Fixed issue with setting of maxStringLength applying globally to the tika instance.

I have extended the Tika class to allow for setting of how much text to
extract from a document to be on a per call basis.

src/main/java/org/elasticsearch/index/mapper/attachment/AttachmentMapper.java

@@ -278,10 +278,8 @@ public class AttachmentMapper implements Mapper {
 
         String parsedContent;
         try {
-            // Set the maximum length of strings returned by the parseToString method, -1 sets no limit
-            tika().setMaxStringLength(contentLength);
-            
-            parsedContent = tika().parseToString(new FastByteArrayInputStream(content), metadata);
+            // Set the maximum length of strings returned by the parseToString method, -1 sets no limit            
+            parsedContent = tika().parseToString(new FastByteArrayInputStream(content), metadata, contentLength);
         } catch (TikaException e) {
             throw new MapperParsingException("Failed to extract [" + contentLength + "] characters of text for [" + name + "]", e);
         }

src/main/java/org/elasticsearch/plugin/mapper/attachments/tika/TikaExtended.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch 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.elasticsearch.plugin.mapper.attachments.tika;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.apache.tika.Tika;
+import org.apache.tika.exception.TikaException;
+import org.apache.tika.metadata.Metadata;
+import org.apache.tika.parser.ParseContext;
+import org.apache.tika.parser.Parser;
+import org.apache.tika.sax.BodyContentHandler;
+import org.apache.tika.sax.WriteOutContentHandler;
+import org.xml.sax.SAXException;
+
+
+/**
+ * Extends the Tika class, so as to provide a way for setting the maximumStringLength on a per parse document basis.
+ */
+public class TikaExtended extends Tika {
+
+	public String parseToString(InputStream stream, Metadata metadata, int maxExtractedStringLength) throws IOException, TikaException {
+		
+		// setup
+		WriteOutContentHandler writeHandler = new WriteOutContentHandler(maxExtractedStringLength);
+		BodyContentHandler contentHandler = new BodyContentHandler(writeHandler);
+		Parser parser = getParser();
+		ParseContext context = new ParseContext();
+		context.set(Parser.class, parser);
+
+		try {
+			parser.parse(stream, contentHandler, metadata, context);
+		} catch (SAXException e) {
+			if (!writeHandler.isWriteLimitReached(e)) {
+				throw new TikaException("Unexpected SAX processing failure", e);
+			}
+		} finally {
+			stream.close();
+		}
+
+		return writeHandler.toString();
+	}
+}

src/main/java/org/elasticsearch/plugin/mapper/attachments/tika/TikaInstance.java

@@ -19,16 +19,15 @@
 
 package org.elasticsearch.plugin.mapper.attachments.tika;
 
-import org.apache.tika.Tika;
 
 /**
  *
  */
 public class TikaInstance {
 
-    private static final Tika tika = new Tika();
+    private static final TikaExtended tika = new TikaExtended();
 
-    public static Tika tika() {
+    public static TikaExtended tika() {
         return tika;
     }
 }