I was writing simple refactoring and noticed a strange thing. The comment line before the node I am rewriting disappears after refactoring. Also comments after the node in question are transferred inside the node and break the indentation in the new place. This is very strange and I want to ask if it is a bug in jdt or I did something wrong and oblivious.
For example my code suppose to refactor if-else statements in a way that the shortest branch would appear first.
when I try to refactor this:
// pre
if(a==6) {
a = 5;
return false;
} else {
a++;
}
//post
I get this:
if (!(a==6)) {
a++;
}
//post
else {
a = 5;
return false;
}
The relevant snippet where the refactoring is done:
protected ASTRewrite createRewrite(CompilationUnit cu, SubProgressMonitor pm) {
pm.beginTask("Creating rewrite operation...", 1);
final AST ast = cu.getAST();
final ASTRewrite rewrite = ASTRewrite.create(ast);
cu.accept(new ASTVisitor() {
public boolean visit(IfStatement node) {
if (node.getStartPosition() > selection.getOffset() + selection.getLength() || node.getStartPosition() < selection.getOffset())
return true;
if (node.getElseStatement() == null)
return true;
int thenCount = countNodes(node.getThenStatement());
int elseCount = countNodes(node.getElseStatement());
if(thenCount <= elseCount)
return true;
IfStatement newnode = ast.newIfStatement();
PrefixExpression neg = negateExpression(ast, rewrite, node.getExpression());
newnode.setExpression(neg);
newnode.setThenStatement((org.eclipse.jdt.core.dom.Statement) rewrite.createMoveTarget(node.getElseStatement()));
newnode.setElseStatement((org.eclipse.jdt.core.dom.Statement) rewrite.createMoveTarget(node.getThenStatement()));
rewrite.replace(node, newnode, null);
return true;
}
});
pm.done();
return rewrite;
}
The // pre comment goes away because the parser considers it to be part of the next statement (represented by node), which you replace with newNode. When node goes away, so does the attached comment.
still thinking about why the // post ends up where it does... Try replacing the newNode before setting its then and else statements
Related
I am doing a project for nand2tetris. We write a program in Jack and test it on VMEmulator. The class looks like this:
class List {
field int data;
field List next;
/* Creates a new List object. */
constructor List new(int car, List cdr) {
let data = car;
let next = cdr;
return this;
}
/* Disposes this List by recursively disposing its tail. */
method void dispose() {
if (~(next = null)) {
do next.dispose();
}
// Use an OS routine to recycle the memory held by this object.
do Memory.deAlloc(this);
return;
}
/* Prints the list*/
method void print() {
do Output.printString(" -> ");
do Output.printInt(data);
if (~(next = null)) {
do next.print();
}
return;
}
/* Inserts the argument in the right position of the list (ascending order)*/
method void insertInOrder(int ins){
var List prev, curr, insert;
let prev = this;
let curr = prev.getnext();
while (ins > prev.getdata()){
if (ins < curr.getdata()){
let insert = List.new(ins, curr);
do prev.setnext(insert);
}
else{
let prev = prev.getnext();
let curr = prev.getnext();
}
}
return;
}
/* Searches the argument in the list, if found, it returns the corresponding List object*/
method List find(int toFind){
var List temp;
var List equal;
var boolean found;
let temp = this;
let found = false;
while (~(next = null)){
if(toFind = temp.getdata()){
let equal = temp;
let found = true;
}
let temp = temp.getnext();
}
if (found){
return equal;
}
else{
return null;
}
}
method List getnext(){
return next;
}
method void setnext(List object){
let next = object;
return;
}
method int getdata(){
return data;
}
}
It has one private variable data and a pointer next. So I wrote getter and setter method to return those values. Other methods are fine only the getdata()method is incorrect. When it runs through the VMEmulator, it shows the error Out of segment space in List.getdata.3. This shows in the VMEmulator.
0function List.getdata0
1push argument0
2pop pointer0
3push this 0
4return
the error is at the 4th line return. When I change the Jack code, the same error is still at the 4th line.
What exactly is the problem in my getter method?
When you run a VM program on the VMEmulator you must first manually set the pointers to the various segments, otherwise you may get an "Out of segment space" error.
