/**
* Copyright Alex Objelean
*/
package ro.isdc.wro.util;
/**
* A clone of {@link LazyInitializer}, which doesn't throw any checked exception when get method is invoked.
*
* @author Alex Objelean
* @created 10 Apr 2012
* @since 1.4.6
*/
public abstract class LazyInitializer<T> {
/** Stores the managed object. */
volatile T object;
/**
* Returns the object wrapped by this instance. On first access the object is created. After that it is cached and can
* be accessed pretty fast.
*
* @return the object initialized by this {@code LazyInitializer} the object
*/
public final T get() {
// use a temporary variable to reduce the number of reads of the volatile field
T result = object;
if (result == null) {
synchronized (this) {
result = object;
if (result == null) {
object = result = initialize();
}
}
}
return result;
}
/**
* @return true if the object was already initialized.
*/
public final boolean isInitialized() {
return object != null;
}
/**
* Creates and initializes the object managed by this {@code LazyInitializer}. This method is called by {@link #get()}
* when the object is accessed for the first time. An implementation can focus on the creation of the object. No
* synchronization is needed, as this is already handled by {@code get()}.
*
* @return the managed data object
*/
protected abstract T initialize();
}