Package overit.geocall.util

Class DALazy<T>

java.lang.Object

overit.geocall.util.DALazy<T>

All Implemented Interfaces:

Serializable, DAThrowingSupplier<T>

public class DALazy<T>
extends Object
implements DAThrowingSupplier<T>

DALazy is a simple in-memory caching class.
The DALazy class suits the caching of database calls, complex object graph building routines, and web service calls that should be cached for performance.
This implementation differs from Lazy because it implements DAThrowingSupplier, and can therefore raise DAExceptions and DAValidateExceptions.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected final DAThrowingSupplier<T>	supplier
protected Object	value

Constructor Summary

Constructors

Constructor	Description
DALazy()	Creates an empty DALazy. Calls to get() will throw UnsupportedOperationException.
DALazy(DAThrowingSupplier<T> supplier)	Creates a DALazy object with the defined DAThrowingSupplier.

Method Summary

Modifier and Type	Method	Description
final T	get()	Returns the value, computing it from the supplier if necessary.
final T	get(DAThrowingSupplier<T> supplier, T def)	Returns the value retrieved from the DAThrowingSupplier.
final T	get(T def)	Returns the value, computing it from the supplier if necessary.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

supplier

protected final DAThrowingSupplier<T> supplier

value

protected transient volatile Object value

Constructor Details

DALazy

public DALazy()

Creates an empty DALazy.
Calls to get() will throw UnsupportedOperationException.

DALazy

public DALazy(DAThrowingSupplier<T> supplier)

Creates a DALazy object with the defined DAThrowingSupplier.

Parameters:

supplier - DAThrowingSupplier used to compute the value.

Method Details

get

public final T get()
            throws DAException,
DAValidateException

Returns the value, computing it from the supplier if necessary.

Specified by:

get in interface DAThrowingSupplier<T>

Returns:

the computed value.

Throws:

DAException - if the supplier throws one.

DAValidateException - if the supplier throws one.

get

public final T get(T def)
            throws DAException,
DAValidateException

Returns the value, computing it from the supplier if necessary. If the supplier returns null, returns the provided default.

Parameters:

def - the default value if supplier returns null.

Returns:

the value or default.

Throws:

DAException - if the supplier throws one.

DAValidateException - if the supplier throws one.

get

public final T get(DAThrowingSupplier<T> supplier,
 T def)
            throws DAException,
DAValidateException

Returns the value retrieved from the DAThrowingSupplier.

Parameters:

supplier - The DAThrowingSupplier.

def - The default value to return in case the value retrieved from the DAThrowingSupplier is null.

Returns:

The value retrieved from the DAThrowingSupplier.

Throws:

DAValidateException - in case of db validation error.

DAException - in case of db communication error.