From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Thu, 13 Nov 2008 23:13:50 +0000 (+0100)
Subject: Add MapWriter.
X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=e31fcc622092336df5f94587769012f724629a40;p=jSite2.git

Add MapWriter.
---

diff --git a/src/net/pterodactylus/util/collection/MapWriter.java b/src/net/pterodactylus/util/collection/MapWriter.java
new file mode 100644
index 0000000..2a555ca
--- /dev/null
+++ b/src/net/pterodactylus/util/collection/MapWriter.java
@@ -0,0 +1,184 @@
+/*
+ * jSite-next - MapWriter.java -
+ * Copyright © 2008 David Roden
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+package net.pterodactylus.util.collection;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Writer;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Map.Entry;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import net.pterodactylus.util.io.Closer;
+import net.pterodactylus.util.logging.Logging;
+import net.pterodactylus.util.number.Hex;
+
+/**
+ * Helper class that emulates the function of
+ * {@link Properties#store(java.io.OutputStream, String)} and
+ * {@link Properties#load(java.io.InputStream)} but does not suffer from the
+ * drawbacks of {@link Properties} (namely the fact that a
+ * <code>Properties</code> can not contain <code>null</code> values).
+ *
+ * @author David Roden &lt;droden@gmail.com&gt;
+ */
+public class MapWriter {
+
+	/** The logger. */
+	private static final Logger logger = Logging.getLogger(MapWriter.class.getName());
+
+	/**
+	 * Writes the given map to the given writer.
+	 *
+	 * @param writer
+	 *            The writer to write the map’s content to
+	 * @param map
+	 *            The map to write
+	 * @throws IOException
+	 *             if an I/O error occurs
+	 */
+	public static void write(Writer writer, Map<String, String> map) throws IOException {
+		for (Entry<String, String> entry : map.entrySet()) {
+			if (entry.getValue() != null) {
+				writer.write(encode(entry.getKey()));
+				writer.write('=');
+				writer.write(encode(entry.getValue()));
+				writer.write('\n');
+			}
+		}
+	}
+
+	/**
+	 * Reads a map from the given reader. Lines are read from the given reader
+	 * until a line is encountered that does not contain a colon (“:”) or equals
+	 * sign (“=”).
+	 *
+	 * @param reader
+	 *            The reader to read from
+	 * @return The map that was read
+	 * @throws IOException
+	 *             if an I/O error occurs
+	 */
+	public static Map<String, String> read(Reader reader) throws IOException {
+		logger.log(Level.FINE, "MapWriter.read(reader=" + reader + ")");
+		Map<String, String> map = new HashMap<String, String>();
+		BufferedReader bufferedReader = new BufferedReader(reader);
+		try {
+			String line;
+			while ((line = bufferedReader.readLine()) != null) {
+				logger.log(Level.FINEST, "Read line: “" + line + "”");
+				if (line.startsWith("#") || (line.length() == 0)) {
+					continue;
+				}
+				if (line.indexOf('=') == -1) {
+					break;
+				}
+				int split = line.indexOf('=');
+				String key = decode(line.substring(0, split));
+				String value = decode(line.substring(split + 1));
+				map.put(key, value);
+			}
+		} finally {
+			Closer.close(bufferedReader);
+		}
+		return map;
+	}
+
+	//
+	// PRIVATE METHODS
+	//
+
+	/**
+	 * Encodes the given String by replacing certain “unsafe” characters. CR
+	 * (0x0d) is replaced by “\r”, LF (0x0a) is replaced by “\n”, the backslash
+	 * (‘\’) will be replaced by “\\”, other characters that are either smaller
+	 * than 0x20 or larger than 0x7f or that are ‘:’ or ‘=’ will be replaced by
+	 * their unicode notation (“\u0000” for NUL, 0x00). All other values are
+	 * copied verbatim.
+	 *
+	 * @param value
+	 *            The value to encode
+	 * @return The encoded value
+	 */
+	static String encode(String value) {
+		StringBuilder encodedString = new StringBuilder();
+		for (char character : value.toCharArray()) {
+			if (character == 0x0d) {
+				encodedString.append("\\r");
+			} else if (character == 0x0a) {
+				encodedString.append("\\n");
+			} else if (character == '\\') {
+				encodedString.append("\\\\");
+			} else if ((character < 0x20) || (character == '=') || (character > 0x7f)) {
+				encodedString.append("\\u").append(Hex.toHex(character, 4));
+			} else {
+				encodedString.append(character);
+			}
+		}
+		return encodedString.toString();
+	}
+
+	/**
+	 * Decodes the given value by reversing the changes made by
+	 * {@link #encode(String)}.
+	 *
+	 * @param value
+	 *            The value to decode
+	 * @return The decoded value
+	 */
+	static String decode(String value) {
+		StringBuilder decodedString = new StringBuilder();
+		boolean backslash = false;
+		int hexDigit = 0;
+		char[] hexDigits = new char[4];
+		for (char character : value.toCharArray()) {
+			if (hexDigit > 0) {
+				hexDigits[hexDigit - 1] = character;
+				hexDigit++;
+				if (hexDigit > 4) {
+					decodedString.append((char) Integer.parseInt(new String(hexDigits), 16));
+					hexDigit = 0;
+				}
+			} else if (backslash) {
+				if (character == '\\') {
+					decodedString.append('\\');
+				} else if (character == 'r') {
+					decodedString.append('\r');
+				} else if (character == 'n') {
+					decodedString.append('\n');
+				} else if (character == 'u') {
+					hexDigit = 1;
+				}
+				backslash = false;
+			} else if (character == '\\') {
+				backslash = true;
+				continue;
+			} else {
+				decodedString.append(character);
+			}
+		}
+		return decodedString.toString();
+	}
+
+}