Request for help with generics-related compiler warnings
Greetings, Wicket Wizards,
I am updating a sample Wicket program from 1.3.6 to 1.4.3 and running into
a few generics-related issues. I am hoping you folks can quickly set me
straight. My code appears to run successfully and passes its JUnit tests,
despite the warnings I would like to remove. The purpose of the code is
to demonstrate simple use of Forms, Lists, and Tables and associated
testing of these constructs using WicketTester.
First off, although you hopefully will not need to, you can download the
sample code from here:
http://ics-wicket-examples.googlecode.com/files/wicket-example02-1.0.1106.zip
Unzip, cd into the directory, and type ant, It should download Ivy, then
download Wicket, Jetty, SLF4J, and JUnit, and finally compile the system,
generating the following generic-related warnings. Let me now show you
what they are:
Problem 1: please take a look at line 39 of TablePage.java:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TablePage.java
The problematic line is:
new ListDataProvider(contacts)
and obviously requires a generic argument, but neither of the following
work:
new ListDataProviderContact(contacts) // my preferred guess
new ListDataProviderListContact(contacts)
The compiler warning is:
[javac] TablePage.java:39: warning: [unchecked] unchecked call to
ListDataProvider(java.util.ListT) as a member of the raw type
org.apache.wicket.markup.repeater.data.ListDataProvider
[javac] new ListDataProvider(contacts)) {
[javac] ^
[javac] TablePage.java:39: warning: [unchecked] unchecked conversion
[javac] found :
org.apache.wicket.markup.repeater.data.ListDataProvider
[javac] required:
org.apache.wicket.markup.repeater.data.IDataProviderjava.util.Listedu.hawaii.wicket.TablePage.Contact
[javac] new ListDataProvider(contacts)) {
[javac] ^
Problem 2: on line 49 of the same file, TablePage.java:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TablePage.java
The line is:
Contact contact = (Contact) item.getModelObject();
Since the preceding line provides a parameterized declaration of item
(ItemListContact item), I don't understand why I need to cast here.
But the code does not compile if I don't. Then, I get the following
warning:
[javac] TablePage.java:49: warning: [unchecked] unchecked cast
[javac] found : java.util.Listedu.hawaii.wicket.TablePage.Contact
[javac] required: edu.hawaii.wicket.TablePage.Contact
[javac] Contact contact = (Contact) item.getModelObject();
[javac]
^
Problem 3: WicketTester and generics.
I clearly don't understand how to test with WicketTester. Take a look at
lines 37-39 of TestListPage:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TestListPage.java
This is a mess, and generates the following warning:
[javac] TestListPage.java:39: warning: [unchecked] unchecked cast
[javac] found : capture#294 of ?
[javac] required: java.util.Listjava.lang.String
[javac] ListString metaVars = (ListString)
varsModel.getObject();
I have a feeling that my whole approach to getting values out of the table
for testing is wrong, but I don't know what the correct approach is.
If any of you can give me a hand, the first Mai Tai is on me the next time
you are in Hawaii.
Thanks!
Philip
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Re: Request for help with generics-related compiler warnings
This does not produces any warnings
public class TablePage extends WebPage {
/** Support serialization. */
private static final long serialVersionUID = 1L;
/**
* Creates a page containing a table of Contacts.
*/
public TablePage() {
// Initialize our list of Contact instances.
// Use ArrayList, not List, since ArrayList is Serializable.
ArrayListContact contacts = new ArrayListContact();
contacts.add(new Contact(Joe Smith, 123 Honu St., Kailua, HI
96734));
contacts.add(new Contact(Sally Forth, 456 Alapapa St., Honolulu, HI
96813));
// Create the dataview to display our list of contact instances.
// Note that the following commented out line is OK from a type
perspective.
// ListDataProviderContact test = new
ListDataProviderContact(contacts);
// But we can't say new ListDataProviderContact in the next line. Why?
DataViewContact dataView = new DataViewContact(ContactList,
new ListDataProviderContact(contacts)) {
/** For serialization. */
private static final long serialVersionUID = 1L;
/**
* Display each row in the table.
*
* @param item A Contact instance to be displayed.
