org.apache.cayenne.reflect.IdMapKeyAccessor Maven / Gradle / Ivy
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package org.apache.cayenne.reflect;
import java.util.Map;
import org.apache.cayenne.ObjectId;
import org.apache.cayenne.Persistent;
/**
* A stateless read-only accessor of the map key value that is based on the Persistent
* object id. For single-column ID's the accessor returns a single value (e.g. an
* Integer). For multi-column ID's it returns the ObjectId.
*
* @since 3.0
*/
public class IdMapKeyAccessor implements Accessor {
public static final Accessor SHARED_ACCESSOR = new IdMapKeyAccessor();
public String getName() {
return "IdMapKeyAccessor";
}
public Object getValue(Object object) throws PropertyException {
if (object instanceof Persistent) {
ObjectId id = ((Persistent) object).getObjectId();
if (id.isTemporary()) {
return id;
}
Map map = id.getIdSnapshot();
if (map.size() == 1) {
Map.Entry pkEntry = map.entrySet().iterator().next();
return pkEntry.getValue();
}
return id;
}
else {
throw new IllegalArgumentException("Object must be Persistent: " + object);
}
}
public void setValue(Object object, Object newValue) throws PropertyException {
throw new UnsupportedOperationException("Setting map key is not supported");
}
}