jdk/src/share/classes/java/util/Properties.java
changeset 2 90ce3da70b43
child 3705 6d494ca143b8
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/Properties.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,1112 @@
+/*
+ * Copyright 1995-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.util;
+
+import java.io.IOException;
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.io.Writer;
+import java.io.OutputStreamWriter;
+import java.io.BufferedWriter;
+
+/**
+ * The <code>Properties</code> class represents a persistent set of
+ * properties. The <code>Properties</code> can be saved to a stream
+ * or loaded from a stream. Each key and its corresponding value in
+ * the property list is a string.
+ * <p>
+ * A property list can contain another property list as its
+ * "defaults"; this second property list is searched if
+ * the property key is not found in the original property list.
+ * <p>
+ * Because <code>Properties</code> inherits from <code>Hashtable</code>, the
+ * <code>put</code> and <code>putAll</code> methods can be applied to a
+ * <code>Properties</code> object.  Their use is strongly discouraged as they
+ * allow the caller to insert entries whose keys or values are not
+ * <code>Strings</code>.  The <code>setProperty</code> method should be used
+ * instead.  If the <code>store</code> or <code>save</code> method is called
+ * on a "compromised" <code>Properties</code> object that contains a
+ * non-<code>String</code> key or value, the call will fail. Similarly,
+ * the call to the <code>propertyNames</code> or <code>list</code> method
+ * will fail if it is called on a "compromised" <code>Properties</code>
+ * object that contains a non-<code>String</code> key.
+ *
+ * <p>
+ * The {@link #load(java.io.Reader) load(Reader)} <tt>/</tt>
+ * {@link #store(java.io.Writer, java.lang.String) store(Writer, String)}
+ * methods load and store properties from and to a character based stream
+ * in a simple line-oriented format specified below.
+ *
+ * The {@link #load(java.io.InputStream) load(InputStream)} <tt>/</tt>
+ * {@link #store(java.io.OutputStream, java.lang.String) store(OutputStream, String)}
+ * methods work the same way as the load(Reader)/store(Writer, String) pair, except
+ * the input/output stream is encoded in ISO 8859-1 character encoding.
+ * Characters that cannot be directly represented in this encoding can be written using
+ * <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.3">Unicode escapes</a>
+ * ; only a single 'u' character is allowed in an escape
+ * sequence. The native2ascii tool can be used to convert property files to and
+ * from other character encodings.
+ *
+ * <p> The {@link #loadFromXML(InputStream)} and {@link
+ * #storeToXML(OutputStream, String, String)} methods load and store properties
+ * in a simple XML format.  By default the UTF-8 character encoding is used,
+ * however a specific encoding may be specified if required.  An XML properties
+ * document has the following DOCTYPE declaration:
+ *
+ * <pre>
+ * &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"&gt;
+ * </pre>
+ * Note that the system URI (http://java.sun.com/dtd/properties.dtd) is
+ * <i>not</i> accessed when exporting or importing properties; it merely
+ * serves as a string to uniquely identify the DTD, which is:
+ * <pre>
+ *    &lt;?xml version="1.0" encoding="UTF-8"?&gt;
+ *
+ *    &lt;!-- DTD for properties --&gt;
+ *
+ *    &lt;!ELEMENT properties ( comment?, entry* ) &gt;
+ *
+ *    &lt;!ATTLIST properties version CDATA #FIXED "1.0"&gt;
+ *
+ *    &lt;!ELEMENT comment (#PCDATA) &gt;
+ *
+ *    &lt;!ELEMENT entry (#PCDATA) &gt;
+ *
+ *    &lt;!ATTLIST entry key CDATA #REQUIRED&gt;
+ * </pre>
+ *
+ * @see <a href="../../../technotes/tools/solaris/native2ascii.html">native2ascii tool for Solaris</a>
+ * @see <a href="../../../technotes/tools/windows/native2ascii.html">native2ascii tool for Windows</a>
+ *
+ * <p>This class is thread-safe: multiple threads can share a single
+ * <tt>Properties</tt> object without the need for external synchronization.
+ *
+ * @author  Arthur van Hoff
+ * @author  Michael McCloskey
+ * @author  Xueming Shen
+ * @since   JDK1.0
+ */
+public
+class Properties extends Hashtable<Object,Object> {
+    /**
+     * use serialVersionUID from JDK 1.1.X for interoperability
+     */
+     private static final long serialVersionUID = 4112578634029874840L;
+
+    /**
+     * A property list that contains default values for any keys not
+     * found in this property list.
+     *
+     * @serial
+     */
+    protected Properties defaults;
+
+    /**
+     * Creates an empty property list with no default values.
+     */
+    public Properties() {
+        this(null);
+    }
+
+    /**
+     * Creates an empty property list with the specified defaults.
+     *
+     * @param   defaults   the defaults.
