Persisting a domain model with JDO 2.0 - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 175

Listing 5.4 ExecuteNamedQueryWithMapCallback

public class ExecuteNamedQueryWithMapCallback implements
JdoCallback {

private String queryName;

private Map parameters;

private Class type;

public ExecuteNamedQueryWithMapCallback
bbbbbbbbbbbb ➥ (String queryName,
Map parameters,
Class type) {
this.queryName = queryName;
this.parameters = parameters;
this.type = type;
}

B Creates ExecuteNamedQuery
WithMapCallback

C Tests for
equality

public boolean equals(Object other) {
if (other == null)
return false;
if (!(other instanceof ExecuteNamedQueryWithMapCallback))
return false;

ExecuteNamedQueryWithMapCallback x =
(ExecuteNamedQueryWithMapCallback) other;

return queryName.equals(x.queryName)
&& parameters.equals(x.parameters)
&& type.equals(x.type);
}
public int hashCode() {
return queryName.hashCode()
^ parameters.hashCode()
^ type.hashCode();
}

D Executes the
named query

public Object doInJdo(PersistenceManager pm)
throws JDOException {
Query query = pm.newNamedQuery(type, queryName);
return query.executeWithMap(parameters);
}
}

Let's take a closer look at ExecuteNamedQueryWithMapCallback :