/**
* 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.hadoop.hive.ql.udf.generic;
import java.io.Serializable;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.SettableUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorConverter.HiveVarcharConverter;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.SettableHiveVarcharObjectInspector;
import org.apache.hadoop.hive.serde2.typeinfo.VarcharTypeParams;
@Description(name = "varchar",
value = "CAST(<value> as VARCHAR(length)) - Converts the argument to a varchar value.",
extended = "Values will be truncated if the input value is too long to fit"
+ " within the varchar length."
+ "Example:\n "
+ " > SELECT CAST(1234 AS varchar(10)) FROM src LIMIT 1;\n"
+ " '1234'")
public class GenericUDFToVarchar extends GenericUDF
implements SettableUDF, Serializable {
private static final Log LOG = LogFactory.getLog(GenericUDFToVarchar.class.getName());
private transient PrimitiveObjectInspector argumentOI;
private transient HiveVarcharConverter converter;
// The varchar type parameters need to be set prior to initialization,
// and must be preserved when the plan serialized to other processes.
private VarcharTypeParams typeParams;
public GenericUDFToVarchar() {
}
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
if (arguments.length != 1) {
throw new UDFArgumentException("VARCHAR cast requires a value argument");
}
try {
argumentOI = (PrimitiveObjectInspector) arguments[0];
} catch (ClassCastException e) {
throw new UDFArgumentException(
"The function VARCHAR takes only primitive types");
}
// Check if this UDF has been provided with type params for the output varchar type
SettableHiveVarcharObjectInspector outputOI;
if (typeParams != null) {
outputOI = (SettableHiveVarcharObjectInspector)
PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(
PrimitiveObjectInspectorUtils.getTypeEntryFromTypeSpecs(
PrimitiveCategory.VARCHAR, typeParams));
} else {
outputOI = PrimitiveObjectInspectorFactory.writableHiveVarcharObjectInspector;
}
converter = new HiveVarcharConverter(argumentOI, outputOI);
return outputOI;
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
Object o0 = arguments[0].get();
if (o0 == null) {
return null;
}
return converter.convert(o0);
}
@Override
public String getDisplayString(String[] children) {
assert (children.length == 1);
StringBuilder sb = new StringBuilder();
sb.append("CAST( ");
sb.append(children[0]);
sb.append(" AS VARCHAR(");
String paramsStr = "";
if (typeParams != null) {
paramsStr = typeParams.toString();
}
sb.append(paramsStr);
sb.append(")");
return sb.toString();
}
/**
* Provide varchar type parameters for the output object inspector.
* This should be done before the UDF is initialized.
*/
@Override
public void setParams(Object typeParams) throws UDFArgumentException {
if (converter != null) {
LOG.warn("Type converter already initialized, setting type params now will not be useful");
}
if (typeParams instanceof VarcharTypeParams) {
this.typeParams = (VarcharTypeParams)typeParams;
} else {
throw new UDFArgumentException(
"Was expecting VarcharTypeParams, instead got " + typeParams.getClass().getName());
}
}
@Override
public Object getParams() {
return typeParams;
}
}