Added CleanSourceActionListener.

src/main/java/nl/andrewlalis/blockbookbinder/control/CleanSourceActionListener.java

@@ -0,0 +1,45 @@
+package nl.andrewlalis.blockbookbinder.control;
+
+import nl.andrewlalis.blockbookbinder.view.SourceTextPanel;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+/**
+ * Listener for an action where the source text is 'cleaned' by removing any
+ * trailing whitespace, and removing unnecessary newlines.
+ */
+public class CleanSourceActionListener implements ActionListener {
+	private final SourceTextPanel sourceTextPanel;
+
+	public CleanSourceActionListener(SourceTextPanel sourceTextPanel) {
+		this.sourceTextPanel = sourceTextPanel;
+	}
+
+	@Override
+	public void actionPerformed(ActionEvent e) {
+		final String source = this.sourceTextPanel.getSourceText();
+		String updated = source.trim()
+				.replaceAll("(?>\\v)+(\\v)", "\n\n") // Replace large chunks of newline with just two.
+				.replace("  ", " "); // Remove any double spaces.
+		updated = this.removeNewlineWrapping(updated);
+		this.sourceTextPanel.setSourceText(updated);
+	}
+
+	private String removeNewlineWrapping(String source) {
+		final StringBuilder sb = new StringBuilder(source.length());
+		final char[] sourceChars = source.toCharArray();
+		for (int i = 0; i < sourceChars.length; i++) {
+			char c = sourceChars[i];
+			if (
+					c == '\n'
+							&& (i - 1 >= 0 && !Character.isWhitespace(sourceChars[i - 1]))
+							&& (i + 1 < sourceChars.length && !Character.isWhitespace(sourceChars[i + 1]))
+			) {
+				c = ' ';
+			}
+			sb.append(c);
+		}
+		return sb.toString();
+	}
+}

src/main/java/nl/andrewlalis/blockbookbinder/view/SourceTextPanel.java

@@ -1,5 +1,6 @@
 package nl.andrewlalis.blockbookbinder.view;
 
+import nl.andrewlalis.blockbookbinder.control.CleanSourceActionListener;
 import nl.andrewlalis.blockbookbinder.control.ConvertToBookActionListener;
 
 import javax.swing.*;
@@ -38,9 +39,17 @@ public class SourceTextPanel extends JPanel {
 		JButton convertButton = new JButton("Convert to Book");
 		convertButton.addActionListener(new ConvertToBookActionListener(this, bookPreviewPanel));
 		rightPanelButtonPanel.add(convertButton);
+
+		JButton cleanButton = new JButton("Clean");
+		cleanButton.addActionListener(new CleanSourceActionListener(this));
+		rightPanelButtonPanel.add(cleanButton);
 	}
 
 	public String getSourceText() {
 		return this.textArea.getText();
 	}
+
+	public void setSourceText(String text) {
+		this.textArea.setText(text);
+	}
 }