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        <h1>JavaCC Parser Generator Integration Tutorial for the NetBeans Platform</h1>

        <p>This tutorial shows you how to generate 
            a parser with <a href="http://javacc.java.net/">JavaCC</a>
            and use it to create features in a NetBeans editor. </p>

        <p class="notes"><b>Note:</b> Prior to starting to work on this tutorial,
            you must have completed the 
            <a href="nbm-javacc-lexer.html">JavaCC Lexer Generator Integration Tutorial</a>,
            since that tutorial shows how to create the module structure, file type support,
            and lexer used in the instructions that follow.</p>

        <p>You will learn how to create several features in a NetBeans editor,
            based on your JavaCC parser, such as a syntax error parser, as shown below:</p>

        <p><img src="../images/tutorials/javacc/72/result-3.png" alt="source."/></p>

        <p><b>Contents</b></p>

        <p><img src="../images/articles/74/netbeans_stamp_74_73_72.png" class="stamp" width="114" height="114" alt="Content on this page applies to NetBeans IDE 7.2" title="Content on this page applies to NetBeans IDE 7.2"/></p>
        <ul class="toc">
            <li><a href="#generating">Generating a Parser from JavaCC</a></li>
            <li><a href="#integrating">Integrating the JavaCC Parser with NetBeans APIs</a></li>
            <li>Implementing New Features
                <ul>
                    <li><a href="#error-feature">Error Parsing</a></li>
                    <li><a href="#indent-feature">Indentation</a></li>
                    <li><a href="#format-feature">Reformatting</a></li>
                    <li><a href="#brace-feature">Brace Matching</a></li>
                    <li><a href="#fold-feature">Code Folding</a></li>
                </ul>
            </li>
        </ul>

        <p><b>To follow this tutorial, you need the software and resources listed in the following 
                table.</b></p>

        <table>
            <tbody>
                <tr>
                    <th class="tblheader" scope="col">Software or Resource</th>
                    <th class="tblheader" scope="col">Version Required</th>
                </tr> 
                <tr>
                    <td class="tbltd1"><a href="https://netbeans.org/downloads/index.html">NetBeans IDE</a></td>
                    <td class="tbltd1">version 7.2 or above</td>
                </tr>
                <tr>
                    <td class="tbltd1"><a href="http://java.sun.com/javase/downloads/index.jsp">Java Developer Kit (JDK)</a></td>
                    <td class="tbltd1">version 7 or above</td>
                </tr>
            </tbody>
        </table>
        <p class="tips">For troubleshooting purposes, you are welcome to download the <a href="http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.2/tutorials/SimpleJava2">completed tutorial source code</a>.</p>

        <!-- ===================================================================================== -->

        <h2><a name="generating"></a>Generating a Parser from JavaCC</h2>
        <p>Let's now use JavaCC to generate a parser, in the same way as
            we generated a lexer in the 
            <a href="nbm-javacc-lexer.html">JavaCC Lexer Generator Integration Tutorial</a>. We'll need
            to edit the JavaCC grammar file less than we did in the previous tutorial, since we're
            not going to remove the parser generator as we did last time.</p>
        <div class="indent">

            <ol>
                <li><p>Create a new package named <tt>org.simplejava.jccparser</tt> in your project.
                        Copy into the new package the same <tt>Java1.5.jj</tt> file that you copied
                        in the
                        previous tutorial, from the JavaCC distribution, as before. This time, also
                        include the "MyToken.java" file:</p>
                    <br/>
                    <p><img src="../images/tutorials/javacc/72/parser-2.png" alt="source."/></p>
                    <br/>
                    <p>In your project structure, you should now see your new package and new file:</p>
                    <br/>
                    <p><img src="../images/tutorials/javacc/72/parser-1.png" alt="source."/></p>
                    <br/>
                    <p>We're now going to slightly tweak the <tt>Java1.5.jj</tt> file again so that it fits our
                        parsing needs.</p>
                    <br/>
                    <ul>                    
                        <li><p>The <tt>MyToken</tt> class can't be compiled because it is missing a package statement.
                                Add it:</p>

                            <pre class="examplecode">package org.simplejava.jccparser;</pre>
                            <p>The class will still not compile because the implementing class <tt>Token</tt>
                                does not exist yet. We will generate that class in the next step.</p>
                        </li>
                        <li><p>We need to make sure that the classes
                                that JavaCC will generate for us will be generated with the correct package statements.
                                Add "package org.simplejava.jccparser;" 
                                to <tt>Java1.5.jj</tt> file after the "PARSER_BEGIN(JavaParser)" line:</p>

                            <pre class="examplecode">PARSER_BEGIN(JavaParser)

