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        <title>NetBeans Hyperlink Navigation Tutorial</title>
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        <h1>NetBeans Hyperlink Navigation Tutorial</h1>

        <p>In this tutorial, you learn how to programmatically define hyperlinks in HTML files. You will
            do this by implementing the NetBeans API <a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html">HyperlinkProvider</a> class.
            The hyperlink will be visible when the user holds down the Ctrl key and then uses
            the mouse to move over a predefined identifier in an HTML document, as shown here:</p>

        <p><img alt="" src="../images/tutorials/hyperlink/hyperlink-69-1.png"/></p>

        <p>When the hyperlink is clicked, something happens relevant to the identifier,
            for example, a related file can open or a message can be displayed.</p>

        <p>Though the focus of this tutorial is on hyperlinking in an HTML file,
            the principles shown here could equally be applied to other types of files,
            such as to Java source files, XML files, JSP files, Properties files, or Manifest files.</p>

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        <p><b class="notes">Note:</b> This document is applicable to NetBeans IDE 7.2 and
            NetBeans Platform 7.2. If you
            are using an earlier version, see <a href="71/nbm-hyperlink.html">the previous version
                of this document</a>.</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="#getting">Getting Started</a></li>
            <li><a href="#implementing">Implementing the HyperlinkProvider Class</a></li>
            <li><a href="#registering">Registering the HyperlinkProvider Implementation Class</a></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></p>
        <h2><a name="getting"></a>Getting Started</h2>

        <p>In this section, we use a wizard to create a module project.
            We declare dependencies on modules that provide the NetBeans API classes
            needed by our hyperlink module.</p>

        <div class="indent">

            <ol>

                <li>Choose File &gt; New Project. In the New Project wizard,
                    choose NetBeans Modules under Categories and Module
                    under Projects. Click Next. </li>
                <li>Type <tt>MySpecialHyperlink</tt> in Project Name
                    and set Project Location to an appropriate folder on your disk. Click Next.</li>

                <li>Type <tt>org.netbeans.modules.myspecialhyperlink</tt> in Code Name Base.
                    Click Finish.</li>

                <li><p>In the Projects window, expand the project,
                        right-click the Libraries node, and click
                        Add Module Dependency.
                        Add dependencies on the following APIs:</p>
                    <br/>
                    <ul>
                        <li>Dialogs API</li>
                        <li>Editor Library</li>
                        <li>Editor Library 2</li>
                        <li>HTML Lexer</li>
                        <li>Lexer</li>
                        <li>MIME Lookup API</li>
                    </ul>
                    <p>You should now see the following:</p>
                    <br/>
                    <p><img alt="" src="../images/tutorials/hyperlink/72/add-libs.png"/></p>

                </li>

            </ol>

        </div>

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        <h2><a name="implementing"></a>Implementing the HyperlinkProvider Class</h2>

        <p>The <a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html">HyperlinkProvider</a> class
            implements three methods, each of which is discussed in detail below, accompanied by a
            practical example in the context of our module.</p>

        <p class="tips"> An alternative approach, which lets you define a tooltip
            on your hyperlink, is provided by the <a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProviderExt.html">HyperlinkProviderExt</a> class,
             which is discussed <a href="https://blogs.oracle.com/geertjan/entry/hyperlink_for_freemarker">here</a> and <a href="https://blogs.oracle.com/geertjan/entry/jump_to_declaration_for_freemarker">here</a>.
        </p>

        <p>Below, we first we set up the class and then
            we implement each of the three methods in turn.</p>

        <div class="indent">

            <h3 class="tutorial"><a name="method1"></a>Setting Up the HyperlinkProvider Class</h3>

            <p>Setting up our class means implementing <a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html">HyperlinkProvider</a>
                and initializing the values we will need in our implementation.</p>

            <div class="indent">

                <ol>

                    <li>Create a Java class in <tt>org.netbeans.modules.myspecialhyperlink</tt>,
                        and name it <tt>MySpecialHyperlinkProvider</tt>.</li>

                    <li>Change the class signature so that <tt><a href="http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html">org.netbeans.lib.editor.hyperlink.spi.HyperlinkProvider</a></tt> is implemented.</li>

                    <li>Note that the following import statements will be needed in this tutorial:

                        <pre class="examplecode">import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.text.Document;
import org.netbeans.api.editor.mimelookup.MimeRegistration;
import org.netbeans.api.html.lexer.HTMLTokenId;
import org.netbeans.api.lexer.Token;
import org.netbeans.api.lexer.TokenHierarchy;
import org.netbeans.api.lexer.TokenSequence;
import org.netbeans.lib.editor.hyperlink.spi.HyperlinkProvider;
import org.openide.DialogDisplayer;
import org.openide.NotifyDescriptor;</pre>
                    </li>
                    <li>Add the following initial values at the top of the class:

                        <pre class="examplecode">public static final Pattern MY_SPECIAL_PATTERN =
    Pattern.compile(".*\\[myspecial:(.*?):myspecial\\].*");

private String target;
private int targetStart;
private int targetEnd;</pre></li>

                </ol>

            </div>

        </div>

        <div class="indent">

            <h3 class="tutorial"><a name="method1"></a>isHyperlinkPoint(Document doc, int offset)</h3>

            <p><tt><a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html#isHyperlinkPoint(javax.swing.text.Document,%20int)">isHyperlinkPoint(Document doc, int offset)</a></tt>
                determines whether there should be a hyperlink at the given offset within the given document.</p>

