Making the Java Coder More Productive Introduction to New Coding Features in JDeveloper

Transcription

1 Making the Java Coder More Productive Introduction to New Coding Features in JDeveloper This document describes several Java Coding scenarios. It either uses predefined source files or creates certain classes on the fly. Check for Updates: 1. Install latest Service Update (only available for ; SU s for are not yet available as it has just been released) 2. Install JUnit Tasks: 1. In Tools Preferences go to Tasks panel 2. Add custom Source Tag DEMO with priority High - this helps identifying all upcoming demo steps 3. Select View Tasks Window 4. In Tasks window select Current File from dropdown box Code Assist: Errors: * Demonstrate use of Quick Fix via Code Assist feature. public class Errors { private static final double CONSTANT_PI = 3.14f; public Errors() { // DEMO Pick Quick Fix "Create Inner Class Foo" Foo[] bar = new Foo[0]; // DEMO Pick Quick Fix "Cast To 'float'" float d = CONSTANT_PI; System.out.println(d); Table 1: Errors.java 1. Mouse Over in File Margin Overview (grey area right of code editor) to get information on problem 2. Place cursor in token with red wriggleline and press Ctrl+Alt+Enter to open Quick Fix menu 3. Use Code Assist menu for Foo and pick Create Inner Class Foo 4. Use Code Assist menu for CONSTANT_PI and pick Cast to float Invert or Negate If Statements o Invert If Statement: condition is modified and branches get swapped o Negate Expression: condition is modified * Demonstrate inverting and negating If contructs. public class IfStatements { public void testifstatements() { boolean b = false; boolean b2 = true; int i = 0; // DEMO Invert a primitive type if (b) { System.out.println("This is b"); else { System.out.println("This is!b");

2 // DEMO Negate a primitive type if (i <= 0) { System.out.println("This is i <= 0"); // DEMO Invert a more complex If construct if (b b2) { System.out.println("This is b b2"); else { System.out.println("This is!b &&!b2"); Table 2: IfStatements.java 1. Use Code Assist menu to invert if (b) 2. Use Code Assist menu to negate if (i <= 0) 3. Use Code Assist menu to invert if (b b2) QuickJavadoc * DEMO Click in the QuickJavadoc declaration and choose Source Quick Javadoc. * DEMO Press Ctrl+D. * DEMO Select Quick Javadoc from the code editor's context menu. * * These inline link tags should display and link properly: * <ul> * <li> {@link java.lang.stringbuffer#capacity Capacity - link text should be * "Capacity" * <li> {@link java.lang.stringbuffer#append(char[], int, int) - link text * should be "java.lang.stringbuffer.append(char[], int, int)" * <li> {@link java.lang.stringbuffer The StringBuffer Class - link text should * be "The StringBuffer Class" * </ul> public class QuickJavadoc { * DEMO QuickJavadoc also available for fields. public static final String SOME_TEXT = "Hello World!"; * DEMO...Constructors public QuickJavadoc() { * DEMO...and, of course, methods. i some input some output FileNotFoundException if i is less than 0 public String foo(int i) throws FileNotFoundException { if (i < 0) { throw new FileNotFoundException(); return "found " + i; Table 3: QuickJavadoc.java 1. Click in the QuickJavadoc declaration and choose Source Quick Javadoc 2. Place cursor inside identifier and press Ctrl+D 3. Place cursor inside identifier and select Quick Javadoc from the code editor's context menu. Unused Members Points out all unused methods, fields, parameters, and variables in this class.

3 * DEMO identification of unused methods, fields, parameters, and variables. public final class Unused { public Unused() { this(false, false); private boolean used_b = false; private int used_i = 0; private String used_s = ""; // Violation: parameter unused_b not used // Note: despite its name the constructor is really used private Unused(boolean used_b, boolean unused_b) { this.used_b = used_b; // Violation: method Unused and parameter unused_i not used private Unused(int used_i, int unused_i) { this.used_i = used_i; // Violation: method Unused parameter unused_s not used private Unused(String used_s, String unused_s) { this.used_s = used_s; // Violation: parameter unused_i not used public void calling(int used_i, int unused_i) { int used_j = used_i; // Violation: local variable not used int unused_j = used_j; // Violation: method unused_private_method not used private void unused_private_method() { public int unused_public_field; protected int unused_protected_field; // Violation: field unused_private_field not used private int unused_private_field; int unused_default_access_field; Table 4: Unused.java Code Highlighting: Highlight all syntactical identic tokens. * Demonstrate Code Highlighting. All syntactical identic tokens will get * highlighted. Cumulative highlighting is possible. public class Highlighted { * DEMO 1) Place cursor in method name and click on Highlight icon in main * tool bar. * DEMO 2) Place cursor in parameter and click on Highlight icon. * * D1) Method name should get highlighted, but parameter name not. * D2) Parameter name should get highlighted, but method name not. public boolean ishighlighted(boolean ishighlighted) { * D1) This variable should not get highlighted. * D2) This variable should not get highlighted. ishighlighted = false; return ishighlighted; public void foo() {

