SOLR-1737 FieldStreamDataSource: A dataSource which can give out an InputStream from Field data

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@903966 13f79535-47bb-0310-9956-ffa450edef68

contrib/dataimporthandler/CHANGES.txt

@@ -39,6 +39,8 @@ New Features
 
 * SOLR-1721 : Add explicit option to run DataImportHandler in synchronous mode (Alexey Serba via noble)
 
+* SOLR-1737 : Added FieldStreamDataSource (noble)
+
 Optimizations
 ----------------------
 

contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/FieldStreamDataSource.java

@@ -0,0 +1,95 @@
+/**
+ * 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.solr.handler.dataimport;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.sql.Blob;
+import java.util.Properties;
+
+import static org.apache.solr.handler.dataimport.DataImportHandlerException.SEVERE;
+
+
+/**
+ * This can be useful for users who have a DB field containing BLOBs which may be Rich documents
+ * <p/>
+ * The datasouce may be configured as follows
+ * <p/>
+ * <datasource name="f1" type="FieldStreamDataSource" />
+ * <p/>
+ * The enity which uses this datasource must keep and attribute dataField
+ * <p/>
+ * The fieldname must be resolvable from VariableResolver
+ * <p/>
+ * This may be used with any EntityProcessor which uses a DataSource<InputStream> eg:TikaEntityProcessor
+ * <p/>
+ *
+ * @version $Id$
+ * @since 1.5
+ */
+public class FieldStreamDataSource extends DataSource<InputStream> {
+  private static final Logger LOG = LoggerFactory.getLogger(FieldReaderDataSource.class);
+  protected VariableResolver vr;
+  protected String dataField;
+  private EntityProcessorWrapper wrapper;
+
+  public void init(Context context, Properties initProps) {
+    dataField = context.getEntityAttribute("dataField");
+    wrapper = (EntityProcessorWrapper) context.getEntityProcessor();
+    /*no op*/
+  }
+
+  public InputStream getData(String query) {
+    Object o = wrapper.getVariableResolver().resolve(dataField);
+    if (o == null) {
+      throw new DataImportHandlerException(SEVERE, "No field available for name : " + dataField);
+    }
+    if (o instanceof Blob) {
+      Blob blob = (Blob) o;
+      try {
+        //Most of the JDBC drivers have getBinaryStream defined as public
+        // so let us just check it
+        Method m = blob.getClass().getDeclaredMethod("getBinaryStream");
+        if (Modifier.isPublic(m.getModifiers())) {
+          return (InputStream) m.invoke(blob);
+        } else {
+          // force invoke
+          m.setAccessible(true);
+          return (InputStream) m.invoke(blob);
+        }
+      } catch (Exception e) {
+        LOG.info("Unable to get data from BLOB");
+        return null;
+
+      }
+    } else if (o instanceof byte[]) {
+      byte[] bytes = (byte[]) o;
+      return new ByteArrayInputStream(bytes);
+    } else {
+      throw new RuntimeException("unsupported type : " + o.getClass());
+    } 
+
+  }
+
+  public void close() {
+  }
+}