Simplify name and alias annotation processing

log4j-core-test/src/main/java/org/apache/logging/log4j/core/test/junit/Named.java

@@ -16,17 +16,12 @@
  */
 package org.apache.logging.log4j.core.test.junit;
 
-import static java.util.Optional.ofNullable;
-import static org.apache.logging.log4j.util.Strings.trimToNull;
-
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import java.util.Optional;
-import org.apache.logging.log4j.plugins.name.AnnotatedElementNameProvider;
-import org.apache.logging.log4j.plugins.name.NameProvider;
+import org.apache.logging.log4j.plugins.NameProvider;
 
 /**
  * Specifies the name of an {@link org.apache.logging.log4j.core.Appender} to inject into JUnit 5 tests from the specified
@@ -38,17 +33,10 @@
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.PARAMETER)
 @Documented
-@NameProvider(Named.Provider.class)
+@NameProvider
 public @interface Named {
     /**
      * Specifies the name of the configuration item to inject. If blank, uses the name of the annotated parameter.
      */
     String value() default "";
-
-    class Provider implements AnnotatedElementNameProvider<Named> {
-        @Override
-        public Optional<String> getSpecifiedName(final Named annotation) {
-            return ofNullable(trimToNull(annotation.value()));
-        }
-    }
 }

log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/PluginAliases.java

@@ -21,8 +21,7 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.apache.logging.log4j.core.config.plugins.util.PluginAliasesProvider;
-import org.apache.logging.log4j.plugins.name.AliasesProvider;
+import org.apache.logging.log4j.plugins.AliasesProvider;
 
 /**
  * Identifies a list of aliases for a Plugin, PluginAttribute, or PluginBuilderAttribute.
@@ -31,7 +30,7 @@
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.PARAMETER, ElementType.TYPE, ElementType.FIELD})
-@AliasesProvider(PluginAliasesProvider.class)
+@AliasesProvider
 @Deprecated(since = "3.0", forRemoval = true)
 @SuppressWarnings("removal")
 public @interface PluginAliases {

log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/PluginAttribute.java

@@ -21,9 +21,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.apache.logging.log4j.core.config.plugins.util.PluginAttributeNameProvider;
+import org.apache.logging.log4j.plugins.NameProvider;
 import org.apache.logging.log4j.plugins.QualifierType;
-import org.apache.logging.log4j.plugins.name.NameProvider;
 import org.apache.logging.log4j.util.Strings;
 
 /**
@@ -37,7 +36,7 @@
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.PARAMETER, ElementType.FIELD})
-@NameProvider(PluginAttributeNameProvider.class)
+@NameProvider
 @QualifierType
 @Deprecated(since = "3.0", forRemoval = true)
 @SuppressWarnings("removal")

log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/PluginBuilderAttribute.java

@@ -21,9 +21,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.apache.logging.log4j.core.config.plugins.util.PluginBuilderAttributeNameProvider;
+import org.apache.logging.log4j.plugins.NameProvider;
 import org.apache.logging.log4j.plugins.QualifierType;
-import org.apache.logging.log4j.plugins.name.NameProvider;
 import org.apache.logging.log4j.util.Strings;
 
 /**
@@ -33,7 +32,7 @@
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.PARAMETER, ElementType.FIELD})
-@NameProvider(PluginBuilderAttributeNameProvider.class)
+@NameProvider
 @QualifierType
 @Deprecated(since = "3.0", forRemoval = true)
 @SuppressWarnings("removal")

log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/PluginElement.java

@@ -21,9 +21,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.apache.logging.log4j.core.config.plugins.util.PluginElementNameProvider;
+import org.apache.logging.log4j.plugins.NameProvider;
 import org.apache.logging.log4j.plugins.QualifierType;
-import org.apache.logging.log4j.plugins.name.NameProvider;
 
