- ResourceDMBean now uses MethodHandles for faster access to attrs (h…

…ttps://issues.redhat.com/browse/JGRP-2787)

src/org/jgroups/jmx/ResourceDMBean.java

@@ -10,6 +10,8 @@
 import org.jgroups.util.Util;
 
 import javax.management.*;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
@@ -91,11 +93,18 @@ public ResourceDMBean(Object instance) {
     }
 
 
-
     public MBeanInfo getMBeanInfo() {
         return new MBeanInfo(obj.getClass().getCanonicalName(), "DynamicMBean", attrInfo, null, opInfo, null);
     }
 
+    public void forAllAttributes(BiConsumer<String,AttributeEntry> c) {
+        if(c == null)
+            return;
+        for(Map.Entry<String,AttributeEntry> e: atts.entrySet()) {
+            c.accept(e.getKey(), e.getValue());
+        }
+    }
+
     public Object getAttribute(String name) {
         if(name == null || name.isEmpty())
             throw new NullPointerException("Invalid attribute requested " + name);
@@ -521,10 +530,7 @@ protected boolean setNamedAttribute(Attribute attribute) {
 
 
 
-
-
-
-    protected static class AttributeEntry {
+    public static class AttributeEntry {
 
         /** The name of the field or method. Can be different from the key in atts when name in @Property or
          * @ManagedAttribute  was used */
@@ -533,21 +539,23 @@ protected static class AttributeEntry {
         protected Accessor                 getter;
         protected Accessor                 setter;
 
-        protected AttributeEntry(String name, MBeanAttributeInfo info) {
+        public AttributeEntry(String name, MBeanAttributeInfo info) {
             this(name, info, null, null);
         }
 
-        protected AttributeEntry(String name, MBeanAttributeInfo info, Accessor getter, Accessor setter) {
+        public AttributeEntry(String name, MBeanAttributeInfo info, Accessor getter, Accessor setter) {
             this.name=name;
             this.info=info;
             this.getter=getter;
             this.setter=setter;
         }
 
-        protected Accessor       getter()                    {return getter;}
-        protected AttributeEntry getter(Accessor new_getter) {this.getter=new_getter; return this;}
-        protected Accessor       setter()                    {return setter;}
-        protected AttributeEntry setter(Accessor new_setter) {this.setter=new_setter; return this;}
+        public String             name()                      {return name;}
+        public MBeanAttributeInfo info()                      {return info;}
+        public Accessor           getter()                    {return getter;}
+        public AttributeEntry     getter(Accessor new_getter) {this.getter=new_getter; return this;}
+        public Accessor           setter()                    {return setter;}
+        public AttributeEntry     setter(Accessor new_setter) {this.setter=new_setter; return this;}
 
 
         public String toString() {
@@ -588,21 +596,39 @@ public Object invoke(Object new_val) throws Exception {
     }
 
     public static class FieldAccessor implements Accessor {
-        protected final Field  field;
-        protected final Object target;
+        protected final Field                       field;
+        protected final Object                      target;
+        protected static final MethodHandles.Lookup LOOKUP=MethodHandles.lookup();
+        protected       MethodHandle                mh;
 
         public FieldAccessor(Field field, Object target) {
             this.field=field;
             this.target=target;
             if(!field.isAccessible())
                 field.setAccessible(true);
+            try {
+                mh=LOOKUP.unreflectGetter(field);
+            }
+            catch(IllegalAccessException e) {
+                // todo: log warning?
+                // throw new RuntimeException(e);
+            }
         }
 
         public Field getField() {return field;}
 
         public Object invoke(Object new_val) throws Exception {
-            if(new_val == null)
+            if(new_val == null) {
+                if(mh != null) {
+                    try {
+                        return mh.invoke(target);
+                    }
+                    catch(Throwable e) {
+                        ;
+                    }
+                }
                 return field.get(target);
+            }
             else {
                 field.set(target, new_val);
                 return null;

src/org/jgroups/protocols/Fragmentation.java

@@ -18,8 +18,7 @@ public class Fragmentation extends Protocol {
 
     @Property(description="The max number of bytes in a message. Larger messages will be fragmented",
       type=AttributeType.BYTES)
-    protected int                 frag_size=60000;
-
+    protected int       frag_size=60000;
     protected LongAdder num_frags_sent=new LongAdder();
     protected LongAdder num_frags_received=new LongAdder();
 

src/org/jgroups/util/ExtractMetrics.java

@@ -0,0 +1,94 @@
+package org.jgroups.util;
+
+import org.jgroups.JChannel;
+import org.jgroups.jmx.ResourceDMBean;
+import org.jgroups.stack.Protocol;
+
+import javax.management.MBeanAttributeInfo;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * Extracts all attributes and methods annotated with {@link org.jgroups.annotations.ManagedAttribute} and returns them
+ * as a map of names associated with [getter-method/description tuples]. E.g. for an attribute called foo, a method
+ * foo() or getFoo() is searched for.
+ * @author Bela Ban
+ * @since  5.4, 5.3.6
+ */
+public class ExtractMetrics {
+    protected JChannel ch;
+
+    public static class Entry {
+        protected final String description;
+        protected final Supplier<Object> method;
+
+        protected Entry(String description, Supplier<Object> method) {
+            this.description=description;
+            this.method=method;
+        }
+
+        public String getDescription() {
+            return description;
+        }
+
+        public Supplier<Object> getMethod() {
+            return method;
+        }
+
+        @Override
+        public String toString() {
+            return String.format("  %s [%s]", method.get(), description);
+        }
+    }
+
+    public static Map<String,Map<String,Entry>> extract(JChannel ch) {
+        Map<String,Map<String,Entry>> map=new HashMap<>();
+        for(Protocol p: ch.stack().getProtocols()) {
+            map.put(p.getName(), extract(p));
+        }
+        return map;
+    }
+
+
+    public static Map<String,Entry> extract(Protocol p) {
+        Map<String,Entry> map=new HashMap<>();
+
+        ResourceDMBean dm=new ResourceDMBean(p);
+        dm.forAllAttributes((k,v) -> {
+            MBeanAttributeInfo info=v.info();
+            String descr=info != null? info.getDescription() : "n/a";
+            Supplier<Object> getter=() -> {
+                try {
+                    return v.getter() != null? v.getter().invoke(null) : null;
+                }
+                catch(Exception e) {
+                    System.err.printf("failed getting value for %s\n", k);
+                    return null;
+                }
+            };
+            map.put(k, new Entry(descr, getter));
+        });
+
+        return map;
+    }
+
+    protected void start() throws Exception {
+        ch=new JChannel().connect("bla").name("X");
+        Map<String,Map<String,Entry>> map=extract(ch);
+        for(Map.Entry<String,Map<String,Entry>> e: map.entrySet()) {
+            System.out.printf("\n%s:\n---------------\n", e.getKey());
+            for(Map.Entry<String,Entry> e2: e.getValue().entrySet()) {
+                System.out.printf("  %s: %s\n", e2.getKey(), e2.getValue());
+            }
+        }
+        Util.close(ch);
+    }
+
+    public static void main(String[] args) throws Throwable {
+        new ExtractMetrics().start();
+
+    }
+}
+
+