<b>package org.simplejava.jccparser;</b>

import java.io.*;</pre>

                        </li>
                    </ul></li>

                <li><p>That's all we need to do. The <tt>Java1.5.jj</tt> file is ready now and we 
                        can generate our parser from the command line, in the same
                        way as in the previous tutorial. The result should be as follows:</p>
                    <br/>
                    <p><img src="../images/tutorials/javacc/72/parser-3.png" alt="source."/></p>
                    <br/>
                    <p>As you can see, JavaCC has generated several files, which we will use in the next sections.
                        All the files should be compilable, that is, there should be no error
                        marks anywhere in the module, as can be seen in the screenshot above.</p>
                </li>

            </ol>        
        </div>
        <p>You've now completed the JavaCC part of the tutorial. 
            The time has come to use the generated files to extend
            your NetBeans Lexer plugin.</p> 


        <!-- ======================================================================================= -->

        <h2><a name="integrating"></a>Integrating the JavaCC Parser with NetBeans APIs</h2>
        <p>In this section, we take the files generated in the previous section
            and integrate them with the <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/overview-summary.html">NetBeans Parsing API</a>.</p>
        <div class="indent">
            <ol>
                <li><p>In the Projects window, right-click the Libraries node, and choose
                        Add Module Dependency. Look for the "Parsing API" module in the list.
                        When you click OK, you should see the "Parsing API" module is now
                        a dependency in your module:</p>
                    <br/>
                    <p><img src="../images/tutorials/javacc/72/parser-4.png" alt="source."/></p>
                    <br/>
                </li>
                <li><p>In your module, create a new package named <tt>org.simplejava.parser</tt>.</p>
                </li>
                <li><p>The first NetBeans APIclass you need to implement is <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/Parser.html">org.netbeans.modules.parsing.spi.Parser</a></tt>. 
                        Create a class named <tt>SJParser</tt> and define it as follows:</p>
                    <pre class="examplecode">package org.simplejava.parser;

import java.io.Reader;
import java.io.StringReader;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.event.ChangeListener;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/api/Snapshot.html">org.netbeans.modules.parsing.api.Snapshot</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/api/Task.html">org.netbeans.modules.parsing.api.Task</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/Parser.html">org.netbeans.modules.parsing.spi.Parser</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/ParserResultTask.html">org.netbeans.modules.parsing.spi.Parser.Result</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/SourceModificationEvent.html">org.netbeans.modules.parsing.spi.SourceModificationEvent</a>;
import org.simplejava.jccparser.JavaParser;

public class SJParser extends <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/Parser.html">Parser</a> {

    private Snapshot snapshot;
    private JavaParser javaParser;

    @Override
    public void parse (Snapshot snapshot, Task task, SourceModificationEvent event) {
        this.snapshot = snapshot;
        Reader reader = new StringReader(snapshot.getText().toString ());
        javaParser = new JavaParser(reader);
        try {
            javaParser.CompilationUnit ();
        } catch (org.simplejava.jccparser.ParseException ex) {
            Logger.getLogger (SJParser.class.getName()).log (Level.WARNING, null, ex);
        }
    }

    @Override
    public Result getResult (Task task) {
        return new SJParserResult (snapshot, javaParser);
    }

    @Override
    public void cancel () {
    }

    @Override
    public void addChangeListener (ChangeListener changeListener) {
    }

    @Override
    public void removeChangeListener (ChangeListener changeListener) {
    }

    
    public static class SJParserResult extends Result {

        private JavaParser javaParser;
        private boolean valid = true;

        SJParserResult (Snapshot snapshot, JavaParser javaParser) {
            super (snapshot);
            this.javaParser = javaParser;
        }

        public JavaParser getJavaParser () throws org.netbeans.modules.parsing.spi.ParseException {
            if (!valid) throw new org.netbeans.modules.parsing.spi.ParseException ();
            return javaParser;
        }

        @Override
        protected void invalidate () {
            valid = false;
        }

    }
    
}</pre></li>                    

                <li><p>Register the parser in the language class created
                        in the previous tutorial, as follows:</p>

                    <pre class="java">package org.simplejava;

import org.netbeans.api.lexer.Language;
import org.netbeans.modules.csl.spi.DefaultLanguageConfig;
import org.netbeans.modules.csl.spi.LanguageRegistration;
import org.netbeans.modules.parsing.spi.Parser;
import org.simplejava.lexer.SJTokenId;
import org.simplejava.parser.SJParser;

@LanguageRegistration(mimeType = "text/x-sj")
public class SJLanguage extends DefaultLanguageConfig {

    @Override
    public Language getLexerLanguage() {
        return SJTokenId.getLanguage();
    }