+     */
+    public Properties(Properties defaults) {
+        this.defaults = defaults;
+    }
+
+    /**
+     * Calls the <tt>Hashtable</tt> method <code>put</code>. Provided for
+     * parallelism with the <tt>getProperty</tt> method. Enforces use of
+     * strings for property keys and values. The value returned is the
+     * result of the <tt>Hashtable</tt> call to <code>put</code>.
+     *
+     * @param key the key to be placed into this property list.
+     * @param value the value corresponding to <tt>key</tt>.
+     * @return     the previous value of the specified key in this property
+     *             list, or <code>null</code> if it did not have one.
+     * @see #getProperty
+     * @since    1.2
+     */
+    public synchronized Object setProperty(String key, String value) {
+        return put(key, value);
+    }
+
+
+    /**
+     * Reads a property list (key and element pairs) from the input
+     * character stream in a simple line-oriented format.
+     * <p>
+     * Properties are processed in terms of lines. There are two
+     * kinds of line, <i>natural lines</i> and <i>logical lines</i>.
+     * A natural line is defined as a line of
+     * characters that is terminated either by a set of line terminator
+     * characters (<code>\n</code> or <code>\r</code> or <code>\r\n</code>)
+     * or by the end of the stream. A natural line may be either a blank line,
+     * a comment line, or hold all or some of a key-element pair. A logical
+     * line holds all the data of a key-element pair, which may be spread
+     * out across several adjacent natural lines by escaping
+     * the line terminator sequence with a backslash character
+     * <code>\</code>.  Note that a comment line cannot be extended
+     * in this manner; every natural line that is a comment must have
+     * its own comment indicator, as described below. Lines are read from
+     * input until the end of the stream is reached.
+     *
+     * <p>
+     * A natural line that contains only white space characters is
+     * considered blank and is ignored.  A comment line has an ASCII
+     * <code>'#'</code> or <code>'!'</code> as its first non-white
+     * space character; comment lines are also ignored and do not
+     * encode key-element information.  In addition to line
+     * terminators, this format considers the characters space
+     * (<code>' '</code>, <code>'&#92;u0020'</code>), tab
+     * (<code>'\t'</code>, <code>'&#92;u0009'</code>), and form feed
+     * (<code>'\f'</code>, <code>'&#92;u000C'</code>) to be white
+     * space.
+     *
+     * <p>
+     * If a logical line is spread across several natural lines, the
+     * backslash escaping the line terminator sequence, the line
+     * terminator sequence, and any white space at the start of the
+     * following line have no affect on the key or element values.
+     * The remainder of the discussion of key and element parsing
+     * (when loading) will assume all the characters constituting
+     * the key and element appear on a single natural line after
+     * line continuation characters have been removed.  Note that
+     * it is <i>not</i> sufficient to only examine the character
+     * preceding a line terminator sequence to decide if the line
+     * terminator is escaped; there must be an odd number of
+     * contiguous backslashes for the line terminator to be escaped.
+     * Since the input is processed from left to right, a
+     * non-zero even number of 2<i>n</i> contiguous backslashes
+     * before a line terminator (or elsewhere) encodes <i>n</i>
+     * backslashes after escape processing.
+     *
+     * <p>
+     * The key contains all of the characters in the line starting
+     * with the first non-white space character and up to, but not
+     * including, the first unescaped <code>'='</code>,
+     * <code>':'</code>, or white space character other than a line
+     * terminator. All of these key termination characters may be
+     * included in the key by escaping them with a preceding backslash
+     * character; for example,<p>
+     *
+     * <code>\:\=</code><p>
+     *
+     * would be the two-character key <code>":="</code>.  Line
+     * terminator characters can be included using <code>\r</code> and
+     * <code>\n</code> escape sequences.  Any white space after the
+     * key is skipped; if the first non-white space character after
+     * the key is <code>'='</code> or <code>':'</code>, then it is
+     * ignored and any white space characters after it are also
+     * skipped.  All remaining characters on the line become part of
+     * the associated element string; if there are no remaining
+     * characters, the element is the empty string
+     * <code>&quot;&quot;</code>.  Once the raw character sequences
+     * constituting the key and element are identified, escape
+     * processing is performed as described above.
+     *
+     * <p>
+     * As an example, each of the following three lines specifies the key
+     * <code>"Truth"</code> and the associated element value
+     * <code>"Beauty"</code>:
+     * <p>
+     * <pre>
+     * Truth = Beauty
+     *  Truth:Beauty
+     * Truth                    :Beauty
+     * </pre>
+     * As another example, the following three lines specify a single
+     * property:
+     * <p>
+     * <pre>
+     * fruits                           apple, banana, pear, \
+     *                                  cantaloupe, watermelon, \
+     *                                  kiwi, mango
+     * </pre>
+     * The key is <code>"fruits"</code> and the associated element is:
+     * <p>
+     * <pre>"apple, banana, pear, cantaloupe, watermelon, kiwi, mango"</pre>
+     * Note that a space appears before each <code>\</code> so that a space
+     * will appear after each comma in the final result; the <code>\</code>,
+     * line terminator, and leading white space on the continuation line are
+     * merely discarded and are <i>not</i> replaced by one or more other
+     * characters.
