I've created a very simple page which executes your JPQL query and shows the results as JSON, using GSON.
It has no features besides a textarea and the formatted output.
Here it is.
Before the code, let me warn you that GSON can't deal with circular references on it's own.
You need to cut them at appropriate places, by either using @XmlTransient to prevent that particular member to be serialized,
or by serializing it differently, e.g. using toString(). I think GSON follows most, if not all, JAXB annotations, so that's the way.
First, add GSON to classpath.
<!-- GSON - for JpaQueryPage --> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.2.2</version> </dependency>
And here is the Wicket page - HTML and Java.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>JPA Query Page</title> </head> <body> <form wicket:id="form"> <textarea wicket:id="query" style="min-width: 60em;" rows="5">SELECT p FROM Product p</textarea> <br/> Example: <code>SELECT p FROM Product p LEFT JOIN FETCH p.customFields</code> <br/> <input type="submit" value="Perform"/> <table style="font-family: monospace; font-size: 8pt;"> <tr wicket:id="result"> <td wicket:id="item" style="white-space: pre">Some query result...</td> </tr> </table> </form> </body> </html>
package org.jboss.essc.web.pages.test;
import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.form.TextArea;
import org.apache.wicket.markup.html.list.ListItem;
import org.apache.wicket.markup.html.list.ListView;
import org.apache.wicket.model.CompoundPropertyModel;
import org.jboss.essc.web.model.ProductCustomField;
import org.jboss.essc.web.model.ReleaseCustomField;
/**
*
* @author Ondrej Zizka
*/
public class JpaQueryPage extends WebPage {
@PersistenceContext EntityManager em;
private String query = "";
private List<Object> result = Collections.EMPTY_LIST;
public JpaQueryPage() {
Form form = new Form("form", new CompoundPropertyModel(this) ){
@Override protected void onSubmit() {
try {
result = em.createQuery( query ).getResultList();
}
catch (Exception ex){
result = new ArrayList(2);
result.add( ex );
result.add( query );
}
}
};
add( form );
form.add( new TextArea("query") );
this.query =
"SELECT rel, rel.product FROM Release rel\n"
+ " LEFT JOIN FETCH rel.product.customFields\n"
+ " LEFT OUTER JOIN FETCH rel.customFields\n"
+ " WHERE rel.product.name = 'EAP' AND rel.version = '6.0.1.GA'";
form.add( new ListView("result") {
@Override
protected void populateItem( ListItem item ) {
String content;
try {
content = toJSON( item.getModelObject() );
} catch (Throwable ex){
try {
content = item.getModelObject().toString();
} catch (Exception ex2) {
content = item.getModelObject().getClass() + " but toString() threw: " + ex2.toString();
}
}
item.add( new Label("item", content) );
}
} );
}// const
/**
* Convert any object to JSON.
*/
private static String toJSON( Object object ) {
//Gson gson = new Gson();
Gson gson = new GsonBuilder()
.setPrettyPrinting()
.addDeserializationExclusionStrategy( new ExclusionStrategy() {
@Override public boolean shouldSkipField( FieldAttributes f ) {
return false;
}
@Override public boolean shouldSkipClass( Class<?> clazz ) {
if( ReleaseCustomField.class.equals( clazz ) )
return true;
if( ProductCustomField.class.equals( clazz ) )
return true;
return false;
}
} )
.create();
return gson.toJson(object);
}
}// class
HTH.
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