            <pre class="examplecode">@Override
public boolean isHyperlinkPoint(Document doc, int offset) {
    return verifyState(doc, offset);
}

public boolean verifyState(Document doc, int offset) {
    TokenHierarchy hi = TokenHierarchy.get(doc);
    TokenSequence&lt;HTMLTokenId&gt; ts = hi.tokenSequence(HTMLTokenId.language());
    if (ts != null) {
        ts.move(offset);
        ts.moveNext();
        Token&lt;HTMLTokenId&gt; tok = ts.token();
        int newOffset = ts.offset();
        String matcherText = tok.text().toString();
        Matcher m = MY_SPECIAL_PATTERN.matcher(matcherText);
        if (m.matches()) {
            target = m.group(1);
            int idx = matcherText.indexOf(target);
            targetStart = newOffset + idx;
            targetEnd = targetStart + target.length();
            return true;
        }
    }
    return false;
}</pre>

        </div>

        <div class="indent">

            <h3 class="tutorial"><a name="method2"></a>getHyperlinkSpan(Document doc, int offset)</h3>

            <p><tt><a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html#getHyperlinkSpan(javax.swing.text.Document,%20int)">getHyperlinkSpan(Document doc, int offset)</a></tt> determines the length of the hyperlink.</p>

            <pre class="examplecode">@Override
public int[] getHyperlinkSpan(Document document, int offset) {
    if (verifyState(document, offset)) {
        return new int[]{targetStart, targetEnd};
    } else {
        return null;
    }
}</pre>

        </div>


        <div class="indent">
            <h3 class="tutorial"><a name="method3"></a>performClickAction(Document doc, int offset)</h3>


            <p><tt><a href="https://netbeans.org/download/dev/javadoc/org-netbeans-modules-editor-lib/org/netbeans/lib/editor/hyperlink/spi/HyperlinkProvider.html#performClickAction(javax.swing.text.Document,%20int)">performClickAction(Document doc, int offset)</a></tt>
                determines what happens when the hyperlink is clicked. In general, a document
                should open, the cursor should move to a certain place in a document, or both.
                Here a simple message is displayed with the identified special content:</p>

            <pre class="examplecode">@Override
public void performClickAction(Document document, int offset) {
    if (verifyState(document, offset)) {
        NotifyDescriptor.Message msg = new NotifyDescriptor.Message(target);
        DialogDisplayer.getDefault().notify(msg);
    }
}</pre>


        </div>


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        <h2><a name="registering"></a>Registering the HyperlinkProvider Implementation Class</h2>

        <p>Finally, you need to register the hyperlink provider implementation class. 
            Do this via the class-level annotation shown in the highlighted line
            in the completed Java source
            below:</p>

        <pre class="examplecode">package org.netbeans.modules.myspecialhyperlink;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.text.Document;
import org.netbeans.api.editor.mimelookup.MimeRegistration;
import org.netbeans.api.html.lexer.HTMLTokenId;
import org.netbeans.api.lexer.Token;
import org.netbeans.api.lexer.TokenHierarchy;
import org.netbeans.api.lexer.TokenSequence;
import org.netbeans.lib.editor.hyperlink.spi.HyperlinkProvider;
import org.openide.DialogDisplayer;
import org.openide.NotifyDescriptor;

<b>@MimeRegistration(mimeType = "text/html", service = HyperlinkProvider.class)</b>
public class MySpecialHyperlinkProvider implements HyperlinkProvider {

    public static final Pattern MY_SPECIAL_PATTERN =
            Pattern.compile(".*\\[myspecial:(.*?):myspecial\\].*");
    private String target;
    private int targetStart;
    private int targetEnd;

    @Override
    public boolean isHyperlinkPoint(Document doc, int offset) {
        return verifyState(doc, offset);
    }

    public boolean verifyState(Document doc, int offset) {
        TokenHierarchy hi = TokenHierarchy.get(doc);
        TokenSequence&lt;HTMLTokenId&gt; ts = hi.tokenSequence(HTMLTokenId.language());
        if (ts != null) {
            ts.move(offset);
            ts.moveNext();
            Token&lt;HTMLTokenId&gt; tok = ts.token();
            int newOffset = ts.offset();
            String matcherText = tok.text().toString();
            Matcher m = MY_SPECIAL_PATTERN.matcher(matcherText);
            if (m.matches()) {
                target = m.group(1);
                int idx = matcherText.indexOf(target);
                targetStart = newOffset + idx;
                targetEnd = targetStart + target.length();
                return true;
            }
        }
        return false;
    }

    @Override
    public int[] getHyperlinkSpan(Document document, int offset) {
        if (verifyState(document, offset)) {
            return new int[]{targetStart, targetEnd};
        } else {
            return null;
        }
    }

    @Override
    public void performClickAction(Document document, int offset) {
        if (verifyState(document, offset)) {
            NotifyDescriptor.Message msg = new NotifyDescriptor.Message(target);
            DialogDisplayer.getDefault().notify(msg);
        }
    }
    
}</pre>

        <p class="tips">If you create a hyperlink for a different MIME type, you need to change the
            <tt>text/html</tt> folder in the annotation above to the 
            appropriate MIME type. Read <a href="http://blogs.oracle.com/geertjan/entry/hyperlink_in_a_plain_text">Hyperlink in a Plain Text File</a>
            to learn about a different implementation of the above class.</p>

        <p>Now that the HyperlinkProvider is registered, you can run the module and
            try out your new hyperlinks, with this result:</p>
        <p><img alt="" src="../images/tutorials/hyperlink/hyperlink-69-1.png"/></p>

        <div class="feedback-box"><a href="https://netbeans.org/about/contact_form.html?to=3&amp;subject=Feedback:%20Hyperlink%207.2%20Module%20Tutorial">Send Us Your Feedback</a></div>

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