java/sql-dk/src/info/globalcode/sql/dk/Functions.java
author František Kučera <franta-hg@frantovo.cz>
Wed, 15 Jan 2014 21:38:02 +0100
branchv_0
changeset 162 7863d8a423d4
parent 127 d63de8a0a61f
child 166 5488c2dcf680
permissions -rw-r--r--
InfoLister: preserve order of databases to test and to list driver properties
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/**
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 * SQL-DK
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 * Copyright © 2013 František Kučera (frantovo.cz)
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 *
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 * This program is free software: you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation, either version 3 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program. If not, see <http://www.gnu.org/licenses/>.
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 */
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package info.globalcode.sql.dk;
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import info.globalcode.sql.dk.configuration.NameIdentified;
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import java.io.BufferedReader;
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import java.io.File;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.PrintWriter;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.Map;
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/**
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 *
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 * @author Ing. František Kučera (frantovo.cz)
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 */
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public class Functions {
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	private Functions() {
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	}
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	public static boolean equalz(Object a, Object b) {
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		return a == null ? b == null : a.equals(b);
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	}
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	/**
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	 *
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	 * @param text String to be examinated
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	 * @param trim whether text should be trimmed before examination
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	 * @return whether text is not empty and one or more characters long (after prospective trim)
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	 */
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	public static boolean isEmpty(String text, boolean trim) {
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		if (text == null) {
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			return true;
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		} else {
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			if (trim) {
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				text = text.trim();
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			}
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			return text.isEmpty();
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		}
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	}
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	/**
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	 * @see #isEmpty(java.lang.String, boolean)
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	 */
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	public static boolean isNotEmpty(String text, boolean trim) {
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		return !isEmpty(text, trim);
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	}
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	public boolean isEmpty(Collection c) {
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		return c == null || c.isEmpty();
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	}
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	public boolean isNotEmpty(Collection c) {
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		return !isEmpty(c);
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	}
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	public boolean isEmpty(Map m) {
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		return m == null || m.isEmpty();
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	}
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	public boolean isNotEmpty(Map m) {
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		return !isEmpty(m);
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	}
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	/**
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	 * @return empty collection if given one is null | or the original one
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	 */
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	public static <T> Collection<T> notNull(Collection<T> c) {
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		if (c == null) {
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			return Collections.emptyList();
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		} else {
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			return c;
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		}
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	}
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	public static <T extends NameIdentified> T findByName(Collection<T> collection, String name) {
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		for (T element : notNull(collection)) {
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			if (element != null && equalz(element.getName(), name)) {
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				return element;
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			}
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		}
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		return null;
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	}
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	/**
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	 * Copy file from Java resources to file system.
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	 */
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	public static void installResource(String resourceName, File target) throws IOException {
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		try (BufferedReader reader = new BufferedReader(new InputStreamReader(Functions.class.getClassLoader().getResourceAsStream(resourceName)))) {
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			try (PrintWriter writer = new PrintWriter(target)) {
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				while (true) {
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					String line = reader.readLine();
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					if (line == null) {
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						break;
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					} else {
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						writer.println(line);
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					}
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				}
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			}
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		}
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	}
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	public static String rpad(String s, int n) {
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		if (n > 0) {
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			return String.format("%1$-" + n + "s", s);
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		} else {
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			return s;
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		}
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	}
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	public static String lpad(String s, int n) {
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		if (n > 0) {
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			return String.format("%1$" + n + "s", s);
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		} else {
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			return s;
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		}
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	}
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	public static String repeat(char ch, int count) {
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		char[] array = new char[count];
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		Arrays.fill(array, ch);
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		return new String(array);
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	}
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	private final static char[] HEX_ALPHABET = "0123456789abcdef".toCharArray();
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	public static String toHex(byte[] bytes) {
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		char[] hexChars = new char[bytes.length * 2];
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		for (int j = 0; j < bytes.length; j++) {
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			int v = bytes[j] & 0xFF;
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			hexChars[j * 2] = HEX_ALPHABET[v >>> 4];
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			hexChars[j * 2 + 1] = HEX_ALPHABET[v & 0x0F];
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		}
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		return new String(hexChars);
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	}
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}