Group items tagged

best strategies for implementation of equals() and hashcode() in your persistent classes

The general contract is: if you want to store an object in a List, Map or a Set then it is an requirement that equals and hashCode are implemented so they obey the standard contract as specified in the  documentation

Why are equals() and hashcode() importantNormally, most Java objects provide a built-in equals() and hashCode() based on the object's identity; so each new() object will be different from all others.

"Bean Validation" specification (aka JSR-303) standardizes an annotation-based validation framework for Java

Flex doesn't provide by itself such framework. The standard way of processing validation is to use Validator subclasses and to bind each validator to each user input (see Validating data). This method is at least time consuming for the developer, source of inconsistancies between the client-side and the server-side validation processes, and source of redundancies in your MXML code.

GraniteDS introduces an ActionsScript3 implementation of the Bean Validation specification and provides code generation tools integration so that your Java constraint annotations are reproduced in your AS3 beans

EqualsVerifierEqualsVerifier can be used in Java unit tests to verify whether the contract for the equals and hashCode methods in a class is met. The contracts are described in the Javadoc comments for the java.lang.Object class.

Mapping enum to database column using JPA/Hibernate You can use any of the 3 approaches discussed above. Map the enum to an integer column. The persistence implementation should automatically convert enum to ordinal() and back for you. Map the enum to a String column. The persistence implementation should automatically convert the enum value to String value via the name() function. Map the enum using a business value. You should mark the enum field as @Transient, and create another String field which you can map to a String column in your database table. Here’s an example code snippet. view plaincopy to clipboardprint?@Entity  public class Product {   @Column   private String colorValue;     @Transient   public Color getColor() {    return Color.fromValue(colorValue);   }     public void setColor(Color color) {    this.colorValue = color.toValue();   }  }  

Approach 3: Using a user defined business value – Recommended approach! This approach involves assigning a an explicit user defined value to each enum constant and defining a toValue() and fromValue() methods on the enum to do the serialization and deserialization.

public enum Color {   RED("RED"), GREEN("GREEN"), BLUE("BLUE"), UNKNOWN("UNKNOWN");     private final String value;     Color(String value) {     this.value = value;   }     public static Color fromValue(String value) {     if (value != null) {       for (Color color : values()) {         if (color.value.equals(value)) {           return color;         }       }     }       // you may return a default value     return getDefault();     // or throw an exception     // throw new IllegalArgumentException("Invalid color: " + value);   }     public String toValue() {     return value;   }     public static Color getDefault() {     return UNKNOWN;   }  }  public enum Color { RED("RED"), GREEN("GREEN"), BLUE("BLUE"), UNKNOWN("UNKNOWN"); private final String value; Color(String value) { this.value = value; } public static Color fromValue(String value) { if (value != null) { for (Color color : values()) { if (color.value.equals(value)) { return color; } } } // you may return a default value return getDefault(); // or throw an exception // throw new IllegalArgumentException("Invalid color: " + value); } public String toValue() { return value; } public static Color getDefault() { return UNKNOWN; } } This approach is better than approach 1 and approach 2 above. It neither depends on the order in which the enum constants are declared nor on the constant names.

Permission as a statement that defines an explicit behavior or action

lowest-level constructs in security polices

explicitly define only "what" the application can do

Property Mgmt

Property Mgmt

Property Mgmt

first token is the

second token is the

Computer security

authentication, authorization and audit

In any access control model, the entities that can perform actions in the system are called subjects, and the entities representing resources to which access may need to be controlled are called objects

queries are also known as native queries

SQL Queries

reasons why a developer using JP QL might want to integrate SQL queries into their application