Further workarounds for java being rubbish, by having a dedicated class to create concrete instances of interfaces for you

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/ooxml@637610 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/interfaces-jdk14/org/apache/poi/ss/usermodel/CreationHelper.java

@@ -0,0 +1,19 @@
+/* ====================================================================
+   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.usermodel;
+
+public interface CreationHelper {}

src/ooxml/interfaces-jdk15/org/apache/poi/ss/usermodel/Cell.java

@@ -153,17 +153,6 @@ public interface Cell {
 
     String getCellFormula();
 
-    /**
-     * Creates a RichTextString, which you can then pass to
-     *  {@link #setCellValue(RichTextString)}. This is required
-     *  because Java is broken, and won't allow you to define
-     *  static methods or constructors on interfaces, and without
-     *  that there's no way to get a RichTextString without
-     *  creating the appropriate concrete class. 
-     * @param text The text to initialise the RichTextString with
-     */
-    RichTextString createRichTextString(String text);
-    
     /**
      * get the value of the cell as a number.  For strings we throw an exception.
      * For blank cells we return a 0.

src/ooxml/interfaces-jdk15/org/apache/poi/ss/usermodel/CreationHelper.java

@@ -0,0 +1,42 @@
+/* ====================================================================
+   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.usermodel;
+
+/**
+ * An object that handles instantiating concrete
+ *  classes of the various instances one needs for 
+ *  HSSF and XSSF.
+ * Works around a major shortcoming in Java, where we
+ *  can't have static methods on interfaces or abstract
+ *  classes.
+ * This allows you to get the appropriate class for
+ *  a given interface, without you having to worry
+ *  about if you're dealing with HSSF or XSSF, despite
+ *  Java being quite rubbish.
+ */
+public interface CreationHelper {
+    /**
+     * Creates a new RichTextString instance 
+     * @param text The text to initialise the RichTextString with
+     */
+    RichTextString createRichTextString(String text);
+    
+    /**
+     * Creates a new DataFormat instance
+     */
+    DataFormat createDataFormat();
+}

src/ooxml/interfaces-jdk15/org/apache/poi/ss/usermodel/DataFormat.java

@@ -18,14 +18,12 @@
 package org.apache.poi.ss.usermodel;
 
 public interface DataFormat {
-
     /**
      * get the format index that matches the given format string.
      * Creates a new format if one is not found.  Aliases text to the proper format.
      * @param format string matching a built in format
      * @return index of format.
      */
-
     short getFormat(String format);
 
     /**
@@ -33,7 +31,5 @@ public interface DataFormat {
      * @param index of a format
      * @return string represented at index of format or null if there is not a  format at that index
      */
-
     String getFormat(short index);
-
 }

src/ooxml/interfaces-jdk15/org/apache/poi/ss/usermodel/Workbook.java

@@ -455,4 +455,13 @@ public interface Workbook {
      */
     List getAllEmbeddedObjects();
 
+    /**
+     * Returns an object that handles instantiating concrete
+     *  classes of the various instances one needs for 
+     *  HSSF and XSSF.
+     * Works around a major shortcoming in Java, where we
+     *  can't have static methods on interfaces or abstract
+     *  classes.
+     */
+    CreationHelper getCreationHelper();
 }

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFCreationHelper.java

@@ -0,0 +1,43 @@
+/* ====================================================================
+   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.xssf.usermodel;
+
+import org.apache.poi.ss.usermodel.CreationHelper;
+import org.apache.poi.ss.usermodel.DataFormat;
+import org.apache.poi.ss.usermodel.RichTextString;
+
+public class XSSFCreationHelper implements CreationHelper {
+	private XSSFWorkbook workbook;
+	private XSSFDataFormat dataFormat;
+	XSSFCreationHelper(XSSFWorkbook wb) {
+		workbook = wb;
+		
+		// Create the things we only ever need one of
+		dataFormat = new XSSFDataFormat();
+	}
+	
+    /**
+     * Creates a new XSSFRichTextString for you.
+     */
+	public RichTextString createRichTextString(String text) {
+		return new XSSFRichTextString(text);
+	}
+	
+	public DataFormat createDataFormat() {
+		return dataFormat;
+	}
+}

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFDataFormat.java

@@ -0,0 +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.xssf.usermodel;
+
+import org.apache.poi.ss.usermodel.DataFormat;
+
+/**
+ * TODO - figure out how this should really work for XSSF
+ */
+public class XSSFDataFormat implements DataFormat {
+	public short getFormat(String format) {
+		return -1;
+	}
+
+	public String getFormat(short index) {
+		return null;
+	}
+}

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java

@@ -27,6 +27,7 @@ import javax.xml.namespace.QName;
 
 import org.apache.poi.POIXMLDocument;
 import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.CreationHelper;
 import org.apache.poi.ss.usermodel.DataFormat;
 import org.apache.poi.ss.usermodel.Font;
 import org.apache.poi.ss.usermodel.Name;
@@ -533,4 +534,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook {
         this.sharedStringSource = sharedStringSource;
     }
 
+    public CreationHelper getCreationHelper() {
+    	return new XSSFCreationHelper(this);
+    }
 }