    @Override
    public String getDisplayName() {
        return "SJ";
    }

    <b>@Override
    public Parser getParser() {
        return new SJParser();
    }</b>
    
}</pre>
                </li>

            </ol>          

        </div>

        <p>You now have an implementation of the NetBeans Parsing API based
            on a JavaCC parser generated from a JavaCC grammar definition. 
            Your parser generated by JavaCC is registered 
            in the NetBeans Platform. You can compile and run the module.
            However, your parser will never be called simply because
            you don't have code asking for the parser results. Since
            there is no client of your parser yet, let's create one in
            the next section.</p> 
        <!-- ======================================================================================= -->

        <h2><a name="error-feature"></a>Implementing a New Feature: Error Parsing</h2>
        <p>Now you will create a first client of your <tt>SJParser</tt>. 
            This client (task) will show syntax errors in the
            NetBeans editor sidebar, also known as its "gutter".</p> 
        <p>Before working on the related code, we need to
            make some modifications to the generated
            parser. The parser throws a <tt>ParseException</tt> when it finds 
            the first error in the source code. This is the default behavior of parsers 
            generated by JavaCC. But in the NetBeans editor we need to detect more than 
            just one syntax error. Therefore, we need to add some simple error recovery
            to the parser before integrating the NetBeans error parsing code with it.</p>
        <div class="indent">
            <h3><a name="error-feature-1"></a>Adding Simple Error Recovery to the Parser</h3>
            <div class="indent">

                <ol>
                    <li><p>The tweaks below should both be done in <tt>Java1.5.jj</tt> file in your
                            <tt>org.simplejava.jccparser</tt> package.</p>
                        <ul>
                            <li><p>Change "ERROR_REPORTING = false;" to "ERROR_REPORTING = true;":</p>
                                <pre class="examplecode">options {
  JAVA_UNICODE_ESCAPE = true;
  <b>ERROR_REPORTING = true;</b>
  STATIC = false;
  COMMON_TOKEN_ACTION = false;
  TOKEN_FACTORY = "MyToken";
  JDK_VERSION = "1.5";
}</pre>

                            </li>
                            <li><p>Add "import java.util.*;" to your Java1.5.jj file:</p>

                                <pre class="examplecode">PARSER_BEGIN(JavaParser)

package org.simplejava.jccparser;

import java.io.*;
<b>import java.util.*;</b></pre>                        

                            </li></ul></li>

                    <li><p>Run JavaCC on the <tt>Java1.5.jj</tt> file again, the same way as 
                            you did in the previous section.</p>
                    </li>

                    <li><p>These additions and changes
                            should be done in your <tt>JavaParser</tt> class.</p>
                        <br/>
                        <ul>
                            <li><p>Add the following method to your <tt>JavaParser</tt> body:</p>
                                <pre class="examplecode">public List&lt;ParseException&gt; syntaxErrors = new ArrayList&lt;ParseException&gt;();

void recover (ParseException ex, int recoveryPoint) {
    syntaxErrors.add (ex);
    Token t;
    do {
        t = getNextToken ();
    } while (t.kind != EOF && t.kind != recoveryPoint);
}</pre>
                            </li>


                            <li>Catch <tt>ParseExceptions</tt> in <tt>CompilationUnit</tt>, 
                                <tt>FieldDeclaration</tt>, <tt>MethodDeclaration</tt>, 
                                and <tt>Statement</tt>:

                                <pre class="examplecode">final public void CompilationUnit() throws ParseException {
    <b>try {</b>
        if (jj_2_1(2147483647)) {
            PackageDeclaration();
        } else {
            ;
        }
        label_1:
        while (true) {
            switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
                case IMPORT:
                    ;
                    break;
                default:
                    break label_1;
            }
            ImportDeclaration();
        }
        label_2:
        while (true) {
            switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
                case ABSTRACT:
                case CLASS:
                case ENUM:
                case FINAL:
                case INTERFACE:
                case NATIVE:
                case PRIVATE:
                case PROTECTED:
                case PUBLIC:
                case STATIC:
                case STRICTFP:
                case SYNCHRONIZED:
                case TRANSIENT:
                case VOLATILE:
                case SEMICOLON:
                case AT:
                    ;
                    break;
                default:
                    break label_2;
            }
            TypeDeclaration();
        }
        switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
            case 127:
                jj_consume_token(127);
                break;
            default:
                ;
        }
        switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
            case STUFF_TO_IGNORE:
                jj_consume_token(STUFF_TO_IGNORE);
                break;
            default:
                ;
        }
        jj_consume_token(0);
    <b>} catch (ParseException ex) {
        recover(ex, SEMICOLON);
    }</b>
}</pre>

