--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/src/jdk.jfr/share/classes/jdk/jfr/AnnotationElement.java	2018-04-09 15:33:30.373852274 +0200
@@ -0,0 +1,420 @@
+/*
+ * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.StringJoiner;
+
+import jdk.jfr.internal.Type;
+import jdk.jfr.internal.TypeLibrary;
+import jdk.jfr.internal.Utils;
+
+/**
+ * Describes event metadata, such as labels, descriptions and units.
+ * <p>
+ * The following example shows how {@code AnnotationElement} can be used to dynamically define events,
+ *
+ * <pre>
+ * <code>
+ *   List{@literal <}AnnotationElement{@literal >} typeAnnotations = new ArrayList{@literal <}{@literal >}();
+ *   typeannotations.add(new AnnotationElement(Name.class, "com.example.HelloWorld");
+ *   typeAnnotations.add(new AnnotationElement(Label.class, "Hello World"));
+ *   typeAnnotations.add(new AnnotationElement(Description.class, "Helps programmer getting started"));
+ *
+ *   List{@literal <}AnnotationElement{@literal >} fieldAnnotations = new ArrayList{@literal <}{@literal >}();
+ *   fieldAnnotations.add(new AnnotationElement(Label.class, "Message"));
+ *
+ *   List{@literal <}ValueDescriptor{@literal >} fields = new ArrayList{@literal <}{@literal >}();
+ *   fields.add(new ValueDescriptor(String.class, "message", fieldAnnotations));
+ *
+ *   EventFactory f = EventFactory.create(typeAnnotations, fields);
+ *   Event event = f.newEvent();
+ *   event.commit();
+ * </code>
+ * </pre>
+ *
+ * @since 9
+ */
+public final class AnnotationElement {
+    private final Type type;
+    private final List<Object> annotationValues;
+    private final List<String> annotationNames;
+    private final boolean inBootClassLoader;
+
+    // package private
+    AnnotationElement(Type type, List<Object> objects, boolean boot) {
+        Objects.requireNonNull(type);
+        Objects.requireNonNull(objects);
+        this.type = type;
+        if (objects.size() != type.getFields().size()) {
+            StringJoiner descriptors = new StringJoiner(",", "[", "]");
+            for (ValueDescriptor v : type.getFields()) {
+                descriptors.add(v.getName());
+            }
+            StringJoiner values = new StringJoiner(",", "[", "]");
+            for (Object object : objects) {
+                descriptors.add(String.valueOf(object));
+            }
+            throw new IllegalArgumentException("Annotation " + descriptors + " for " + type.getName() + " doesn't match number of values " + values);
+        }
+
+        List<String> n = new ArrayList<>();
+        List<Object> v = new ArrayList<>();
+        int index = 0;
+        for (ValueDescriptor valueDescriptor : type.getFields()) {
+            Object object = objects.get(index);
+            if (object == null) {
+                throw new IllegalArgumentException("Annotation value can't be null");
+            }
+            Class<?> valueType = object.getClass();
+            if (valueDescriptor.isArray()) {
+                valueType = valueType.getComponentType();
+            }
+            checkType(Utils.unboxType(valueType));
+            n.add(valueDescriptor.getName());
+            v.add(object);
+            index++;
+        }
+        this.annotationValues = Utils.smallUnmodifiable(v);
+        this.annotationNames = Utils.smallUnmodifiable(n);
+        this.inBootClassLoader = boot;
+    }
+
+    /**
+     * Creates an annotation element to use for dynamically defined events.
+     * <p>
+     * Supported value types are {@code byte}, {@code int}, {@code short},
+     * {@code long}, {@code double}, {@code float}, {@code boolean}, {@code char},
+     * and {@code String}. Enums, arrays and classes, are not supported.
+     * <p>
+     * If {@code annotationType} contains annotations (directly present, indirectly
+     * present, or associated), then those annotation are recursively included.
+     * However, both the {@code annotationType} and any annotation found recursively
+     * must have the {@link MetadataDefinition} annotation.
+     * <p>
+     * To statically define events, see {@link Event} class.