+     * <p>
+     * As a third example, the line:
+     * <p>
+     * <pre>cheeses
+     * </pre>
+     * specifies that the key is <code>"cheeses"</code> and the associated
+     * element is the empty string <code>""</code>.<p>
+     * <p>
+     *
+     * <a name="unicodeescapes"></a>
+     * Characters in keys and elements can be represented in escape
+     * sequences similar to those used for character and string literals
+     * (see <a
+     * href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.3">&sect;3.3</a>
+     * and <a
+     * href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.10.6">&sect;3.10.6</a>
+     * of the <i>Java Language Specification</i>).
+     *
+     * The differences from the character escape sequences and Unicode
+     * escapes used for characters and strings are:
+     *
+     * <ul>
+     * <li> Octal escapes are not recognized.
+     *
+     * <li> The character sequence <code>\b</code> does <i>not</i>
+     * represent a backspace character.
+     *
+     * <li> The method does not treat a backslash character,
+     * <code>\</code>, before a non-valid escape character as an
+     * error; the backslash is silently dropped.  For example, in a
+     * Java string the sequence <code>"\z"</code> would cause a
+     * compile time error.  In contrast, this method silently drops
+     * the backslash.  Therefore, this method treats the two character
+     * sequence <code>"\b"</code> as equivalent to the single
+     * character <code>'b'</code>.
+     *
+     * <li> Escapes are not necessary for single and double quotes;
+     * however, by the rule above, single and double quote characters
+     * preceded by a backslash still yield single and double quote
+     * characters, respectively.
+     *
+     * <li> Only a single 'u' character is allowed in a Uniocde escape
+     * sequence.
+     *
+     * </ul>
+     * <p>
+     * The specified stream remains open after this method returns.
+     *
+     * @param   reader   the input character stream.
+     * @throws  IOException  if an error occurred when reading from the
+     *          input stream.
+     * @throws  IllegalArgumentException if a malformed Unicode escape
+     *          appears in the input.
+     * @since   1.6
+     */
+    public synchronized void load(Reader reader) throws IOException {
+        load0(new LineReader(reader));
+    }
+
+    /**
+     * Reads a property list (key and element pairs) from the input
+     * byte stream. The input stream is in a simple line-oriented
+     * format as specified in
+     * {@link #load(java.io.Reader) load(Reader)} and is assumed to use
+     * the ISO 8859-1 character encoding; that is each byte is one Latin1
+     * character. Characters not in Latin1, and certain special characters,
+     * are represented in keys and elements using
+     * <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.3">Unicode escapes</a>.
+     * <p>
+     * The specified stream remains open after this method returns.
+     *
+     * @param      inStream   the input stream.
+     * @exception  IOException  if an error occurred when reading from the
+     *             input stream.
+     * @throws     IllegalArgumentException if the input stream contains a
+     *             malformed Unicode escape sequence.
+     * @since 1.2
+     */
+    public synchronized void load(InputStream inStream) throws IOException {
+        load0(new LineReader(inStream));
+    }
+
+    private void load0 (LineReader lr) throws IOException {
+        char[] convtBuf = new char[1024];
+        int limit;
+        int keyLen;
+        int valueStart;
+        char c;
+        boolean hasSep;
+        boolean precedingBackslash;
+
+        while ((limit = lr.readLine()) >= 0) {
+            c = 0;
+            keyLen = 0;
+            valueStart = limit;
+            hasSep = false;
+
+            //System.out.println("line=<" + new String(lineBuf, 0, limit) + ">");
+            precedingBackslash = false;
+            while (keyLen < limit) {
+                c = lr.lineBuf[keyLen];
+                //need check if escaped.
+                if ((c == '=' ||  c == ':') && !precedingBackslash) {
+                    valueStart = keyLen + 1;
+                    hasSep = true;
+                    break;
+                } else if ((c == ' ' || c == '\t' ||  c == '\f') && !precedingBackslash) {
+                    valueStart = keyLen + 1;
+                    break;
+                }
+                if (c == '\\') {
+                    precedingBackslash = !precedingBackslash;
+                } else {
+                    precedingBackslash = false;
+                }
+                keyLen++;
+            }
+            while (valueStart < limit) {
+                c = lr.lineBuf[valueStart];
+                if (c != ' ' && c != '\t' &&  c != '\f') {
+                    if (!hasSep && (c == '=' ||  c == ':')) {
+                        hasSep = true;
+                    } else {
+                        break;
+                    }
+                }
+                valueStart++;
+            }
+            String key = loadConvert(lr.lineBuf, 0, keyLen, convtBuf);
+            String value = loadConvert(lr.lineBuf, valueStart, limit - valueStart, convtBuf);
+            put(key, value);
+        }
+    }
+
+    /* Read in a "logical line" from an InputStream/Reader, skip all comment
+     * and blank lines and filter out those leading whitespace characters
+     * (\u0020, \u0009 and \u000c) from the beginning of a "natural line".
