public class noorderedlist {
node head;
public void afadd(int element){
node newnode=new node(element);
if(head==null){
head=newnode;
return;
}
node temp=head;
while(temp.next != null){
temp = temp.next;
}
temp.next = newnode;
}
public void print(){
node currentnode=head;
while(currentnode!=null){
System.out.print(currentnode.element);
currentnode=currentnode.next;
}
public class node {
node next=null;
int element;
public node(int element){
this.element=element;
}
i want to write method to add point in a single link list,it works but i have a problem.why the head will change after the change of the temp?i hear about that is the shallow copy,but why the shallow copy does not work in"temp=temp.next"?,according to that in the loop the temp is changing then the head should change like "head=temp.next", but when i execute the print method the element of the head does not change but it adds a new point in the end of the link list. so what's going on here?
Related
I tried to make a dynamic scroll view to display selectable options that can be both generated or destroyed during runtime but for some reason it only lets me to generate up to three, otherwise I get a Missing Reference Exception.
When I generate one then delete it, it will also give a Missing Reference Exception.
But when I generate two, then delete one or even two, everything works just fine no matter what I do.
How can I fix this strange Behaviour?
The code:
private List<JL> JLList;
public List<GameObject> JLID;
public GameObject ButtonPrefab;
public GameObject PrefabParent;
public GameObject JLMenuManager;
public GameObject ScrollViewContent;
private void Update()
{
JLList = JLMenuManager.GetComponent<AddJL>().JLList;
CheckForChange();
}
private void GenerateOptions()
{
foreach (Transform child in ScrollViewContent.transform)
{
Destroy(child.gameObject);
}
for (int i = 0; i < JLList.Count; i++)
{
GameObject newJLOption = Instantiate(ButtonPrefab, PrefabParent.transform);
JLID.Add(newJLOption);
newJLOption = JLID[i];
int JLIndex = i;
newJLOption.GetComponent<Button>().onClick.AddListener(() => LoadJLOptions(JLIndex));
}
}
private void LoadJLOptions(int JLIndex)
{
SendMessage("SetJL", JLIndex);
Debug.Log(JLIndex);
}
private void CheckForChange()
{
int allJLOptions = ScrollViewContent.transform.childCount;
if (allJLOptions != JLList.Count)
{
GenerateOptions();
}
}
It seems like it is only spawning in how many JLList.Count is set to, open your script JLList and there should be a variable called count . Check how many that is set to. If it is 3, then that is your issue. If not, then follow what #BugFinder said and try remove them from the list
Something that has been bothering me for a long time is why do the following lines of code have the same results.
Code 1:
Transform[] childs = gameObject.GetComponentsInChildren<Transform>();
foreach(Transform child in childs) { Debug.Log(child.name); }
Code 2:
foreach(Transform child in gameObject.transform) { Debug.Log(child.name); }
This is actuallly a pseudo-code, I didn't really test it but should be enough to explain.
My question is, what's happening on Code 2 ? Is gameObject.transform actually an array of Transform ? Why doesn't Code 2 print the name of the parent gameObject ?
Maybe this is something very simple and obvious I'm just overlooking but I can't make it out right now.
Transform implements the IEnumerable interface. This interface is what allows the use of the foreach keyword.
public partial class Transform : Component, IEnumerable
The IEnumerable interface requires implementation of the GetEnumerator() method. The enumerator is responsible for keeping track of the position in the underlying collection and indicating if there are more items to be iterated over.
