* specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.configuration;

/**
 * A request to configure a bean from some configuration in the POM or similar.
 *
 */
public interface BeanConfigurationRequest {

    /**
     * Gets the bean to configure. Eventually, a valid request must have a bean set.
     *

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package ioutil

import (
	"io"
	"sync"
)

// PipeWriter is similar to io.PipeWriter with wait group
type PipeWriter struct {
	*io.PipeWriter
	once sync.Once
	done func()
}

// CloseWithError close with supplied error the writer end.

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.configuration;

/**
 * Unmarshals some textual configuration from the POM or similar into the properties of a bean. This component works
 * similar to the way Maven configures plugins from the POM, i.e. some configuration like {@code <param>value</param>}

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

// Init represents the structure.
type Init struct {
	done uint32
	m    sync.Mutex
}

// Do is similar to sync.Once.Do - makes one successful
// call to the function. ie, it invokes the function
// if it is not successful yet.
func (l *Init) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {
		return l.do(f)

Let's imagine that you have some **machine learning models** that you want to use to handle requests. 🤖

The same models are shared among requests, so, it's not one model per request, or one per user or something similar.

Let's imagine that loading the model can **take quite some time**, because it has to read a lot of **data from disk**. So you don't want to do it for every request.

 * the JDK collection types and the Guava collection types (listed below).
 *
 * <h2>Collection types</h2>
 *
 * <dl>
 *   <dt>{@link Multimap}
 *   <dd>A new type, which is similar to {@link java.util.Map}, but may contain multiple entries
 *       with the same key. Some behaviors of {@link Multimap} are left unspecified and are provided
 *       only by the subtypes mentioned below.

 * the JDK collection types and the Guava collection types (listed below).
 *
 * <h2>Collection types</h2>
 *
 * <dl>
 *   <dt>{@link Multimap}
 *   <dd>A new type, which is similar to {@link java.util.Map}, but may contain multiple entries
 *       with the same key. Some behaviors of {@link Multimap} are left unspecified and are provided
 *       only by the subtypes mentioned below.

          <description>Specify the version when the Mojo was added to the API. Similar to Javadoc since.</description>
        </field>
        <field>
          <name>deprecated</name>
          <version>1.0.0+</version>
          <type>String</type>
          <description>
            Description with the reason of Mojo deprecation. Similar to Javadoc {@code @deprecated}

Then we can use `secrets.compare_digest()` to ensure that `credentials.username` is `"stanleyjobson"`, and that `credentials.password` is `"swordfish"`.

{* ../../docs_src/security/tutorial007_an_py39.py hl[1,12:24] *}

This would be similar to:

```Python
if not (credentials.username == "stanleyjobson") or not (credentials.password == "swordfish"):
    # Return some error
    ...
```

* Proper syncing and shutdown logic. Checking for when an informer has fully started can be quite tricky; `kclient` automatically handles it.

Under the `kclient` package, `clienttest` also provides similar interfaces meant for writing unit tests.

*All Istio informer usage should use this library and not operate on Kubernetes informers directly.*