Java tutorial
/******************************************************************************* * Copyright (c) 2005, 2011 Spring IDE Developers * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-v10.html * * Contributors: * Spring IDE Developers - initial API and implementation *******************************************************************************/ package org.springframework.ide.eclipse.core; import java.util.Collection; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.Set; /** * Miscellaneous string utility methods. * @author Torsten Juergeleit * @author Christian Dupuis */ public final class StringUtils { public static final char SINGLE_QUOTE = '\''; public static final char DOUBLE_QUOTE = '\"'; private static final String NL = System.getProperty("line.separator"); private static final String INDENT = " "; /** * Returns concatenated text from given two texts delimited by given * delimiter. Both texts can be empty or <code>null</code>. */ public static String concatenate(String text1, String text2, String delimiter) { StringBuffer buf = new StringBuffer(); if (text1 != null && text1.length() > 0) { buf.append(text1); } if (text2 != null && text2.length() > 0) { if (buf.length() > 0) { buf.append(delimiter); } buf.append(text2); } return buf.toString(); } /** * Convenience method to return a <code>Collection</code> as a delimited * (e.g. CSV) <code>String</code>. * @param coll <code>Collection</code> to display * @param delim delimiter to use (probably a ",") */ public static String collectionToDelimitedString(Collection coll, String delim) { if (coll == null) { return ""; } StringBuffer sb = new StringBuffer(); Iterator it = coll.iterator(); int i = 0; while (it.hasNext()) { if (i > 0) { sb.append(delim); } sb.append(it.next()); i++; } return sb.toString(); } /** * Returns <code>true</code> if given string has a leading and trailing * single or double quote character. */ public static boolean isQuoted(String string) { if (string == null || string.length() < 2) { return false; } int lastIndex = string.length() - 1; char firstChar = string.charAt(0); char lastChar = string.charAt(lastIndex); return ((firstChar == SINGLE_QUOTE && lastChar == SINGLE_QUOTE) || (firstChar == DOUBLE_QUOTE && lastChar == DOUBLE_QUOTE)); } /** * Returns <code>true</code> if given string's first character is upper * case as per {@link Character#isUpperCase(char)}. */ public static boolean isCapitalized(String string) { if (string != null && string.length() > 0) { return !Character.isUpperCase(string.charAt(0)); } return false; } /** * Capitalize a <code>String</code>, changing the first letter to upper * case as per {@link Character#toUpperCase(char)}. No other letters are * changed. * @param str the String to capitalize, may be null * @return the capitalized String, <code>null</code> if null */ public static String capitalize(String str) { return changeFirstCharacterCase(str, true); } /** * Uncapitalize a <code>String</code>, changing the first letter to * lower case as per {@link Character#toLowerCase(char)}. * No other letters are changed. * @param str the String to uncapitalize, may be null * @return the uncapitalized String, <code>null</code> if null */ public static String uncapitalize(String str) { return changeFirstCharacterCase(str, false); } private static String changeFirstCharacterCase(String str, boolean capitalize) { if (str == null || str.length() == 0) { return str; } StringBuffer buf = new StringBuffer(str.length()); if (capitalize) { buf.append(Character.toUpperCase(str.charAt(0))); } else { buf.append(Character.toLowerCase(str.charAt(0))); } buf.append(str.substring(1)); return buf.toString(); } public static boolean isAlphaNumeric(String str) { int strLen; if (str == null || (strLen = str.length()) == 0) { return false; } for (int i = 0; i < strLen; i++) { char c = str.charAt(i); if (!Character.isLetterOrDigit(c) && c != ' ') { return false; } } return true; } /** * Convenience method to convert a CSV string list to a set. * Note that this will suppress duplicates. * @param str CSV String * @return a Set of String entries in the list */ public static Set<String> commaDelimitedListToSet(String str) { Set<String> set = new LinkedHashSet<String>(); String[] tokens = org.springframework.util.StringUtils.commaDelimitedListToStringArray(str); for (int i = 0; i < tokens.length; i++) { set.add(tokens[i]); } return set; } /** * Pretty prints the given un-formatted JSON string. */ public static String prettyPrintJson(String json) { if (json == null) { return ""; } StringBuilder b = new StringBuilder(); char[] chars = json.toCharArray(); // keeps track of the current indent level int indent = 0; // Keep track of all " characters to find out if we are in the middle of a string value long quoteCount = 0; for (int i = 0; i < chars.length; i++) { char c = chars[i]; if (c == '"') { b.append(c); quoteCount++; } // Opening { and [ should get a line break appended and increase the indent level else if (c == '{' || c == '[') { b.append(c).append(NL); indent++; indent(b, indent); } // Opening } and ] should get a line break prepended and decrease the indent level else if (c == '}' || c == ']') { b.append(NL); indent--; indent(b, indent); b.append(c); } // After a , should go a line break but only if we are currently not within a string value else if (c == ',' && quoteCount % 2 == 0) { b.append(c).append(NL); indent(b, indent); } else { b.append(c); } } return b.toString(); } private static void indent(StringBuilder b, int level) { for (int i = 0; i < level; i++) { b.append(INDENT); } } public static boolean hasText(String name) { return name != null && !"".equals(name.trim()); } }