Content

• What is UJO?
• How to write the first UJO object?
• Default values
• Interface UjoExt
• How to create the JavaBean?
• XML serialization
• Support of the JTable component
• Support the object-relation mapping (ORM)
• What about the extensions?
• Performance
• Other possibilities of usage?
• Referential Application
• Project home
• License
• FAQ
• Release notes

What is UJO ?

• an easy object introspection without a heavy PropertyDescriptor implementation
• value type safe solution
• a transfer of the UJO object properties (not values) by a collection
• the core of the building has two interfaces for an easy implementation
• the object-relation mapping (ORM) support

• the possibility to copy all or selected attributes from source to new object by a one statement (method)
• clone the object by a selected depth
• use a generic comparator
• find a property by its text name
• write a value by the found property to an another object or a collection of objects
• restore a default value of the property
• easy text conversions of the properties
• simplified work with an arrays (you can't initialize array before add method e.g.)
• generic toString() method for easy debugging
• easy visualization of UJO object(s) by JTable
• easy persistence of UJO to different formats include XML
• criteria tool for searching the Ujo objects in list
• the object itself recommends the availability of its attributes
• there is possible to implement a listener to only one place for each properties include children
• support of JavaBeans
• checking by unit tests
• tiny framework without further dependencies
• open source

• UjoProperty.setValue(Ujo, VALUE) - to write the value into the object and
• UjoProperty.getValue(Ujo) - to read the value (you can use an alias called of() optionally)

• MapUjo - easy for developers to implement with a sufficient performance for common applications based on the object HashMap
• ArrayUjo - hight performance objects are comparable to the speed of the JavaBeans, implemented by the object array
• BeanUjo - the implementation maps the keys directly to the methods of JavaBean object using Java reflection

How ?

The class code

import org.ujoframework.implementation.map.*;
public class Person extends MapUjo {
 
  public static final UjoProperty<Person,String > NAME = newProperty("Name", String.class);
  public static final UjoProperty<Person,Boolean> MALE = newProperty("Male", Boolean.class);
  public static final UjoProperty<Person,Double > CASH = newProperty("Cash", Double.class);
 
}

1. Person.writeValue(UjoProperty, Object), or
2. UjoProperty.setValue(person, Object).

import static org.Person.*;
Person person = new Person();

// Writing:
NAME.setValue(person, "Paul Ponec");
MALE.setValue(person, true);
CASH.setValue(person, 34.5);

// Reading:
String  name = NAME.of(person); // method of() is an alias for UjoProperty.getValue()
boolean male = MALE.of(person);
double  cash = CASH.of(person);

import static org.Person.*;
Person person = new Person(); // An extension of MapUjoExt

// Writing:
person.set(NAME, "Paul Ponec");
person.set(MALE, true);
person.set(CASH, 34.5);

// Reading:
String  name = person.get(NAME);
boolean male = person.get(MALE);
double  cash = person.get(CASH);

• to complement the generic data types to the right side of the expression according to the left side, or
• to switch off the -Xlint:unchecked parameter. The switched off parameter is implied to the IDE NetBeans setting.
• the class can be equipped an annotation @SuppressWarnings("unchecked")
  I've chosen this possibility myself, the code is getting clearer and in the case of collision in the same line it´s possible to find it out easily.
• since version 0.72 is possible to use a type safe method newProperty(name, type) pro building a Property object.