4 * Variable name should not get highlighted. boolean ishighlighted = true; * D1) Method name should get highlighted, but parameter name not. * D2) Parameter name should get highlighted, but method name not. ishighlighted(ishighlighted); * Class type and name should not get highlighted. ishighlighted ic = new ishighlighted(); * This class identifier should not get highlighted. private class ishighlighted { public void bar() { * D1) Method name should get highlighted. * D2) Parameter should get highlighted although it does not have * an identifier but a primitive type value. ishighlighted(true); Table 5: Highlighted.java 1. Place cursor in method name and click on Highlight icon in main tool bar 2. Place cursor in parameter and click on Highlight icon 3. Clear highlighting and accumulate highlighting Smart Code Templates aka Live Code Templates import java.util.arraylist; import java.util.collection; import java.util.date; import java.util.hashmap; import java.util.list; import java.util.vector; * Demonstrate Smart Code Templates a.k.a. Live Code Templates. class Templates { public void usecodetemplates() { int i = 100; Date date = new Date(); List<Date> list = new ArrayList<Date>(); HashMap<String, Date> map = new HashMap<String, Date>(); // DEMO enter "fori" and press Ctrl+Enter // DEMO enter "itli", in template choose list and then Date; check CodeAssist Table 6: Templates.java 1. Press Ctrl+Enter to get list of all templates 2. enter fori and press Ctrl+Enter to expand template 3. enter itli and press Ctrl+Enter to expand template; in template choose list and then Date; check CodeAssist for an addition treat(!) 4. Go to Tools Preferences and go to panel Code Editor Code Templates to enter your own templates

5 Smart Code Insight: If you press Ctrl+Space, the popup list shows all available methods, fields and classes. Most of the offered items may not be applicable. To limit the list to those items, press Ctrl+Alt+Space. import java.awt.dimension; * Demonstrate Code Insight and Smart Code Insight. public class SmartCodeInsight { private static final int HEIGHT = 15; private int getint() { return -1; public void showsmartcodeinsight() { Dimension dim = new Dimension(10, 20); * DEMO uncomment next statement and place cursor right of '.' * 1) use Ctrl+Space -> shows all available methods and fields of Dimension * 2) use Ctrl+Alt+Space -> shows all available AND applicable methods * and fields of Dimension if cursor right of '.' and of this class if * left of '.' // int height1 = dim. * DEMO uncomment next statement and place cursor right of '=' * 1) use Ctrl+Space -> shows all available methods, fields, and classes * 2) use Ctrl+Alt+Space -> shows all available AND applicable methods * and fields of this class // int height2 = Table 7: SmartCodeInsight.java 1. Place cursor right of int height1 = dim. and press Ctrl+Alt+Space 2. While popup list is shown use cursor keys to move left of. and note the difference 3. Place cursor right of int height2 = and press Ctrl+Alt+Space Nice Little Tricks: * Demonstrate various small tips and tricks: * a) Copy DOS path * b) Edit Copy Path * c) Extended Copy * d) Surround With * e) Go to Source from stack trace public class NiceLittleTricks { private void showsmartcopypaste() { // DEMO copy DOS file path String dospath = ""; // DEMO select Edit Copy Path while file node selected in Navigator String filepath = ""; // DEMO for Extended Paste press Ctrl+Shift+V public static void main(string[] args) { NiceLittleTricks c = new NiceLittleTricks(); c.showsmartcopypaste(); // DEMO Use Surround With from context menu and pick try-catch c.catchme(); public int catchme() throws Exception { throw new Exception("Catch me if you can!");

6 Table 8: NiceLittleTricks.java 1. Copy a string containing a DOS path and JDeveloper will guard all \ with an additional escape character \ 2. In the Navigator select any file node and select Edit Copy Path; now paste string into your code 3. Press Ctrl+Shift+V to open Extended Copy dialog to get to a list of previously copied strings 4. Use Surround With from context menu to place try-catch around call of method catchme() 5. Maximize code editor by double clicking into the tab 6. Split Code Editor vertical or horizontal by dragging the divider above the vertical slider or right of the horizontal slider 7. Dock Code Editor vertical or horizontal Navigation in Code Editor: import java.util.arraylist; import java.util.list; import nicelittletricks.nicelittletricks; * Demonstrate View Type Hierarchy and Go to Java Source dialog. public class Navigation { private void showhierarchy() { // DEMO select List or list and select View Type Hierarchy // from context menu List list = new ArrayList(); // DEMO While searching for Subtype Hierarchy use Ctrl+Minus // and enter class name e.g. ArrayList or use Browse button // to open Go to Java Source dialog // DEMO run this class and go to source from stack trace public static void main(string[] args) { NiceLittleTricks c = new NiceLittleTricks(); try { // DEMO place cursor inside catchme() // and select Find Usages from context menu c.catchme(); catch (Exception e) { e.printstacktrace(); Table 9: Navigation.java 1. Place cursor somewhere inside List list and select Navigate Hierarchy View 2. In dropdown box of Hierarchy Panel switch to Subtype Hierarchy; note that this will take a while; in the meantime Press Ctrl+Minus to open Go to Source dialog; enter class name in text field or use Browse 4. Run class Navigation and use stack trace to go to source code 5. Press Alt+Home to find node for this file in Navigator 6. Place cursor in c.catchme() and select Find Usages from context menu Code Folding: 1. Open project MyJavaApp; if project does not exist, use these steps to create it: a. In New Gallery select Client Tier Swing/AWT Java Application b. In Create Java Application dialog accept default settings c. In Create Frame dialog select all checkboxes d. Copy code of class Frame1_AboutBoxPanel1 and make it an inner private class of Frame1 class 2. Open Frame1.java in Source view 3. Hover over [+] of a collapsed area 4. Use context menu of Folding Gutter to manage expansion

