maputils.java

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    /**
     * Gets a short from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The short is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a short, <code>defaultValue</code> if null map input
     */
    public static short getShortValue(final Map map, final Object key, short defaultValue) {
        Short shortObject = getShort(map, key);
        if (shortObject == null) {
            return defaultValue;
        }
        return shortObject.shortValue();
    }

    /**
     * Gets an int from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The int is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as an int, <code>defaultValue</code> if null map input
     */
    public static int getIntValue(final Map map, final Object key, int defaultValue) {
        Integer integerObject = getInteger(map, key);
        if (integerObject == null) {
            return defaultValue;
        }
        return integerObject.intValue();
    }

    /**
     * Gets a long from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The long is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a long, <code>defaultValue</code> if null map input
     */
    public static long getLongValue(final Map map, final Object key, long defaultValue) {
        Long longObject = getLong(map, key);
        if (longObject == null) {
            return defaultValue;
        }
        return longObject.longValue();
    }

    /**
     * Gets a float from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The float is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a float, <code>defaultValue</code> if null map input
     */
    public static float getFloatValue(final Map map, final Object key, float defaultValue) {
        Float floatObject = getFloat(map, key);
        if (floatObject == null) {
            return defaultValue;
        }
        return floatObject.floatValue();
    }

    /**
     * Gets a double from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The double is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a double, <code>defaultValue</code> if null map input
     */
    public static double getDoubleValue(final Map map, final Object key, double defaultValue) {
        Double doubleObject = getDouble(map, key);
        if (doubleObject == null) {
            return defaultValue;
        }
        return doubleObject.doubleValue();
    }

    // Conversion methods
    //-------------------------------------------------------------------------
    /**
     * Gets a new Properties object initialised with the values from a Map.
     * A null input will return an empty properties object.
     * 
     * @param map  the map to convert to a Properties object, may not be null
     * @return the properties object
     */
    public static Properties toProperties(final Map map) {
        Properties answer = new Properties();
        if (map != null) {
            for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {
                Map.Entry entry = (Map.Entry) iter.next();
                Object key = entry.getKey();
                Object value = entry.getValue();
                answer.put(key, value);
            }
        }
        return answer;
    }

    /**
     * Creates a new HashMap using data copied from a ResourceBundle.
     * 
     * @param resourceBundle  the resource bundle to convert, may not be null
     * @return the hashmap containing the data
     * @throws NullPointerException if the bundle is null
     */
    public static Map toMap(final ResourceBundle resourceBundle) {
        Enumeration enumeration = resourceBundle.getKeys();
        Map map = new HashMap();

        while (enumeration.hasMoreElements()) {
            String key = (String) enumeration.nextElement();
            Object value = resourceBundle.getObject(key);
            map.put(key, value);
        }
        
        return map;
    }
 
    // Printing methods
    //-------------------------------------------------------------------------
    /**
     * Prints the given map with nice line breaks.
     * <p>
     * This method prints a nicely formatted String describing the Map.
     * Each map entry will be printed with key and value.
     * When the value is a Map, recursive behaviour occurs.
     * <p>
     * This method is NOT thread-safe in any special way. You must manually
     * synchronize on either this class or the stream as required.
     *
     * @param out  the stream to print to, must not be null
     * @param label  The label to be used, may be <code>null</code>.
     *  If <code>null</code>, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  The map to print, may be <code>null</code>.
     *  If <code>null</code>, the text 'null' is output.
     * @throws NullPointerException if the stream is <code>null</code>
     */
    public static void verbosePrint(
        final PrintStream out,
        final Object label,
        final Map map) {

        verbosePrintInternal(out, label, map, new ArrayStack(), false);
    }

    /**
     * Prints the given map with nice line breaks.
     * <p>
     * This method prints a nicely formatted String describing the Map.
     * Each map entry will be printed with key, value and value classname.
     * When the value is a Map, recursive behaviour occurs.
     * <p>
     * This method is NOT thread-safe in any special way. You must manually
     * synchronize on either this class or the stream as required.
     *
     * @param out  the stream to print to, must not be null
     * @param label  The label to be used, may be <code>null</code>.
     *  If <code>null</code>, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  The map to print, may be <code>null</code>.
     *  If <code>null</code>, the text 'null' is output.
     * @throws NullPointerException if the stream is <code>null</code>
     */
    public static void debugPrint(
        final PrintStream out,
        final Object label,
        final Map map) {

        verbosePrintInternal(out, label, map, new ArrayStack(), true);
    }

    // Implementation methods
    //-------------------------------------------------------------------------
    /**
     * Logs the given exception to <code>System.out</code>.
     * <p>
     * This method exists as Jakarta Collections does not depend on logging.
     *
     * @param ex  the exception to log
     */
    protected static void logInfo(final Exception ex) {
        System.out.println("INFO: Exception: " + ex);
    }

