* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.io.Serial;

import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;

/**
 * @since 4.0.0
 */
@Experimental

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.io.Serial;

import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;

/**
 * @since 4.0.0
 */
@Experimental

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services.xml;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.model.Model;

/**
 * Reads or writes a {@link Model} using XML.
 *
 * @since 4.0.0
 */

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.annotations;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * The annotated element can be {@code null}.
 *

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.repository.legacy;

import javax.inject.Named;
import javax.inject.Singleton;

/**
 * Wagon for testing, for protocol <code>a</code>
 *
 */
@Named("a")
@Singleton

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.repository.legacy;

import javax.inject.Named;
import javax.inject.Singleton;

/**
 * Wagon for testing, for protocols <code>b1</code> and <code>b2</code>
 *
 */
@Named("b")
@Singleton

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.repository.legacy;

import javax.inject.Named;
import javax.inject.Singleton;

/**
 * Wagon for testing, for protocol <code>c</code>
 *
 */
@Named("c")
@Singleton

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.plugin.descriptor;

/**
 */
public class InvalidParameterException extends InvalidPluginDescriptorException {
    public InvalidParameterException(String element, int i) {

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.execution;

/**
 * This exception will be thrown when something fails while persisting build resumption data.
 * @see BuildResumptionDataRepository#persistResumptionData
 */

package once

// Singleton contains a pointer to T that must be set once.
// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v