                                <pre class="examplecode">final public void FieldDeclaration(int modifiers) throws ParseException {
    <b>try {</b>
        Type();
        VariableDeclarator();
        label_11:
        while (true) {
            switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
                case COMMA:
                    ;
                    break;
                default:
                    break label_11;
            }
            jj_consume_token(COMMA);
            VariableDeclarator();
        }
        jj_consume_token(SEMICOLON);
    <b>} catch (ParseException ex) {
        recover(ex, SEMICOLON);
    }</b>
}</pre>

                                <pre class="examplecode">final public void MethodDeclaration(int modifiers) throws ParseException {
    <b>try {</b>
        switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
            case LT:
                TypeParameters();
                break;
            default:
                ;
        }
        ResultType();
        MethodDeclarator();
        switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
            case THROWS:
                jj_consume_token(THROWS);
                NameList();
                break;
            default:
                ;
        }
        switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
            case LBRACE:
                Block();
                break;
            case SEMICOLON:
                jj_consume_token(SEMICOLON);
                break;
            default:
                jj_consume_token(-1);
                throw new ParseException();
        }
    <b>} catch (ParseException ex) {
        recover(ex, SEMICOLON);
    }</b>
}</pre>

                                <pre class="examplecode">final public void Statement() throws ParseException {
    <b>try {</b>
        if (jj_2_36(2)) {
            LabeledStatement();
        } else {
            switch ((jj_ntk == -1) ? jj_ntk() : jj_ntk) {
                case ASSERT:
                    AssertStatement();
                    break;
                case LBRACE:
                    Block();
                    break;
                case SEMICOLON:
                    EmptyStatement();
                    break;
                case BOOLEAN:
                case BYTE:
                case CHAR:
                case DOUBLE:
                case FALSE:
                case FLOAT:
                case INT:
                case LONG:
                case NEW:
                case NULL:
                case SHORT:
                case SUPER:
                case THIS:
                case TRUE:
                case VOID:
                case INTEGER_LITERAL:
                case FLOATING_POINT_LITERAL:
                case CHARACTER_LITERAL:
                case STRING_LITERAL:
                case IDENTIFIER:
                case LPAREN:
                case INCR:
                case DECR:
                    StatementExpression();
                    jj_consume_token(SEMICOLON);
                    break;
                case SWITCH:
                    SwitchStatement();
                    break;
                case IF:
                    IfStatement();
                    break;
                case WHILE:
                    WhileStatement();
                    break;
                case DO:
                    DoStatement();
                    break;
                case FOR:
                    ForStatement();
                    break;
                case BREAK:
                    BreakStatement();
                    break;
                case CONTINUE:
                    ContinueStatement();
                    break;
                case RETURN:
                    ReturnStatement();
                    break;
                case THROW:
                    ThrowStatement();
                    break;
                case SYNCHRONIZED:
                    SynchronizedStatement();
                    break;
                case TRY:
                    TryStatement();
                    break;
                default:
                    jj_consume_token(-1);
                    throw new ParseException();
            }
        }
    <b>} catch (ParseException ex) {
        recover(ex, SEMICOLON);
    }</b>
}</pre></li></ul></li>

                </ol>
            </div>
            <p>We have added some very basic error recovery to our
                parser so that we can display some
                syntax errors in the NetBeans editor in the next section.</p>
            <h3><a name="error-feature-2"></a>Integrating Syntax Error Reporting</h3>
            <p>At this point, we're ready to implement our first <tt>ParserResultTask</tt>. 
                This task consists of three standard steps:</p>
            <div class="indent">

                <ol><li>Create a factory, i.e., <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/TaskFactory.html">TaskFactory</a></tt>.</li>
                    <li>Create a task, i.e., <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/ParserResultTask.html">ParserResultTask</a></tt>.</li> 
                    <li>Register the factory in the layer file.</li>
                </ol>
            </div>
            <p>The above steps are standard in the sense that they are
                common to all tasks implementing the NetBeans Parsing API.</p>
            <div class="indent">

                <ol>
                    <li><p>Add dependencies on the NetBeans "Editor Hints" module and the
                            "MIME Lookup API" module.</p></li>
                    <li><p>Create the <tt>SJSyntaxErrorHighlightingTask</tt> class:</p>

