Add support for window functions (ideas from Andrey Karepin). fixes patch #3

git-svn-id: https://svn.code.sf.net/p/openhms/code/sqlbuilder/trunk@548 f9ba57bc-9804-47c6-9de9-2f2ff8aac994

Author: jahlborn

src/changes/changes.xml

@@ -8,6 +8,9 @@
       <action dev="jahlborn" type="add" system="SourceForge2Patches" issue="4">
         Add the EXTRACT expression (thanks to Andrey Karepin).
       </action>
+      <action dev="jahlborn" type="add" system="SourceForge2Patches" issue="3">
+        Add support for window functions (ideas from Andrey Karepin).
+      </action>
     </release>
     <release version="2.1.6" date="2016-12-18">
       <action dev="jahlborn" type="update" system="SourceForge2Features" issue="19">

src/main/java/com/healthmarketscience/sqlbuilder/FunctionCall.java

@@ -33,6 +33,7 @@ public class FunctionCall extends Expression
   private boolean _isDistinct;
   private SqlObject _functionName;
   private SqlObjectList<SqlObject> _params = SqlObjectList.create();
+  private SqlObject _window;
 
   public FunctionCall(Function function) {
     this((Object)function);
@@ -82,11 +83,31 @@ public FunctionCall addColumnParams(Column... columns) {
   public FunctionCall addNumericValueParam(Object obj) {
     return addCustomParams(obj);
   }
+
+  /**
+   * Sets the window clause for this function call, like
+   * <code>"OVER (&lt;windowClause&gt;)"</code>.
+   * @see WindowDefinitionClause
+   */
+  public FunctionCall setWindow(Object window) {
+    _window = Converter.toCustomColumnSqlObject(window);
+    return this;
+  }
+    
+  /**
+   * Sets the window clause for this function call to a reference to the named
+   * window definition, like <code>"OVER &lt;windowClauseName&gt;"</code>.
+   */
+  public FunctionCall setWindowByName(String windowName) {
+    _window = new CustomSql(windowName);
+    return this;
+  }
 
   @Override
   protected void collectSchemaObjects(ValidationContext vContext) {
     _functionName.collectSchemaObjects(vContext);
     _params.collectSchemaObjects(vContext);
+    collectSchemaObjects(_window, vContext);
   }
 
   @Override
@@ -96,6 +117,9 @@ public void appendTo(AppendableExt app) throws IOException {
       app.append("DISTINCT ");
     }
     app.append(_params).append(")");
+    if(_window != null) {
+      app.append(" OVER ").append(_window);
+    } 
   }
 
   /**
@@ -147,4 +171,34 @@ public static FunctionCall countAll() {
       .addCustomParams(ALL_SYMBOL);
   }
 
+  /**
+   * Convenience method for generating a FunctionCall using the ROW_NUMBER
+   * aggregate function.
+   *
+   * @see "SQL 2003"
+   */
+  public static FunctionCall rowNumber() {
+    return (new FunctionCall(new CustomSql("ROW_NUMBER")));
+  }
+  
+  /**
+   * Convenience method for generating a FunctionCall using the RANK
+   * aggregate function.
+   *
+   * @see "SQL 2003"
+   */
+  public static FunctionCall rank() {
+    return (new FunctionCall(new CustomSql("RANK")));
+  }
+  
+  /**
+   * Convenience method for generating a FunctionCall using the DENSE_RANK
+   * aggregate function.
+   *
+   * @see "SQL 2003"
+   */
+  public static FunctionCall denseRank() {
+    return (new FunctionCall(new CustomSql("DENSE_RANK")));
+  }
+  
 }

src/main/java/com/healthmarketscience/sqlbuilder/SelectQuery.java

@@ -99,6 +99,8 @@ public enum Hook implements HookAnchor
     /** Anchor for the " HAVING " sub-clause (only possible if there is a
         GROUP BY clause) */
       HAVING, 
+    /** Anchor for the " WINDOW " clause */
+      WINDOW, 
     /** Anchor for the " ORDER BY " clause */
       ORDER_BY, 
     /** Anchor for the " FOR UPDATE " clause */
@@ -117,6 +119,7 @@ public enum Hook implements HookAnchor
   private SqlObjectList<SqlObject> _grouping = SqlObjectList.create();
   private SqlObjectList<SqlObject> _ordering = SqlObjectList.create();
   private ComboCondition _having = ComboCondition.and();
+  private SqlObjectList<SqlObject> _windows = SqlObjectList.create();
   private SqlObject _offset;
   private SqlObject _fetchCount;
 
@@ -424,8 +427,7 @@ public ComboCondition getHavingClause() {
   /** 
    * Adds a condition to the HAVING clause for the select query (AND'd with
    * any other HAVING conditions).  Note that the HAVING clause will only be
-   * generated if some conditions have
-   been added.
+   * generated if some conditions have been added.
    * <p>
    * For convenience purposes, the SelectQuery generates it's own
    * ComboCondition allowing multiple HAVING conditions to be AND'd together.
@@ -437,12 +439,26 @@ public SelectQuery addHaving(Condition newCondition) {
     return this;
   }
 