This is implemented in Transform below
public IEnumerator GetEnumerator()
{
return new Transform.Enumerator(this);
}
private class Enumerator : IEnumerator
{
Transform outer;
int currentIndex = -1;
internal Enumerator(Transform outer)
{
this.outer = outer;
}
//*undocumented*
public object Current
{
get { return outer.GetChild(currentIndex); }
}
//*undocumented*
public bool MoveNext()
{
int childCount = outer.childCount;
return ++currentIndex < childCount;
}
//*undocumented*
public void Reset() { currentIndex = -1; }
}
I'm trying to add an annotation to some selected fields using Eclipse JDT infrastructure. However, this is not run as a plugin. I added all the required dependencies to a separate project so this can be run in batch mode. However I found out that, the ListRewrite is not inserting my annotation at the right place. I have given the code below. I initially get all the field declarations in a map using a visitor and then add them one by one using the code below.
FieldDeclaration fld = lVrblDet.listStringVarMap.get(propName);
final MarkerAnnotation autoWiredAnnotate = ast.newMarkerAnnotation(); autoWiredAnnotate.setTypeName(ast.newName("MyAnnot"));
lrw = rewriter.getListRewrite(fld, FieldDeclaration.MODIFIERS2_PROPERTY);
lrw.insertLast(autoWiredAnnotate, null);
Document document = new Document(cu.toString());
try {
TextEdit edits = rewriter.rewriteAST(document, null);
edits.apply(document);
} catch (MalformedTreeException | IllegalArgumentException | BadLocationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
However the expected output is sometimes offset by 1 character.The input and output classes have been given below.
Input Class:
#SuppressWarnings("unchecked")
public class SampleClassA {
public SampleClassB classB;
public SampleClassB getClassB() {
return classB;
}
public void setClassB(SampleClassB classB) {
this.classB = classB;
}
#Deprecated
public void printNameFromSmapleClassB() {
System.out.println(this.classB.name);
}
}
Output Class:
#SuppressWarnings("unchecked") public class SampleClassA {
p #MyAnnot
ublic SampleClassB classB;
public SampleClassB getClassB(){
return classB;
}
public void setClassB( SampleClassB classB){
this.classB=classB;
}
#Deprecated public void printNameFromSmapleClassB(){
System.out.println(this.classB.name);
}
}
As you can see in the code above, the Annotation messed with the modifier. I have tried multiple combinations of insertFirst,insertLast.Examples on the net are incomplete. Can somebody point me the mistake/the right resource ?
I just couldn't get it to work with ListRewrite. I don't know what I was doing wrong. So I wrote a visitor to store all the FieldDeclarations in a map.
#Override
public boolean visit(FieldDeclaration node) {
for (Object obj : node.fragments()) {
listStringVarMap.put(((VariableDeclarationFragment) obj).getName().toString(), node);
}
return false;
}
I looped through the map and inserted the annotation nodes as a modifiers, for the declarations that met my criteria. Please do remember to turn on recormodifications for the compilation unit you are modifying.
CompilationUnit cu = jFileAst.getEquivCompilUnit();
cu.recordModifications();
FieldDeclaration fldDecl = lVrblDet.listStringVarMap.get(propName);
importVo = (JavaAnnotImportVo) javaAstNodeCreator
.createASTNode(SpringAnnotationEnum.AutowireAnnotation, ast);
cu.imports().add(importVo.getImpDecl());
fldDecl.modifiers().add(0, importVo.getAnnotNode());
Finally write to file on disk/save back. Formatting(optional) before saving is a good idea, because the node insertions mess up with the code formatting.
Is there a way of mimicking MonoBehaviour copy semantics in ScriptableObjects?
Say I have a MonoBehaviour like so:
public class DummyClassBehaviour : MonoBehaviour {
public DummyClass DummyClassTest; //ScriptableObject
public DummyClassBehaviour DummyBehaviourTest; //Another DummyClassBehaviour
}
And a ScriptableObject:
public class DummyClass : ScriptableObject {
public string Text = "";
}
When I duplicate(CTRL+D) a GameObject w/ DummyClassBehaviour attached, 'DummyBehaviourTest' copies as you would expect: If it references a MonoBehaviour in the GameObject I'm copying, the copy mechanism updates the reference to the same MonoBehaviour type in the new GameObject. If it references a MonoBehaviour in another GameObject, that reference remains unchanged.
