java qr code generator tutorial Working with Microsoft Internet Explorer in Java

Produce qr codes in Java Working with Microsoft Internet Explorer

then we will be told that we have an Object, which is also technically correct but probably not what we intended. Finally, there are times when we may want to exhaustively discover all of an object s properties and functions. We can do this using the simple for loop:

The MustOverride and MustInherit keywords force derived classes to implement specific members of the base class. But what if you want the derived class to implement all members of the base class You could use MustOverride next to each method and property, but a better way is to use an interface. Interfaces define abstract classes, classes consisting only of definitions, no implementation. (OOP purists will point out that a class with even just one MustOverride flag is also an abstract class. Fine.) Interfaces create a contract, an agreement that the implementing class or structure agrees to carry out. The Interface statement begins the interface definition process. By convention, all interface names begin with the capital letter I.

// ** Part 1 is in listing 6.10; part 2 in listing 6.11 Stage { scene: Scene { content: [ Scene list,view,panel graph bits ]; fill: LinearGradient { endX:0; endY:1; proportional: true; stops: [ Stop { offset:0.55; color:Color.BLACK; } , Stop { offset:1; color:Color.STEELBLUE; } ]; }; }; title: "Player v2"; resizable: false; } Handy label function makeLabel(str:String) : Text { Text { content: str; font: font; fill: Color.LIGHTBLUE; textOrigin: TextOrigin.TOP; }; } function getVideoPath(i:Integer) : String { def f = new File(sourceDir,sourceFiles[i]); return f.toURI().toString(); }

B.3.1

Summary

We call this automatic dirty checking (an object with modifications that haven t yet been propagated to the database is considered dirty). Again, this state isn t visible to the application. We call this feature transparent transaction-level write-behind, meaning that Hibernate propagates state changes to the database as late as possible but hides this detail from the application. Hibernate can detect exactly which attributes have been modified, so it s possible to include only the columns that need updating in the SQL UPDATE statement. This might bring performance gains, particularly with certain databases. However, it isn t usually a significant difference, and, in theory, it could harm performance in some environments. So, by default, Hibernate includes all columns in the SQL UPDATE statement (hence, Hibernate can generate this basic SQL at startup, not at runtime). If you only want to update modified columns, you can enable dynamic SQL generation by setting dynamic-update="true" in a class mapping. (Note that this feature is extremely difficult to implement in a handcoded persistence layer.) We talk about Hibernate s transaction semantics and the synchronization process (known as flushing) in more detail in the next chapter. Finally, a persistent instance may be made transient via a delete() call to the persistence manager API, resulting in deletion of the corresponding row of the database table.

First we approached fonts from three different angles:

Since you re walking the object graph twice, once for the Location name and again for the Location state, the query compiler will join the Location instance to the Event twice. Joining the Location to the Event in the FROM clause results in only one join and a more efficient query. Joined objects can also be returned in the SELECT clause of the HQL statement. The HQL SELECT clause is discussed next.