javax.enterprise.inject.Instance Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "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 javax.enterprise.inject;
import java.lang.annotation.Annotation;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import javax.enterprise.util.TypeLiteral;
import javax.inject.Provider;
/**
* The Instance interface provides a method for obtaining
* instances of beans with required types and qualifiers.
*
* @version $Rev$ $Date$
*
* @param bean required type
*/
public interface Instance extends Iterable, Provider
{
/**
* Creates new Instance with given
* qualifiers.
*
* @param qualifiers
* @return new child instance with given qualifiers.
*/
Instance select(Annotation... qualifiers);
/**
* Returns new child instance with given class and qualifiers.
*
* @param subtype info
* @param subtype subtype class
* @param qualifiers qualifiers
* @return new child instance with given class and qualifiers
*/
Instance select(Class subtype, Annotation... qualifiers);
/**
* Return new child instance with given class info and qualifiers.
*
* @param subtype info
* @param subtype subtype class
* @param qualifiers qualifiers
* @return new child instance with given class info and qualifiers
*/
Instance select(TypeLiteral subtype, Annotation... qualifiers);
/**
* Return true if resolution is unsatisfied, false otherwise.
*
* @return true if resolution is unsatisfied, false otherwise
*/
boolean isUnsatisfied();
/**
* Returns true if resolution is ambiguous, false otherwise.
*
* @return true if resolution is ambiguous, false otherwise.
*/
boolean isAmbiguous();
/**
* @return {@code true} if there is exactly one {@link javax.enterprise.inject.spi.Bean}
* which resolves according to the currently selected type and qualifiers.
* In other words: whether the Instance can serve an actual Contextual Reference.
*
* @since 2.0
*/
default boolean isResolvable()
{
return !isAmbiguous() && !isUnsatisfied();
}
/**
* @return a Stream of all the beans available for the currently selected type and qualifiers,
* or an empty Stream if {@link #isUnsatisfied()}
*/
default Stream stream()
{
return StreamSupport.stream(spliterator(), false);
}
/**
* Destroy the given Contextual Instance.
* This is especially intended for {@link javax.enterprise.context.Dependent} scoped beans
* which might otherwise create mem leaks.
* @param instance
*/
void destroy(T instance);
}