To understand the necessary settings, look at what the corresponding .tst file does. An alternative method is to insert the proposed code inside a function, since the function call automatically makes this type of setting.
You can get this error when you try to access member data of an object which is not constructed. Could it be that the List cdr in the constructor was not properly constructed?
I am trying to delete the largest node in binary search tree, I thougth that these code below should be able to do it but for some reason it is not. Could someone help please!
public void remove() {
Node current = root;
while(true){
Node parent = current;
current = current.getRighChild();
if (current == null){
parent.setRighChild(null);
return;
}
}
}
public void remove()
{
root = deleteMax(root);
}
private Node deleteMax(Node x ) {
if (x.getRighChild() == null)
{
return x.getLeftChild();
}
x.setRighChild(deleteMax(x.getRighChild()));
return x;
}
In your code if the right node is empty you are still deleting it. Instead of deleting the current if it is the max. Try something like this:
removeLargest() {
current = getRoot();
rightNode == null;
while (root.Right){
current == root.Right
}
if (current.left()){
rotate()
}
current.delete()
}
I created a code in while loop in Orange HRM.
I am taking data for UID & Pwd from a text file.
But while Executing that it executes 1st line also, which is not necessary.
I want to skip the first line (UID, PWD) and proceed further.
I want the Solution with While as well as with For Loop.
I think It's simple but i am unable to do it immediately.
Please find my code written with while loop.
BufferedReader br = new BufferedReader(new FileReader("E:/WorkSpace/Test/InputData/uid.txt"));
String sCurrentLine;
while ((sCurrentLine = br.readLine())!= null)
{
String str[] = sCurrentLine.split(" ");
driver.findElement(By.id("txtUsername")).sendKeys(str[0]);
driver.findElement(By.id("txtPassword")).sendKeys(str[1]);
driver.findElement(By.id("btnLogin")).click();
Thread.sleep(3000);
if (driver.findElement(By.tagName("a")).getAttribute("id").contains("welcome"))
{
System.out.println("Login is Successful");
temp = true;
break;
}
else
{
System.out.println("Login Failed");
temp = false;
driver.navigate().to("http://opensource.demo.orangehrm.com/");
}
if (temp) {
break;
}
}
If you want to skip the first line, read it before the loop:
br.readLine()
while ((sCurrentLine = br.readLine())!= null)
{
...
Couldn't you just move the code you want executed only once, outside of the loop? Put it right before the loop, and it'll be executed, then go immediately into the loop.
Or you could have something like:
for(int i=0; i<length; i++) {
if (i == 0) {
//code you want executed
}
}
My website went down for a few days, therefore I am trying to produce some error handling while the MVC app doesnt have access to certain resources so if something doesnt become unavailable again the WHOLE THING doesnt have to go down.
At the moment a controller is trying to access viewbag.moreNewProducts that isnt available.
public ActionResult Index(string search)
{
string[] newProductLines = this.getMoreNewProducts();
string[] newNews = this.getMoreNews();
string[] newPromotions = this.getMorePromotions();
string[] fewerProductLines = this.getLessNewProducts(newProductLines);
ViewBag.moreNewProducts = newProductLines;
ViewBag.moreNews = newNews;
ViewBag.morePromotions = newPromotions;
ViewBag.lessNewProducts = fewerProductLines;
bool disableShowMore = false;
This is where I run into an error: " foreach (string line in newProductLines)"
public string[] getLessNewProducts(string[] newProductLines)
{
int charCount = 0;
int arrayCount = 0;
string[] displayProductLines = new string[6];
bool continueWriting;
if (newProductLines == null)
{
foreach (string line in newProductLines)
{
continueWriting = false;
for (int i = 0; charCount < 250 && i < line.Length && arrayCount < 5; i++)
{
string index = newProductLines[arrayCount].Substring(i, 1);
displayProductLines[arrayCount] += index;
charCount++;
continueWriting = true;
}
if (continueWriting == true)
{
arrayCount++;
}
}
string[] LessNewProducts = new string[arrayCount];
for (int d = 0; d < arrayCount; d++)
{
LessNewProducts[d] = displayProductLines[d];
}
return LessNewProducts;
}
else
{
return null;
}
}
how do I get around an if else statement so the whole thing doesnt have to crash?