+     * Method returns the char length of the "logical line" and stores
+     * the line in "lineBuf".
+     */
+    class LineReader {
+        public LineReader(InputStream inStream) {
+            this.inStream = inStream;
+            inByteBuf = new byte[8192];
+        }
+
+        public LineReader(Reader reader) {
+            this.reader = reader;
+            inCharBuf = new char[8192];
+        }
+
+        byte[] inByteBuf;
+        char[] inCharBuf;
+        char[] lineBuf = new char[1024];
+        int inLimit = 0;
+        int inOff = 0;
+        InputStream inStream;
+        Reader reader;
+
+        int readLine() throws IOException {
+            int len = 0;
+            char c = 0;
+
+            boolean skipWhiteSpace = true;
+            boolean isCommentLine = false;
+            boolean isNewLine = true;
+            boolean appendedLineBegin = false;
+            boolean precedingBackslash = false;
+            boolean skipLF = false;
+
+            while (true) {
+                if (inOff >= inLimit) {
+                    inLimit = (inStream==null)?reader.read(inCharBuf)
+                                              :inStream.read(inByteBuf);
+                    inOff = 0;
+                    if (inLimit <= 0) {
+                        if (len == 0 || isCommentLine) {
+                            return -1;
+                        }
+                        return len;
+                    }
+                }
+                if (inStream != null) {
+                    //The line below is equivalent to calling a
+                    //ISO8859-1 decoder.
+                    c = (char) (0xff & inByteBuf[inOff++]);
+                } else {
+                    c = inCharBuf[inOff++];
+                }
+                if (skipLF) {
+                    skipLF = false;
+                    if (c == '\n') {
+                        continue;
+                    }
+                }
+                if (skipWhiteSpace) {
+                    if (c == ' ' || c == '\t' || c == '\f') {
+                        continue;
+                    }
+                    if (!appendedLineBegin && (c == '\r' || c == '\n')) {
+                        continue;
+                    }
+                    skipWhiteSpace = false;
+                    appendedLineBegin = false;
+                }
+                if (isNewLine) {
+                    isNewLine = false;
+                    if (c == '#' || c == '!') {
+                        isCommentLine = true;
+                        continue;
+                    }
+                }
+
+                if (c != '\n' && c != '\r') {
+                    lineBuf[len++] = c;
+                    if (len == lineBuf.length) {
+                        int newLength = lineBuf.length * 2;
+                        if (newLength < 0) {
+                            newLength = Integer.MAX_VALUE;
+                        }
+                        char[] buf = new char[newLength];
+                        System.arraycopy(lineBuf, 0, buf, 0, lineBuf.length);
+                        lineBuf = buf;
+                    }
+                    //flip the preceding backslash flag
+                    if (c == '\\') {
+                        precedingBackslash = !precedingBackslash;
+                    } else {
+                        precedingBackslash = false;
+                    }
+                }
+                else {
+                    // reached EOL
+                    if (isCommentLine || len == 0) {
+                        isCommentLine = false;
+                        isNewLine = true;
+                        skipWhiteSpace = true;
+                        len = 0;
+                        continue;
+                    }
+                    if (inOff >= inLimit) {
+                        inLimit = (inStream==null)
+                                  ?reader.read(inCharBuf)
+                                  :inStream.read(inByteBuf);
+                        inOff = 0;
+                        if (inLimit <= 0) {
+                            return len;
+                        }
+                    }
+                    if (precedingBackslash) {
+                        len -= 1;
+                        //skip the leading whitespace characters in following line
+                        skipWhiteSpace = true;
+                        appendedLineBegin = true;
+                        precedingBackslash = false;
+                        if (c == '\r') {
+                            skipLF = true;
+                        }
+                    } else {
+                        return len;
+                    }
+                }
+            }
+        }
+    }
+
+    /*
+     * Converts encoded &#92;uxxxx to unicode chars
+     * and changes special saved chars to their original forms
+     */
+    private String loadConvert (char[] in, int off, int len, char[] convtBuf) {
+        if (convtBuf.length < len) {
+            int newLen = len * 2;
+            if (newLen < 0) {
+                newLen = Integer.MAX_VALUE;
+            }
+            convtBuf = new char[newLen];
+        }
+        char aChar;
+        char[] out = convtBuf;
+        int outLen = 0;
+        int end = off + len;
+
+        while (off < end) {
+            aChar = in[off++];
+            if (aChar == '\\') {
+                aChar = in[off++];
+                if(aChar == 'u') {
+                    // Read the xxxx
+                    int value=0;
+                    for (int i=0; i<4; i++) {
+                        aChar = in[off++];
+                        switch (aChar) {
+                          case '0': case '1': case '2': case '3': case '4':
+                          case '5': case '6': case '7': case '8': case '9':
+                             value = (value << 4) + aChar - '0';