                        <pre class="examplecode">package org.simplejava.parser;

import java.util.ArrayList;
import java.util.List;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.StyledDocument;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/Parser.Result.html">org.netbeans.modules.parsing.spi.Parser.Result</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/ParserResultTask.html">org.netbeans.modules.parsing.spi.ParserResultTask</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/Scheduler.html">org.netbeans.modules.parsing.spi.Scheduler</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/SchedulerEvent.html">org.netbeans.modules.parsing.spi.SchedulerEvent</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-spi-editor-hints/org/netbeans/spi/editor/hints/ErrorDescription.html">org.netbeans.spi.editor.hints.ErrorDescription</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-spi-editor-hints/org/netbeans/spi/editor/hints/ErrorDescriptionFactory.html">org.netbeans.spi.editor.hints.ErrorDescriptionFactory</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-spi-editor-hints/org/netbeans/spi/editor/hints/HintsController.html">org.netbeans.spi.editor.hints.HintsController</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-spi-editor-hints/org/netbeans/spi/editor/hints/Severity.html">org.netbeans.spi.editor.hints.Severity</a>;
import org.openide.text.NbDocument;
import org.openide.util.Exceptions;
import org.simplejava.jccparser.ParseException;
import org.simplejava.jccparser.Token;
import org.simplejava.parser.SJParser.SJParserResult;

public class SJSyntaxErrorHighlightingTask extends <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/ParserResultTask.html">ParserResultTask</a> {

    @Override
    public void run (Result result, SchedulerEvent event) {
        try {
            SJParserResult sjResult = (SJParserResult) result;
            List&lt;ParseException&gt; syntaxErrors = sjResult.getJavaParser ().syntaxErrors;
            Document document = result.getSnapshot ().getSource ().getDocument (false);
            List&lt;ErrorDescription&gt; errors = new ArrayList&lt;ErrorDescription&gt; ();
            for (ParseException syntaxError : syntaxErrors) {
                Token token = syntaxError.currentToken;
                int start = NbDocument.findLineOffset ((StyledDocument) document, token.beginLine - 1) + token.beginColumn - 1;
                int end = NbDocument.findLineOffset ((StyledDocument) document, token.endLine - 1) + token.endColumn;
                ErrorDescription errorDescription = ErrorDescriptionFactory.createErrorDescription(
                    Severity.ERROR,
                    syntaxError.getMessage (),
                    document,
                    document.createPosition(start),
                    document.createPosition(end)
                );
                errors.add (errorDescription);
            }
            HintsController.setErrors (document, "simple-java", errors);
        } catch (BadLocationException ex1) {
            Exceptions.printStackTrace (ex1);
        } catch (org.netbeans.modules.parsing.spi.ParseException ex1) {
            Exceptions.printStackTrace (ex1);
        }
    }

    @Override
    public int getPriority () {
        return 100;
    }

    @Override
    public Class getSchedulerClass () {
        return Scheduler.EDITOR_SENSITIVE_TASK_SCHEDULER;
    }

    @Override
    public void cancel () {
    }

}</pre></li>

                    <li><p>Create the <tt>SJSyntaxErrorHighlightingTaskFactory</tt> class
                            in the <tt>org.simplejava.parser</tt> package:</p>

                        <pre class="examplecode">package org.simplejava.parser;

import java.util.Collection;
import java.util.Collections;
import org.netbeans.api.editor.mimelookup.MimeRegistration;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/api/Snapshot.html">org.netbeans.modules.parsing.api.Snapshot</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/TaskFactory.html">org.netbeans.modules.parsing.spi.TaskFactory</a>;

@MimeRegistration(mimeType="text/x-sj",service=TaskFactory.class)
public class SJSyntaxErrorHighlightingTaskFactory extends <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-parsing-api/org/netbeans/modules/parsing/spi/TaskFactory.html">TaskFactory</a> {

    @Override
    public Collection create (Snapshot snapshot) {
        return Collections.singleton (new SJSyntaxErrorHighlightingTask());
    }

}</pre></li>

                </ol>   
            </div>
            <p>When you install the module into your application and make a syntax error in a SJ file,
                you should see the error highlighting in the sidebar of the
                NetBeans editor:</p>

            <br/>
            <p><img src="../images/tutorials/javacc/72/result-3.png" alt="source."/></p>
            <br/>

        </div>

        <!-- ======================================================================================= -->

        <h2><a name="indent-feature"></a>Implementing a New Feature: Indentation</h2>
        <p>Next, we'll create the skeleton of
            an indentation task for our language.</p>
        <div class="indent">

            <ol>
                <li>Add a dependency on the "<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/overview-summary.html">Editor Indentation</a>" module.</li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.html">IndentTask</a></tt>:</p>
                    <pre class="examplecode">package org.simplejava.parser;

import javax.swing.text.BadLocationException;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/Context.html">org.netbeans.modules.editor.indent.spi.Context</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ExtraLock.html">org.netbeans.modules.editor.indent.spi.ExtraLock</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.html">org.netbeans.modules.editor.indent.spi.IndentTask</a>;
import org.openide.awt.StatusDisplayer;

public class SJIndentTask implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.html">IndentTask</a> {

    private Context context;