 /**
  * Identifies a parameter as a Plugin and corresponds with an XML element (or equivalent) in configuration files.
@@ -32,7 +31,7 @@
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.PARAMETER, ElementType.FIELD})
-@NameProvider(PluginElementNameProvider.class)
+@NameProvider
 @QualifierType
 @Deprecated(since = "3.0", forRemoval = true)
 @SuppressWarnings("removal")

log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/PluginValue.java

@@ -21,9 +21,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.apache.logging.log4j.core.config.plugins.util.PluginValueNameProvider;
+import org.apache.logging.log4j.plugins.NameProvider;
 import org.apache.logging.log4j.plugins.QualifierType;
-import org.apache.logging.log4j.plugins.name.NameProvider;
 
 /**
  * Identifies a parameter as a value. These correspond with property values generally, but are meant as values to be
@@ -35,7 +34,7 @@
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.PARAMETER, ElementType.FIELD})
-@NameProvider(PluginValueNameProvider.class)
+@NameProvider
 @QualifierType
 @Deprecated(since = "3.0", forRemoval = true)
 @SuppressWarnings("removal")

log4j-plugins-test/src/test/java/org/apache/logging/log4j/plugins/di/KeyTest.java

@@ -25,13 +25,11 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
-import java.util.Optional;
+import org.apache.logging.log4j.plugins.NameProvider;
 import org.apache.logging.log4j.plugins.Named;
 import org.apache.logging.log4j.plugins.Namespace;
 import org.apache.logging.log4j.plugins.Ordered;
 import org.apache.logging.log4j.plugins.QualifierType;
-import org.apache.logging.log4j.plugins.name.AnnotatedElementNameProvider;
-import org.apache.logging.log4j.plugins.name.NameProvider;
 import org.junit.jupiter.api.Test;
 
 // TODO: add tests for more complex types with generics etc
@@ -107,18 +105,11 @@ void forField() {
 
     @Retention(RetentionPolicy.RUNTIME)
     @QualifierType
-    @NameProvider(CustomQualifierNameProvider.class)
+    @NameProvider
     @interface CustomQualifier {
         String value();
     }
 
-    static class CustomQualifierNameProvider implements AnnotatedElementNameProvider<CustomQualifier> {
-        @Override
-        public Optional<String> getSpecifiedName(final CustomQualifier annotation) {
-            return Optional.of(annotation.value());
-        }
-    }
-
     @Retention(RetentionPolicy.RUNTIME)
     @Namespace("logical")
     @interface LogicalNamespace {}

log4j-plugins/src/main/java/org/apache/logging/log4j/plugins/name/NameProvider.java → log4j-plugins/src/main/java/org/apache/logging/log4j/plugins/AliasesProvider.java

@@ -14,24 +14,25 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.plugins.name;
+package org.apache.logging.log4j.plugins;
 
-import java.lang.annotation.Annotation;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * Meta annotation for specifying named annotations and how to get a specified name from the named annotation.
+ * Marks another annotation as one providing aliases for an object. The annotation must define an element
+ * named {@code value} of type {@code String[]} that contains the aliases. An offset can define where to
+ * begin reading the aliases.
  */
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.ANNOTATION_TYPE)
-public @interface NameProvider {
+public @interface AliasesProvider {
     /**
-     * Strategy for extracting a specified name from an annotated element.
+     * Offset within the {@code value} array to read aliases from.
      */
-    Class<? extends AnnotatedElementNameProvider<? extends Annotation>> value();
+    int offset() default 0;
 }

log4j-plugins/src/main/java/org/apache/logging/log4j/plugins/name/AliasesProvider.java → log4j-plugins/src/main/java/org/apache/logging/log4j/plugins/NameProvider.java

@@ -14,18 +14,20 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.plugins.name;
+package org.apache.logging.log4j.plugins;
 
-import java.lang.annotation.Annotation;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+/**
+ * Marks another annotation as one providing a name for an object. The name is obtained from
+ * the annotation element named {@code value}. This element can be a {@code String} or {@code String[]}.
+ * When specified as an array, the first element is used.
+ */
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.ANNOTATION_TYPE)
-public @interface AliasesProvider {
-    Class<? extends AnnotatedElementAliasesProvider<? extends Annotation>> value();
-}
+public @interface NameProvider {}