1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.android.tradefed.util; 17 18 import java.io.PrintWriter; 19 import java.util.ArrayList; 20 import java.util.List; 21 22 /** 23 * Helper class to display a matrix of String elements so each element column is lined up 24 */ 25 public class TableFormatter { 26 27 private int mColumnSpacing = 2; 28 29 /** 30 * Sets the number of whitespace characters between each column. 31 * 32 * @param spacing the number of whitespace characters 33 * @return the {@link TableFormatter} 34 */ setColumnSpacing(int spacing)35 public TableFormatter setColumnSpacing(int spacing) { 36 mColumnSpacing = spacing; 37 return this; 38 } 39 40 /** 41 * Display given String elements as an table with aligned columns. 42 * 43 * @param table a matrix of String elements. Rows can be different length 44 * @param writer the {@link PrintWriter} to dump output to 45 */ displayTable(List<List<String>> table, PrintWriter writer)46 public void displayTable(List<List<String>> table, PrintWriter writer) { 47 if (table.size() <= 0) { 48 throw new IllegalArgumentException(); 49 } 50 // build index of max column sizes 51 List<Integer> maxColumnSizes = getColumnSizes(table); 52 for (List<String> rowData : table) { 53 for (int col = 0; col < rowData.size(); col++) { 54 writer.append(rowData.get(col)); 55 int numPaddingChars = maxColumnSizes.get(col) - rowData.get(col).length(); 56 insertPadding(numPaddingChars, writer); 57 } 58 writer.println(); 59 } 60 } 61 insertPadding(int numChars, PrintWriter writer)62 private void insertPadding(int numChars, PrintWriter writer) { 63 for (int i = 0; i < numChars; i++) { 64 writer.append(' '); 65 } 66 } 67 getColumnSizes(List<List<String>> table)68 private List<Integer> getColumnSizes(List<List<String>> table) { 69 List<Integer> maxColumnSizes = new ArrayList<Integer>(); 70 for (List<String> rowData : table) { 71 for (int colIndex = 0; colIndex < rowData.size(); colIndex++) { 72 if (colIndex >= maxColumnSizes.size()) { 73 maxColumnSizes.add(colIndex, 0); 74 } 75 // add column spacing to string length so there is at least that amount of space 76 // between columns 77 int stringSize = rowData.get(colIndex).length() + mColumnSpacing; 78 if (maxColumnSizes.get(colIndex) < stringSize) { 79 maxColumnSizes.set(colIndex, stringSize); 80 } 81 } 82 } 83 84 return maxColumnSizes; 85 } 86 } 87