    SJIndentTask(Context context) {
        this.context = context;
    }

    @Override
    public void reindent() throws BadLocationException {
        StatusDisplayer.getDefault().setStatusText("We will indent this now...");
    }

    @Override
    public ExtraLock indentLock() {
        return null;
    }
    
}</pre>

                    <p class="notes"><b>Note:</b> The indent task will 
                        make a callback to the <tt>reindent()</tt> method
                        when the Enter key is pressed in the NetBeans editor. 
                        The <tt>Context</tt> object contains everything that
                        you need, including the editor document object. 
                        To complete the above implementation,
                        it should be a matter of taking the text after the cursor
                        and before the next line to indent the code as desired.</p>

                </li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.Factory.html">IndentTask.Factory</a></tt>:</p>  
                    <pre class="java">package org.simplejava.parser;

import org.netbeans.api.editor.mimelookup.MimeRegistration;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/Context.html">org.netbeans.modules.editor.indent.spi.Context</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.html">org.netbeans.modules.editor.indent.spi.IndentTask</a>;

@MimeRegistration(mimeType="text/x-sj",service=IndentTask.Factory.class)
public class SJIndentTaskFactory implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/IndentTask.Factory.html">IndentTask.Factory</a> {

    @Override
    public IndentTask createTask(Context context) {
        return new SJIndentTask(context);
    }

}</pre>

                </li>
            </ol>

        </div>

        <p>When you install the module into the application, open an SJ file,
            and press Enter, you will see a message
            in the status bar, showing you that the indentation integration is working
            correctly.</p>

        <!-- ======================================================================================= -->

        <h2><a name="format-feature"></a>Implementing a New Feature: Reformatting</h2>
        <p>Next, we'll create the skeleton of
            a reformat task for our language.</p>
        <div class="indent">

            <ol>
                <li>If you have not already done so in the previous section,
                    add a dependency on the "<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/overview-summary.html">Editor Indentation</a>" module.</li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.html">ReformatTask</a></tt>:</p>
                    <pre class="examplecode">package org.simplejava.parser;

import javax.swing.text.BadLocationException;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/Context.html">org.netbeans.modules.editor.indent.spi.Context</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ExtraLock.html">org.netbeans.modules.editor.indent.spi.ExtraLock</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.html">org.netbeans.modules.editor.indent.spi.ReformatTask</a>;
import org.openide.awt.StatusDisplayer;

public class SJReformatTask implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.html">ReformatTask</a> {

    private Context context;

    public SJReformatTask(Context context) {
        this.context = context;
    }

    @Override
    public void reformat() throws BadLocationException {
        StatusDisplayer.getDefault().setStatusText("We will format this now...");
    }

    @Override
    public ExtraLock reformatLock() {
        return null;
    }
    
}</pre>

                    <p class="notes"><b>Note:</b> The reformat task will 
                        make a callback to the <tt>reformat()</tt> method
                        when Alt-Shift-F is pressed in the NetBeans editor. 
                        The <tt>Context</tt> object contains everything that
                        you need, including the editor document object. 
                        To complete the above reformatting,
                        it should be a matter of taking the text after the cursor
                        and before the next line to reformat the code as desired.</p>

                </li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.Factory.html">ReformatTask.Factory</a></tt>:</p>  
                    <pre class="java">package org.simplejava.parser;

import org.netbeans.api.editor.mimelookup.MimeRegistration;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/Context.html">org.netbeans.modules.editor.indent.spi.Context</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.Factory.html">org.netbeans.modules.editor.indent.spi.ReformatTask</a>;

@MimeRegistration(mimeType="text/x-sj",service=ReformatTask.Factory.class)
public class SJReformatTaskFactory implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-indent/org/netbeans/modules/editor/indent/spi/ReformatTask.Factory.html">ReformatTask.Factory</a> {

    @Override
    public ReformatTask createTask(Context context) {
        return new SJReformatTask(context);
    }
    
}</pre>

                </li>
        </div>

        </ol>

        <p>When you install the module into the application, open an SJ file,
            and choose Source | Format (Alt-Shift-F), you will see a message
            in the status bar, showing you that the extension point is working
            correctly.</p>

        <!-- ======================================================================================= -->