+                             break;
+                          case 'a': case 'b': case 'c':
+                          case 'd': case 'e': case 'f':
+                             value = (value << 4) + 10 + aChar - 'a';
+                             break;
+                          case 'A': case 'B': case 'C':
+                          case 'D': case 'E': case 'F':
+                             value = (value << 4) + 10 + aChar - 'A';
+                             break;
+                          default:
+                              throw new IllegalArgumentException(
+                                           "Malformed \\uxxxx encoding.");
+                        }
+                     }
+                    out[outLen++] = (char)value;
+                } else {
+                    if (aChar == 't') aChar = '\t';
+                    else if (aChar == 'r') aChar = '\r';
+                    else if (aChar == 'n') aChar = '\n';
+                    else if (aChar == 'f') aChar = '\f';
+                    out[outLen++] = aChar;
+                }
+            } else {
+                out[outLen++] = aChar;
+            }
+        }
+        return new String (out, 0, outLen);
+    }
+
+    /*
+     * Converts unicodes to encoded &#92;uxxxx and escapes
+     * special characters with a preceding slash
+     */
+    private String saveConvert(String theString,
+                               boolean escapeSpace,
+                               boolean escapeUnicode) {
+        int len = theString.length();
+        int bufLen = len * 2;
+        if (bufLen < 0) {
+            bufLen = Integer.MAX_VALUE;
+        }
+        StringBuffer outBuffer = new StringBuffer(bufLen);
+
+        for(int x=0; x<len; x++) {
+            char aChar = theString.charAt(x);
+            // Handle common case first, selecting largest block that
+            // avoids the specials below
+            if ((aChar > 61) && (aChar < 127)) {
+                if (aChar == '\\') {
+                    outBuffer.append('\\'); outBuffer.append('\\');
+                    continue;
+                }
+                outBuffer.append(aChar);
+                continue;
+            }
+            switch(aChar) {
+                case ' ':
+                    if (x == 0 || escapeSpace)
+                        outBuffer.append('\\');
+                    outBuffer.append(' ');
+                    break;
+                case '\t':outBuffer.append('\\'); outBuffer.append('t');
+                          break;
+                case '\n':outBuffer.append('\\'); outBuffer.append('n');
+                          break;
+                case '\r':outBuffer.append('\\'); outBuffer.append('r');
+                          break;
+                case '\f':outBuffer.append('\\'); outBuffer.append('f');
+                          break;
+                case '=': // Fall through
+                case ':': // Fall through
+                case '#': // Fall through
+                case '!':
+                    outBuffer.append('\\'); outBuffer.append(aChar);
+                    break;
+                default:
+                    if (((aChar < 0x0020) || (aChar > 0x007e)) & escapeUnicode ) {
+                        outBuffer.append('\\');
+                        outBuffer.append('u');
+                        outBuffer.append(toHex((aChar >> 12) & 0xF));
+                        outBuffer.append(toHex((aChar >>  8) & 0xF));
+                        outBuffer.append(toHex((aChar >>  4) & 0xF));
+                        outBuffer.append(toHex( aChar        & 0xF));
+                    } else {
+                        outBuffer.append(aChar);
+                    }
+            }
+        }
+        return outBuffer.toString();
+    }
+
+    private static void writeComments(BufferedWriter bw, String comments)
+        throws IOException {
+        bw.write("#");
+        int len = comments.length();
+        int current = 0;
+        int last = 0;
+        char[] uu = new char[6];
+        uu[0] = '\\';
+        uu[1] = 'u';
+        while (current < len) {
+            char c = comments.charAt(current);
+            if (c > '\u00ff' || c == '\n' || c == '\r') {
+                if (last != current)
+                    bw.write(comments.substring(last, current));
+                if (c > '\u00ff') {
+                    uu[2] = toHex((c >> 12) & 0xf);
+                    uu[3] = toHex((c >>  8) & 0xf);
+                    uu[4] = toHex((c >>  4) & 0xf);
+                    uu[5] = toHex( c        & 0xf);
+                    bw.write(new String(uu));
+                } else {
+                    bw.newLine();
+                    if (c == '\r' &&
+                        current != len - 1 &&
+                        comments.charAt(current + 1) == '\n') {
+                        current++;
+                    }
+                    if (current == len - 1 ||
+                        (comments.charAt(current + 1) != '#' &&
+                        comments.charAt(current + 1) != '!'))
+                        bw.write("#");
+                }
+                last = current + 1;
+            }
+            current++;
+        }
+        if (last != current)
+            bw.write(comments.substring(last, current));
+        bw.newLine();
+    }
+
+    /**
+     * Calls the <code>store(OutputStream out, String comments)</code> method
+     * and suppresses IOExceptions that were thrown.
+     *
+     * @deprecated This method does not throw an IOException if an I/O error
+     * occurs while saving the property list.  The preferred way to save a
+     * properties list is via the <code>store(OutputStream out,
+     * String comments)</code> method or the
+     * <code>storeToXML(OutputStream os, String comment)</code> method.
