fix bugs in aggregators

bee-engine/src/main/java/com/dianping/bee/engine/evaluator/function/AvgEvaluator.java

@@ -17,21 +17,22 @@ public class AvgEvaluator extends AbstractEvaluator<Avg, Number> {
 		Expression first = expr.getArguments().get(0);
 		Object val = eval(ctx, first);
 
-		if (val != null) {
+		if (val != null && val instanceof Number) {
 			m_sum += ((Number) val).doubleValue();
 			m_count++;
 		}
+
 		return 0;
 	}
 
 	@Override
 	public Object getAggregatedValue() {
-		return m_sum / m_count;
+		return m_count == 0 ? 0 : m_sum / m_count;
 	}
 
 	@Override
 	public Class<?> getResultType(Avg expr) {
-		return Number.class;
+		return Double.class;
 	}
 
 	@Override

bee-engine/src/main/java/com/dianping/bee/engine/evaluator/function/CountEvaluator.java

@@ -4,15 +4,15 @@ import com.alibaba.cobar.parser.ast.expression.primary.function.groupby.Count;
 import com.dianping.bee.engine.evaluator.AbstractEvaluator;
 import com.dianping.bee.engine.spi.RowContext;
 
-public class CountEvaluator extends AbstractEvaluator<Count, Long> {
+public class CountEvaluator extends AbstractEvaluator<Count, Number> {
 	public static final String ID = Count.class.getName();
 
 	private long m_count;
 
 	@Override
-	public Long evaluate(RowContext ctx, Count expr) {
+	public Number evaluate(RowContext ctx, Count expr) {
 		m_count++;
-		return 0L;
+		return 0;
 	}
 
 	@Override

bee-engine/src/main/java/com/dianping/bee/engine/evaluator/function/MaxEvaluator.java

@@ -16,8 +16,10 @@ public class MaxEvaluator extends AbstractEvaluator<Max, Number> {
 		Object val = eval(ctx, first);
 
 		if (val != null && val instanceof Number) {
-			if (((Number) val).doubleValue() > m_max) {
-				m_max = ((Number) val).doubleValue();
+			Number value = (Number) val;
+
+			if (value.doubleValue() > m_max) {
+				m_max = value.doubleValue();
 			}
 		}
 
@@ -26,12 +28,12 @@ public class MaxEvaluator extends AbstractEvaluator<Max, Number> {
 
 	@Override
 	public Object getAggregatedValue() {
-		return m_max;
+		return m_max == Double.MIN_VALUE ? 0 : m_max;
 	}
 
 	@Override
 	public Class<?> getResultType(Max expr) {
-		return Number.class;
+		return Double.class;
 	}
 
 	@Override

bee-engine/src/main/java/com/dianping/bee/engine/evaluator/function/MinEvaluator.java

@@ -16,8 +16,10 @@ public class MinEvaluator extends AbstractEvaluator<Min, Number> {
 		Object val = eval(ctx, first);
 
 		if (val != null && val instanceof Number) {
-			if (((Number) val).doubleValue() < m_min) {
-				m_min = ((Number) val).doubleValue();
+			Number value = (Number) val;
+
+			if (value.doubleValue() < m_min) {
+				m_min = value.doubleValue();
 			}
 		}
 
@@ -26,12 +28,12 @@ public class MinEvaluator extends AbstractEvaluator<Min, Number> {
 
 	@Override
 	public Object getAggregatedValue() {
-		return m_min;
+		return m_min == Double.MAX_VALUE ? 0 : m_min;
 	}
 
 	@Override
 	public Class<?> getResultType(Min expr) {
-		return Number.class;
+		return Double.class;
 	}
 
 	@Override

bee-engine/src/main/java/com/dianping/bee/engine/evaluator/function/SumEvaluator.java

@@ -16,7 +16,9 @@ public class SumEvaluator extends AbstractEvaluator<Sum, Number> {
 		Object val = eval(ctx, first);
 
 		if (val != null) {
-			m_sum += ((Number) val).doubleValue();
+			Number value = (Number) val;
+
+			m_sum += value.doubleValue();
 		}
 
 		return 0;
@@ -29,7 +31,7 @@ public class SumEvaluator extends AbstractEvaluator<Sum, Number> {
 
 	@Override
 	public Class<?> getResultType(Sum expr) {
-		return Number.class;
+		return Double.class;
 	}
 
 	@Override

bee-engine/src/main/java/com/dianping/bee/engine/spi/Statement.java

@@ -10,5 +10,7 @@ public interface Statement {
 
 	public RowSet query();
 
+	public String getSQL();
+
 	public IndexMeta getIndexMeta();
 }

bee-engine/src/main/java/com/dianping/bee/engine/spi/internal/DefaultRowListener.java

@@ -87,6 +87,7 @@ public class DefaultRowListener extends ContainerHolder implements RowListener {
 
 				if (field.isAggregator(ctx)) {
 					m_values[i] = field.getAggregatedValue();
+					field.reset();
 				}
 
 				cells[i] = new DefaultCell(field, m_values[i]);

bee-engine/src/main/java/com/dianping/bee/engine/spi/internal/DefaultStatementManager.java

