Revert invalid commits from JDK9 branch

build.gradle

@@ -24,7 +24,7 @@ apply plugin: 'idea'
 defaultTasks 'build'
 
 group = 'com.lmax'
-version = new Version(major: 3, minor: 5, revision: 0)
+version = new Version(major: 3, minor: 4, revision: 3)
 
 ext {
     fullName = 'Disruptor Framework'
@@ -41,10 +41,8 @@ ext {
     if (!project.hasProperty('sonatypePassword')) sonatypePassword = ''
 }
 
-
 sourceSets {
     perf.java.srcDir file('src/perftest/java')
-    java9.java.srcDir file('src/main/java9')
 }
 
 eclipse.classpath.plusConfigurations += [ sourceSets.perf.compileClasspath ]
@@ -57,40 +55,24 @@ dependencies {
 //    checkstyle 'com.puppycrawl.tools:checkstyle:8.12'
     testCompile 'junit:junit:4.12'
     perfCompile 'org.hdrhistogram:HdrHistogram:2.1.10'
-    java9Compile sourceSets.main.output
 }
 
 idea.module {
     testSourceDirs += sourceSets.perf.allSource.srcDirs
     scopes.TEST.plus += [ configurations.perfCompile ]
 }
 
+sourceCompatibility = 1.7
+targetCompatibility = 1.7
+
+
 compileJava {
     // Suppress warnings about using Unsafe and sun.misc
     options.compilerArgs << '-XDignore.symbol.file'
     options.fork = true
     options.debug = true
     options.forkOptions.executable = javaCompilerExecutable
     options.warnings = false
-    sourceCompatibility = 1.7
-    targetCompatibility = 1.7
-}
-
-compileJava9Java {
-    sourceCompatibility = 1.9
-    targetCompatibility = 1.9
-//    options.compilerArgs.addAll(['--release', '9'])
-}
-
-task testJava9(type: Test) {
-    dependsOn jar
-    def jdkHome = System.getenv("JAVA_9")
-    classpath = files(jar.archivePath, classpath) - sourceSets.main.output
-    executable = file("$jdkHome/bin/java")
-    doFirst {
-        println classpath.asPath
-        println "$name runs test using JDK 9"
-    }
 }
 
 tasks.withType(Test) {
@@ -114,19 +96,12 @@ javadoc {
 }
 
 jar {
-    manifest.attributes(
-            'Built-By': System.properties['user.name'],
-            'Bundle-Name': fullName,
-            'Bundle-Vendor': teamName,
-            'Bundle-Description': fullDescription,
-            'Bundle-DocURL': siteUrl,
-            'Multi-Release': true,
-            'Automatic-Module-Name': moduleName
-    )
-
-    into('META-INF/versions/9') {
-        from sourceSets.java9.output
-    }
+    manifest.attributes('Built-By': System.properties['user.name'],
+                        'Bundle-Name': fullName,
+                        'Bundle-Vendor': teamName,
+                        'Bundle-Description': fullDescription,
+                        'Bundle-DocURL': siteUrl,
+                        'Automatic-Module-Name': moduleName)
 }
 
 task sourcesJar(type: Jar) {

src/main/java/com/lmax/disruptor/RingBuffer.java

@@ -16,7 +16,10 @@
 package com.lmax.disruptor;
 
 
+import sun.misc.Unsafe;
+
 import com.lmax.disruptor.dsl.ProducerType;
+import com.lmax.disruptor.util.Util;
 
 abstract class RingBufferPad
 {
@@ -25,40 +28,69 @@ abstract class RingBufferPad
 
 abstract class RingBufferFields<E> extends RingBufferPad
 {
+    private static final int BUFFER_PAD;
+    private static final long REF_ARRAY_BASE;
+    private static final int REF_ELEMENT_SHIFT;
+    private static final Unsafe UNSAFE = Util.getUnsafe();
+
+    static
+    {
+        final int scale = UNSAFE.arrayIndexScale(Object[].class);
+        if (4 == scale)
+        {
+            REF_ELEMENT_SHIFT = 2;
+        }
+        else if (8 == scale)
+        {
+            REF_ELEMENT_SHIFT = 3;
+        }
+        else
+        {
+            throw new IllegalStateException("Unknown pointer size");
+        }
+        BUFFER_PAD = 128 / scale;
+        // Including the buffer pad in the array base offset
+        REF_ARRAY_BASE = UNSAFE.arrayBaseOffset(Object[].class) + 128;
+    }
+
+    private final long indexMask;
     private final Object[] entries;
+    protected final int bufferSize;
     protected final Sequencer sequencer;
 
     RingBufferFields(
         EventFactory<E> eventFactory,
         Sequencer sequencer)
     {
         this.sequencer = sequencer;
+        this.bufferSize = sequencer.getBufferSize();
 
-        if (sequencer.getBufferSize() < 1)
+        if (bufferSize < 1)
         {
             throw new IllegalArgumentException("bufferSize must not be less than 1");
         }
-        if (Integer.bitCount(sequencer.getBufferSize()) != 1)
+        if (Integer.bitCount(bufferSize) != 1)
         {
             throw new IllegalArgumentException("bufferSize must be a power of 2");
         }
 
-        this.entries = new Object[sequencer.getBufferSize()];
+        this.indexMask = bufferSize - 1;
+        this.entries = new Object[sequencer.getBufferSize() + 2 * BUFFER_PAD];
         fill(eventFactory);
     }
 
     private void fill(EventFactory<E> eventFactory)
     {
-        for (int i = 0; i < entries.length; i++)
+        for (int i = 0; i < bufferSize; i++)
         {
-            entries[i] = eventFactory.newInstance();
+            entries[BUFFER_PAD + i] = eventFactory.newInstance();
         }
     }
 
     @SuppressWarnings("unchecked")
     protected final E elementAt(long sequence)
     {
-        return (E) entries[(int) (sequence & (entries.length - 1))];
+        return (E) UNSAFE.getObject(entries, REF_ARRAY_BASE + ((sequence & indexMask) << REF_ELEMENT_SHIFT));
     }
 }
 
@@ -405,7 +437,7 @@ public long getCursor()
      */
     public int getBufferSize()
     {
-        return sequencer.getBufferSize();
+        return bufferSize;
     }
 
     /**
@@ -878,9 +910,9 @@ private void checkBatchSizing(int batchStartsAt, int batchSize)
         {
             throw new IllegalArgumentException("Both batchStartsAt and batchSize must be positive but got: batchStartsAt " + batchStartsAt + " and batchSize " + batchSize);
         }
-        else if (batchSize > sequencer.getBufferSize())
+        else if (batchSize > bufferSize)
         {
-            throw new IllegalArgumentException("The ring buffer cannot accommodate " + batchSize + " it only has space for " + sequencer.getBufferSize() + " entities.");
+            throw new IllegalArgumentException("The ring buffer cannot accommodate " + batchSize + " it only has space for " + bufferSize + " entities.");
         }
     }
 
@@ -1092,7 +1124,8 @@ private void translateAndPublishBatch(
     public String toString()
     {
         return "RingBuffer{" +
-            "sequencer=" + sequencer +
+            "bufferSize=" + bufferSize +
+            ", sequencer=" + sequencer +
             "}";
     }
 }