+     *
+     * @param   out      an output stream.
+     * @param   comments   a description of the property list.
+     * @exception  ClassCastException  if this <code>Properties</code> object
+     *             contains any keys or values that are not
+     *             <code>Strings</code>.
+     */
+    @Deprecated
+    public synchronized void save(OutputStream out, String comments)  {
+        try {
+            store(out, comments);
+        } catch (IOException e) {
+        }
+    }
+
+    /**
+     * Writes this property list (key and element pairs) in this
+     * <code>Properties</code> table to the output character stream in a
+     * format suitable for using the {@link #load(java.io.Reader) load(Reader)}
+     * method.
+     * <p>
+     * Properties from the defaults table of this <code>Properties</code>
+     * table (if any) are <i>not</i> written out by this method.
+     * <p>
+     * If the comments argument is not null, then an ASCII <code>#</code>
+     * character, the comments string, and a line separator are first written
+     * to the output stream. Thus, the <code>comments</code> can serve as an
+     * identifying comment. Any one of a line feed ('\n'), a carriage
+     * return ('\r'), or a carriage return followed immediately by a line feed
+     * in comments is replaced by a line separator generated by the <code>Writer</code>
+     * and if the next character in comments is not character <code>#</code> or
+     * character <code>!</code> then an ASCII <code>#</code> is written out
+     * after that line separator.
+     * <p>
+     * Next, a comment line is always written, consisting of an ASCII
+     * <code>#</code> character, the current date and time (as if produced
+     * by the <code>toString</code> method of <code>Date</code> for the
+     * current time), and a line separator as generated by the <code>Writer</code>.
+     * <p>
+     * Then every entry in this <code>Properties</code> table is
+     * written out, one per line. For each entry the key string is
+     * written, then an ASCII <code>=</code>, then the associated
+     * element string. For the key, all space characters are
+     * written with a preceding <code>\</code> character.  For the
+     * element, leading space characters, but not embedded or trailing
+     * space characters, are written with a preceding <code>\</code>
+     * character. The key and element characters <code>#</code>,
+     * <code>!</code>, <code>=</code>, and <code>:</code> are written
+     * with a preceding backslash to ensure that they are properly loaded.
+     * <p>
+     * After the entries have been written, the output stream is flushed.
+     * The output stream remains open after this method returns.
+     * <p>
+     *
+     * @param   writer      an output character stream writer.
+     * @param   comments   a description of the property list.
+     * @exception  IOException if writing this property list to the specified
+     *             output stream throws an <tt>IOException</tt>.
+     * @exception  ClassCastException  if this <code>Properties</code> object
+     *             contains any keys or values that are not <code>Strings</code>.
+     * @exception  NullPointerException  if <code>writer</code> is null.
+     * @since 1.6
+     */
+    public void store(Writer writer, String comments)
+        throws IOException
+    {
+        store0((writer instanceof BufferedWriter)?(BufferedWriter)writer
+                                                 : new BufferedWriter(writer),
+               comments,
+               false);
+    }
+
+    /**
+     * Writes this property list (key and element pairs) in this
+     * <code>Properties</code> table to the output stream in a format suitable
+     * for loading into a <code>Properties</code> table using the
+     * {@link #load(InputStream) load(InputStream)} method.
+     * <p>
+     * Properties from the defaults table of this <code>Properties</code>
+     * table (if any) are <i>not</i> written out by this method.
+     * <p>
+     * This method outputs the comments, properties keys and values in
+     * the same format as specified in
+     * {@link #store(java.io.Writer, java.lang.String) store(Writer)},
+     * with the following differences:
+     * <ul>
+     * <li>The stream is written using the ISO 8859-1 character encoding.
+     *
+     * <li>Characters not in Latin-1 in the comments are written as
+     * <code>&#92;u</code><i>xxxx</i> for their appropriate unicode
+     * hexadecimal value <i>xxxx</i>.
+     *
+     * <li>Characters less than <code>&#92;u0020</code> and characters greater
+     * than <code>&#92;u007E</code> in property keys or values are written
+     * as <code>&#92;u</code><i>xxxx</i> for the appropriate hexadecimal
+     * value <i>xxxx</i>.
+     * </ul>
+     * <p>
+     * After the entries have been written, the output stream is flushed.
+     * The output stream remains open after this method returns.
+     * <p>
+     * @param   out      an output stream.
+     * @param   comments   a description of the property list.
+     * @exception  IOException if writing this property list to the specified
+     *             output stream throws an <tt>IOException</tt>.
+     * @exception  ClassCastException  if this <code>Properties</code> object
+     *             contains any keys or values that are not <code>Strings</code>.
+     * @exception  NullPointerException  if <code>out</code> is null.
