Strings.java

/*
 * Copyright 2008-2011 the original author or authors.
 * 
 * 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.nominanuda.lang;

import static java.util.Arrays.asList;
import static java.util.stream.Collectors.toList;

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.text.MessageFormat;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Pattern;

import com.nominanuda.code.ThreadSafe;

@ThreadSafe
public abstract class Strings {
	public static final Charset UTF8 = StandardCharsets.UTF_8;
	public static final Charset ASCII = StandardCharsets.US_ASCII;
	public static boolean nullOrEmpty(String s) {
		return s == null || 0 == s.length();
	}
	public static boolean notNullOrEmpty(String s) {
		return ! nullOrEmpty(s);
	}
	public static boolean nullOrBlank(String s) {
		return s == null || "".equals(s.trim());
	}
	public static boolean notNullOrBlank(String s) {
		return ! nullOrBlank(s);
	}

	public static String join(String separator, Object... strings) {
		int len = strings.length;
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < len; i++) {
			sb.append(strings[i].toString());
			if (i < len - 1) {
				sb.append(separator);
			}
		}
		return sb.toString();
	}
	public static String join(String separator, Iterable<?> collection) {
		return join(separator, collection.iterator());
	}
	public static String join(String separator, Iterator<?> itr) {
		StringBuilder sb = new StringBuilder();
		while (itr.hasNext()) {
			sb.append(itr.next().toString());
			if (itr.hasNext()) {
				sb.append(separator);
			}
		}
		return sb.toString();
	}
	
	public static String joinNotNull(String separator, Object... strings) {
		return join(separator, asList(strings).stream().filter(x -> x != null).collect(toList()));
	}
	public static String joinNotNullOrEmpty(String separator, Object... strings) {
		return join(separator, asList(strings).stream().filter(x -> x != null && notNullOrEmpty(x.toString())).collect(toList()));
	}
	public static String joinNotNullOrBlank(String separator, Object... strings) {
		return join(separator, asList(strings).stream().filter(x -> x != null && notNullOrBlank(x.toString())).collect(toList()));
	}
	
	public static List<String> splitAndTrim(String str, String regex) {
		return splitAndTrim(str, Pattern.compile(regex));
	}
	public static List<String> splitAndTrim(String str, Pattern regex) {
		String[] arr = regex.split(str);
		LinkedList<String> l = new LinkedList<String>();
		for(String s : arr) {
			l.add(s.trim());
		}
		return l;
	}
	
	public static String pathConcat(String... segments) {
		StringBuilder sb = new StringBuilder();
		boolean lastEndsWithSlash = false;
		boolean first = true;
		for (String s : segments) {
			if (first) {
				sb.append(s);
				first = false;
			} else {
				if ((! lastEndsWithSlash) && (! s.startsWith("/"))) {
					sb.append("/");
					sb.append(s);
				} else if (lastEndsWithSlash && s.startsWith("/")) {
					sb.append(s.substring(1));
				} else {
					sb.append(s);
				}
			}
			lastEndsWithSlash = s.endsWith("/");
		}
		return sb.toString();
	}

	public static String F(String pattern, Object... arguments) {
		for(int i = 0; i < arguments.length; i++) {
			if(null == arguments[i]) {
				throw new NullPointerException("arguments " + i + " is null");
			} else {
				arguments[i] = arguments[i].toString();
			}
  		}
		return MessageFormat.format(pattern, arguments);
	}

	public static <T> String J(String separator, Iterable<T> someT) {
		return join(separator, someT);
	}

	public static String J(String separator, String decorator, List<String> strings) {
		StringBuilder result = new StringBuilder();
		for (String string : strings) {
			result.append(decorator);
			result.append(string);
			result.append(decorator);
			result.append(separator);
		}
		return result.toString().replaceAll(separator.concat("$"), "");
	}

	public static String J(String separator, String... strings) {
		StringBuilder result = new StringBuilder();
		for (String string : strings) {
			result.append(string);
			result.append(separator);
		}
		return result.toString().replaceAll(separator.concat("$"), "");
	}
}