1 files changed, 97 insertions, 0 deletions
diff --git a/sangria-core/src/main/java/com/tavianator/sangria/core/UniqueAnnotations.java b/sangria-core/src/main/java/com/tavianator/sangria/core/UniqueAnnotations.java
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@@ -0,0 +1,97 @@
+/*********************************************************************
+ * Sangria                                                           *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>      *
+ *                                                                   *
+ * This library is free software. It comes without any warranty, to  *
+ * the extent permitted by applicable law. You can redistribute it   *
+ * and/or modify it under the terms of the Do What The Fuck You Want *
+ * To Public License, Version 2, as published by Sam Hocevar. See    *
+ * the COPYING file or http://www.wtfpl.net/ for more details.       *
+ *********************************************************************/
+
+package com.tavianator.sangria.core;
+
+import java.lang.annotation.Annotation;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.concurrent.atomic.AtomicLong;
+import javax.inject.Qualifier;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Re-implementation of Guice's internal UniqueAnnotations utility.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.0
+ * @since 1.0
+ */
+public class UniqueAnnotations {
+    private static final AtomicLong SEQUENCE = new AtomicLong();
+
+    private UniqueAnnotations() {
+        // Not for instantiating
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Qualifier
+    @VisibleForTesting
+    @interface UniqueAnnotation {
+        long value();
+    }
+
+    /**
+     * Actual implementation of {@link UniqueAnnotation}.
+     */
+    @SuppressWarnings("ClassExplicitlyAnnotation")
+    private static class UniqueAnnotationImpl implements UniqueAnnotation {
+        private final long value;
+
+        UniqueAnnotationImpl(long value) {
+            this.value = value;
+        }
+
+        @Override
+        public long value() {
+            return value;
+        }
+
+        public Class<? extends Annotation> annotationType() {
+            return UniqueAnnotation.class;
+        }
+
+        @Override
+        public String toString() {
+            return "@" + UniqueAnnotation.class.getName() + "(value=" + value + ")";
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == this) {
+                return true;
+            } else if (!(obj instanceof UniqueAnnotation)) {
+                return false;
+            }
+
+            UniqueAnnotation other = (UniqueAnnotation)obj;
+            return value == other.value();
+        }
+
+        @Override
+        public int hashCode() {
+            return (127*"value".hashCode()) ^ Long.valueOf(value).hashCode();
+        }
+    }
+
+    /**
+     * @return An {@link Annotation} that will be unequal to every other annotation.
+     */
+    public static Annotation create() {
+        return create(SEQUENCE.getAndIncrement());
+    }
+
+    @VisibleForTesting
+    static Annotation create(long value) {
+        return new UniqueAnnotationImpl(value);
+    }
+}