diff --git a/tools/droiddoc/src/Errors.java b/tools/droiddoc/src/Errors.java
new file mode 100644
index 0000000..1431314
--- /dev/null
+++ b/tools/droiddoc/src/Errors.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+public class Errors
+{
+    public static boolean hadError = false;
+    private static boolean warningsAreErrors = false;
+    private static TreeSet<Message> allErrors = new TreeSet<Message>();
+
+    private static class Message implements Comparable {
+        SourcePositionInfo pos;
+        String msg;
+
+        Message(SourcePositionInfo p, String m) {
+            pos = p;
+            msg = m;
+        }
+
+        public int compareTo(Object o) {
+            Message that = (Message)o;
+            int r = this.pos.compareTo(that.pos);
+            if (r != 0) return r;
+            return this.msg.compareTo(that.msg);
+        }
+
+        public String toString() {
+            String whereText = this.pos == null ? "unknown: " : this.pos.toString() + ':';
+            return whereText + this.msg;
+        }
+    }
+
+    public static void error(Error error, SourcePositionInfo where, String text) {
+        if (error.level == HIDDEN) {
+            return;
+        }
+
+        String which = (!warningsAreErrors && error.level == WARNING) ? " warning " : " error ";
+        String message = which + error.code + ": " + text;
+
+        if (where == null) {
+            where = new SourcePositionInfo("unknown", 0, 0);
+        }
+
+        allErrors.add(new Message(where, message));
+
+        if (error.level == ERROR || (warningsAreErrors && error.level == WARNING)) {
+            hadError = true;
+        }
+    }
+
+    public static void printErrors() {
+        for (Message m: allErrors) {
+            System.err.println(m.toString());
+        }
+    }
+
+    public static int HIDDEN = 0;
+    public static int WARNING = 1;
+    public static int ERROR = 2;
+
+    public static void setWarningsAreErrors(boolean val) {
+        warningsAreErrors = val;
+    }
+
+    public static class Error {
+        public int code;
+        public int level;
+
+        public Error(int code, int level)
+        {
+            this.code = code;
+            this.level = level;
+        }
+    }
+
+    public static Error UNRESOLVED_LINK = new Error(1, WARNING);
+    public static Error BAD_INCLUDE_TAG = new Error(2, WARNING);
+    public static Error UNKNOWN_TAG = new Error(3, WARNING);
+    public static Error UNKNOWN_PARAM_TAG_NAME = new Error(4, WARNING);
+    public static Error UNDOCUMENTED_PARAMETER = new Error(5, HIDDEN);
+    public static Error BAD_ATTR_TAG = new Error(6, ERROR);
+    public static Error BAD_INHERITDOC = new Error(7, HIDDEN);
+    public static Error HIDDEN_LINK = new Error(8, WARNING);
+    public static Error HIDDEN_CONSTRUCTOR = new Error(9, WARNING);
+    public static Error UNAVAILABLE_SYMBOL = new Error(10, ERROR);
+    public static Error HIDDEN_SUPERCLASS = new Error(11, WARNING);
+    public static Error DEPRECATED = new Error(12, HIDDEN);
+    public static Error DEPRECATION_MISMATCH = new Error(13, WARNING);
+    public static Error MISSING_COMMENT = new Error(14, WARNING);
+    public static Error IO_ERROR = new Error(15, HIDDEN);
+
+    public static Error[] ERRORS = {
+            UNRESOLVED_LINK,
+            BAD_INCLUDE_TAG,
+            UNKNOWN_TAG,
+            UNKNOWN_PARAM_TAG_NAME,
+            UNDOCUMENTED_PARAMETER,
+            BAD_ATTR_TAG,
+            BAD_INHERITDOC,
+            HIDDEN_LINK,
+            HIDDEN_CONSTRUCTOR,
+            UNAVAILABLE_SYMBOL,
+            HIDDEN_SUPERCLASS,
+            DEPRECATED,
+            IO_ERROR,
+        };
+
+    public static boolean setErrorLevel(int code, int level) {
+        for (Error e: ERRORS) {
+            if (e.code == code) {
+                e.level = level;
+                return true;
+            }
+        }
+        return false;
+    }
+}