How to transfer an array list of objects over the wire through GWTP action - gwt-platform

Question

I am trying to create an action in which the server needs to response an array list of objects over the wire to the client through GWTP Action.
Category class
package com.business.share;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.Id;
public class Category implements Serializable{
Long id;
protected String name;
protected String description;
protected boolean status;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public boolean getStatus() {
return status;
}
public void setStatus(boolean status) {
this.status = status;
}
}
GetCategories class
package com.business.client.action;
import java.util.ArrayList;
import com.gwtplatform.dispatch.shared.ActionImpl;
import com.business.client.action.GetCategoriesResult;
import com.business.share.Category;
public class GetCategories extends ActionImpl<GetCategoriesResult> {
private ArrayList<Category> categories;
#SuppressWarnings("unused")
public GetCategories() {
// For serialization only
}
public GetCategories(ArrayList<Category> categories) {
this.categories = categories;
}
public ArrayList<Category> getCategories() {
return categories;
}
}
GetCategoriesResult class
package com.business.client.action;
import java.util.ArrayList;
import com.gwtplatform.dispatch.shared.Result;
import com.business.share.Category;
public class GetCategoriesResult implements Result {
private ArrayList<Category> categories;
#SuppressWarnings("unused")
private GetCategoriesResult() {
// For serialization only
}
public GetCategoriesResult(ArrayList<Category> categories) {
this.categories = categories;
}
public ArrayList<Category> getCategories() {
return categories;
}
}
GetCategoriesActionHandler class
package com.business.server.handler;
import java.util.ArrayList;
import com.gwtplatform.dispatch.server.actionhandler.ActionHandler;
import com.business.client.action.GetCategories;
import com.business.client.action.GetCategoriesResult;
import com.business.share.Category;
import com.google.inject.Inject;
import com.googlecode.objectify.Objectify;
import com.googlecode.objectify.ObjectifyService;
import com.googlecode.objectify.Query;
import com.gwtplatform.dispatch.server.ExecutionContext;
import com.gwtplatform.dispatch.shared.ActionException;
public class GetCategoriesActionHandler implements
ActionHandler<GetCategories, GetCategoriesResult> {
#Inject
public GetCategoriesActionHandler() {
}
#Override
public GetCategoriesResult execute(GetCategories action,
ExecutionContext context) throws ActionException {
ArrayList<Category> categories = new ArrayList<Category>();
// dummy data
Category cat1 = new Category();
cat1.setName("cat1");
cat1.setDescription("cat1 desc");
cat1.setStatus(true);
Category cat2 = new Category();
cat1.setName("cat2");
cat1.setDescription("cat2 desc");
cat1.setStatus(false);
categories.add(cat1);
categories.add(cat2);
return new GetCategoriesResult(categories);
}
#Override
public void undo(GetCategories action, GetCategoriesResult result,
ExecutionContext context) throws ActionException {
}
#Override
public Class<GetCategories> getActionType() {
return GetCategories.class;
}
}
And this is a piece of code in CategoryPresenter, which sends async to server.
#Override
protected void onReset() {
super.onReset();
GetCategories getCategoriesAction = new GetCategories();
dispatchAsync.execute(getCategoriesAction, getCategoriesCallback);
}
private final AsyncCallback<GetCategoriesResult> getCategoriesCallback =
new AsyncCallback<GetCategoriesResult>() {
#Override
public void onFailure(Throwable caught) {
}
#Override
public void onSuccess(GetCategoriesResult result) {
getView().getCategoryListBox().clear();
ArrayList<Category> categories = result.getCategories();
for(Category category : categories) {
getView().getCategoryListBox().addItem(category.getName());
}
}
};
I don't know what wrong with this piece of code, but GWT compiler always gives error like this.
Compiling module com.business.Business
Validating newly compiled units
Ignored 3 units with compilation errors in first pass.
Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.
Finding entry point classes
[ERROR] Errors in 'file:/.blah..blah..blah../businessapp/src/com/business/client/presenter/CategoryPresenter.java'
[ERROR] Line 75: No source code is available for type com.business.share.Category; did you forget to inherit a required module?
[ERROR] Errors in 'file:/.blah..blah..blah../businessapp/src/com/business/client/action/GetCategoriesResult.java'
[ERROR] Line 11: No source code is available for type com.business.share.Category; did you forget to inherit a required module?
[ERROR] Unable to find type 'com.business.client.Business'
[ERROR] Hint: Previous compiler errors may have made this type unavailable
[ERROR] Hint: Check the inheritance chain from your module; it may not be inheriting a required module or a module may not be adding its source path entries properly
Following this error message, it means, com.business.share.Category is not found, but this file is physically stored in that package already. I don't understand why GWT could not find it. I noticed anywhere that I make call Category class, it brings this error always.
Somebody's got an idea on what's going on?
[EDIT]
The problem is solved.
In my Business.gwt.xml, I have
<source path='shared'/>
But my share package is com.business.share (without d)
I just rename the package name from share to shared.

Answer 1

Try to add an empty constructor to the Category class.