@@ -66,7 +66,11 @@ public class DefaultStatementManager extends ContainerHolder implements Statemen
 
 			try {
 				statement.accept(builder);
-				return builder.getStatement();
+
+				SingleTableStatement stmt = builder.getStatement();
+
+				stmt.setSQL(sql);
+				return stmt;
 			} finally {
 				release(builder);
 			}

bee-engine/src/main/java/com/dianping/bee/engine/spi/internal/SelectField.java

@@ -55,6 +55,10 @@ class SelectField implements ColumnMeta {
 		}
 	}
 
+	public Object getAggregatedValue() {
+		return getEvaluator(null).getAggregatedValue();
+	}
+
 	@SuppressWarnings("unchecked")
 	private Evaluator<Expression, Object> getEvaluator(RowContext ctx) {
 		if (m_evaluator == null) {
@@ -66,6 +70,14 @@ class SelectField implements ColumnMeta {
 		return m_evaluator;
 	}
 
+	public String getName() {
+		return m_name;
+	}
+
+	public Class<?> getType() {
+		return m_type;
+	}
+
 	@SuppressWarnings("unchecked")
 	public boolean isAggregator(RowContext ctx) {
 		if (m_expr != null) {
@@ -77,15 +89,7 @@ class SelectField implements ColumnMeta {
 		}
 	}
 
-	public String getName() {
-		return m_name;
-	}
-
-	public Class<?> getType() {
-		return m_type;
-	}
-
-	public Object getAggregatedValue() {
-		return getEvaluator(null).getAggregatedValue();
+	public void reset() {
+		m_evaluator = null;
 	}
 }
\ No newline at end of file

bee-engine/src/main/java/com/dianping/bee/engine/spi/internal/SingleTableStatement.java

@@ -5,6 +5,9 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.codehaus.plexus.logging.LogEnabled;
+import org.codehaus.plexus.logging.Logger;
+
 import com.dianping.bee.engine.RowSet;
 import com.dianping.bee.engine.spi.ColumnMeta;
 import com.dianping.bee.engine.spi.Index;
@@ -16,10 +19,12 @@ import com.dianping.bee.engine.spi.Statement;
 import com.site.lookup.ContainerHolder;
 import com.site.lookup.annotation.Inject;
 
-public class SingleTableStatement extends ContainerHolder implements Statement {
+public class SingleTableStatement extends ContainerHolder implements Statement, LogEnabled {
 	@Inject
 	protected RowContext ctx;
 
+	private String m_sql;
+
 	private IndexMeta m_index;
 
 	private RowFilter m_rowFilter;
@@ -30,6 +35,8 @@ public class SingleTableStatement extends ContainerHolder implements Statement {
 
 	private Map<String, List<Object>> m_attributes = new HashMap<String, List<Object>>();
 
+	private Logger m_logger;
+
 	public void addAttribute(String name, Object value) {
 		List<Object> list = m_attributes.get(name);
 
@@ -41,6 +48,11 @@ public class SingleTableStatement extends ContainerHolder implements Statement {
 		list.add(value);
 	}
 
+	@Override
+	public void enableLogging(Logger logger) {
+		m_logger = logger;
+	}
+
 	@Override
 	public ColumnMeta getColumnMeta(int colIndex) {
 		return m_fields.get(colIndex);
@@ -56,6 +68,11 @@ public class SingleTableStatement extends ContainerHolder implements Statement {
 		return m_index;
 	}
 
+	@Override
+	public String getSQL() {
+		return m_sql;
+	}
+
 	@Override
 	public RowSet query() {
 		Index index = lookup(m_index.getIndexClass());
@@ -72,6 +89,7 @@ public class SingleTableStatement extends ContainerHolder implements Statement {
 
 			return listener.getRowSet();
 		} catch (Exception e) {
+			m_logger.error(String.format("Error when handling query(%s)!", this), e);
 			throw new RuntimeException(e);
 		} finally {
 			ctx.afterQuery();
@@ -94,4 +112,8 @@ public class SingleTableStatement extends ContainerHolder implements Statement {
 	public void setSelectFields(List<SelectField> fields) {
 		m_fields = fields;
 	}
+
+	public void setSQL(String sql) {
+		m_sql = sql;
+	}
 }

bee-engine/src/test/java/com/dianping/bee/jdbc/TestServer.java → bee-engine/src/test/java/com/dianping/bee/engine/TestServer.java

@@ -12,13 +12,12 @@
  * accordance with the terms of the license agreement you entered into
  * with dianping.com.
  */
-package com.dianping.bee.jdbc;
+package com.dianping.bee.engine;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
-import com.dianping.bee.engine.TestEnvConfigurator;
 import com.dianping.bee.server.SimpleServer;
 import com.site.lookup.ComponentTestCase;