        <h2><a name="brace-feature"></a>Implementing a New Feature: Brace Matching</h2>
        <p>Now, let's look at brace matching. When the user selects an opening brace,
            the closing brace should be highlighted, and vice versa. Moreover, when Ctrl-[ is pressed
            on the keyboard, the cursor should move back and forth between matching braces.</p>
        <p class="tips">This feature is especially useful
            if your language is likely to be used to create deeply nested code structures.
        </p>
        <p>In the first screenshot, the opening brace is selected, which results
            in it being highlighted, together with the closing brace, so that you
            can see where a code phrase or code block begins and ends and you can
            toggle between them by pressing Ctrl-[:</p>

        <p><img style="border:1px solid black" src="../images/tutorials/javacc/72/add-brace-1.png" alt="source."/></p>
        <p>Similarly, here another code block is made visible by selecting
            either the opening or closing brace, causing the matching
            brace to also be highlighted, and enabling the cursor to be
            toggled between the matching braces via Ctrl-[:</p>
        <p><img style="border:1px solid black" src="../images/tutorials/javacc/72/add-brace-2.png" alt="source."/></p>


        <div class="indent">

            <ol>
                <li>Add a dependency on the "<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/overview-summary.html">Editor Brace Matching</a>" module.</li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/BracesMatcherFactory.html">BracesMatcherFactory</a></tt>:</p>  
                    <pre class="java">package org.simplejava.parser;

import org.netbeans.api.editor.mimelookup.MimeRegistration;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/BracesMatcher.html">org.netbeans.spi.editor.bracesmatching.BracesMatcher</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/BracesMatcherFactory.html">org.netbeans.spi.editor.bracesmatching.BracesMatcherFactory</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/MatcherContext.html">org.netbeans.spi.editor.bracesmatching.MatcherContext</a>;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/support/BracesMatcherSupport.html">org.netbeans.spi.editor.bracesmatching.support.BracesMatcherSupport</a>;

@MimeRegistration(mimeType="text/x-sj",service=BracesMatcherFactory.class)
public class SJBracesMatcherFactory implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/BracesMatcherFactory.html">BracesMatcherFactory</a> {

    @Override
    public BracesMatcher createMatcher(MatcherContext context) {
        return BracesMatcherSupport.defaultMatcher(context, -1, -1);
    }
    
}</pre>

                    <p class="tips">The <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/support/BracesMatcherSupport.html">BracesMatcherSupport</a></tt> package provides
                        a number of useful implementations of <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-bracesmatching/org/netbeans/spi/editor/bracesmatching/BracesMatcher.html">BracesMatcher</a></tt>. One of these is used
                        in the code above.</p>

                </li>
        </div>

        </ol>

        <p>When you install the module into the application, open an SJ file,
            and select a brace, you should see that the brace is highlighted,
            together with its matching brace. Press Ctrl-[ to toggle between
            matching braces.</p>

        <!-- ======================================================================================= -->

        <h2><a name="fold-feature"></a>Implementing a New Feature: Code Folding</h2>
        <p>The "<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/overview-summary.html">Editor Code Folding</a>" module
            provides the functionality you need to implement for creating your own code folds.</p>
        <p>In this tutorial, we will create a code fold for the "FORMAL_COMMENT" token provided
            by our lexer:</p>
        <p><img style="border:1px solid black" src="../images/tutorials/javacc/72/add-fold-1.png" alt="source."/></p>
        <p>When collapsed, the fold will look like this:</p>
        <p><img style="border:1px solid black" src="../images/tutorials/javacc/72/add-fold-2.png" alt="source."/></p>

        <div class="indent">

            <ol>
                <li>Add a dependency on the "<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/overview-summary.html">Editor Code Folding</a>" module.</li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManager.html">FoldManager</a></tt>:</p>
                    <pre class="examplecode">package org.simplejava.parser;

import javax.swing.event.DocumentEvent;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import org.netbeans.api.editor.fold.Fold;
import org.netbeans.api.editor.fold.FoldHierarchy;
import org.netbeans.api.editor.fold.FoldType;
import org.netbeans.api.lexer.Token;
import org.netbeans.api.lexer.TokenHierarchy;
import org.netbeans.api.lexer.TokenSequence;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldHierarchyTransaction.html">org.netbeans.spi.editor.fold.FoldHierarchyTransaction</a>;
import org.netbeans.spi.editor.fold.FoldManager;
import <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldOperation.html">org.netbeans.spi.editor.fold.FoldOperation</a>;
import org.openide.util.Exceptions;
import org.simplejava.lexer.SJTokenId;

public class SJFoldManager implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManager.html">FoldManager</a> {

    private FoldOperation operation;
    public static final FoldType COMMENT_FOLD_TYPE = new FoldType("/*...*/");

    @Override
    public void init(FoldOperation operation) {
        this.operation = operation;
    }

