* ============LICENSE_END=========================================================
*/
-
-
package org.onap.appc.pool;
import java.io.Closeable;
import java.util.concurrent.atomic.AtomicBoolean;
/**
- * This class is used as a "wrapper" for any closeable elements that are cached in a pool. It is implemented as a
- * dynamic proxy, so that it appears to be the same class of object to the client as the interface being cached. The
- * generic type being cached MUST be an interface.
- * @param <T>
- * The generic type that we create a cached element for. This type is used to wrap instances of this type and
- * expose access to the {@link java.io.Closeable} interface by using a dynamic proxy.
+ * This class is used as a "wrapper" for any closeable elements that are cached in a pool. It is
+ * implemented as a dynamic proxy, so that it appears to be the same class of object to the client
+ * as the interface being cached. The generic type being cached MUST be an interface.
+ *
+ * @param <T> The generic type that we create a cached element for. This type is used to wrap
+ * instances of this type and expose access to the {@link java.io.Closeable} interface by
+ * using a dynamic proxy.
*/
-public class CachedElement<T extends Closeable> implements Closeable, InvocationHandler, CacheManagement {
+public class CachedElement<T extends Closeable>
+ implements Closeable, InvocationHandler, CacheManagement {
/**
* The pool that is managing this cached element
private T element;
/**
- * A thread-safe atomic indicator that tells us that the wrapped element has been released to the pool already, and
- * not to do it again.
+ * A thread-safe atomic indicator that tells us that the wrapped element has been released to
+ * the pool already, and not to do it again.
*/
private AtomicBoolean released = new AtomicBoolean(false);
/**
* Create a new instance of a cached element dynamic proxy for use in the pool.
* <p>
- * This returns an instance of the proxy to the caller that appears to be the same interface(s) as the object being
- * cached. The dynamic proxy then intercepts all open and close semantics and directs that element to the pool.
+ * This returns an instance of the proxy to the caller that appears to be the same interface(s)
+ * as the object being cached. The dynamic proxy then intercepts all open and close semantics
+ * and directs that element to the pool.
* </p>
* <p>
- * If the object being proxied does not implement the {@link CacheManagement} interface, then that interface is
- * added to the dynamic proxy being created. This interface is actually implemented by the invocation handler (this
- * object) for the proxy and allows direct access to the wrapped object inside the proxy.
+ * If the object being proxied does not implement the {@link CacheManagement} interface, then
+ * that interface is added to the dynamic proxy being created. This interface is actually
+ * implemented by the invocation handler (this object) for the proxy and allows direct access to
+ * the wrapped object inside the proxy.
* </p>
*
- * @param pool
- * The pool that we are caching these elements within
- * @param element
- * The element actually being cached
- * @param interfaces
- * The interface list of interfaces the element must implement (usually one)
+ * @param pool The pool that we are caching these elements within
+ * @param element The element actually being cached
+ * @param interfaces The interface list of interfaces the element must implement (usually one)
* @return The dynamic proxy
*/
@SuppressWarnings("unchecked")
- public static <T extends Closeable> T newInstance(Pool<T> pool, T element, Class<?>[] interfaces) {
+ public static <T extends Closeable> T newInstance(Pool<T> pool, T element,
+ Class<?>[] interfaces) {
ClassLoader cl = element.getClass().getClassLoader();
CachedElement<T> ce = new CachedElement<>(pool, element);
boolean found = false;
/**
* Construct a cached element and assign it to the pool as a free element
*
- * @param pool
- * The pool that the element will be managed within
- * @param element
- * The element we are caching
+ * @param pool The pool that the element will be managed within
+ * @param element The element we are caching
*/
@SuppressWarnings("unchecked")
public CachedElement(Pool<T> pool, T element) {
/**
* This method delegates the close call to the actual wrapped element.
* <p>
- * NOTE: This is not the same method that is called by the dynamic proxy. This method is in place to satisfy the
- * signature of the {@link java.io.Closeable} interface. If it were to be called directly, then we will delegate the
- * close to the underlying context. However, when the cached element is called as a synamic proxy, entry is in the
+ * NOTE: This is not the same method that is called by the dynamic proxy. This method is in
+ * place to satisfy the signature of the {@link java.io.Closeable} interface. If it were to be
+ * called directly, then we will delegate the close to the underlying context. However, when the
+ * cached element is called as a synamic proxy, entry is in the
* {@link #invoke(Object, Method, Object[])} method.
* </p>
*
}
/**
- * This method is the magic part of dynamic proxies. When the caller makes a method call based on the interface
- * being proxied, this method is given control. This informs us of the method and arguments of the call. The object
- * reference is that of the dynamic proxy itself, which is us.
+ * This method is the magic part of dynamic proxies. When the caller makes a method call based
+ * on the interface being proxied, this method is given control. This informs us of the method
+ * and arguments of the call. The object reference is that of the dynamic proxy itself, which is
+ * us.
* <p>
- * Here we will check to see if the user is trying to close the "element" (the dynamic proxy acts like the wrapped
- * element). If he is, then we don't really close it, but instead release the element that we are wrapping back to
- * the free pool. Once this has happened, we mark the element as "closed" (from the perspective of this dynamic
- * proxy) so that we wont try to release it again.
+ * Here we will check to see if the user is trying to close the "element" (the dynamic proxy
+ * acts like the wrapped element). If he is, then we don't really close it, but instead release
+ * the element that we are wrapping back to the free pool. Once this has happened, we mark the
+ * element as "closed" (from the perspective of this dynamic proxy) so that we wont try to
+ * release it again.
* </p>
* <p>
- * If the method is the <code>equals</code> method then we assume that we are comparing the cached element in one
- * dynamic proxy to the cached element in another. We execute the comparison between the cached elements, and not
- * the dynamic proxies themselves. This preserves the allusion to the caller that the dynamic proxy is the object
- * being wrapped.
+ * If the method is the <code>equals</code> method then we assume that we are comparing the
+ * cached element in one dynamic proxy to the cached element in another. We execute the
+ * comparison between the cached elements, and not the dynamic proxies themselves. This
+ * preserves the allusion to the caller that the dynamic proxy is the object being wrapped.
* </p>
* <p>
- * For convenience, we also implement the <code>getWrappedObject</code> method so that the dynamic proxy can be
- * called to obtain the actual wrapped object if desired. Note, to use this method, the caller would have to invoke
- * it through reflection.
+ * For convenience, we also implement the <code>getWrappedObject</code> method so that the
+ * dynamic proxy can be called to obtain the actual wrapped object if desired. Note, to use this
+ * method, the caller would have to invoke it through reflection.
* </p>
* <p>
- * If the method being invoked is not one that we intercept, then we simply delegate that method onto the wrapped
- * object.
+ * If the method being invoked is not one that we intercept, then we simply delegate that method
+ * onto the wrapped object.
* </p>
*
- * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
+ * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method,
+ * java.lang.Object[])
*/
- @SuppressWarnings({
- "unchecked", "nls"
- })
+ @SuppressWarnings({"unchecked", "nls"})
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Exception {
Object result = null;
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