#1405 Introduce LocalResult factory: simple refactoring

h2/src/main/org/h2/command/dml/Call.java

@@ -12,6 +12,7 @@ import org.h2.engine.Session;
 import org.h2.expression.Expression;
 import org.h2.expression.ExpressionVisitor;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.value.Value;
 
@@ -34,9 +35,9 @@ public class Call extends Prepared {
         LocalResult result;
         if (isResultSet) {
             Expression[] expr = expression.getExpressionColumns(session);
-            result = new LocalResult(session, expr, expr.length);
+            result = LocalResultFactory.createRow(session, expr, expr.length);
         } else {
-            result = new LocalResult(session, expressions, 1);
+            result = LocalResultFactory.createRow(session, expressions, 1);
         }
         result.done();
         return result;
@@ -66,9 +67,9 @@ public class Call extends Prepared {
         if (isResultSet) {
             v = v.convertTo(Value.RESULT_SET);
             ResultSet rs = v.getResultSet();
-            return LocalResult.read(session, rs, maxrows);
+            return LocalResultFactory.read(session, rs, maxrows);
         }
-        LocalResult result = new LocalResult(session, expressions, 1);
+        LocalResult result = LocalResultFactory.createRow(session, expressions, 1);
         Value[] row = { v };
         result.addRow(row);
         result.done();

h2/src/main/org/h2/command/dml/Explain.java

@@ -16,6 +16,7 @@ import org.h2.expression.Expression;
 import org.h2.expression.ExpressionColumn;
 import org.h2.mvstore.db.MVTableEngine.Store;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.store.PageStore;
 import org.h2.table.Column;
@@ -72,7 +73,7 @@ public class Explain extends Prepared {
         Database db = session.getDatabase();
         ExpressionColumn expr = new ExpressionColumn(db, column);
         Expression[] expressions = { expr };
-        result = new LocalResult(session, expressions, 1);
+        result = LocalResultFactory.createRow(session, expressions, 1);
         if (maxrows >= 0) {
             String plan;
             if (executeCommand) {

h2/src/main/org/h2/command/dml/ScriptCommand.java

@@ -43,6 +43,7 @@ import org.h2.index.Cursor;
 import org.h2.index.Index;
 import org.h2.message.DbException;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.result.Row;
 import org.h2.schema.Constant;
@@ -137,7 +138,7 @@ public class ScriptCommand extends ScriptBase {
     private LocalResult createResult() {
         Expression[] expressions = { new ExpressionColumn(
                 session.getDatabase(), new Column("SCRIPT", Value.STRING)) };
-        return new LocalResult(session, expressions, 1);
+        return LocalResultFactory.createRow(session, expressions, 1);
     }
 
     @Override

h2/src/main/org/h2/command/dml/Select.java

@@ -32,6 +32,7 @@ import org.h2.index.IndexType;
 import org.h2.message.DbException;
 import org.h2.result.LazyResult;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.result.ResultTarget;
 import org.h2.result.Row;
@@ -687,7 +688,7 @@ public class Select extends Query {
 
     @Override
     public ResultInterface queryMeta() {
-        LocalResult result = new LocalResult(session, expressionArray,
+        LocalResult result = LocalResultFactory.createRow(session, expressionArray,
                 visibleColumnCount);
         result.done();
         return result;
@@ -858,12 +859,12 @@ public class Select extends Query {
     }
 
     private LocalResult createLocalResult(LocalResult old) {
-        return old != null ? old : new LocalResult(session, expressionArray,
+        return old != null ? old : LocalResultFactory.createRow(session, expressionArray,
                 visibleColumnCount);
     }
 
     private LocalResult convertToDistinct(ResultInterface result) {
-        LocalResult distinctResult = new LocalResult(session, expressionArray, visibleColumnCount);
+        LocalResult distinctResult = LocalResultFactory.createRow(session, expressionArray, visibleColumnCount);
         distinctResult.setDistinct();
         result.reset();
         while (result.next()) {

h2/src/main/org/h2/command/dml/SelectUnion.java

@@ -20,6 +20,7 @@ import org.h2.expression.ValueExpression;
 import org.h2.message.DbException;
 import org.h2.result.LazyResult;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.result.ResultTarget;
 import org.h2.table.Column;
@@ -130,14 +131,14 @@ public class SelectUnion extends Query {
     @Override
     public ResultInterface queryMeta() {
         int columnCount = left.getColumnCount();
-        LocalResult result = new LocalResult(session, expressionArray, columnCount);
+        LocalResult result = LocalResultFactory.createRow(session, expressionArray, columnCount);
         result.done();
         return result;
     }
 
     public LocalResult getEmptyResult() {
         int columnCount = left.getColumnCount();
-        return new LocalResult(session, expressionArray, columnCount);
+        return LocalResultFactory.createRow(session, expressionArray, columnCount);
     }
 