*/
public void populateItem(ItemContact item) {
Contact contact = (Contact) item.getModelObject();
item.add(new Label(Name, contact.getName()));
item.add(new Label(Address, contact.getAddress()));
}
};
// Add the dataview to the TablePage.
add(dataView);
}
/**
* An inner class implementing a record of data to be displayed as a row
in the table. Package
* private so that TestTablePage can access it.
*
* @author Philip Johnson
*/
static class Contact implements Serializable {
/** Support serialization. */
private static final long serialVersionUID = 2L;
private String name;
private String address;
/**
* Create a new contact, given a name and an address.
*
* @param name The name.
* @param address The address.
*/
public Contact(String name, String address) {
this.name = name;
this.address = address;
}
/**
* Return the name.
*
* @return The name of this contact.
*/
public String getName() {
return name;
}
/**
* Return the address of this contact.
*
* @return The address.
*/
public String getAddress() {
return address;
}
}
}
at least on my IDE
Best,
Ernesto
On Sat, Nov 7, 2009 at 9:42 AM, Philip Johnson john...@hawaii.edu wrote:
Greetings, Wicket Wizards,
I am updating a sample Wicket program from 1.3.6 to 1.4.3 and running into
a few generics-related issues. I am hoping you folks can quickly set me
straight. My code appears to run successfully and passes its JUnit tests,
despite the warnings I would like to remove. The purpose of the code is to
demonstrate simple use of Forms, Lists, and Tables and associated testing of
these constructs using WicketTester.
First off, although you hopefully will not need to, you can download the
sample code from here:
http://ics-wicket-examples.googlecode.com/files/wicket-example02-1.0.1106.zip
Unzip, cd into the directory, and type ant, It should download Ivy, then
download Wicket, Jetty, SLF4J, and JUnit, and finally compile the system,
generating the following generic-related warnings. Let me now show you
what they are:
Problem 1: please take a look at line 39 of TablePage.java:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TablePage.java
The problematic line is:
new ListDataProvider(contacts)
and obviously requires a generic argument, but neither of the following
work:
new ListDataProviderContact(contacts) // my preferred guess
new ListDataProviderListContact(contacts)
The compiler warning is:
[javac] TablePage.java:39: warning: [unchecked] unchecked call to
ListDataProvider(java.util.ListT) as a member of the raw type
org.apache.wicket.markup.repeater.data.ListDataProvider
[javac] new ListDataProvider(contacts)) {
[javac] ^
[javac] TablePage.java:39: warning: [unchecked] unchecked conversion
[javac] found : org.apache.wicket.markup.repeater.data.ListDataProvider
[javac] required:
org.apache.wicket.markup.repeater.data.IDataProviderjava.util.Listedu.hawaii.wicket.TablePage.Contact
[javac] new ListDataProvider(contacts)) {
[javac] ^
Problem 2: on line 49 of the same file, TablePage.java:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TablePage.java
The line is:
Contact contact = (Contact) item.getModelObject();
Since the preceding line provides a parameterized declaration of item
(ItemListContact item), I don't understand why I need to cast here. But
the code does not compile if I don't. Then, I get the following warning:
[javac] TablePage.java:49:
Re: Request for help with generics-related compiler warnings
and the casting is no longer needed
DataViewContact dataView = new DataViewContact(ContactList,
new ListDataProviderContact(contacts)) {
/** For serialization. */
private static final long serialVersionUID = 1L;
/**
* Display each row in the table.
*
* @param item A Contact instance to be displayed.
*/
public void populateItem(ItemContact item) {
Contact contact = item.getModelObject();
item.add(new Label(Name, contact.getName()));
item.add(new Label(Address, contact.getAddress()));
}
};
Regards,
Ernesto
On Sat, Nov 7, 2009 at 10:14 AM, Ernesto Reinaldo Barreiro
reier...@gmail.com wrote:
This does not produces any warnings
public class TablePage extends WebPage {
/** Support serialization. */
private static final long serialVersionUID = 1L;
/**
* Creates a page containing a table of Contacts.
*/
public TablePage() {
// Initialize our list of Contact instances.
// Use ArrayList, not List, since ArrayList is Serializable.