    @Override
    public void initFolds(FoldHierarchyTransaction transaction) {
        FoldHierarchy hierarchy = operation.getHierarchy();
        Document document = hierarchy.getComponent().getDocument();
        TokenHierarchy&lt;Document&gt; hi = TokenHierarchy.get(document);
        TokenSequence&lt;SJTokenId&gt; ts = (TokenSequence&lt;SJTokenId&gt;) hi.tokenSequence();
        FoldType type = null;
        int start = 0;
        int offset = 0;
        while (ts.moveNext()) {
            offset = ts.offset();
            Token&lt;SJTokenId&gt; token = ts.token();
            SJTokenId id = token.id();
            if (id.name().equals("FORMAL_COMMENT") && type == null) {
                type = COMMENT_FOLD_TYPE;
                start = offset;
                try {
                    operation.addToHierarchy(
                        type, 
                        type.toString(), 
                        false, 
                        start, 
                        offset + token.length(), 
                        0, 
                        0, 
                        hierarchy, 
                        transaction);
                } catch (BadLocationException ex) {
                    Exceptions.printStackTrace(ex);
                }
            }
        }
    }

    @Override
    public void insertUpdate(DocumentEvent de, FoldHierarchyTransaction fht) {
    }

    @Override
    public void removeUpdate(DocumentEvent de, FoldHierarchyTransaction fht) {
    }

    @Override
    public void changedUpdate(DocumentEvent de, FoldHierarchyTransaction fht) {
    }

    @Override
    public void removeEmptyNotify(Fold fold) {
    }

    @Override
    public void removeDamagedNotify(Fold fold) {
    }

    @Override
    public void expandNotify(Fold fold) {
    }

    @Override
    public void release() {
    }
    
}</pre>

                </li>
                <li><p>Create a new <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManagerFactory.html">FoldManagerFactory</a></tt>:</p>  
                    <pre class="java">package org.simplejava.parser;

import org.netbeans.api.editor.mimelookup.MimeRegistration;
<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManager.html">import org.netbeans.spi.editor.fold.FoldManager</a>;
<a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManagerFactory.html">import org.netbeans.spi.editor.fold.FoldManagerFactory</a>;

@MimeRegistration(mimeType="text/x-sj",service=FoldManagerFactory.class)
public class SJFoldManagerFactory implements <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-fold/org/netbeans/spi/editor/fold/FoldManagerFactory.html">FoldManagerFactory</a> {

    @Override
    public FoldManager createFoldManager() {
        return new SJFoldManager();
    }
    
}</pre>

                </li>

            </ol>

        </div>

        <p>When you install the module into the application, open an SJ file,
            and type a multiline comment at the top of the file, as shown
            at the start of this section,  a code fold will automatically
            appear around the comment.</p>


        <!-- ======================================================================================= -->

        <p></p>
        <div class="feedback-box"><a href="https://netbeans.org/about/contact_form.html?to=3&amp;subject=Feedback:%20JavaCC%20Parser%207.2%20Tutorial">Send Us Your Feedback</a></div>

        <!-- ======================================================================================== -->

        <h2><a name="nextsteps"></a>Next Steps</h2>
        <p class="tips">This tutorial is the official version of
            the second part of <a href="http://wiki.netbeans.org/How_to_create_support_for_a_new_language">http://wiki.netbeans.org/How_to_create_support_for_a_new_language</a>,
            which, aside from being a rough draft, is partly out of date for the NetBeans Platform.</p>
        <p>For more information about creating and developing NetBeans modules, see the following resources: </p>
        <ul>
            <li><a href="https://platform.netbeans.org/index.html">NetBeans Platform Homepage</a></li>
            <li><a href="https://netbeans.org/download/dev/javadoc/">NetBeans API List (Current Development Version)</a></li>
            <li><a href="https://netbeans.org/kb/trails/platform.html">Other Related Tutorials</a></li>
        </ul>

        <!-- ======================================================================================== -->

        <!--<h2><a name="version"></a>Versioning </h2>

        <table width="76%" >
            <tbody>
                <tr>
                    <td>
                        <b>Version</b>
                    </td>
                    <td>
                        <b>Date</b>
                    </td>
                    <td>
                        <b>Changes</b>
                    </td>
                </tr>
                <tr>
                    <td>
                        1
                    </td>
                    <td>
                        9 January 2012
                    </td>
                    <td>
                        <ul><li>Initial version.</li>
                            <li>To do:
                                <ul>
                                    <li></li>
                                    <li></li>
                                    <li></li>
                                    <li></li>
                                    <li></li>
                                </ul>
                            </li>
                        </ul>
                    </td>
                </tr>
            </tbody>
        </table>-->

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