net.anotheria.asg.util.data.DataObjectUtils Maven / Gradle / Ivy
package net.anotheria.asg.util.data;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import net.anotheria.asg.data.DataObject;
import net.anotheria.util.ArrayUtils;
/**
* Utilities for handling and manipulating single or multiple objects of any subclass of DataObject.
*
* @author denis
* @version $Id: $Id
*/
public class DataObjectUtils {
private DataObjectUtils() {
}
/**
* Creates for the List of dataObjects same ordered List of dataObjects' IDs except the case when null id was happened.
*
* @param dataObjects - objects for which IDs List is created
* @return List of ID's
*/
public static List getIds(List dataObjects){
List ret = new ArrayList(dataObjects.size());
for(T d: dataObjects)
ret.add(d.getId());
return ret;
}
/**
* Returns for the dataObjects the List that is filled with specified property values of each dataObject.
*
* @param propertyName - name of the property to get from dataObjects
* @param propertyClass - class of the property
* @param dataObjects - dataObjects to get property values.
* @return List that is filled with specified property values
*/
public static List getProperties(String propertyName, Class
propertyClass, List dataObjects){
List ret = new ArrayList
(dataObjects.size());
for(T d: dataObjects)
ret.add(propertyClass.cast(d.getPropertyValue(propertyName)));
return ret;
}
/**
* Creates Map of dataObjects by their IDs.
*
* @param dataObjects - dataObjects to create map.
* @return Map of pairs ID - dataObject
*/
public static Map createMapById(List dataObjects){
Map ret = new HashMap();
for(T d: dataObjects)
ret.put(d.getId(), d);
return ret;
}
/**
* Creates Map of dataObjects by specified property. Property value must be unique (key property) for each dataObject.
* In other case only one dataObject with not unique property will be added to the map.
*
* @param propertyName - name of the property by which Map is created
* @param propertyClass - class of the property
* @param dataObjects - dataObjects to create map.
* @return Map of pairs Property Value - dataObject
*/
public static Map createMapByKeyProperty(String propertyName, Class propertyClass, List dataObjects){
Map ret = new HashMap();
for(T d: dataObjects)
ret.put(propertyClass.cast(d.getPropertyValue(propertyName)), d);
return ret;
}
/**
* Creates Map of groups (arrays) of dataObjects by specified property. DataObjects with equal property values are put to the same group.
*
* @param propertyName - name of the property by which Map is created
* @param propertyClass - class of the property
* @param dataObjects - dataObjects to create map.
* @return Map of pairs Property Value - dataObjects group
*/
@SuppressWarnings("unchecked")
public static Map createMapByProperty(String propertyName, Class propertyClass, List dataObjects){
Map ret = new HashMap();
for(T d: dataObjects){
P propertyValue = propertyClass.cast(d.getPropertyValue(propertyName));
T[] data = ret.get(propertyValue);
if(data == null)
data = (T[])java.lang.reflect.Array.newInstance(d.getClass(), 0);
ret.put(propertyValue, ArrayUtils.addToArray(data, d));
}
return ret;
}
}