*/
package org.opendaylight.yangtools.yang.model.api.meta;
+import static java.util.Objects.requireNonNull;
+
+import com.google.common.annotations.Beta;
+import com.google.common.collect.Collections2;
import java.util.Collection;
+import java.util.Optional;
+import java.util.stream.Stream;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
+import org.eclipse.jdt.annotation.NonNull;
/**
* Represents declared statement.
* @param <A> Argument type ({@link Void} if statement does not have argument.)
*/
public interface DeclaredStatement<A> extends ModelStatement<A> {
-
/**
* Returns statement argument as was present in original source.
*
@Nullable String rawArgument();
/**
- * Returns collection of explicitly declared child statements, while preserving its original
- * ordering from original source.
+ * Returns collection of explicitly declared child statements, while preserving its original ordering from original
+ * source.
*
- * @return Collection of statements, which were explicitly declared in
- * source of model.
+ * @return Collection of statements, which were explicitly declared in source of model.
*/
@Nonnull Collection<? extends DeclaredStatement<?>> declaredSubstatements();
+
+ /**
+ * Returns collection of explicitly declared child statements, while preserving its original ordering from original
+ * source.
+ *
+ * @param type {@link DeclaredStatement} type
+ * @return Collection of statements, which were explicitly declared in source of model.
+ * @throws NullPointerException if {@code type} is null
+ */
+ default <S extends DeclaredStatement<?>> @NonNull Collection<? extends S> declaredSubstatements(
+ final Class<S> type) {
+ requireNonNull(type);
+ return Collections2.transform(Collections2.filter(declaredSubstatements(), type::isInstance), type::cast);
+ }
+
+ /**
+ * Find the first effective substatement of specified type.
+ *
+ * @param type {@link DeclaredStatement} type
+ * @return First declared substatement, or empty if no match is found.
+ * @throws NullPointerException if {@code type} is null
+ */
+ @Beta
+ default <T extends DeclaredStatement<?>> @NonNull Optional<T> findFirstDeclaredSubstatement(
+ @NonNull final Class<T> type) {
+ requireNonNull(type);
+ return streamDeclaredSubstatements(type).filter(type::isInstance).findFirst().map(type::cast);
+ }
+
+ /**
+ * Find the first declared substatement of specified type and return its value.
+ *
+ * @return First declared substatement's argument, or empty if no match is found.
+ * @throws NullPointerException if {@code type} is null
+ */
+ @Beta
+ default <V, T extends DeclaredStatement<V>> @NonNull Optional<V> findFirstDeclaredSubstatementArgument(
+ @NonNull final Class<T> type) {
+ return findFirstDeclaredSubstatement(type).map(DeclaredStatement::argument);
+ }
+
+ /**
+ * Find all declared substatements of specified type and return them as a stream.
+ *
+ * @return A stream of all declared substatements of specified type.
+ * @throws NullPointerException if {@code type} is null
+ */
+ @Beta
+ default <T extends DeclaredStatement<?>> @NonNull Stream<T> streamDeclaredSubstatements(
+ @NonNull final Class<T> type) {
+ requireNonNull(type);
+ return declaredSubstatements().stream().filter(type::isInstance).map(type::cast);
+ }
}