+  /**
+   * Adds a named window definition to the select query's WINDOW definitions
+   * <p>
+   * {@code Object} -&gt; {@code SqlObject} conversions handled by
+   * {@link Converter#toCustomSqlObject}.
+   * @see "SQL 2003"
+   */
+  public SelectQuery addWindowDefinition(String name, Object window) {
+    _windows.addObject(new NamedWindowDefinition(
+                           name, Converter.toCustomSqlObject(window)));
+    return this;
+  }
+
   /**
    * Sets the value for the "OFFSET" clause.  Note that this clause is defined
    * in "SQL 2008".
    * <p>
    * {@code Object} -&gt; {@code SqlObject} conversions handled by
    * {@link Converter#toValueSqlObject}.
+   * @see "SQL 2008"
    */
   public SelectQuery setOffset(Object offset) {
     _offset = Converter.toValueSqlObject(offset);
@@ -455,6 +471,7 @@ public SelectQuery setOffset(Object offset) {
    * <p>
    * {@code Object} -&gt; {@code SqlObject} conversions handled by
    * {@link Converter#toValueSqlObject}.
+   * @see "SQL 2008"
    */
   public SelectQuery setFetchNext(Object fetchCount) {
     _fetchCount = Converter.toValueSqlObject(fetchCount);
@@ -489,14 +506,15 @@ public SelectQuery addCustomization(CustomSyntax obj) {
   }
 
   @Override
-    protected void collectSchemaObjects(ValidationContext vContext) {
+  protected void collectSchemaObjects(ValidationContext vContext) {
     super.collectSchemaObjects(vContext);
     _joins.collectSchemaObjects(vContext);
     _columns.collectSchemaObjects(vContext);
     _condition.collectSchemaObjects(vContext);
     _grouping.collectSchemaObjects(vContext);
     _ordering.collectSchemaObjects(vContext);
     _having.collectSchemaObjects(vContext);
+    _windows.collectSchemaObjects(vContext);
     if(_offset != null) {
       _offset.collectSchemaObjects(vContext);
     }
@@ -506,7 +524,7 @@ protected void collectSchemaObjects(ValidationContext vContext) {
   }
 
   @Override
-    public void validate(ValidationContext vContext)
+  public void validate(ValidationContext vContext)
     throws ValidationException
   { 
     // if we have joins, check the tables, otherwise, the join tables will
@@ -624,7 +642,7 @@ private static void validateValue(SqlObject valueObj, String type, int minVal) {
   }
 
   @Override
-    protected void appendTo(AppendableExt app, SqlContext newContext)
+  protected void appendTo(AppendableExt app, SqlContext newContext)
     throws IOException
   {
     newContext.setUseTableAliases(true);
@@ -658,6 +676,9 @@ protected void appendTo(AppendableExt app, SqlContext newContext)
       // BY clause)
       maybeAppendTo(app, Hook.HAVING, " HAVING ", _having, !_having.isEmpty());
     }
+
+    // append window definition clauses
+    maybeAppendTo(app, Hook.WINDOW, " WINDOW ", _windows, !_windows.isEmpty());
 
     // append ordering clause
     maybeAppendTo(app, Hook.ORDER_BY, " ORDER BY ", _ordering, 
@@ -742,7 +763,7 @@ static boolean hasAllColumns(SqlObjectList<? extends SqlObject> columns) {
    * Outputs the right side of a join clause
    * <code>"&lt;joinType&gt; &lt;toTable&gt; ON &lt;joinCondition&gt;"</code>.
    */
-  private static class JoinTo extends SqlObject
+  private static final class JoinTo extends SqlObject
   {
     private SqlObject _toTable;
     private JoinType _joinType;
@@ -793,7 +814,30 @@ public void appendTo(AppendableExt app) throws IOException {
         app.append(", ").append(_toTable);
       }
     }
-    
   }
 
+  /**
+   * Outputs a named window definition clause like
+   * <code>"&lt;name&gt; AS &lt;windowDefinition&gt;"</code>.
+   */
+  private static final class NamedWindowDefinition extends SqlObject
+  {
+    private final String _name;
+    private final SqlObject _definition;
+
+    private NamedWindowDefinition(String name, SqlObject definition) {
+      _name = name;
+      _definition = definition;
+    }
+
+    @Override
+    protected void collectSchemaObjects(ValidationContext vContext) {
+      _definition.collectSchemaObjects(vContext);
+    }
+
+    @Override
+    public void appendTo(AppendableExt app) throws IOException {
+      app.append(_name).append(" AS ").append(_definition);
+    }
+  }
 }

src/main/java/com/healthmarketscience/sqlbuilder/SetOperationQuery.java

@@ -25,7 +25,7 @@
 /**
  * Base query for queries which generate a series of SELECT queries joined by
  * one or more "set operations", such as UNION [ALL], EXCEPT [ALL], and
- * INSERSECT [ALL].
+ * INTERSECT [ALL].
  *
  * @author James Ahlborn
  */

src/main/java/com/healthmarketscience/sqlbuilder/SqlObject.java

@@ -104,10 +104,14 @@ protected void doValidate() throws ValidationException
   /**
    * Utility method for classes which may not be in this package to invoke
    * {@link #collectSchemaObjects(ValidationContext)} on a SqlObject.
+   * @param obj relevant sql object, may be {@code null}
+   * @param vContext current ValidationContext
    */
   public static void collectSchemaObjects(
       SqlObject obj, ValidationContext vContext) {
-    obj.collectSchemaObjects(vContext);
+    if(obj != null) {
+      obj.collectSchemaObjects(vContext);
+    }
   }
 
   /**