formula improvements from josh

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/ooxml@696969 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/ss/formula/FormulaRenderer.java

@@ -1,3 +1,20 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
 package org.apache.poi.ss.formula;
 
 import java.util.List;
@@ -11,6 +28,13 @@ import org.apache.poi.hssf.record.formula.OperationPtg;
 import org.apache.poi.hssf.record.formula.ParenthesisPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
 
+/**
+ * Common logic for rendering formulas.<br/>
+ * 
+ * For POI internal use only
+ * 
+ * @author Josh Micich
+ */
 public class FormulaRenderer {
     /**
      * Convenience method which takes in a list then passes it to the

src/java/org/apache/poi/ss/formula/FormulaRenderingWorkbook.java

@@ -1,8 +1,32 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
 package org.apache.poi.ss.formula;
 
 import org.apache.poi.hssf.record.formula.NamePtg;
 import org.apache.poi.hssf.record.formula.NameXPtg;
 
+/**
+ * Abstracts a workbook for the purpose of converting formula to text.<br/>
+ * 
+ * For POI internal use only
+ * 
+ * @author Josh Micich
+ */
 public interface FormulaRenderingWorkbook {
 
 	String getSheetNameByExternSheet(int externSheetIndex);

src/java/org/apache/poi/ss/formula/WorkbookDependentFormula.java

@@ -1,5 +1,30 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
 package org.apache.poi.ss.formula;
 
+/**
+ * Should be implemented by any {@link Ptg} subclass that needs a workbook to render its formula.
+ * <br/>
+ * 
+ * For POI internal use only
+ * 
+ * @author Josh Micich
+ */
 public interface WorkbookDependentFormula {
 	String toFormulaString(FormulaRenderingWorkbook book);
 }