org.devgateway.eudevfin.importing.metadata.streamprocessors.ExcelStreamProcessor.java Source code

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Here is the source code for org.devgateway.eudevfin.importing.metadata.streamprocessors.ExcelStreamProcessor.java

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/*******************************************************************************
 * Copyright (c) 2014 Development Gateway.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 *******************************************************************************/
/**
 *
 */
package org.devgateway.eudevfin.importing.metadata.streamprocessors;

import java.io.IOException;
import java.io.InputStream;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.devgateway.eudevfin.importing.metadata.exception.EntityMapperGenerationException;
import org.devgateway.eudevfin.importing.metadata.exception.InvalidDataException;
import org.devgateway.eudevfin.importing.metadata.mapping.MapperInterface;

/**
 * @author Alex
 *
 */
public class ExcelStreamProcessor implements IMetadataStreamProcessor {

    private static final int METADATA_INFO_ROW_NUM = 1;

    private static final int MAPPER_CLASS_COL_NUM = 1;

    private static final int MAPPER_CLASS_ROW_NUM = 0;

    private static final int ACTUAL_DATA_START_ROW_NUM = 3;

    public final static Integer OFFSET = 1;

    private HSSFWorkbook workbook;
    private HSSFSheet sheet;

    private List<String> metadataInfoList;
    private String mapperClassName;

    private int currentRowNum = ACTUAL_DATA_START_ROW_NUM;

    private int endRowNum;

    private final InputStream inputStream;

    public ExcelStreamProcessor(final InputStream is) {
        this.inputStream = is;
        try {
            this.workbook = new HSSFWorkbook(is);
            this.sheet = this.workbook.getSheetAt(0);
            this.endRowNum = this.sheet.getLastRowNum();

            this.generateMetadataInfoList();
            this.findMapperClassName();
        } catch (final IOException e) {
            e.printStackTrace();
        }

    }

    @Override
    public Object generateNextObject() {
        if (this.currentRowNum <= this.endRowNum) {
            final HSSFRow row = this.sheet.getRow(this.currentRowNum);
            try {
                final MapperInterface mapper = this.instantiateMapper();
                final Object entity = this.generateObject(mapper, row);
                return entity;
            } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {

                e.printStackTrace();

                throw new EntityMapperGenerationException("Problems generating object", e);
            } finally {
                this.currentRowNum++;
            }
        }
        return null;

    }

    @Override
    public boolean hasNextObject() {
        if (this.currentRowNum <= this.endRowNum) {
            return true;
        }
        return false;

    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    private Object generateObject(final MapperInterface<?> mapper, final HSSFRow row)
            throws ClassNotFoundException, InstantiationException, IllegalAccessException {

        boolean allCellsAreNull = true;
        final List<String> values = new ArrayList<String>();
        for (int j = OFFSET; j < this.metadataInfoList.size() + OFFSET; j++) {
            final HSSFCell cell = row.getCell(j);
            if (cell != null) {
                allCellsAreNull = false;
                String val = null;
                if (HSSFCell.CELL_TYPE_STRING == cell.getCellType()) {
                    val = cell.getStringCellValue();
                } else if (HSSFCell.CELL_TYPE_NUMERIC == cell.getCellType()) {
                    //               HSSFDataFormatter dataFormatter   = new HSSFDataFormatter();
                    //               val   = dataFormatter.formatCellValue(cell);
                    val = new BigDecimal(cell.getNumericCellValue()).toString();
                }
                if (val != null && val.trim().length() > 0) {
                    values.add(val.trim());
                } else {
                    values.add(null);
                }

            } else {
                values.add(null);
            }

        }
        if (allCellsAreNull) {
            return null;
        }
        final Object result = mapper.createEntity(values);
        return result;
    }

    /**
     *
     * @param mapperClassName the name of the mapper class that needs to be instantiated
     * @param metadataInfoList the metainformation needed for each field of the mapping
     * @throws ClassNotFoundException
     * @throws InstantiationException
     * @throws IllegalAccessException
     */
    @SuppressWarnings("rawtypes")
    private MapperInterface<?> instantiateMapper() {
        try {
            final Class clazz = Class.forName(this.mapperClassName);
            final MapperInterface<?> mapper = (MapperInterface<?>) clazz.newInstance();
            mapper.setMetainfos(this.metadataInfoList);

            return mapper;
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
            e.printStackTrace();
            throw new EntityMapperGenerationException("Problems generating objects", e);
        }
    }

    private void findMapperClassName() {
        final HSSFRow row = this.sheet.getRow(MAPPER_CLASS_ROW_NUM);
        final HSSFCell cell = row.getCell(MAPPER_CLASS_COL_NUM);
        if (HSSFCell.CELL_TYPE_STRING == cell.getCellType()) {
            this.mapperClassName = cell.getStringCellValue();
        } else {
            throw new InvalidDataException("Expecting mapper name in cell B1");
        }
    }

    private void generateMetadataInfoList() {
        this.metadataInfoList = new ArrayList<String>();
        final HSSFRow row = this.sheet.getRow(METADATA_INFO_ROW_NUM);
        final short end = row.getLastCellNum();
        for (short i = 1; i < end; i++) {
            final HSSFCell cell = row.getCell((int) i);
            if (cell != null) {
                if (HSSFCell.CELL_TYPE_STRING == cell.getCellType()) {
                    final String value = cell.getStringCellValue();
                    this.metadataInfoList.add(value);
                } else {
                    throw new InvalidDataException("Expecting mapper name in cell B1");
                }
            } else {
                break;
            }
        }

    }

    @Override
    public void close() {
        try {
            this.inputStream.close();
        } catch (final IOException e) {
            e.printStackTrace();
        }

    }

    @Override
    public List<String> getMetadataInfoList() {
        return this.metadataInfoList;
    }

    public void setMetadataInfoList(final List<String> metadataInfoList) {
        this.metadataInfoList = metadataInfoList;
    }

    @Override
    public String getMapperClassName() {
        return this.mapperClassName;
    }

    public void setMapperClassName(final String mapperClassName) {
        this.mapperClassName = mapperClassName;
    }

}