GenericUDF udf在不同數據壓縮格式下的處理

package com.**.udf;

import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.lazy.LazyString;
import org.apache.hadoop.hive.serde2.objectinspector.ListObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
import org.apache.hadoop.io.Text;

;
import java.util.ArrayList;
import java.util.List;

public final class GetVersionId extends GenericUDF {

    private ListObjectInspector queueInspector1;
    private ListObjectInspector queueInspector2;
    private StringObjectInspector valueInspector3;


    @Override
    public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
        // 參數個數校驗
        if (arguments.length != 3) {
            throw new UDFArgumentLengthException("The function argument is error, and get " + arguments.length);
        }

        queueInspector1 = (ListObjectInspector) arguments[0];
        queueInspector2 = (ListObjectInspector) arguments[1];
        valueInspector3 = (StringObjectInspector) arguments[2];
        return PrimitiveObjectInspectorFactory.javaStringObjectInspector;
    }

    /**
     * @param - List<T>,list<T>
     * @return
     * @author lxt 。
     */
    public Object evaluate(DeferredObject[] arguments) throws HiveException {
        @SuppressWarnings("unchecked")
        List<Text> versionIds = (List<Text>) queueInspector1.getList(arguments[0].get());
        List<Text> versionDts = (List<Text>) queueInspector2.getList(arguments[1].get());
        String eventTime = valueInspector3.getPrimitiveWritableObject(arguments[2].get()).toString();

        try {
            for (int i = versionDts.size() - 1; i >= 0; i--) {
                if (eventTime.compareTo(versionDts.get(i).toString()) >= 0) {
                    return versionIds.get(i).toString();
                }
            }
            if (versionDts.size() > 0 && eventTime.compareTo(versionDts.get(0).toString()) < 0) {
                return versionIds.get(0).toString();
            } else {
                return "";
            }


        } catch (ClassCastException e) {
            List<String> versionIdStrs = new ArrayList<>();
            int elemNum = this.queueInspector1.getListLength(arguments[0].get());
            for (int i = 0; i < elemNum; i++) {
                LazyString lelement = (LazyString) this.queueInspector1.getListElement(arguments[0].get(), i);
                String element = PrimitiveObjectInspectorFactory.javaStringObjectInspector.getPrimitiveJavaObject(lelement);
                versionIdStrs.add(element);
            }

            List<String> versionDtStrs = new ArrayList<>();
            elemNum = this.queueInspector2.getListLength(arguments[1].get());
            for (int i = 0; i < elemNum; i++) {
                LazyString lelement = (LazyString) this.queueInspector2.getListElement(arguments[1].get(), i);
                String element = PrimitiveObjectInspectorFactory.javaStringObjectInspector.getPrimitiveJavaObject(lelement);
                versionDtStrs.add(element);
            }


            for (int i = versionDtStrs.size() - 1; i >= 0; i--) {
                if (eventTime.compareTo(versionDtStrs.get(i)) >= 0) {
                    return versionIdStrs.get(i);
                }
            }
            if (versionDtStrs.size() > 0 && eventTime.compareTo(versionDtStrs.get(0)) < 0) {
                return versionIdStrs.get(0);
            } else {
                return "";
            }
        }


    }


    @Override
    public String getDisplayString(String[] strings) {
        return "this method requires three parameters";
    }


}