easyexcel/src/main/java/com/alibaba/excel/write/style/AbstractColumnCellStyleStrategy.java

package com.alibaba.excel.write.style;

import java.util.HashMap;
import java.util.Map;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Workbook;

import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.util.StyleUtil;
import com.sun.istack.internal.Nullable;

/**
 *
 * Use the same style for the column
 *
 * @author zhuangjiaju
 */
public abstract class AbstractColumnCellStyleStrategy extends AbstractCellStyleStrategy {

    private Workbook workbook;
    private Map<Integer, CellStyle> headCellStyleCache = new HashMap<Integer, CellStyle>();
    private Map<Integer, CellStyle> contentCellStyleCache = new HashMap<Integer, CellStyle>();

    @Override
    protected void initCellStyle(Workbook workbook) {
        this.workbook = workbook;
    }

    @Override
    protected void setHeadCellStyle(Cell cell, Head head, int relativeRowIndex) {
        int columnIndex = head.getColumnIndex();
        if (headCellStyleCache.containsKey(columnIndex)) {
            CellStyle cellStyle = headCellStyleCache.get(columnIndex);
            if (cellStyle != null) {
                cell.setCellStyle(cellStyle);
            }
            return;
        }
        com.alibaba.excel.metadata.CellStyle headCellStyle = headCellStyle(head);
        if (headCellStyle == null) {
            headCellStyleCache.put(columnIndex, null);
        } else {
            CellStyle cellStyle = StyleUtil.buildHeadCellStyle(workbook, headCellStyle(head));
            headCellStyleCache.put(columnIndex, cellStyle);
            cell.setCellStyle(cellStyle);
        }
    }

    @Override
    protected void setContentCellStyle(Cell cell, Head head, int relativeRowIndex) {
        int columnIndex = head.getColumnIndex();
        if (contentCellStyleCache.containsKey(columnIndex)) {
            CellStyle cellStyle = contentCellStyleCache.get(columnIndex);
            if (cellStyle != null) {
                cell.setCellStyle(cellStyle);
            }
            return;
        }
        com.alibaba.excel.metadata.CellStyle contentCellStyle = contentCellStyle(head);
        if (contentCellStyle == null) {
            contentCellStyleCache.put(columnIndex, null);
        } else {
            CellStyle cellStyle = StyleUtil.buildContentCellStyle(workbook, contentCellStyle(head));
            contentCellStyleCache.put(columnIndex, cellStyle);
            cell.setCellStyle(cellStyle);
        }
    }

    /**
     * Returns the column width corresponding to each column head
     *
     * @param head
     * @return
     */
    protected abstract com.alibaba.excel.metadata.CellStyle headCellStyle(@Nullable Head head);

    /**
     * Returns the column width corresponding to each column head
     *
     * @param head
     * @return
     */
    protected abstract com.alibaba.excel.metadata.CellStyle contentCellStyle(@Nullable Head head);

}