/**
* 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 static org.apache.solr.handler.dataimport.DataImportHandlerException.SEVERE;
import static org.apache.solr.handler.dataimport.DataImportHandlerException.wrapAndThrow;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.sql.Blob;
import java.sql.Clob;
import java.util.Properties;
/**
* This can be useful for users who have a DB field containing xml and wish to use a nested XPathEntityProcessor
* <p/>
* The datasouce may be configured as follows
* <p/>
* <datasource name="f1" type="FieldReaderDataSource" />
* <p/>
* The enity which uses this datasource must keep the url value as the variable name url="field-name"
* <p/>
* The fieldname must be resolvable from VariableResolver
* <p/>
* This may be used with any EntityProcessor which uses a DataSource<Reader> eg:XPathEntityProcessor
* <p/>
* Supports String, BLOB, CLOB data types and there is an extra field (in the entity) 'encoding' for BLOB types
*
* @version $Id: FieldReaderDataSource.java 833959 2009-11-09 01:16:52Z ehatcher $
* @since 1.4
*/
public class FieldReaderDataSource extends DataSource<Reader> {
private static final Logger LOG = LoggerFactory.getLogger(FieldReaderDataSource.class);
protected VariableResolver vr;
protected String dataField;
private String encoding;
private EntityProcessorWrapper entityProcessor;
public void init(Context context, Properties initProps) {
dataField = context.getEntityAttribute("dataField");
encoding = context.getEntityAttribute("encoding");
entityProcessor = (EntityProcessorWrapper) context.getEntityProcessor();
/*no op*/
}
public Reader getData(String query) {
Object o = entityProcessor.getVariableResolver().resolve(dataField);
if (o == null) {
throw new DataImportHandlerException (SEVERE, "No field available for name : " +dataField);
}
if (o instanceof String) {
return new StringReader((String) o);
} else if (o instanceof Clob) {
Clob clob = (Clob) o;
try {
//Most of the JDBC drivers have getCharacterStream defined as public
// so let us just check it
return readCharStream(clob);
} catch (Exception e) {
LOG.info("Unable to get data from CLOB");
return null;
}
} else 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 getReader(m, blob);
} else {
// force invoke
m.setAccessible(true);
return getReader(m, blob);
}
} catch (Exception e) {
LOG.info("Unable to get data from BLOB");
return null;
}
} else {
return new StringReader(o.toString());
}
}
static Reader readCharStream(Clob clob) {
try {
Method m = clob.getClass().getDeclaredMethod("getCharacterStream");
if (Modifier.isPublic(m.getModifiers())) {
return (Reader) m.invoke(clob);
} else {
// force invoke
m.setAccessible(true);
return (Reader) m.invoke(clob);
}
} catch (Exception e) {
wrapAndThrow(SEVERE, e,"Unable to get reader from clob");
return null;//unreachable
}
}
private Reader getReader(Method m, Blob blob)
throws IllegalAccessException, InvocationTargetException, UnsupportedEncodingException {
InputStream is = (InputStream) m.invoke(blob);
if (encoding == null) {
return (new InputStreamReader(is));
} else {
return (new InputStreamReader(is, encoding));
}
}
public void close() {
}
}