+     * @since 1.2
+     */
+    public void store(OutputStream out, String comments)
+        throws IOException
+    {
+        store0(new BufferedWriter(new OutputStreamWriter(out, "8859_1")),
+               comments,
+               true);
+    }
+
+    private void store0(BufferedWriter bw, String comments, boolean escUnicode)
+        throws IOException
+    {
+        if (comments != null) {
+            writeComments(bw, comments);
+        }
+        bw.write("#" + new Date().toString());
+        bw.newLine();
+        synchronized (this) {
+            for (Enumeration e = keys(); e.hasMoreElements();) {
+                String key = (String)e.nextElement();
+                String val = (String)get(key);
+                key = saveConvert(key, true, escUnicode);
+                /* No need to escape embedded and trailing spaces for value, hence
+                 * pass false to flag.
+                 */
+                val = saveConvert(val, false, escUnicode);
+                bw.write(key + "=" + val);
+                bw.newLine();
+            }
+        }
+        bw.flush();
+    }
+
+    /**
+     * Loads all of the properties represented by the XML document on the
+     * specified input stream into this properties table.
+     *
+     * <p>The XML document must have the following DOCTYPE declaration:
+     * <pre>
+     * &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"&gt;
+     * </pre>
+     * Furthermore, the document must satisfy the properties DTD described
+     * above.
+     *
+     * <p>The specified stream is closed after this method returns.
+     *
+     * @param in the input stream from which to read the XML document.
+     * @throws IOException if reading from the specified input stream
+     *         results in an <tt>IOException</tt>.
+     * @throws InvalidPropertiesFormatException Data on input stream does not
+     *         constitute a valid XML document with the mandated document type.
+     * @throws NullPointerException if <code>in</code> is null.
+     * @see    #storeToXML(OutputStream, String, String)
+     * @since 1.5
+     */
+    public synchronized void loadFromXML(InputStream in)
+        throws IOException, InvalidPropertiesFormatException
+    {
+        if (in == null)
+            throw new NullPointerException();
+        XMLUtils.load(this, in);
+        in.close();
+    }
+
+    /**
+     * Emits an XML document representing all of the properties contained
+     * in this table.
+     *
+     * <p> An invocation of this method of the form <tt>props.storeToXML(os,
+     * comment)</tt> behaves in exactly the same way as the invocation
+     * <tt>props.storeToXML(os, comment, "UTF-8");</tt>.
+     *
+     * @param os the output stream on which to emit the XML document.
+     * @param comment a description of the property list, or <code>null</code>
+     *        if no comment is desired.
+     * @throws IOException if writing to the specified output stream
+     *         results in an <tt>IOException</tt>.
+     * @throws NullPointerException if <code>os</code> is null.
+     * @throws ClassCastException  if this <code>Properties</code> object
+     *         contains any keys or values that are not
+     *         <code>Strings</code>.
+     * @see    #loadFromXML(InputStream)
+     * @since 1.5
+     */
+    public synchronized void storeToXML(OutputStream os, String comment)
+        throws IOException
+    {
+        if (os == null)
+            throw new NullPointerException();
+        storeToXML(os, comment, "UTF-8");
+    }
+
+    /**
+     * Emits an XML document representing all of the properties contained
+     * in this table, using the specified encoding.
+     *
+     * <p>The XML document will have the following DOCTYPE declaration:
+     * <pre>
+     * &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"&gt;
+     * </pre>
+     *
+     *<p>If the specified comment is <code>null</code> then no comment
+     * will be stored in the document.
+     *
+     * <p>The specified stream remains open after this method returns.
+     *
+     * @param os the output stream on which to emit the XML document.
+     * @param comment a description of the property list, or <code>null</code>
+     *        if no comment is desired.
+     * @throws IOException if writing to the specified output stream
+     *         results in an <tt>IOException</tt>.
+     * @throws NullPointerException if <code>os</code> is <code>null</code>,
+     *         or if <code>encoding</code> is <code>null</code>.
+     * @throws ClassCastException  if this <code>Properties</code> object
+     *         contains any keys or values that are not
+     *         <code>Strings</code>.
+     * @see    #loadFromXML(InputStream)
+     * @since 1.5
+     */
+    public synchronized void storeToXML(OutputStream os, String comment,
+                                       String encoding)
+        throws IOException
+    {
+        if (os == null)
+            throw new NullPointerException();
+        XMLUtils.save(this, os, comment, encoding);
+    }
+
+    /**
+     * Searches for the property with the specified key in this property list.
+     * If the key is not found in this property list, the default property list,
+     * and its defaults, recursively, are then checked. The method returns
+     * <code>null</code> if the property is not found.
+     *
+     * @param   key   the property key.
+     * @return  the value in this property list with the specified key value.
+     * @see     #setProperty
+     * @see     #defaults
+     */
+    public String getProperty(String key) {
+        Object oval = super.get(key);
+        String sval = (oval instanceof String) ? (String)oval : null;
+        return ((sval == null) && (defaults != null)) ? defaults.getProperty(key) : sval;
+    }
+
+    /**
+     * Searches for the property with the specified key in this property list.
+     * If the key is not found in this property list, the default property list,
+     * and its defaults, recursively, are then checked. The method returns the
+     * default value argument if the property is not found.
