GRIFFIN: "case" implementation for strings - in a hurry to support client...

GRIFFIN: "case" implementation for strings - in a hurry to support client tomorrow. This only manually tested. Unit tests to follow.

core/src/main/java/com/questdb/griffin/engine/functions/conditional/CaseFunctionFactory.java

+/*******************************************************************************
+ *    ___                  _   ____  ____
+ *   / _ \ _   _  ___  ___| |_|  _ \| __ )
+ *  | | | | | | |/ _ \/ __| __| | | |  _ \
+ *  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+ *   \__\_\\__,_|\___||___/\__|____/|____/
+ *
+ * Copyright (C) 2014-2019 Appsicle
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+
+package com.questdb.griffin.engine.functions.conditional;
+
+import com.questdb.cairo.CairoConfiguration;
+import com.questdb.cairo.ColumnType;
+import com.questdb.cairo.sql.Function;
+import com.questdb.cairo.sql.Record;
+import com.questdb.griffin.FunctionFactory;
+import com.questdb.griffin.SqlException;
+import com.questdb.griffin.engine.functions.StrFunction;
+import com.questdb.std.ObjList;
+
+public class CaseFunctionFactory implements FunctionFactory {
+    @Override
+    public String getSignature() {
+        return "case(V)";
+    }
+
+    @Override
+    //todo: unit test this and add support for all types
+    public Function newInstance(ObjList<Function> args, int position, CairoConfiguration configuration) throws SqlException {
+        int n = args.size();
+        int returnType = -1;
+        final ObjList<Function> vars = new ObjList<>(n);
+
+        Function elseBranch;
+        if (n % 2 == 1) {
+            elseBranch = args.getQuick(n - 1);
+            n--;
+        } else {
+            elseBranch = null;
+        }
+
+
+        for (int i = 0; i < n; i += 2) {
+            Function bool = args.getQuick(i);
+            Function outcome = args.getQuick(i + 1);
+
+            if (bool.getType() != ColumnType.BOOLEAN) {
+                throw SqlException.position(bool.getPosition()).put("BOOLEAN expected, found ").put(ColumnType.nameOf(bool.getType()));
+            }
+
+            if (i == 0) {
+                returnType = outcome.getType();
+            } else if (returnType != outcome.getType()) {
+                throw SqlException.position(outcome.getPosition()).put(ColumnType.nameOf(returnType)).put(" expected, found ").put(ColumnType.nameOf(outcome.getType()));
+            }
+
+            vars.add(bool);
+            vars.add(outcome);
+        }
+
+        switch (returnType) {
+            case ColumnType.STRING:
+                return new StrCaseFunction(position, vars, elseBranch);
+            default:
+                throw SqlException.$(position, "not implemented for type '").put(ColumnType.nameOf(returnType)).put('\'');
+
+        }
+    }
+
+    private static class StrCaseFunction extends StrFunction {
+        private final ObjList<Function> args;
+        private final int argsLen;
+        private final Function elseBranch;
+
+        public StrCaseFunction(int position, ObjList<Function> args, Function elseBranch) {
+            super(position);
+            this.args = args;
+            this.argsLen = args.size();
+            this.elseBranch = elseBranch;
+        }
+
+        @Override
+        public CharSequence getStr(Record rec) {
+            for (int i = 0; i < argsLen; i += 2) {
+                if (args.getQuick(i).getBool(rec)) {
+                    return args.getQuick(i + 1).getStr(rec);
+                }
+            }
+            return elseBranch == null ? null : elseBranch.getStr(rec);
+        }
+
+        @Override
+        public CharSequence getStrB(Record rec) {
+            for (int i = 0; i < argsLen; i += 2) {
+                if (args.getQuick(i).getBool(rec)) {
+                    return args.getQuick(i + 1).getStrB(rec);
+                }
+            }
+            return elseBranch.getStrB(rec);
+        }
+    }
+}

core/src/main/resources/META-INF/services/com.questdb.griffin.FunctionFactory

-################################################################################
-#    ___                  _   ____  ____
-#   / _ \ _   _  ___  ___| |_|  _ \| __ )
-#  | | | | | | |/ _ \/ __| __| | | |  _ \
-#  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
-#   \__\_\\__,_|\___||___/\__|____/|____/
-#
-# Copyright (C) 2014-2018 Appsicle
-#
-# This program is free software: you can redistribute it and/or  modify
-# it under the terms of the GNU Affero General Public License, version 3,
-# as published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Affero General Public License for more details.
-#
-# You should have received a copy of the GNU Affero General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-################################################################################
-
-################################################################################
-#    ___                  _   ____  ____
-#   / _ \ _   _  ___  ___| |_|  _ \| __ )
-#  | | | | | | |/ _ \/ __| __| | | |  _ \
-#  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
-#   \__\_\\__,_|\___||___/\__|____/|____/
-#
-# Copyright (C) 2014-2018 Appsicle
-#
-# This program is free software: you can redistribute it and/or  modify
-# it under the terms of the GNU Affero General Public License, version 3,
-# as published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Affero General Public License for more details.
-#
-# You should have received a copy of the GNU Affero General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-################################################################################
-
-################################################################################
-#    ___                  _   ____  ____
-#   / _ \ _   _  ___  ___| |_|  _ \| __ )
-#  | | | | | | |/ _ \/ __| __| | | |  _ \
-#  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
-#   \__\_\\__,_|\___||___/\__|____/|____/
-#
-# Copyright (C) 2014-2018 Appsicle
-#
-# This program is free software: you can redistribute it and/or  modify
-# it under the terms of the GNU Affero General Public License, version 3,
-# as published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Affero General Public License for more details.
-#
-# You should have received a copy of the GNU Affero General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-################################################################################
-
 # logical operations
 com.questdb.griffin.engine.functions.bool.OrFunctionFactory
 com.questdb.griffin.engine.functions.bool.AndFunctionFactory
@@ -184,3 +115,5 @@ com.questdb.griffin.engine.functions.groupby.CountGroupByFunctionFactory
 # round()
 com.questdb.griffin.engine.functions.math.RoundDoubleFunctionFactory
 
+# case conditional statement
+com.questdb.griffin.engine.functions.conditional.CaseFunctionFactory
\ No newline at end of file