The implementation of the equals() method

public boolean equals(Object obj) {
  return UjoManager.getInstanceManager().equals(this, (Ujo) obj );
}

Implementation of the clone() method

public Object clone() {
  return UjoManager.getInstanceManager().clone(this, 1, null);
}

Implementation of the hash() method

public int hash() {
  return UjoManager.getInstanceManager().getHash(this);
}

Interface UjoExt

Default values

{ 
  private Double cash = 10.0; 
}

{ 
  public static final UjoProperty<Person, Double> CASH = newProperty("Cash", 10.0);
}

• the default value is available even if the original property value is changed
• if any property value is changed to a NULL then the property method returns the default value (the feature can be suppressd by overriding method: Ujo.readProperty)
• interface UjoProperty provides some methods to use the default value

How to create the JavaBean?

import org.ujoframework.implementation.map.*;
public class Person extends MapUjo {

  public static final UjoProperty<Person, String> NAME = newProperty("name", String.class);
  public static final UjoProperty<Person, Double> CASH = newProperty("cash", Double.class);
    
  public void setName(String name) {
    NAME.setValue(this, name);
  }
  public String getName() {
    return NAME.getValue(this);
  }
  public void setCash(Double cash) {
    CASH.setValue(this, cash);
  }
  public Double getCash() {
    return CASH.getValue(this);
  }
}

import org.ujoframework.implementation.bean.*;
public class Person extends BeanUjo {

  public static final BeanProperty<Person, String> NAME = newProperty("name", String.class);
  public static final BeanProperty<Person, Double> CASH = newProperty("cash", Double.class);
  
  private String myname;
  private Double mycash;
  
  public void setName(String name) {
    this.myname = name;
  }
  public String getName() {
    return myname;
  }
  public void setCash(Double cash) {
    this.mycash = cash;
  }
  public Double getCash() {
    return mycash;
  }
}

XML serialization

Person person = somePersonProvider().getPerson();

// Make Serialization:
UjoManagerXML.getInstance().saveXML(writer, person, null, "My Export");

// Make Deserialization:
person = UjoManagerXML.getInstance().parseXML(inputStream, Person.class, "My Import");

<?xml version="1.0" encoding="UTF-8"?>
<body>
  <Name>Paul Ponec</Name>
  <Male>true</Male>
  <Cash>34.5</Cash>
</body>

List property

public class Person extends MapUjo { 
  public static final UjoProperty <Person,String> NAME  = newProperty("Name", String.class);
  public static final ListProperty<Person,Child> CHILDS = newListProperty("Child", Child.class);
}

Hidden elements

• the action type (XML export, Resource Bundle export, ...) include an action context
• the attribute
• his value

public boolean readAuthorization(UjoAction action, UjoProperty property, Object value) {
  switch(action.getType()) {
    case ACTION_XML_EXPORT: 
      return property!=NAME;
    default: {
      return super.readAuthorization(action, property, value);
    }
  }
}

The attributes

@XmlAttribute
public static final UjoProperty<Ujo,String> NAME = newProperty("Name", String.class);

Body value

@@XmlElementBody
public static final UjoProperty<Ujo,String> MALE = newProperty("Male", String.class);

<?xml version="1.0" encoding="UTF-8"?>
<body Name="Paul Ponec">
  true
  <Cash>34.5</Cash>
</body>

• there is recommended that only one property was signed by the annotation XmlElementBody in the class
• if more XmlElementBody annotated properties are identified than the framework will be considered the valid property with the highest index
• if a property has an annotation XmlAttribute so the XmlElementBody is ignored.

Support of the JTable component

// Create a model for all attributes:
UjoTableModel<Person> model = new UjoTableModel(Person.NAME, Person.MALE, Person.BIRTH);
// or simply: ... model = new UjoTableModel(Person.class)
jTable.setModel(model);

// We can set an data optionally:
List<Person> persons = new ArrayList();
model.setRows(persons);

// Add a row:
model.addRow(new Person());

// Set a value:
model.setValueAt("Prokop", 0, Person.NAME );

// Get the last row of table:
Person person = model.getRowLast();

// Sort the model:
model.sort(Person.NAME); // or descending:
model.sort(Person.NAME.descending());

Confrontation with the AbstractTableModel

• getColumnName(int column)
• getColumnClass(int column)
• getColumnCount()
• getRowCount()
• getValueAt(int rowIndex, int columnIndex)
• setValueAt(Object value, int rowIndex, int columnIndex)

