TableFormatter.java

/*
 * Copyright 1999-2017 Alibaba Group Holding Ltd.
 *
 * Licensed 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 com.alibaba.druid.support.console;

import java.util.List;

public class TableFormatter {

	public static String format(List<String[]> rows) {
		String[] titleRow  = rows.get(0);
		int[] maxLens = new int[titleRow.length];
        for (String[] row : rows) {
            for (int j = 0; j < row.length; j++) {
                int len = displayLen(row[j]);
                if (len > maxLens[j]) {
                    maxLens[j] = len;
                }
            }
        }
		StringBuilder sb = new StringBuilder();
		sb.append(makeSplitLine(maxLens));
		for (int i=0; i<rows.size(); i++) {
			String[] row = rows.get(i);
			sb.append("|");
			for (int j=0; j<row.length; j++) {
				sb.append( padStr( row[j], maxLens[j]));
				sb.append(" |");
			}
			sb.append("\n");
			//title row
			if (i==0) {
				sb.append(makeSplitLine(maxLens));
			}
		}

		sb.append(makeSplitLine(maxLens));
		return sb.toString();
	}

	public static String makeSplitLine(int[] maxLens) {
		StringBuilder sb = new StringBuilder("+");
		for (int len : maxLens) {
			for (int i=0; i<len; i++) {
				sb.append("-");
			}
			sb.append("-+");
		}
		sb.append("\n");
		return sb.toString();
	}

	public static int displayLen(String value) {
		return value.length();
	}

	public static String padStr(String old, int length) {
		if (old == null ) {
		    return "";
		}
		int vLen = displayLen(old);
		if (vLen > length) {
		    return old;
		}
		StringBuilder sb = new StringBuilder(old);
		for (int i=0; i< length -vLen ; i++) {
			sb.append(" ");
		}
		return sb.toString();
	}

}