+     *
+     * @param annotationType interface extending
+     *        {@code java.lang.annotation.Annotation}, not {@code null}
+     * @param values a map with keys that match method names of the specified
+     *        annotation interface
+     * @throws IllegalArgumentException if value/key is {@code null}, an unsupported
+     *         value type is used, or a value/key is used that doesn't match the
+     *         signatures in the {@code annotationType}
+     */
+    public AnnotationElement(Class<? extends Annotation> annotationType, Map<String, Object> values) {
+        Objects.requireNonNull(annotationType);
+        Objects.requireNonNull(values);
+        Utils.checkRegisterPermission();
+        // copy values to avoid modification after validation
+        HashMap<String, Object> map = new HashMap<>(values);
+        for (Map.Entry<String, Object> entry : map.entrySet()) {
+            if (entry.getKey() == null) {
+                throw new NullPointerException("Name of annotation method can't be null");
+            }
+            if (entry.getValue() == null) {
+                throw new NullPointerException("Return value for annotation method can't be null");
+            }
+        }
+
+        if (AnnotationElement.class.isAssignableFrom(annotationType) && annotationType.isInterface()) {
+            throw new IllegalArgumentException("Must be interface extending " + Annotation.class.getName());
+        }
+        if (!isKnownJFRAnnotation(annotationType) && annotationType.getAnnotation(MetadataDefinition.class) == null) {
+            throw new IllegalArgumentException("Annotation class must be annotated with jdk.jfr.MetadataDefinition to be valid");
+        }
+        if (isKnownJFRAnnotation(annotationType)) {
+            this.type = new Type(annotationType.getCanonicalName(), Type.SUPER_TYPE_ANNOTATION, Type.getTypeId(annotationType));
+        } else {
+            this.type = TypeLibrary.createAnnotationType(annotationType);
+        }
+        Method[] methods = annotationType.getDeclaredMethods();
+        if (methods.length != map.size()) {
+            throw new IllegalArgumentException("Number of declared methods must match size of value map");
+        }
+        List<String> n = new ArrayList<>();
+        List<Object> v = new ArrayList<>();
+        Set<String> nameSet = new HashSet<>();
+        for (Method method : methods) {
+            String fieldName = method.getName();
+            Object object = map.get(fieldName);
+            if (object == null) {
+                throw new IllegalArgumentException("No method in annotation interface " + annotationType.getName() + " matching name " + fieldName);
+            }
+            Class<?> fieldType = object.getClass();
+
+            if (fieldType == Class.class) {
+                throw new IllegalArgumentException("Annotation value for " + fieldName + " can't be class");
+            }
+            if (object instanceof Enum) {
+                throw new IllegalArgumentException("Annotation value for " + fieldName + " can't be enum");
+            }
+            if (!fieldType.equals(object.getClass())) {
+                throw new IllegalArgumentException("Return type of annotation " + fieldType.getName() + " must match type of object" + object.getClass());
+            }
+
+            if (fieldType.isArray()) {
+                Class<?> componentType = fieldType.getComponentType();
+                checkType(componentType);
+                if (componentType.equals(String.class)) {
+                    String[] stringArray = (String[]) object;
+                    for (int i = 0; i < stringArray.length; i++) {
+                        if (stringArray[i] == null) {
+                            throw new IllegalArgumentException("Annotation value for " + fieldName + " contains null");
+                        }
+                    }
+                }
+            } else {
+                fieldType = Utils.unboxType(object.getClass());
+                checkType(fieldType);
+            }
+            if (nameSet.contains(fieldName)) {
+                throw new IllegalArgumentException("Value with name '" + fieldName + "' already exists");
+            }
+            if (isKnownJFRAnnotation(annotationType)) {
+                ValueDescriptor vd = new ValueDescriptor(fieldType, fieldName, Collections.emptyList(), true);
+                type.add(vd);
+            }
+            n.add(fieldName);
+            v.add(object);
+        }
+        this.annotationValues = Utils.smallUnmodifiable(v);
+        this.annotationNames = Utils.smallUnmodifiable(n);
+        this.inBootClassLoader = annotationType.getClassLoader() == null;
+    }
+
+    /**
+     * Creates an annotation element to use for dynamically defined events.
+     * <p>
+     * Supported value types are {@code byte}, {@code int}, {@code short},
+     * {@code long}, {@code double}, {@code float}, {@code boolean}, {@code char},
+     * and {@code String}. Enums, arrays, and classes are not supported.
+     * <p>
+     * If {@code annotationType} contains annotations (directly present, indirectly
+     * present, or associated), then those annotations are recursively included.
+     * However, both {@code annotationType} and any annotation found recursively
+     * must have the {@link MetadataDefinition} annotation.
+     * <p>
+     * To statically define events, see {@link Event} class.
+     *
+     * @param annotationType interface extending
+     *        {@code java.lang.annotation.Annotation,} not {@code null}
+     * @param value the value that matches the {@code value} method of the specified
+     *        {@code annotationType}
+     * @throws IllegalArgumentException if value/key is {@code null}, an unsupported
+     *         value type is used, or a value/key is used that doesn't match the
+     *         signatures in the {@code annotationType}
+     */
+    public AnnotationElement(Class<? extends Annotation> annotationType, Object value) {
+        this(annotationType, Collections.singletonMap("value", Objects.requireNonNull(value)));
+    }
+
+    /**
+     * Creates an annotation element to use for dynamically defined events.
+     * <p>
+     * Supported value types are {@code byte}, {@code short}, {@code int},
+     * {@code long}, {@code double}, {@code float}, {@code boolean}, {@code char},
+     * and {@code String}. Enums, arrays, and classes are not supported.