ArrayListContact contacts = new ArrayListContact();
contacts.add(new Contact(Joe Smith, 123 Honu St., Kailua, HI
96734));
contacts.add(new Contact(Sally Forth, 456 Alapapa St., Honolulu, HI
96813));
// Create the dataview to display our list of contact instances.
// Note that the following commented out line is OK from a type
perspective.
// ListDataProviderContact test = new
ListDataProviderContact(contacts);
// But we can't say new ListDataProviderContact in the next line.
Why?
DataViewContact dataView = new DataViewContact(ContactList,
new ListDataProviderContact(contacts)) {
/** For serialization. */
private static final long serialVersionUID = 1L;
/**
* Display each row in the table.
*
* @param item A Contact instance to be displayed.
*/
public void populateItem(ItemContact item) {
Contact contact = (Contact) item.getModelObject();
item.add(new Label(Name, contact.getName()));
item.add(new Label(Address, contact.getAddress()));
}
};
// Add the dataview to the TablePage.
add(dataView);
}
/**
* An inner class implementing a record of data to be displayed as a row
in the table. Package
* private so that TestTablePage can access it.
*
* @author Philip Johnson
*/
static class Contact implements Serializable {
/** Support serialization. */
private static final long serialVersionUID = 2L;
private String name;
private String address;
/**
* Create a new contact, given a name and an address.
*
* @param name The name.
* @param address The address.
*/
public Contact(String name, String address) {
this.name = name;
this.address = address;
}
/**
* Return the name.
*
* @return The name of this contact.
*/
public String getName() {
return name;
}
/**
* Return the address of this contact.
*
* @return The address.
*/
public String getAddress() {
return address;
}
}
}
at least on my IDE
Best,
Ernesto
On Sat, Nov 7, 2009 at 9:42 AM, Philip Johnson john...@hawaii.edu wrote:
Greetings, Wicket Wizards,
I am updating a sample Wicket program from 1.3.6 to 1.4.3 and running into
a few generics-related issues. I am hoping you folks can quickly set me
straight. My code appears to run successfully and passes its JUnit tests,
despite the warnings I would like to remove. The purpose of the code is to
demonstrate simple use of Forms, Lists, and Tables and associated testing of
these constructs using WicketTester.
First off, although you hopefully will not need to, you can download the
sample code from here:
http://ics-wicket-examples.googlecode.com/files/wicket-example02-1.0.1106.zip
Unzip, cd into the directory, and type ant, It should download Ivy, then
download Wicket, Jetty, SLF4J, and JUnit, and finally compile the system,
generating the following generic-related warnings. Let me now show you
what they are:
Problem 1: please take a look at line 39 of TablePage.java:
http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TablePage.java
The problematic line is:
new ListDataProvider(contacts)
and obviously requires a generic argument, but neither of the following
work:
new ListDataProviderContact(contacts) // my preferred guess
new ListDataProviderListContact(contacts)
The compiler warning is:
[javac] TablePage.java:39: warning: [unchecked] unchecked call to
ListDataProvider(java.util.ListT) as a member of the raw type
org.apache.wicket.markup.repeater.data.ListDataProvider
[javac] new ListDataProvider(contacts)) {
[javac] ^
[javac] TablePage.java:39: warning: [unchecked] unchecked
Re: Request for help with generics-related compiler warnings
Thanks so much, both of you! Anyone have any ideas about the WicketTester code? Problem 3: WicketTester and generics. I clearly don't understand how to test with WicketTester. Take a look at lines 37-39 of TestListPage: http://code.google.com/p/ics-wicket-examples/source/browse/trunk/example02/src/edu/hawaii/wicket/TestListPage.java This is a mess, and generates the following warning: [javac] TestListPage.java:39: warning: [unchecked] unchecked cast [javac] found : capture#294 of ? [javac] required: java.util.Listjava.lang.String [javac] ListString metaVars = (ListString) varsModel.getObject(); Cheers, Philip -- View this message in context: http://old.nabble.com/Request-for-help-with-generics-related-compiler-warnings-tp26242997p26245535.html Sent from the Wicket - User mailing list archive at Nabble.com. - To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org
