1 files changed, 58 insertions, 2 deletions
diff --git a/java/src/main/java/com/google/protobuf/AbstractMessage.java b/java/src/main/java/com/google/protobuf/AbstractMessage.java
index fb416bdc..b9d83016 100644
--- a/java/src/main/java/com/google/protobuf/AbstractMessage.java
+++ b/java/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -32,9 +32,10 @@ package com.google.protobuf;
 
 import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Internal.EnumLite;
 
-import java.io.InputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -167,11 +168,66 @@ public abstract class AbstractMessage extends AbstractMessageLite
   public int hashCode() {
     int hash = 41;
     hash = (19 * hash) + getDescriptorForType().hashCode();
-    hash = (53 * hash) + getAllFields().hashCode();
+    hash = hashFields(hash, getAllFields());
     hash = (29 * hash) + getUnknownFields().hashCode();
     return hash;
   }
 
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.getType() != FieldDescriptor.Type.ENUM){
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends EnumLite> list = (List<? extends EnumLite>) value;
+        hash = (53 * hash) + hashEnumList(list);
+      } else {
+        hash = (53 * hash) + hashEnum((EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+  /**
+   * Helper method for implementing {@link Message#hashCode()}.
+   * @see Boolean#hashCode()
+   */
+  protected static int hashLong(long n) {
+    return (int) (n ^ (n >>> 32));
+  }
+
+  /**
+   * Helper method for implementing {@link Message#hashCode()}.
+   * @see Boolean#hashCode()
+   */
+  protected static int hashBoolean(boolean b) {
+    return b ? 1231 : 1237;
+  }
+
+  /**
+   * Helper method for implementing {@link Message#hashCode()}.
+   * <p>
+   * This is needed because {@link java.lang.Enum#hashCode()} is final, but we
+   * need to use the field number as the hash code to ensure compatibility
+   * between statically and dynamically generated enum objects.
+   */
+  protected static int hashEnum(EnumLite e) {
+    return e.getNumber();
+  }
+
+  /** Helper method for implementing {@link Message#hashCode()}. */
+  protected static int hashEnumList(List<? extends EnumLite> list) {
+    int hash = 1;
+    for (EnumLite e : list) {
+      hash = 31 * hash + hashEnum(e);
+    }
+    return hash;
+  }
+
   // =================================================================
 
   /**