breader = new BufferedReader(new FileReader(fileName));

String line = breader.readLine();

while (line != null) {

String[] lineSplit = line.split(", ");

if (buyPage.compareTo(lineSplit[1]) == 0)

pageVisits++;

totalVisits++;

line = breader.readLine();

}

breader.close();

/* Write the result */

...

}</code></pre>

</div>

</div>

<h4 id="_the_javaserver_faces_pages">The JavaServer Faces Pages</h4>

<p>The <code>index.xhtml</code> page contains a text area that shows the web server

log. The page provides a button for the user to submit the batch job and

navigate to the next page:</p>

</div>

...

<textarea cols="90" rows="25"

readonly="true">#{jsfBean.getInputLog()}</textarea>

<h:form>

<h:commandButton value="Start Batch Job"

action="#{jsfBean.startBatchJob()}" />

</h:form>

</body></code></pre>

</div>

<p>This page calls the methods of the managed bean to show the log file and

submit the batch job.</p>

</div>

<p>The <code>jobstarted.xhtml</code> page provides a button to check the current

status of the batch job and displays the results when the job finishes:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn"><p>Current Status of the Job: <b>#{jsfBean.jobStatus}</b></p>

<p>#{jsfBean.showResults()}</p>

<h:form>

<h:commandButton value="Check Status"

action="jobstarted"

rendered="#{jsfBean.completed==false}" />

</h:form></code></pre>

</div>

</div>

<h4 id="_the_managed_bean">The Managed Bean</h4>

<p>The <code>JsfBean</code> managed bean submits the job to the batch runtime, checks

on the status of the job, and reads the results from a text file.</p>

</div>

<p>The <code>startBatchJob</code> method submits the job to the batch runtime:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">/* Submit the batch job to the batch runtime.

* JSF Navigation method (return the name of the next page) */

public String startBatchJob() {

jobOperator = BatchRuntime.getJobOperator();

execID = jobOperator.start("webserverlog", null);

return "jobstarted";

}</code></pre>

</div>

<p>The <code>getJobStatus</code> method checks the status of the job:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">/* Get the status of the job from the batch runtime */

public String getJobStatus() {

return jobOperator.getJobExecution(execID).getBatchStatus().toString();

}</code></pre>

</div>

<p>The <code>showResults</code> method reads the results from a text file.</p>

</div>

</div>

<h3 id="_running_the_webserverlog_example_application">Running the webserverlog Example Application</h3>

<p>You can use either NetBeans IDE or Maven to build, package, deploy, and

run the <code>webserverlog</code> example application.</p>

</div>

<p>The following topics are addressed here:</p>

</div>

<ul>

<li>

<p><a href="#BABHIJBE">To Run the webserverlog Example Application Using

NetBeans IDE</a></p>

</li>

<li>

<p><a href="#BABGACCD">To Run the webserverlog Example Application Using

Maven</a></p>

</li>

</ul>

</div>

</div>

<h4 id="_to_run_the_webserverlog_example_application_using_netbeans_ide">To Run the webserverlog Example Application Using NetBeans IDE</h4>

<li>

<p>Make sure that GlassFish Server has been started (see

<a href="usingexamples002.html#BNADI">Starting and Stopping GlassFish

Server</a>).</p>

</li>

<li>

<p>From the File menu, choose Open Project.</p>

</li>

<li>

<p>In the Open Project dialog box, navigate to:</p>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">tut-install/examples/batch</code></pre>

</div>

</li>

<li>

<p>Select the <code>webserverlog</code> folder.</p>

</li>

<li>

<p>Click Open Project.</p>

</li>

<li>

<p>In the Projects tab, right-click the <code>webserverlog</code> project and

select Run.</p>

<p>This command builds and packages the application into a WAR file,

<code>webserverlog.war</code>, located in the <code>target/</code> directory; deploys it to

the server; and launches a web browser window at the following URL:</p>

</div>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">http://localhost:8080/webserverlog/</code></pre>

</div>

</li>

</ol>

</div>

</div>

<h4 id="_to_run_the_webserverlog_example_application_using_maven">To Run the webserverlog Example Application Using Maven</h4>

<li>

<p>Make sure that GlassFish Server has been started (see

<a href="usingexamples002.html#BNADI">Starting and Stopping GlassFish

Server</a>).</p>

</li>

<li>

<p>In a terminal window, go to:</p>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">tut-install/examples/batch/webserverlog/</code></pre>

</div>

</li>

<li>

<p>Enter the following command to deploy the application:</p>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">mvn install</code></pre>

</div>

</li>

<li>

<p>Open a web browser window at the following URL:</p>

<pre class="prettyprint highlight"><code class="language-oac_no_warn" data-lang="oac_no_warn">http://localhost:8080/webserverlog/</code></pre>

</div>

</li>

</ol>

</div>

<hr />

</colgroup>

<tr>

<span style="position:relative;top:-2px;">Previous</span>

</a>

</td>

</a>

</td>

<span style="position:relative;top:-2px;">Contents</span>

</a>

</td>

</tr>

</table>

</a>

</span>

</body>

</html>

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

FilesExpand file tree

batch-processing008.html

Latest commit

History

batch-processing008.html

File metadata and controls