ta_enumlines.html
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<TITLE>Enumerating the Lines in a JTextArea Component
(Java Developers Almanac Example)
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<B><A HREF="../javax.swing.text/pkg.html#JTextArea">JTextArea</A></B><font color="#666666" SIZE="-2">
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<h3>
e983.
Enumerating the Lines in a JTextArea Component</h3>
The contents of a text component are stored in a <code>Document</code> object
which in turn breaks the content up into a hierarchy of <code>Element</code>
objects. In the case of a text area, each line of text (a contiguous
span of characters terminated by a single newline) is stored in a
content element. For example, if the last line of the contents is
terminated by a newline and there are 100 new lines, there will be 100
content elements. All content elements are stored under a single
paragraph element.
<P>
This example demonstrates how to retrieve the paragraph element and
enumerate all children content elements.
<P> See also <a href="../javax.swing.text/GetWrappedLines.html" class="eglink"><font size="-1"><b>e972</b> Retrieving the Visible Lines in a JTextComponent</font></a>.
<pre>
// Create a text area
JTextArea textArea = new JTextArea(<font color="#0066ff"><i>"word1 word2\nword3\nword4"</i></font>);
// Get paragraph element
Element paragraph = textArea.getDocument().getDefaultRootElement();
// Get number of content elements
int contentCount = paragraph.getElementCount();
// Get index ranges for each content element.
// Each content element represents one line.
// Each line includes the terminating newline.
for (int i=0; i<contentCount; i++) {
Element e = paragraph.getElement(i);
int rangeStart = e.getStartOffset();
int rangeEnd = e.getEndOffset();
try {
String line = textArea.getText(rangeStart, rangeEnd-rangeStart);
} catch (BadLocationException ex) {
}
}
</pre>
Here is another way to enumerate the content elements with a
<code>ElementIterator</code>:
<pre>
// Get the text area's document
Document doc = textArea.getDocument();
// Create an iterator using the root element
ElementIterator it = new ElementIterator(doc.getDefaultRootElement());
// Iterate all content elements (which are leaves)
Element e;
while ((e=it.next()) != null) {
if (e.isLeaf()) {
int rangeStart = e.getStartOffset();
int rangeEnd = e.getEndOffset();
try {
String line = textArea.getText(rangeStart, rangeEnd-rangeStart);
} catch (BadLocationException ex) {
}
}
}
</pre>
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Related Examples
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e981. <a class="eglink" href="ta_TextArea.html?l=rel">
Creating a JTextArea Component
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e982. <a class="eglink" href="ta_EditTextArea.html?l=rel">
Modifying Text in a JTextArea Component
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e984. <a class="eglink" href="ta_TabSize.html?l=rel">
Setting the Tab Size of a JTextArea Component
</a>
<br>
e985. <a class="eglink" href="ta_OverrideTab.html?l=rel">
Moving the Focus with the TAB key in a JTextArea Component
</a>
<br>
e986. <a class="eglink" href="ta_Wrap.html?l=rel">
Enabling Word and Line Wrapping in a JTextArea Component
</a>
<br>
e987. <a class="eglink" href="ta_Console.html?l=rel">
Implementing a Console Window with a JTextArea Component
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See also:
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#Actions%20and%20Key%20Bindings">
Actions and Key Bindings
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#Caret%20and%20Selection">
Caret and Selection
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#Events">
Events
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#JEditorPane">
JEditorPane
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#JFormattedTextField">
JFormattedTextField
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#JTextComponent">
JTextComponent
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#JTextField">
JTextField
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#JTextPane">
JTextPane
</a>
<a class="eglink" href="/egs/javax.swing.text/pkg.html?l=rel#Styles">
Styles
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