7 Navigation in Code Editor (reprise): The class Frame1.java is now the perfect opportunity to show another Code Navigation feature: Source Code Navigation via [i] and [o] icons in Line Gutter. 1. Select line public class Frame1 extends JFrame 2. Click on [o] to navigate to overriden class java.awt.container 3. Click on [o] to navigate to implemented interface javax.accessibility.accessible 4. Press Alt+Down to get to next member in class or Alt+Up to get to previous member Code Formatting: Why built-in Code Formatting when there is Jalopy et altera? Having our own Code Formatting feature enables all wizards to generate code conformant to selected style. 1. In Tools Preferences go to Code Style to look at predefined styles 2. Use style editor to modify code style; pick Next Line for all Brace Positions 3. Save modified style 4. Reformat MyJavaApp; all opening braces are now on the next line 5. For Application1.java select Source Implement Interface and select java.util.list Note that all opening braces get automatically placed on the next line Refactoring: 1. Open project RefactoringDemo; if project does not exist, use these steps to create it: a. In New Gallery select Client Tier Swing/AWT Java Application b. In Create Java Application dialog accept default settings c. In Create Frame dialog select all checkboxes 2. Compile project 3. In Navigator select file Frame1.java, then select Refactor Rename; enter name MyFrame and select checkbox Preview 4. In Rename log window click on Do Refactoring icon 5. Verify that renaming deleted Frame1.class 6. Place cursor inside method identifier fileexit_actionperformed() 7. Select Refactor Inline; statement system.exit(0); gets added to MenuHelpAbout.addActionListener() 8. Extract previously inlined method; it becomes a private method inside the anonymous ActionListener class 9. Place cursor inside any occurance of jbinit() and select Refactor Change Method 10. Insert new boolean parameter with default value true Delete Safely: 1. Select class Frame1_AboutBoxPanel1.java 2. Select Refactor Delete Safely 3. Check Usages log window Generate Accessors: * Demonstrate Source Generate Accessors. public class GenerateAccessors { // DEMO Select Source Generate Accessors and enter "_generate" as prefix private int _generateaccessorforint = 0; private String _generateaccessorforstring = ""; Table 10: GenerateAccessors.java 1. Open class GenerateAccessors.java in code editor 2. Select Source Generate Accessors

8 3. Enter prefix _generate; note that the names of the getter and setter methods adopt to this prefix change when you press Refresh Multi-File Find and Replace: 1. Select Search Find in Files 2. Enter text Frame and select Active Project 3. Select Search Find in Files again 4. Enter (keep) text Frame and select Active Application and checkbox Show Results in New Tab Navigation between Code Editors: 1. In the Main toolbar click on Backward and Forward icons to move between previously opened source files 2. Select Navigate Go to Last Edit 3. Select Navigate Recent Files Working with the Navigator: Drag n Drop 1. Open project NavigatorDemo or create a project with multiple packages 2. Move any class from one package to another by clicking on the class in the Navigator and dragging it onto the package node of your choice; note how the code gets refactored 3. Undo move is also possible Custom Properties This is especially useful in a team development environment. Consider the following situation: you want to test your application with a new version of a library without modifying the application s project. To do this take the following steps: 1. Open the project s Properties dialog 2. Go to panel Libraries 3. Select checkbox Use Custom Settings 4. Click on Customize Settings button 5. Add the library, e.g. JDeveloper Extension SDK 6. Close the dialog 7. Compile the project Note that the classpath has now the entries for ide.jar and jdev.jar. Working Sets This new feature is currently only available in the System Navigator. It helps you by filtering the nodes on display, which is very useful in large projects. It does this without modifying the project. 1. Select View System Navigator 2. Expand your project 3. Select any package node 4. In the Navigator s toolbar click on Working Sets icon 5. Pick New From Selection 6. In the dialog give your new set a name e.g. Package1 7. In the Navigator s toolbar click on Working Sets icon again 8. Pick Manage Working Sets 9. Hide or Unhide files by selecting them in the Files tab or enter patterns manually in the Patterns tab (it uses the same annotation as Ant)