gui: highlight words on double click (#210)

jadx-gui/build.gradle

@@ -5,7 +5,7 @@ mainClassName = 'jadx.gui.JadxGUI'
 dependencies {
     compile(project(":jadx-core"))
     compile(project(":jadx-cli"))
-    compile 'com.fifesoft:rsyntaxtextarea:2.5.8'
+    compile 'com.fifesoft:rsyntaxtextarea:2.6.1'
     compile 'com.google.code.gson:gson:2.3.1'
     compile files('libs/jfontchooser-1.0.5.jar')
     compile 'hu.kazocsaba:image-viewer:1.2.3'

jadx-gui/src/main/java/jadx/gui/ui/CodeArea.java

@@ -10,6 +10,8 @@ import javax.swing.text.Caret;
 import javax.swing.text.DefaultCaret;
 import java.awt.*;
 import java.awt.event.ActionEvent;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
 
 import org.fife.ui.rsyntaxtextarea.LinkGenerator;
 import org.fife.ui.rsyntaxtextarea.LinkGeneratorResult;
@@ -17,6 +19,9 @@ import org.fife.ui.rsyntaxtextarea.RSyntaxTextArea;
 import org.fife.ui.rsyntaxtextarea.SyntaxScheme;
 import org.fife.ui.rsyntaxtextarea.Token;
 import org.fife.ui.rsyntaxtextarea.TokenTypes;
+import org.fife.ui.rtextarea.SearchContext;
+import org.fife.ui.rtextarea.SearchEngine;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -66,9 +71,38 @@ class CodeArea extends RSyntaxTextArea {
 			addMenuItems(this, (JClass) node);
 		}
 
+		registerWordHighlighter();
 		setText(node.getContent());
 	}
 
+	private void registerWordHighlighter() {
+		addMouseListener(new MouseAdapter() {
+			@Override
+			public void mouseClicked(MouseEvent evt) {
+				if (evt.getClickCount() % 2 == 0 && !evt.isConsumed()) {
+					evt.consume();
+					String str = getSelectedText();
+					if (str != null) {
+						highlightAllMatches(str);
+					}
+				} else {
+					highlightAllMatches(null);
+				}
+			}
+		});
+	}
+
+	/**
+	 * @param str - if null -> reset current highlights
+	 */
+	private void highlightAllMatches(@Nullable String str) {
+		SearchContext context = new SearchContext(str);
+		context.setMarkAll(true);
+		context.setMatchCase(true);
+		context.setWholeWord(true);
+		SearchEngine.markAll(this, context);
+	}
+
 	private void addMenuItems(CodeArea codeArea, JClass jCls) {
 		Action findUsage = new FindUsageAction(codeArea, jCls);