Remove dependency between Mode and Function

h2/src/main/org/h2/engine/Mode.java

@@ -10,8 +10,6 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Set;
 import java.util.regex.Pattern;
-import org.h2.expression.Function;
-import org.h2.expression.FunctionInfo;
 import org.h2.util.StringUtils;
 import org.h2.value.DataType;
 import org.h2.value.Value;
@@ -206,8 +204,6 @@ public class Mode {
      */
     public HashMap<String, DataType> typeByNameMap = new HashMap<>();
 
-    public HashMap<String, FunctionInfo> functionAliases;
-
     private final String name;
 
     private final ModeEnum modeEnum;
@@ -273,9 +269,6 @@ public class Mode {
         dt.sqlType = Types.NUMERIC;
         dt.name = "SMALLMONEY";
         mode.typeByNameMap.put("SMALLMONEY", dt);
-        HashMap<String, FunctionInfo> functions = new HashMap<>();
-        copyFunction(functions, "RANDOM_UUID", "NEWID");
-        mode.functionAliases = functions;
         add(mode);
 
         mode = new Mode(ModeEnum.MySQL);
@@ -349,10 +342,6 @@ public class Mode {
         add(mode);
     }
 
-    static void copyFunction(HashMap<String, FunctionInfo> functions, String stdName, String newName) {
-        functions.put(newName, new FunctionInfo(Function.getFunctionInfo(stdName), newName));
-    }
-
     private Mode(ModeEnum modeEnum) {
         this.name = modeEnum.name();
         this.modeEnum = modeEnum;

h2/src/main/org/h2/expression/Function.java

@@ -28,6 +28,7 @@ import org.h2.engine.Database;
 import org.h2.engine.Mode;
 import org.h2.engine.Session;
 import org.h2.message.DbException;
+import org.h2.mode.FunctionsMSSQLServer;
 import org.h2.schema.Schema;
 import org.h2.schema.Sequence;
 import org.h2.security.BlockCipher;
@@ -474,7 +475,13 @@ public class Function extends Expression implements FunctionCall {
         addFunction("VALUES", VALUES, 1, Value.NULL, false, true, false);
     }
 
-    protected Function(Database database, FunctionInfo info) {
+    /**
+     * Creates a new instance of function.
+     *
+     * @param database database
+     * @param info function information
+     */
+    public Function(Database database, FunctionInfo info) {
         this.database = database;
         this.info = info;
         if (info.parameterCount == VAR_ARGS) {
@@ -521,12 +528,10 @@ public class Function extends Expression implements FunctionCall {
         }
         FunctionInfo info = FUNCTIONS.get(name);
         if (info == null) {
-            HashMap<String, FunctionInfo> aliases = database.getMode().functionAliases;
-            if (aliases == null) {
-                return null;
-            }
-            info = aliases.get(name);
-            if (info == null) {
+            switch (database.getMode().getEnum()) {
+            case MSSQLServer:
+                return FunctionsMSSQLServer.getFunction(database, name);
+            default:
                 return null;
             }
         }

h2/src/main/org/h2/mode/FunctionsBase.java

+/*
+ * Copyright 2004-2018 H2 Group. Multiple-Licensed under the MPL 2.0,
+ * and the EPL 1.0 (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.mode;
+
+import java.util.HashMap;
+
+import org.h2.expression.Function;
+import org.h2.expression.FunctionInfo;
+
+/**
+ * Base class for mode-specific functions.
+ */
+abstract class FunctionsBase {
+
+    /**
+     * Copy a standard function to a mode functions with a different name.
+     *
+     * @param functions
+     *            mode functions
+     * @param stdName
+     *            the name of the standard function
+     * @param newName
+     *            the name of the mode-specific function
+     */
+    static void copyFunction(HashMap<String, FunctionInfo> functions, String stdName, String newName) {
+        functions.put(newName, new FunctionInfo(Function.getFunctionInfo(stdName), newName));
+    }
+
+}

h2/src/main/org/h2/mode/FunctionsMSSQLServer.java

+/*
+ * Copyright 2004-2018 H2 Group. Multiple-Licensed under the MPL 2.0,
+ * and the EPL 1.0 (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.mode;
+
+import java.util.HashMap;
+
+import org.h2.engine.Database;
+import org.h2.expression.Function;
+import org.h2.expression.FunctionInfo;
+
+/**
+ * Functions for {@link org.h2.engine.Mode.ModeEnum#MSSQLServer} compatibility
+ * mode.
+ */
+public final class FunctionsMSSQLServer extends FunctionsBase {
+    private static final HashMap<String, FunctionInfo> FUNCTIONS = new HashMap<>();
+
+    static {
+        copyFunction(FUNCTIONS, "RANDOM_UUID", "NEWID");
+    }
+
+    /**
+     * Returns mode-specific function for a given name, or {@code null}.
+     *
+     * @param database
+     *            the database
+     * @param upperName
+     *            the upper-case name of a function
+     * @return the function with specified name or {@code null}
+     */
+    public static Function getFunction(Database database, String upperName) {
+        FunctionInfo info = FUNCTIONS.get(upperName);
+        return info != null ? new Function(database, info) : null;
+    }
+
+    private FunctionsMSSQLServer() {
+    }
+}