Two things.
Your if (newProductLines == null) statement has the wrong condition on it. I don't believe that you want to enter that if newProductLines is null. You can inverse this condition to get the desired result(if (newProductLines != null)).
If you run into another situation later where you need to catch an error, you can always use the try-catch block to catch exceptions that you are expecting.
try
{
//code that could cause the error here
}
catch(NullReferenceException nullRefExcep)
{
//what you want it to do if the null reference exception occurs
}
if (newProductLines == null)
should be replaced with if (newProductLines != null) so you don't have to handle the code with newProductLines as null. Basically, with this condition you will always have the NullReferenceException unless you manage your exception with a try catch block.
The real question to ask yourself is:
Why would newProductLines be null?
Presumably getMoreNewProducts() found a situation where it thought it would be appropriate to return a null value.
If this is happening because the system has an error that would make your page meaningless, then you may just want to change getMoreNewProducts() so that it throws an exception when that error state occurs. Typically it's safest and easiest to debug programs that fail as soon as they run into an unexpected situation.
If this is happening because there are no new products, then you should just return an empty collection, rather than null. All your code should work just fine after that, without the need for an if/else statement: it will return an empty array for LessNewProducts, which is probably correct.
However, let's assume that there's a situation that you're anticipating will occur from time to time, which will make it impossible for you to retrieve newProductLines at that time, but which you would like the system to handle gracefully otherwise. You could just use null to indicate that the value isn't there, but it's really hard to know which variables might be null and which never should be. It may be wiser to use an optional type to represent that getMoreNewProducts() might not return anything at all, so you can force any consuming code to recognize this possibility and figure out how to deal with it before the project will even compile:
public ActionResult Index(string search)
{
Maybe<string[]> newProductLines = this.getMoreNewProducts();
string[] newNews = this.getMoreNews();
string[] newPromotions = this.getMorePromotions();
Maybe<string[]> fewerProductLines = newProductLines.Select(this.getLessNewProducts);
Disclaimer: I am the author of the Maybe<> class referenced above.
Here are some additional improvements I'd suggest:
Don't use ViewBag. Instead, create a strongly-typed ViewModel so that you can catch errors in your code at compile-time more often:
var viewModel = new ReportModel {
newProductLines = this.getMoreNewProducts(),
newNews = this.getMoreNews(),
...
};
...
return View(viewModel);
Learn to use LINQ. It will simplify a lot of your very complicated code. For example, instead of:
string[] LessNewProducts = new string[arrayCount];
for (int d = 0; d < arrayCount; d++)
{
LessNewProducts[d] = displayProductLines[d];
}
return LessNewProducts;
... you can say:
string[] LessNewProducts = displayProductLines.Take(arrayCount).ToArray();
In fact, I think your entire getLessNewProducts() method can be replaced with this:
return newProductLines
.Where(line => line.Length > 0)
.Select(line => line.Substring(0, Math.Min(line.Length, 250)))
.Take(5);
I am using tree.Panel with TreeStore when I call
sel_node.parentNode.appendChild(node);
tree.getSampleStore().sync();
ExtJS fire event called sample store proxy: update url instead of create url what could I have done wrong?
What exact version of ExtJS4 do you use?
In my situation, with ext-4.0.7-gpl, I debugged a bit a found out that appendChild method creates a node from and object and then performs some update operations concerning the node's position in the tree, like setting next sibling, parent etc., see [1].
When syncing, the store uses getUpdatedRecords and getNewRecords [2] methods to determine which operation to run. update or create. Somehow, our appended children turn out to be updated, not created.
Note that the method doesn't check whether the children of a parent node was loaded, just pushes the new node into an empty childNodes array; after all these operations end, other children of a parent node are never shown in the tree; and if the update operation caused the serverside generation of new id, the code breaks on the line original = me.tree.getNodeById(record.getId()); - there is no such node with the old id generated on client side..
Simply put, I think it's a bug.