Object-relation mapping (ORM)

• framework has a type safe query language which allows the java compiler find some syntax errors
• no confusing proxy business objects
• easy to configure the ORM model by java source code
• great performance

What about the extensions?

public class PersonExt extends Person {

  public static final UjoProperty<PersonExt,Float> WEIGHT = newProperty("Weight", Float.class);
  public static final UjoProperty<PersonExt,Date>  BORN   = newProperty("Born"  , Date.class);

}

Performance

• a number of the test iterations is 5 million
• for each iteration a new instance of the Ujo interface will be created
• there is written the 10 attribute values into the object
• all the values will be read
• the object will be released for a Garbage collector.
• the result values are an arithmetic average from four tests
• executing clasess: ArrayUjoTest, MapUjoTest, BeanUjoTest, PojoTest from JUnit tests

The XML serialization of UJO objects is based on a quick SAX parser, performance tests are very favorable, mainly a comparison to XML serialization implemented in JER (classes XMLEncoder, XMLDecoder).

• all business object are the same type (in scope one test)
• every one business object contains 11 attributes include one for a recursion type of ArrayList
• count of total instances is 6.000 objects
• maximal deep is 4 object levels
• test was performed by a class XmlSpeedTest2 (second pass) from JUnit tests
• the result values are an arithmetic average from four tests

Other possibilities of usage?

Commons

• UjoCriteria allows to search an Ujo objects from the list of Ujo objects.
• PathProperty class is an composite of a UjoProperty objects. The PathProperty class can be used wherever is used UjoProperty - with a one important exception: do not send the PathProperty object to methods Ujo.readValue(...) and Ujo.writeValue(...).
• FactoryUjo is a generic object maker.

Persistence

• you can save all the hierarchy of UJO objects in XML format by the help of the UjoManagerXML class. For another information see the UjoXml class.
• UJO object can be saved in the PropertyResourceBundle format.
• UJO object will be possible to save in CSV format in some future version.
• The usage of UJO objects in the framework Cayenne (solution for the ORM). The Cayenne works with persistent classes analogous to implementation MapUjo. Because the persistent objects are created by pattern, the pattern can be change easily in that way, it will implement the Ujo interface.

Servlet

ServletRequest request;
UjoTextable person;
UjoProperty personName;
...
person.writeValueString(personName, request.getParameters(personName.getName());

Referential Application

• all the persistence is realized by the UJO framework. It is used the saving into XML format in project, parameters are saved into the Resource Bundle format.
• all the data models of the JTable object are straight the instance or a child of the UjoTable class.
• the small size of jWorkSheet application is interesting, it takes up about 170 kB including the UJO library.

• the application can get an translation word from a Google dictionary include a pronunciation in case you are on-line
• you can modify all items of vocabulary, sort columns or mark word to a print
• personal data are stored in a XML file located in the user home subdirectory

Where ?

License

FAQ

• Q: Is the list of the Properties objects ordered by a natural order?
• A: The result depends on the implementation. All properties are sorted by a property index by default. All implementations from the UJO Framework returns its properties in a natural order on condition that the properties where created by a factory method newProperty(..). The ArrayUjo has assigned all indexes explicitly. If the index numers have got the same value then the natural ordering is no guarantee by a Sun Microsystems specificaton.
• Q: What will be the retrieved UJO values, which were not initiated yet?
• A: The result depends on UJO object implementation. The default implementation (AbstractUjo) returns a default value from UjoProperty.
• Q: Are somewhere any other UJO usage?
• A: You find another examples in the jWorkSheet application and in the JUnit tests too.
• Q: Isn't the UJO work slow?
• A: Implementation is very quick, see the chapter Performance.

Release notes

• 2008/09 - The version 0.80 brings an UjoExt interface.
• 2007/10 - The first public version 0.70 is free under the Apache License, Version 2.0.