     @Override
@@ -189,7 +190,7 @@ public class SelectUnion extends Query {
                 return lazyResult;
             }
         }
-        LocalResult result = new LocalResult(session, expressionArray, columnCount);
+        LocalResult result = LocalResultFactory.createRow(session, expressionArray, columnCount);
         if (sort != null) {
             result.setSortOrder(sort);
         }
@@ -239,7 +240,7 @@ public class SelectUnion extends Query {
             break;
         }
         case INTERSECT: {
-            LocalResult temp = new LocalResult(session, expressionArray, columnCount);
+            LocalResult temp = LocalResultFactory.createRow(session, expressionArray, columnCount);
             temp.setDistinct();
             while (l.next()) {
                 temp.addRow(convert(l.currentRow(), columnCount));

h2/src/main/org/h2/command/dml/Set.java

@@ -19,6 +19,7 @@ import org.h2.expression.Expression;
 import org.h2.expression.ValueExpression;
 import org.h2.message.DbException;
 import org.h2.message.Trace;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.result.RowFactory;
 import org.h2.schema.Schema;
@@ -558,6 +559,19 @@ public class Set extends Prepared {
             }
             break;
         }
+        case SetTypes.LOCAL_RESULT_FACTORY: {
+            session.getUser().checkAdmin();
+            String localResultFactoryName = expression.getColumnName();
+            Class<LocalResultFactory> localResultFactoryClass = JdbcUtils.loadUserClass(localResultFactoryName);
+            LocalResultFactory localResultFactory;
+            try {
+                localResultFactory = localResultFactoryClass.getDeclaredConstructor().newInstance();
+                database.setLocalResultFactory(localResultFactory);
+            } catch (Exception e) {
+                throw DbException.convert(e);
+            }
+            break;
+        }
         default:
             DbException.throwInternalError("type="+type);
         }

h2/src/main/org/h2/command/dml/SetTypes.java

@@ -252,7 +252,12 @@ public class SetTypes {
      */
     public static final int AUTHENTICATOR = 48;
 
-    private static final int COUNT = AUTHENTICATOR + 1;
+    /**
+     * The type of a SET LOCAL_RESULT_FACTORY statement.
+     */
+    public static final int LOCAL_RESULT_FACTORY = 49;
+
+    private static final int COUNT = LOCAL_RESULT_FACTORY + 1;
 
     private static final ArrayList<String> TYPES;
 
@@ -311,6 +316,7 @@ public class SetTypes {
         list.add(BUILTIN_ALIAS_OVERRIDE, "BUILTIN_ALIAS_OVERRIDE");
         list.add(COLUMN_NAME_RULES, "COLUMN_NAME_RULES");
         list.add(AUTHENTICATOR, "AUTHENTICATOR");
+        list.add(LOCAL_RESULT_FACTORY, "LOCAL_RESULT_FACTORY");
         TYPES = list;
     }
 

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

@@ -41,6 +41,8 @@ import org.h2.message.Trace;
 import org.h2.message.TraceSystem;
 import org.h2.mvstore.MVStore;
 import org.h2.mvstore.db.MVTableEngine;
+import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.Row;
 import org.h2.result.RowFactory;
 import org.h2.result.SearchRow;
@@ -230,6 +232,7 @@ public class Database implements DataHandler {
     private int queryStatisticsMaxEntries = Constants.QUERY_STATISTICS_MAX_ENTRIES;
     private QueryStatisticsData queryStatisticsData;
     private RowFactory rowFactory = RowFactory.DEFAULT;
+    private LocalResultFactory resultFactory = LocalResultFactory.DEFAULT;
 
     private Authenticator authenticator;
 
@@ -369,6 +372,14 @@ public class Database implements DataHandler {
         this.rowFactory = rowFactory;
     }
 