[1] http://docs.sencha.com/ext-js/4-0/source/NodeInterface.html#Ext-data-NodeInterface-method-appendChild
[2] http://docs.sencha.com/ext-js/4-0/source/AbstractStore.html#Ext-data-AbstractStore-method-getUpdatedRecords
Add: ExtJS 4.1 beta 2 doesn't work better for me
Update with temp solution: I hacked a bit and think I solved the issue by overriding the appendChild method of NodeInterface like below (just to set phantom property so that the record becomes created, not updated).
Please note:
1) You should include your appendChild call in the NodeInterface expand method callback, or the bug with pushing to the empty childNodes will remain: the new node will appear somewhere in the wrong place;
2) I had to override updateIndexes of the AbstractView as well, try not to do this and maybe you'll find out why;
3) there are some issues when the store tries to delete our newly created node the next time it syncs - couldn't trace it yet;
0) I am no way ExtJS or even JS guru, so feel free to correct this hack)
Ext.data.NodeInterface.oldGpv = Ext.data.NodeInterface.getPrototypeBody;
Ext.data.NodeInterface.getPrototypeBody = function(){
var ret = Ext.data.NodeInterface.oldGpv.apply(this, arguments);
ret.appendChild = function(node, suppressEvents, suppressNodeUpdate) {
var me = this,
i, ln,
index,
oldParent,
ps;
if (Ext.isArray(node)) {
for (i = 0, ln = node.length; i < ln; i++) {
me.appendChild(node[i]);
}
} else {
node = me.createNode(node);
if (suppressEvents !== true && me.fireEvent("beforeappend", me, node) === false) {
return false;
}
index = me.childNodes.length;
oldParent = node.parentNode;
if (oldParent) {
if (suppressEvents !== true && node.fireEvent("beforemove", node, oldParent, me, index) === false) {
return false;
}
oldParent.removeChild(node, null, false, true);
}else{
node.phantom = true;
}
if(me.isLoaded()){
index = me.childNodes.length;
if (index === 0) {
me.setFirstChild(node);
}
me.childNodes.push(node);
node.parentNode = me;
node.nextSibling = null;
me.setLastChild(node);
ps = me.childNodes[index - 1];
if (ps) {
node.previousSibling = ps;
ps.nextSibling = node;
ps.updateInfo(suppressNodeUpdate);
} else {
node.previousSibling = null;
}
node.updateInfo(suppressNodeUpdate);
}
//console.log('appendChild was called');
// I don't know what this code mean even given the comment
// in ExtJS native source, commented out
// As soon as we append a child to this node, we are loaded
//if (!me.isLoaded()) {
// me.set('loaded', true);
//}
// If this node didnt have any childnodes before, update myself
//else
//if (me.childNodes.length === 1) {
// me.set('loaded', me.isLoaded());
//}
if (suppressEvents !== true) {
me.fireEvent("append", me, node, index);
if (oldParent) {
node.fireEvent("move", node, oldParent, me, index);
}
}
return node;
}
};
return ret;
};
this is my code to add a node by values taken from a form domainForm. The form opens by clicking an icon in an actioncolumn of our tree grid:
var node = grid.store.getAt(rowIndex);
node.expand(false, function(){
var newDomain = domainForm.getValues();
newDomain.parent = {id: node.raw.id}; // i don't know whether you'll need this
var newNode = node.appendChild(newDomain);
me.store.sync();
});
and updateIndexes overrider:
Ext.override(Ext.view.AbstractView, {
updateIndexes : function(startIndex, endIndex) {
var ns = this.all.elements,
records = this.store.getRange(),
i;
startIndex = startIndex || 0;
endIndex = endIndex || ((endIndex === 0) ? 0 : (ns.length < records.length?(ns.length - 1):records.length-1) );
for(i = startIndex; i <= endIndex; i++){
ns[i].viewIndex = i;
ns[i].viewRecordId = records[i].internalId;
if (!ns[i].boundView) {
ns[i].boundView = this.id;
}
}
}
});
Had the same issue, an update to ext-4.1.0-beta-2 fixed it.
The reason might be wrong format of data that comes from the server in response to your request.
Syncronization doesn't happen. Pass 'success' key with the value of TRUE in the server response.
Hmm ... try this ...
beforeitemexpand(node, eOpts){
if (node.data.expanded) return false
}