+     *
+     * @param   key            the hashtable key.
+     * @param   defaultValue   a default value.
+     *
+     * @return  the value in this property list with the specified key value.
+     * @see     #setProperty
+     * @see     #defaults
+     */
+    public String getProperty(String key, String defaultValue) {
+        String val = getProperty(key);
+        return (val == null) ? defaultValue : val;
+    }
+
+    /**
+     * Returns an enumeration of all the keys in this property list,
+     * including distinct keys in the default property list if a key
+     * of the same name has not already been found from the main
+     * properties list.
+     *
+     * @return  an enumeration of all the keys in this property list, including
+     *          the keys in the default property list.
+     * @throws  ClassCastException if any key in this property list
+     *          is not a string.
+     * @see     java.util.Enumeration
+     * @see     java.util.Properties#defaults
+     * @see     #stringPropertyNames
+     */
+    public Enumeration<?> propertyNames() {
+        Hashtable h = new Hashtable();
+        enumerate(h);
+        return h.keys();
+    }
+
+    /**
+     * Returns a set of keys in this property list where
+     * the key and its corresponding value are strings,
+     * including distinct keys in the default property list if a key
+     * of the same name has not already been found from the main
+     * properties list.  Properties whose key or value is not
+     * of type <tt>String</tt> are omitted.
+     * <p>
+     * The returned set is not backed by the <tt>Properties</tt> object.
+     * Changes to this <tt>Properties</tt> are not reflected in the set,
+     * or vice versa.
+     *
+     * @return  a set of keys in this property list where
+     *          the key and its corresponding value are strings,
+     *          including the keys in the default property list.
+     * @see     java.util.Properties#defaults
+     * @since   1.6
+     */
+    public Set<String> stringPropertyNames() {
+        Hashtable<String, String> h = new Hashtable<String, String>();
+        enumerateStringProperties(h);
+        return h.keySet();
+    }
+
+    /**
+     * Prints this property list out to the specified output stream.
+     * This method is useful for debugging.
+     *
+     * @param   out   an output stream.
+     * @throws  ClassCastException if any key in this property list
+     *          is not a string.
+     */
+    public void list(PrintStream out) {
+        out.println("-- listing properties --");
+        Hashtable h = new Hashtable();
+        enumerate(h);
+        for (Enumeration e = h.keys() ; e.hasMoreElements() ;) {
+            String key = (String)e.nextElement();
+            String val = (String)h.get(key);
+            if (val.length() > 40) {
+                val = val.substring(0, 37) + "...";
+            }
+            out.println(key + "=" + val);
+        }
+    }
+
+    /**
+     * Prints this property list out to the specified output stream.
+     * This method is useful for debugging.
+     *
+     * @param   out   an output stream.
+     * @throws  ClassCastException if any key in this property list
+     *          is not a string.
+     * @since   JDK1.1
+     */
+    /*
+     * Rather than use an anonymous inner class to share common code, this
+     * method is duplicated in order to ensure that a non-1.1 compiler can
+     * compile this file.
+     */
+    public void list(PrintWriter out) {
+        out.println("-- listing properties --");
+        Hashtable h = new Hashtable();
+        enumerate(h);
+        for (Enumeration e = h.keys() ; e.hasMoreElements() ;) {
+            String key = (String)e.nextElement();
+            String val = (String)h.get(key);
+            if (val.length() > 40) {
+                val = val.substring(0, 37) + "...";
+            }
+            out.println(key + "=" + val);
+        }
+    }
+
+    /**
+     * Enumerates all key/value pairs in the specified hashtable.
+     * @param h the hashtable
+     * @throws ClassCastException if any of the property keys
+     *         is not of String type.
+     */
+    private synchronized void enumerate(Hashtable h) {
+        if (defaults != null) {
+            defaults.enumerate(h);
+        }
+        for (Enumeration e = keys() ; e.hasMoreElements() ;) {
+            String key = (String)e.nextElement();
+            h.put(key, get(key));
+        }
+    }
+
+    /**
+     * Enumerates all key/value pairs in the specified hashtable
+     * and omits the property if the key or value is not a string.
+     * @param h the hashtable
+     */
+    private synchronized void enumerateStringProperties(Hashtable<String, String> h) {
+        if (defaults != null) {
+            defaults.enumerateStringProperties(h);
+        }
+        for (Enumeration e = keys() ; e.hasMoreElements() ;) {
+            Object k = e.nextElement();
+            Object v = get(k);
+            if (k instanceof String && v instanceof String) {
+                h.put((String) k, (String) v);
+            }
+        }
+    }
+
+    /**
+     * Convert a nibble to a hex character
+     * @param   nibble  the nibble to convert.
+     */
+    private static char toHex(int nibble) {
+        return hexDigit[(nibble & 0xF)];
+    }
+
+    /** A table of hex digits */
+    private static final char[] hexDigit = {
+        '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
+    };
+}