+    public LocalResultFactory getLocalResultFactory() {
+        return resultFactory;
+    }
+
+    public void setLocalResultFactory(LocalResultFactory resultFactory) {
+        this.resultFactory = resultFactory;
+    }
+
     public static void setInitialPowerOffCount(int count) {
         initialPowerOffCount = count;
     }

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

@@ -13,6 +13,7 @@ import java.util.Map;
 import org.h2.expression.Expression;
 import org.h2.expression.ExpressionColumn;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.Row;
 import org.h2.table.Column;
 import org.h2.table.Table;
@@ -128,7 +129,7 @@ public final class GeneratedKeys {
         Database db = session == null ? null : session.getDatabase();
         if (Boolean.FALSE.equals(generatedKeysRequest)) {
             clear(null);
-            return new LocalResult();
+            return LocalResultFactory.createRow(session);
         }
         ArrayList<ExpressionColumn> expressionColumns;
         if (Boolean.TRUE.equals(generatedKeysRequest)) {
@@ -152,7 +153,7 @@ public final class GeneratedKeys {
                 }
             } else {
                 clear(null);
-                return new LocalResult();
+                return LocalResultFactory.createRow(session);
             }
         } else if (generatedKeysRequest instanceof String[]) {
             if (table != null) {
@@ -182,18 +183,18 @@ public final class GeneratedKeys {
                 }
             } else {
                 clear(null);
-                return new LocalResult();
+                return LocalResultFactory.createRow(session);
             }
         } else {
             clear(null);
-            return new LocalResult();
+            return LocalResultFactory.createRow(session);
         }
         int columnCount = expressionColumns.size();
         if (columnCount == 0) {
             clear(null);
-            return new LocalResult();
+            return LocalResultFactory.createRow(session);
         }
-        LocalResult result = new LocalResult(session, expressionColumns.toArray(new Expression[0]), columnCount);
+        LocalResult result = LocalResultFactory.createRow(session, expressionColumns.toArray(new Expression[0]), columnCount);
         for (Map<Column, Value> map : data) {
             Value[] row = new Value[columnCount];
             for (Map.Entry<Column, Value> entry : map.entrySet()) {

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

@@ -12,6 +12,7 @@ import org.h2.engine.Database;
 import org.h2.engine.Session;
 import org.h2.message.DbException;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.table.Column;
 import org.h2.tools.SimpleResultSet;
 import org.h2.util.MathUtils;
@@ -86,7 +87,7 @@ public class TableFunction extends Function {
             ExpressionColumn col = new ExpressionColumn(db, c);
             header[i] = col;
         }
-        LocalResult result = new LocalResult(session, header, len);
+        LocalResult result = LocalResultFactory.createRow(session, header, len);
         if (distinctRows) {
             result.setDistinct();
         }

h2/src/main/org/h2/result/LocalResultFactory.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.result;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import org.h2.engine.Session;
+import org.h2.expression.Expression;
+import org.h2.message.DbException;
+import org.h2.value.DataType;
+import org.h2.value.Value;
+
+/**
+ * Creates local result.
+ */
+public abstract class LocalResultFactory {
+    /**
+     * Default implementation of local result factory.
+     */
+    public static final LocalResultFactory DEFAULT = new DefaultLocalResultFactory();
+
+    /**
+     * Create a local result object.
+     *
+     * @param session the session
+     * @param expressions the expression array
+     * @param visibleColumnCount the number of visible columns
+     * @return object to collect local result.
+     */
+    public abstract LocalResult create(Session session, Expression[] expressions, int visibleColumnCount);
+
+    /**
+     * Create a local result object.
+     * @return object to collect local result.
+     */
+    public abstract LocalResult create();
+
+    /**
+     * Default implementation of local result factory.
+     */
+    static final class DefaultLocalResultFactory extends LocalResultFactory {
+        @Override
+        public LocalResult create(Session session, Expression[] expressions, int visibleColumnCount) {
+            return new LocalResultImpl(session, expressions, visibleColumnCount);
+        }
+
+        @Override
+        public LocalResult create() {
+            return new LocalResultImpl();
+        }
+    }
+
+    /**
+     * Create a local result object by factory registered at the database.
+     *
+     * @param session the session
+     * @param expressions the expression array
+     * @param visibleColumnCount the number of visible columns
+     * @return objetc to collect local result.
+     */
+    public static LocalResult createRow(Session session, Expression[] expressions, int visibleColumnCount) {
+        return session.getDatabase().getLocalResultFactory().create(session, expressions, visibleColumnCount);
+    }
+
+    /**
+     * Create a local result object by factory registered at the database.
+     *
+     * @param session the session
+     * @return objetc to collect local result.
+     */
+    public static LocalResult createRow(Session session) {
+        return session.getDatabase().getLocalResultFactory().create();
+    }
+
+    /**
+     * Construct a local result set by reading all data from a regular result
+     * set.
+     *
+     * @param session the session
+     * @param rs the result set
+     * @param maxrows the maximum number of rows to read (0 for no limit)
+     * @return the local result set
+     */
+    public static LocalResult read(Session session, ResultSet rs, int maxrows) {
+        Expression[] cols = Expression.getExpressionColumns(session, rs);
+        int columnCount = cols.length;
+        LocalResult result = session.getDatabase().getLocalResultFactory().create(session, cols, columnCount);
+        try {
+            for (int i = 0; (maxrows == 0 || i < maxrows) && rs.next(); i++) {
+                Value[] list = new Value[columnCount];
+                for (int j = 0; j < columnCount; j++) {
+                    int type = result.getColumnType(j);
+                    list[j] = DataType.readValue(session, rs, j + 1, type);
+                }
+                result.addRow(list);
+            }
+        } catch (SQLException e) {
+            throw DbException.convert(e);
+        }
+        result.done();
+        return result;
+    }
+
+}