The ScriptableObject, on the other hand, always references the original. So I end up with N GameObject's all sharing the same ScriptableObject (DummyClass) from the original GameObject. I'm using ScriptableObjects to allow serialization of non-Monobehaviour data classes.
As far as I can tell, and please someone correct me if I'm wrong, you cannot modify the serialization behavior of a ScriptableObject to match that of a MonoBehaviour. Namely that it should update references if a duplicate is made.
Instead I opted for a less than optimal solution, but it works. My class is assigned a unique identifier that gets serialized like everything else. I use this ID in DummyBehaviour.Awake() to create a lookup table that I can then use to reassign my DummyClass.
I'm not going to accept my own answer because I don't feel it answers my original question fully, but it's related:
[System.Serializable]
public class DummyClass {
// Unique id is assigned by DummyBehaviour and is unique to the game object
// that DummyBehaviour is attached to.
public int UniqueID = -1;
public string Text = "";
// Override GetHashCode so Dictionary lookups
public override int GetHashCode(){
int hash = 17;
hash = hash * 31 + UniqueID;
return hash;
}
// override equality function, allows dictionary to do comparisons.
public override bool Equals(object obj)
{
if (object.ReferenceEquals(obj, null))return false;
DummyClass item = obj as DummyClass;
return item.UniqueID == this.UniqueID;
}
// Allow checks of the form 'if(dummyClass)'
public static implicit operator bool(DummyClass a)
{
if (object.ReferenceEquals(a, null)) return false;
return (a.UniqueID==-1)?false:true;
}
public static bool operator ==(DummyClass a, DummyClass b)
{
if (object.ReferenceEquals(a, null))
{
return object.ReferenceEquals(b, null);
}
return a.Equals(b);
}
public static bool operator !=(DummyClass a, DummyClass b)
{
if (object.ReferenceEquals(a, null))
{
return object.ReferenceEquals(b, null);
}
return !a.Equals(b);
}
}
And my MonoBehaviour:
[ExecuteInEditMode]
public class DummyBehaviour : MonoBehaviour {
public List<DummyClass> DummyClasses = new List<DummyClass>();
// reassign references based on uniqueid.
void Awake(){
Dictionary<DummyClass,DummyClass> dmap = new Dictionary<DummyClass,DummyClass>();
// iterate over all dummyclasses, reassign references.
for(int i = 0; i < DummyClasses.Count; i++){
DummyClass2 d = DummyClasses[i];
if(dmap.ContainsKey(d)){
DummyClasses[i] = dmap[d];
} else {
dmap[d] = d;
}
}
DummyClasses[0].Text = "All items same";
}
// helper function, for inspector contextmenu, to add more classes from Editor
[ContextMenu ("AddDummy")]
void AddDummy(){
if(DummyClasses.Count==0)DummyClasses.Add(new DummyClass{UniqueID = 1});
else {
// Every item after 0 points to zero, serialization will remove refs during deep copy.
DummyClasses.Add(DummyClasses[0]);
}
UnityEditor.EditorUtility.SetDirty(this);
}
}
I have a GWT Cell Tree that I use to display a file structure from a CMS. I am using a AsyncDataProvider that loads data from a custom RPC class I created. I also have a Web Socket system that will broadcast events (File create, renamed, moved, deleted etc) from other clients also working in the system.
What I am trying to wrap my head around is when I recieve one of these events, how I correctly update my Cell Tree?
I suppose this problem would be analogus to having two instances of my Cell Tree on the page, which are presenting the same server-side data and wanting to ensure that when the user updated one, that the other updated as well, via using the EventBus.