+     * <p>
+     * If {@code annotationType} contains annotations (directly present, indirectly
+     * present or associated), then those annotation are recursively included.
+     * However, both {@code annotationType} and any annotation found recursively
+     * must have the {@link MetadataDefinition} annotation.
+     * <p>
+     * To statically define events, see {@link Event} class.
+     *
+     * @param annotationType interface extending java.lang.annotation.Annotation,
+     *        not {@code null}
+     */
+    public AnnotationElement(Class<? extends Annotation> annotationType) {
+        this(annotationType, Collections.emptyMap());
+    }
+
+    /**
+     * Returns an immutable list of annotation values in an order that matches the
+     * value descriptors for this {@code AnnotationElement}.
+     *
+     * @return list of values, not {@code null}
+     */
+    public List<Object> getValues() {
+        return annotationValues;
+    }
+
+    /**
+     * Returns an immutable list of descriptors that describes the annotation values
+     * for this {@code AnnotationElement}.
+     *
+     * @return the list of value descriptors for this {@code Annotation}, not
+     *         {@code null}
+     */
+    public List<ValueDescriptor> getValueDescriptors() {
+        return Collections.unmodifiableList(type.getFields());
+    }
+
+    /**
+     * Returns an immutable list of annotation elements for this
+     * {@code AnnotationElement}.
+     *
+     * @return a list of meta annotation, not {@code null}
+     */
+    public List<AnnotationElement> getAnnotationElements() {
+        return type.getAnnotationElements();
+    }
+
+    /**
+     * Returns the fully qualified name of the annotation type that corresponds to
+     * this {@code AnnotationElement}.
+     *
+     * @return type name, not {@code null}
+     */
+    public String getTypeName() {
+        return type.getName();
+    }
+
+    /**
+     * Returns a value for this {@code AnnotationElement}.
+     *
+     * @param name the name of the method in the annotation interface, not
+     *        {@code null}.
+     *
+     * @return the annotation value, not {@code null}.
+     *
+     * @throws IllegalArgumentException if a method with the specified name does
+     *         not exist the annotation
+     */
+    public Object getValue(String name) {
+        Objects.requireNonNull(name);
+        int index = 0;
+        for (String n : annotationNames) {
+            if (name.equals(n)) {
+                return annotationValues.get(index);
+            }
+            index++;
+        }
+        StringJoiner valueNames = new StringJoiner(",", "[", "]");
+        for (ValueDescriptor v : type.getFields()) {
+            valueNames.add(v.getName());
+        }
+        throw new IllegalArgumentException("No value with name '" + name + "'. Valid names are " + valueNames);
+    }
+
+    /**
+     * Returns {@code true} if an annotation value with the specified name exists in
+     * this {@code AnnotationElement}.
+     *
+     * @param name name of the method in the annotation interface to find, not
+     *        {@code null}
+     *
+     * @return {@code true} if method exists, {@code false} otherwise
+     */
+    public boolean hasValue(String name) {
+        Objects.requireNonNull(name);
+        for (String n : annotationNames) {
+            if (name.equals(n)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the first annotation for the specified type if an
+     * {@code AnnotationElement} with the same name exists, else {@code null}.
+     *
+     * @param <A> the type of the annotation to query for and return if it exists
+     * @param annotationType the Class object corresponding to the annotation type,
+     *        not {@code null}
+     * @return this element's annotation for the specified annotation type if
+     *         it it exists, else {@code null}
+     */
+    public final <A> A getAnnotation(Class<? extends Annotation> annotationType) {
+        Objects.requireNonNull(annotationType);
+        return type.getAnnotation(annotationType);
+    }
+
+    /**
+     * Returns the type id for this {@code AnnotationElement}.
+     * <p>
+     * The type id is a unique identifier for the type in the JVM. The id might not
+     * be the same between JVM instances.
+     *
+     * @return the type id, not negative
+     */
+    public long getTypeId() {
+        return type.getId();
+    }
+
+    // package private
+    Type getType() {
+        return type;
+    }
+
+    private static void checkType(Class<?> type) {
+        if (type.isPrimitive()) {
+            return;
+        }
+        if (type == String.class) {
+            return;
+        }
+        throw new IllegalArgumentException("Only primitives types or java.lang.String are allowed");
+    }
+
+    // Whitelist annotation classes that are allowed, even though
+    // they don't have @MetadataDefinition.
+    private static boolean isKnownJFRAnnotation(Class<? extends Annotation> annotationType) {
+        if (annotationType == Registered.class) {
+            return true;
+        }
+        if (annotationType == Threshold.class) {
+            return true;
+        }
+        if (annotationType == StackTrace.class) {
+            return true;
+        }
+        if (annotationType == Period.class) {
+            return true;
+        }
+        if (annotationType == Enabled.class) {
+            return true;
+        }
+        return false;
+    }
+
+    // package private
+    boolean isInBoot() {
+        return inBootClassLoader;
+    }
+
+}