    /**
     * Implementation providing functionality for {@link #debugPrint} and for 
     * {@link #verbosePrint}.  This prints the given map with nice line breaks.
     * If the debug flag is true, it additionally prints the type of the object 
     * value.  If the contents of a map include the map itself, then the text 
     * <em>(this Map)</em> is printed out.  If the contents include a 
     * parent container of the map, the the text <em>(ancestor[i] Map)</em> is 
     * printed, where i actually indicates the number of levels which must be 
     * traversed in the sequential list of ancestors (e.g. father, grandfather, 
     * great-grandfather, etc).  
     *
     * @param out  the stream to print to
     * @param label  the label to be used, may be <code>null</code>.
     *  If <code>null</code>, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  the map to print, may be <code>null</code>.
     *  If <code>null</code>, the text 'null' is output
     * @param lineage  a stack consisting of any maps in which the previous 
     *  argument is contained. This is checked to avoid infinite recursion when
     *  printing the output
     * @param debug  flag indicating whether type names should be output.
     * @throws NullPointerException if the stream is <code>null</code>
     */
    private static void verbosePrintInternal(
        final PrintStream out,
        final Object label,
        final Map map,
        final ArrayStack lineage,
        final boolean debug) {
        
        printIndent(out, lineage.size());

        if (map == null) {
            if (label != null) {
                out.print(label);
                out.print(" = ");
            }
            out.println("null");
            return;
        }
        if (label != null) {
            out.print(label);
            out.println(" = ");
        }

        printIndent(out, lineage.size());
        out.println("{");

        lineage.push(map);

        for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            Object childKey = entry.getKey();
            Object childValue = entry.getValue();
            if (childValue instanceof Map && !lineage.contains(childValue)) {
                verbosePrintInternal(
                    out,
                    (childKey == null ? "null" : childKey),
                    (Map) childValue,
                    lineage,
                    debug);
            } else {
                printIndent(out, lineage.size());
                out.print(childKey);
                out.print(" = ");
                
                final int lineageIndex = lineage.indexOf(childValue);
                if (lineageIndex == -1) {
                    out.print(childValue);
                } else if (lineage.size() - 1 == lineageIndex) {
                    out.print("(this Map)");    
                } else {
                    out.print(
                        "(ancestor["
                            + (lineage.size() - 1 - lineageIndex - 1)
                            + "] Map)");
                }
                
                if (debug && childValue != null) {
                    out.print(' ');
                    out.println(childValue.getClass().getName());
                } else {
                    out.println();
                }
            }
        }
        
        lineage.pop();

        printIndent(out, lineage.size());
        out.println(debug ? "} " + map.getClass().getName() : "}");
    }

    /**
     * Writes indentation to the given stream.
     *
     * @param out  the stream to indent
     */
    private static void printIndent(final PrintStream out, final int indent) {
        for (int i = 0; i < indent; i++) {
            out.print(INDENT_STRING);
        }
    }
    
    // Misc
    //-----------------------------------------------------------------------
    /**
     * Inverts the supplied map returning a new HashMap such that the keys of
     * the input are swapped with the values.
     * <p>
     * This operation assumes that the inverse mapping is well defined.
     * If the input map had multiple entries with the same value mapped to
     * different keys, the returned map will map one of those keys to the 
     * value, but the exact key which will be mapped is undefined.
     * 
     * @see DoubleOrderedMap
     * @param map  the map to invert, may not be null
     * @return a new HashMap containing the inverted data
     * @throws NullPointerException if the map is null
     */
    public static Map invertMap(Map map) {
        Map out = new HashMap(map.size());
        for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            out.put(entry.getValue(), entry.getKey());
        }
        return out;
    }
     
    /**
     * Nice method for adding data to a map in such a way
     * as to not get NPE's. The point being that if the
     * value is null, map.put() will throw an exception.
     * That blows in the case of this class cause you may want to
     * essentially treat put("Not Null", null ) == put("Not Null", "")
     * We will still throw a NPE if the key is null cause that should
     * never happen.
     * 
     * @param map  the map to add to, may not be null
     * @param key  the key
     * @param value  the value
     * @throws NullPointerException if the map is null
     */
    public static void safeAddToMap(Map map, Object key, Object value) throws NullPointerException {
        if (value == null) {
            map.put ( key, "" );
        } else {
           map.put ( key, value );
        }
    }

    // Map decorators
    //-----------------------------------------------------------------------
    /**
     * Returns a synchronized map backed by the given map.
     * <p>
     * You must manually synchronize on the returned buffer's iterator to 
     * avoid non-deterministic behavior: