Start on a factory for text extractors

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/ooxml@645861 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/src/scratchpad/src/org/apache/poi/extractor/ExtractorFactory.java b/src/scratchpad/src/org/apache/poi/extractor/ExtractorFactory.java
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+/* ====================================================================
+   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.extractor;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.PushbackInputStream;
+import java.util.Iterator;
+
+import org.openxml4j.exceptions.InvalidFormatException;
+import org.openxml4j.exceptions.OpenXML4JException;
+import org.openxml4j.opc.Package;
+import org.openxml4j.opc.PackagePart;
+import org.openxml4j.opc.PackageRelationshipCollection;
+
+import org.apache.poi.POITextExtractor;
+import org.apache.poi.POIXMLDocument;
+import org.apache.poi.POIXMLTextExtractor;
+import org.apache.poi.hssf.extractor.ExcelExtractor;
+import org.apache.poi.poifs.filesystem.Entry;
+import org.apache.poi.poifs.filesystem.POIFSFileSystem;
+import org.apache.poi.xslf.XSLFSlideShow;
+import org.apache.poi.xslf.extractor.XSLFPowerPointExtractor;
+import org.apache.poi.xssf.extractor.XSSFExcelExtractor;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.apache.poi.xwpf.XWPFDocument;
+import org.apache.poi.xwpf.extractor.XWPFWordExtractor;
+import org.apache.xmlbeans.XmlException;
+
+/**
+ * Figures out the correct POITextExtractor for your supplied
+ *  document, and returns it.
+ */
+public class ExtractorFactory {
+       public static final String CORE_DOCUMENT_REL =
+               "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument";
+       
+       public POITextExtractor createExtractor(File f) throws IOException, InvalidFormatException, OpenXML4JException, XmlException {
+               FileInputStream finp = new FileInputStream(f);
+               
+               if(POIFSFileSystem.hasPOIFSHeader(finp)) {
+                       return createExtractor(new POIFSFileSystem(finp));
+               }
+               if(POIXMLDocument.hasOOXMLHeader(finp)) {
+                       finp.close();
+                       return createExtractor(Package.open(f.toString()));
+               }
+               throw new IllegalArgumentException("Your File was neither an OLE2 file, nor an OOXML file");
+       }
+       
+       public POITextExtractor createExtractor(InputStream inp) throws IOException, InvalidFormatException, OpenXML4JException, XmlException {
+               // Figure out the kind of stream
+               // If clearly doesn't do mark/reset, wrap up
+               if(! inp.markSupported()) {
+                       inp = new PushbackInputStream(inp, 8);
+               }
+               
+               if(POIFSFileSystem.hasPOIFSHeader(inp)) {
+                       return createExtractor(new POIFSFileSystem(inp));
+               }
+               if(POIXMLDocument.hasOOXMLHeader(inp)) {
+                       return createExtractor(Package.open(inp));
+               }
+               throw new IllegalArgumentException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");
+       }
+       
+       public POIXMLTextExtractor createExtractor(Package pkg) throws IOException, OpenXML4JException, XmlException {
+               PackageRelationshipCollection core = 
+                       pkg.getRelationshipsByType(CORE_DOCUMENT_REL);
+               if(core.size() != 1) {
+                       throw new IllegalArgumentException("Invalid OOXML Package received - expected 1 core document, found " + core.size());
+               }
+               
+               PackagePart corePart = pkg.getPart(core.getRelationship(0));
+               if(corePart.getContentType().equals(XSSFWorkbook.WORKBOOK.getContentType())) {
+                       return new XSSFExcelExtractor(pkg);
+               }
+               if(corePart.getContentType().equals(XWPFDocument.MAIN_CONTENT_TYPE)) {
+                       return new XWPFWordExtractor(pkg);
+               }
+               if(corePart.getContentType().equals(XSLFSlideShow.MAIN_CONTENT_TYPE)) {
+                       return new XSLFPowerPointExtractor(pkg);
+               }
+               throw new IllegalArgumentException("No supported documents found in the OOXML package");
+       }
+       
+       public POITextExtractor createExtractor(POIFSFileSystem fs) throws IOException {
+               // Look for certain entries in the stream, to figure it
+               //  out from
+               for(Iterator entries = fs.getRoot().getEntries(); entries.hasNext(); ) {
+                       Entry entry = (Entry)entries.next();
+                       if(entry.getName().equals("Workbook")) {
+                               return new ExcelExtractor(fs);
+                       }
+               }
+               throw new IllegalArgumentException("No supported documents found in the OLE2 stream");
+       }
+}