h2/src/main/org/h2/table/FunctionTable.java

@@ -19,6 +19,7 @@ import org.h2.index.Index;
 import org.h2.index.IndexType;
 import org.h2.message.DbException;
 import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
 import org.h2.result.ResultInterface;
 import org.h2.result.Row;
 import org.h2.schema.Schema;
@@ -194,7 +195,7 @@ public class FunctionTable extends Table {
             cachedResult.reset();
             return cachedResult;
         }
-        LocalResult result = LocalResult.read(session,  v.getResultSet(), 0);
+        LocalResult result = LocalResultFactory.read(session,  v.getResultSet(), 0);
         if (function.isDeterministic()) {
             cachedResult = result;
             cachedValue = v;

h2/src/test/org/h2/test/db/TestLocalResultFactory.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.test.db;
+
+import java.sql.Connection;
+import java.sql.Statement;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.h2.engine.Session;
+import org.h2.expression.Expression;
+import org.h2.result.LocalResult;
+import org.h2.result.LocalResultFactory;
+import org.h2.test.TestBase;
+import org.h2.test.TestDb;
+
+/**
+ * Test {@link LocalResultFactory} setting.
+ */
+public class TestLocalResultFactory extends TestDb {
+
+    /**
+     * Run just this test.
+     *
+     * @param a ignored
+     */
+    public static void main(String[] a) throws Exception {
+        TestBase.createCaller().init().test();
+    }
+
+    @Override
+    public void test() throws Exception {
+        deleteDb("localResultFactory");
+        Connection conn = getConnection("localResultFactory;LOCAL_RESULT_FACTORY=\"" +
+            MyTestLocalResultFactory.class.getName() + '"');
+        Statement stat = conn.createStatement();
+        stat.execute("create table t1(id int, name varchar)");
+        for (int i = 0; i < 1000; i++) {
+            stat.execute("insert into t1 values(" + i + ", 'name')");
+        }
+        assertEquals(MyTestLocalResultFactory.COUNTER.get(), 0);
+
+        stat.execute("select * from t1");
+
+        assertEquals(MyTestLocalResultFactory.COUNTER.get(),  1);
+
+        conn.close();
+        deleteDb("localResultFactory");
+    }
+
+    /**
+     * Test local result factory.
+     */
+    public static class MyTestLocalResultFactory extends LocalResultFactory {
+        static final AtomicInteger COUNTER = new AtomicInteger();
+
+        @Override public LocalResult create(Session session, Expression[] expressions, int visibleColumnCount) {
+            COUNTER.incrementAndGet();
+            return LocalResultFactory.DEFAULT.create(session, expressions, visibleColumnCount);
+        }
+
+        @Override public LocalResult create() {
+            COUNTER.incrementAndGet();
+            return LocalResultFactory.DEFAULT.create();
+        }
+    }
+}