FR [ 2546052 ] Introduce Query aggregate methods

https://sourceforge.net/tracker/index.php?func=detail&aid=2546052&group_id=176962&atid=879335

base/src/org/compiere/model/Query.java

@@ -19,6 +19,7 @@
  ******************************************************************************/
 package org.compiere.model;
 
+import java.math.BigDecimal;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -39,19 +40,26 @@ import org.compiere.util.Util;
 /**
  * 
  * @author Low Heng Sin
- * @author Teo Sarca, SC ARHIPAC SERVICE SRL
+ * @author Teo Sarca, www.arhipac.ro
  * 			<li>FR [ 1981760 ] Improve Query class
  * 			<li>BF [ 2030280 ] org.compiere.model.Query apply access filter issue
  * 			<li>FR [ 2041894 ] Add Query.match() method
  * 			<li>FR [ 2107068 ] Query.setOrderBy should be more error tolerant
  * 			<li>FR [ 2107109 ] Add method Query.setOnlyActiveRecords
  * 			<li>FR [ 2421313 ] Introduce Query.firstOnly convenient method
+ * 			<li>FR [ 2546052 ] Introduce Query aggregate methods
  * @author Redhuan D. Oon
  * 			<li>FR: [ 2214883 ] Remove SQL code and Replace for Query // introducing SQL String prompt in log.info 
- *			>li>FR: [ 2214883 ] - to introduce .setClient_ID
+ *			<li>FR: [ 2214883 ] - to introduce .setClient_ID
  */
 public class Query
 {
+	public static final String AGGREGATE_COUNT		= "COUNT";
+	public static final String AGGREGATE_SUM		= "SUM";
+	public static final String AGGREGATE_AVG		= "AVG";
+	public static final String AGGREGATE_MIN		= "MIN";
+	public static final String AGGREGATE_MAX		= "MAX";
+	
 	private static CLogger log	= CLogger.getCLogger (Query.class);
 	
 	private Properties ctx = null;
@@ -294,6 +302,68 @@ public class Query
 	{
  		return buildSQL(null, true);
 	}
+
+	/**
+	 * Aggregate given expression on this criteria
+	 * @param sqlExpression
+	 * @param sqlFunction 
+	 * @return aggregated value
+	 */
+	public BigDecimal aggregate(String sqlExpression, String sqlFunction) throws DBException
+	{
+		if (Util.isEmpty(sqlFunction, true))
+		{
+			throw new DBException("No Aggregate Function defined");
+		}
+		if (Util.isEmpty(sqlExpression, true))
+		{
+			if (AGGREGATE_COUNT == sqlFunction)
+			{
+				sqlExpression = "*";
+			}
+			else
+			{
+				throw new DBException("No Expression defined");
+			}
+		}
+		
+		StringBuffer sqlSelect = new StringBuffer("SELECT ").append(sqlFunction).append("(")
+					.append(sqlExpression).append(")")
+					.append(" FROM ").append(table.getTableName());
+		
+		BigDecimal value = null;
+		String sql = buildSQL(sqlSelect, false);
+		PreparedStatement pstmt = null;
+		ResultSet rs = null;
+		try
+		{
+			pstmt = DB.prepareStatement(sql, this.trxName);
+			rs = createResultSet(pstmt);
+			if (rs.next())
+			{
+				value = rs.getBigDecimal(1);
+			}
+			if (rs.next())
+			{
+				throw new DBException("QueryMoreThanOneRecordsFound"); // TODO : translate
+			}
+		}
+		catch (SQLException e)
+		{
+			throw new DBException(e);
+		}
+		finally
+		{
+			DB.close(rs, pstmt);
+			rs = null; pstmt = null;
+		}
+		//
+		if (value == null)
+		{
+			value = Env.ZERO;
+		}
+		return value;
+	}
 	
 	/**
 	 * Count items that match query criteria
@@ -302,25 +372,18 @@ public class Query
 	 */
 	public int count() throws DBException
 	{
-		int count = -1;
+		return aggregate("*", AGGREGATE_COUNT).intValue();
-		String sql = buildSQL(new StringBuffer("SELECT COUNT(*) FROM ").append(table.getTableName()), false);
-		PreparedStatement pstmt = null;
-		ResultSet rs = null;
-		try {
-			pstmt = DB.prepareStatement(sql, this.trxName);
-			rs = createResultSet(pstmt);
-			rs.next();
-			count = rs.getInt(1);
-		}
-		catch (SQLException e) {
-			throw new DBException(e);
-		}
-		finally {
-			DB.close(rs, pstmt);
-		}
-		return count;
 	}
 	
+	/**
+	 * SUM sqlExpression for items that match query criteria
+	 * @param sqlExpression
+	 * @return sum
+	 */
+	public BigDecimal sum(String sqlExpression)
+	{
+		return aggregate(sqlExpression, AGGREGATE_SUM);
+	}
 	/**
 	 * Check if there items for query criteria
 	 * @return true if exists, false otherwise
@@ -548,5 +611,4 @@ public class Query
 		}
 		return retValue;
 	}	//	get_IDs
-
 }

extend/src/test/functional/QueryTest.java

@@ -183,5 +183,47 @@ public class QueryTest extends AdempiereTestCase
 		assertEquals(101, ids[0]);
 		assertEquals(102, ids[1]);
 	}
-
+	
+	public void testAggregate() throws Exception
+	{
+		final int AD_Client_ID = Env.getAD_Client_ID(getCtx());
+		final String sqlFrom = "FROM C_InvoiceLine WHERE IsActive='Y' AND AD_Client_ID="+AD_Client_ID;
+		final Query query = new Query(getCtx(), "C_InvoiceLine", null, getTrxName())
+						.setOnlyActiveRecords(true)
+						.setClient_ID();
+		//
+		// Test COUNT:
+		assertEquals("COUNT not match",
+				DB.getSQLValueBDEx(getTrxName(), "SELECT COUNT(*) "+sqlFrom),
+				query.aggregate(null, Query.AGGREGATE_COUNT));
+		//
+		// Test SUM:
+		assertEquals("SUM not match",
+				DB.getSQLValueBDEx(getTrxName(), "SELECT SUM(LineNetAmt+TaxAmt) "+sqlFrom),
+				query.aggregate("LineNetAmt+TaxAmt", Query.AGGREGATE_SUM));
+		//
+		// Test MIN:
+		assertEquals("MIN not match",
+				DB.getSQLValueBDEx(getTrxName(), "SELECT MIN(LineNetAmt) "+sqlFrom),
+				query.aggregate("LineNetAmt", Query.AGGREGATE_MIN));
+		//
+		// Test MAX:
+		assertEquals("MAX not match",
+				DB.getSQLValueBDEx(getTrxName(), "SELECT MAX(LineNetAmt) "+sqlFrom),
+				query.aggregate("LineNetAmt", Query.AGGREGATE_MAX));
+		//
+		// Test Exception : No Aggregate Function defined
+		assertExceptionThrowed("No Aggregate Function defined", DBException.class, new Runnable(){
+			public void run()
+			{
+				query.aggregate("*", null);
+			}});
+		//
+		// Test Exception : No Expression defined
+		assertExceptionThrowed("No Expression defined", DBException.class, new Runnable(){
+			public void run()
+			{
+				query.aggregate(null, Query.AGGREGATE_SUM);
+			}});
+	}
 }