org.apache.hadoop.hive.ql.udf.generic.GenericUDFSubstringIndex.java Source code

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Here is the source code for org.apache.hadoop.hive.ql.udf.generic.GenericUDFSubstringIndex.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.hadoop.hive.ql.udf.generic;

import static org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils.PrimitiveGrouping.NUMERIC_GROUP;
import static org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils.PrimitiveGrouping.STRING_GROUP;

import org.apache.commons.lang.StringUtils;
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.serde2.objectinspector.ConstantObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters.Converter;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.Text;

/**
 * GenericUDFSubstringIndex.
 *
 */
@Description(name = "substring_index", value = "_FUNC_(str, delim, count) - Returns the substring from string str before count occurrences "
        + "of the delimiter delim.", extended = "If count is positive, everything to the left of the final delimiter (counting from the left) "
                + "is returned. If count is negative, everything to the right of the final delimiter "
                + "(counting from the right) is returned. Substring_index performs a case-sensitive match when searching "
                + "for delim.\n" + "Example:\n > SELECT _FUNC_('www.apache.org', '.', 2);\n 'www.apache'")
public class GenericUDFSubstringIndex extends GenericUDF {
    private transient Converter[] converters = new Converter[3];
    private transient PrimitiveCategory[] inputTypes = new PrimitiveCategory[3];
    private final Text output = new Text();
    private transient String delimConst;
    private transient boolean isDelimConst;
    private transient Integer countConst;
    private transient boolean isCountConst;

    @Override
    public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
        checkArgsSize(arguments, 3, 3);

        checkArgPrimitive(arguments, 0);
        checkArgPrimitive(arguments, 1);
        checkArgPrimitive(arguments, 2);

        checkArgGroups(arguments, 0, inputTypes, STRING_GROUP);
        checkArgGroups(arguments, 1, inputTypes, STRING_GROUP);
        checkArgGroups(arguments, 2, inputTypes, NUMERIC_GROUP);

        obtainStringConverter(arguments, 0, inputTypes, converters);
        obtainStringConverter(arguments, 1, inputTypes, converters);
        obtainIntConverter(arguments, 2, inputTypes, converters);

        if (arguments[1] instanceof ConstantObjectInspector) {
            delimConst = getConstantStringValue(arguments, 1);
            isDelimConst = true;
        }

        if (arguments[2] instanceof ConstantObjectInspector) {
            countConst = getConstantIntValue(arguments, 2);
            isCountConst = true;
        }

        ObjectInspector outputOI = PrimitiveObjectInspectorFactory.writableStringObjectInspector;
        return outputOI;
    }

    @Override
    public Object evaluate(DeferredObject[] arguments) throws HiveException {
        // str
        String str = getStringValue(arguments, 0, converters);
        if (str == null) {
            return null;
        }
        if (str.length() == 0) {
            output.set("");
            return output;
        }

        // delim
        String delim;
        if (isDelimConst) {
            delim = delimConst;
        } else {
            delim = getStringValue(arguments, 1, converters);
        }
        if (delim == null) {
            return null;
        }
        if (delim.length() == 0) {
            output.set("");
            return output;
        }

        // count
        Integer countV;
        if (isCountConst) {
            countV = countConst;
        } else {
            countV = getIntValue(arguments, 2, converters);
        }
        if (countV == null) {
            return null;
        }
        int count = countV.intValue();
        if (count == 0) {
            output.set("");
            return output;
        }

        // get substring
        String res;
        if (count > 0) {
            int idx = StringUtils.ordinalIndexOf(str, delim, count);
            if (idx != -1) {
                res = str.substring(0, idx);
            } else {
                res = str;
            }
        } else {
            int idx = StringUtils.lastOrdinalIndexOf(str, delim, -count);
            if (idx != -1) {
                res = str.substring(idx + 1);
            } else {
                res = str;
            }
        }

        output.set(res);
        return output;
    }

    @Override
    public String getDisplayString(String[] children) {
        return getStandardDisplayString(getFuncName(), children);
    }

    @Override
    protected String getFuncName() {
        return "substring_index";
    }
}