I feel this should be pretty simple but I have spent about 6 hours on it now with no headway. My code is included below:
NOTE: I am not using RequestFactory even though it may look like I am it is my custom RPC framework. Also, FileEntity is just a simple representation of a file which has a name accessible by getName().
private void drawTree() {
// fileService is injected earlier on and is my own custom rpc service
TreeViewModel model = new CustomTreeModel(new FileDataProvider(fileService));
CellTree tree = new CellTree(model, "Root");
tree.setAnimationEnabled(true);
getView().getWorkspace().add(tree);
}
private static class CustomTreeModel implements TreeViewModel {
// I am trying to use a single AsyncDataProvider so I have a single point of loading data which I can manipulate (Not sure if this is the correct way to go)
public CustomTreeModel(FileDataProvider dataProvider) {
this.provider = provider;
}
public <T> NodeInfo<?> getNodeInfo(final T value) {
if (!(value instanceof FileEntity)) {
// I already have the root File loaded in my presenter, if we are at the root of the tree, I just add it via a list here
ListDataProvider<FileEntity> dataProvider = new ListDataProvider<FileEntity>();
dataProvider.getList().add(TreeWorkspacePresenter.rootFolder);
return new DefaultNodeInfo<FileEntity>(dataProvider,
new FileCell());
} else {
// Otherwise I know that we are loading some tree child data, and I invoke the AsyncProvider to load it from the server
provider.setFocusFile(value);
return new DefaultNodeInfo<FileEntity>(provider,
new FileCell());
}
}
public boolean isLeaf(Object value) {
if(value == null || value instanceof Folder)
return false;
return true;
}
}
public class FileDataProvider extends AsyncDataProvider<FileEntity> {
private FileEntity focusFile;
private FileService service;
#Inject
public FileDataProvider(FileService service){
this.service = service;
}
public void setFocusFile(FileEntity focusFile){
this.focusFile = focusFile;
}
#Override
protected void onRangeChanged(HasData<FileEntity> display) {
service.getChildren(((Folder) focusFile),
new Reciever<List<FileEntity>>() {
#Override
public void onSuccess(List<FileEntity> files) {
updateRowData(0, files);
}
#Override
public void onFailure(Throwable error) {
Window.alert(error.toString());
}
});
}
}
/**
* The cell used to render Files.
*/
public static class FileCell extends AbstractCell<FileEntity> {
private FileEntity file;
public FileEntity getFile() {
return file;
}
#Override
public void render(Context context, FileEntity file, SafeHtmlBuilder sb) {
if (file != null) {
this.file = file;
sb.appendEscaped(file.getName());
}
}
}
Currently there is no direct support for individual tree item refresh even in the latest gwt version.
But there is a workaround for this. Each tree item is associated with an value. Using this value you can get the corresponding tree item.
In your case, i assume, you know which item to update/refresh ie you know which File Entity has changed. Use this file entity to search for the corresponding tree item. Once you get the tree item you just need to expand and collapse or collapse and expand its parent item. This makes parent item to re-render its children. Your changed file entity is one among the children. So it get refreshed.
public void refreshFileEntity(FileEntity fileEntity)
{
TreeNode fileEntityNode = getFileEntityNode(fileEntity, cellTree.getRootTreeNode()
// For expnad and collapse run this for loop
for ( int i = 0; i < fileEntityNode.getParent().getChildCount(); i++ )
{
if ( !fileEntityNode.getParent().isChildLeaf( i ) )
{
fileEntityNode.getParent().setChildOpen( i, true );
}
}
}
public TreeNode getFileEntityNode(FileEntity fileEntity, TreeNode treeNode)
{
if(treeNode.getChildren == null)
{
return null;
}
for(TreeNode node : treeNode.getChildren())
{
if(fileEntity.getId().equals( node.getValue.getId() ))
{
return node;
}
getEntityNode(fileEntity, node);
}
}
You can use the dataprovider to update the celltree.
You can update the complete cell tree with:
provider.setList(pList);
provider.refresh();
If you want to update only a special cell you can get the listwrapper from the dataprovider and only set one element.
provider.getList().set(12, element);