abstractpreferences.java

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            removeSpi(key);
            enqueuePreferenceChangeEvent(key, null);
        }
    }

    /**
     * Implements the <tt>clear</tt> method as per the specification in
     * {@link Preferences#clear()}.
     *
     * <p>This implementation obtains this preference node's lock,
     * invokes {@link #keys()} to obtain an array of keys, and
     * iterates over the array invoking {@link #remove(String)} on each key.
     *
     * @throws BackingStoreException if this operation cannot be completed
     *         due to a failure in the backing store, or inability to 
     *         communicate with it.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void clear() throws BackingStoreException {
        synchronized(lock) {
            String[] keys = keys();
            for (int i=0; i<keys.length; i++)
                remove(keys[i]);
        }
    }

    /**
     * Implements the <tt>putInt</tt> method as per the specification in
     * {@link Preferences#putInt(String,int)}.
     *
     * <p>This implementation translates <tt>value</tt> to a string with
     * {@link Integer#toString(int)} and invokes {@link #put(String,String)}
     * on the result.
     *
     * @param key key with which the string form of value is to be associated.
     * @param value value whose string form is to be associated with key.
     * @throws NullPointerException if key is <tt>null</tt>.
     * @throws IllegalArgumentException if <tt>key.length()</tt> exceeds
     *         <tt>MAX_KEY_LENGTH</tt>.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void putInt(String key, int value) {
        put(key, Integer.toString(value));
    }

    /**
     * Implements the <tt>getInt</tt> method as per the specification in
     * {@link Preferences#getInt(String,int)}.
     *
     * <p>This implementation invokes {@link #get(String,String) <tt>get(key,
     * null)</tt>}.  If the return value is non-null, the implementation
     * attempts to translate it to an <tt>int</tt> with
     * {@link Integer#parseInt(String)}.  If the attempt succeeds, the return
     * value is returned by this method.  Otherwise, <tt>def</tt> is returned.
     *
     * @param key key whose associated value is to be returned as an int.
     * @param def the value to be returned in the event that this
     *        preference node has no value associated with <tt>key</tt>
     *        or the associated value cannot be interpreted as an int.
     * @return the int value represented by the string associated with
     *         <tt>key</tt> in this preference node, or <tt>def</tt> if the
     *         associated value does not exist or cannot be interpreted as
     *         an int.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>.
     */
    public int getInt(String key, int def) {
        int result = def;
        try {
            String value = get(key, null);
            if (value != null)
                result = Integer.parseInt(value);
        } catch (NumberFormatException e) {
            // Ignoring exception causes specified default to be returned
        }

        return result;
    }

    /**
     * Implements the <tt>putLong</tt> method as per the specification in
     * {@link Preferences#putLong(String,long)}.
     *
     * <p>This implementation translates <tt>value</tt> to a string with
     * {@link Long#toString(long)} and invokes {@link #put(String,String)}
     * on the result.
     *
     * @param key key with which the string form of value is to be associated.
     * @param value value whose string form is to be associated with key.
     * @throws NullPointerException if key is <tt>null</tt>.
     * @throws IllegalArgumentException if <tt>key.length()</tt> exceeds
     *         <tt>MAX_KEY_LENGTH</tt>.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void putLong(String key, long value) {
        put(key, Long.toString(value));
    }

    /**
     * Implements the <tt>getLong</tt> method as per the specification in
     * {@link Preferences#getLong(String,long)}.
     *
     * <p>This implementation invokes {@link #get(String,String) <tt>get(key,
     * null)</tt>}.  If the return value is non-null, the implementation
     * attempts to translate it to a <tt>long</tt> with
     * {@link Long#parseLong(String)}.  If the attempt succeeds, the return
     * value is returned by this method.  Otherwise, <tt>def</tt> is returned.
     *
     * @param key key whose associated value is to be returned as a long.
     * @param def the value to be returned in the event that this
     *        preference node has no value associated with <tt>key</tt>
     *        or the associated value cannot be interpreted as a long.
     * @return the long value represented by the string associated with
     *         <tt>key</tt> in this preference node, or <tt>def</tt> if the
     *         associated value does not exist or cannot be interpreted as
     *         a long.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>.
     */
    public long getLong(String key, long def) {
        long result = def;
        try {
            String value = get(key, null);
            if (value != null)
                result = Long.parseLong(value);
        } catch (NumberFormatException e) {
            // Ignoring exception causes specified default to be returned
        }

        return result;
    }

    /**
     * Implements the <tt>putBoolean</tt> method as per the specification in
     * {@link Preferences#putBoolean(String,boolean)}.
     *
     * <p>This implementation translates <tt>value</tt> to a string with
     * {@link String#valueOf(boolean)} and invokes {@link #put(String,String)}
     * on the result.
     *
     * @param key key with which the string form of value is to be associated.
     * @param value value whose string form is to be associated with key.
     * @throws NullPointerException if key is <tt>null</tt>.
     * @throws IllegalArgumentException if <tt>key.length()</tt> exceeds
     *         <tt>MAX_KEY_LENGTH</tt>.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void putBoolean(String key, boolean value) {
        put(key, String.valueOf(value));
    }

    /**
     * Implements the <tt>getBoolean</tt> method as per the specification in
     * {@link Preferences#getBoolean(String,boolean)}.
     *
     * <p>This implementation invokes {@link #get(String,String) <tt>get(key,
     * null)</tt>}.  If the return value is non-null, it is compared with
     * <tt>"true"</tt> using {@link String#equalsIgnoreCase(String)}.  If the
     * comparison returns <tt>true</tt>, this invocation returns
     * <tt>true</tt>.  Otherwise, the original return value is compared with
     * <tt>"false"</tt>, again using {@link String#equalsIgnoreCase(String)}.
     * If the comparison returns <tt>true</tt>, this invocation returns
     * <tt>false</tt>.  Otherwise, this invocation returns <tt>def</tt>.
     *
     * @param key key whose associated value is to be returned as a boolean.
     * @param def the value to be returned in the event that this
     *        preference node has no value associated with <tt>key</tt>
     *        or the associated value cannot be interpreted as a boolean.
     * @return the boolean value represented by the string associated with
     *         <tt>key</tt> in this preference node, or <tt>def</tt> if the
     *         associated value does not exist or cannot be interpreted as
     *         a boolean.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>.
     */
    public boolean getBoolean(String key, boolean def) {
        boolean result = def;
        String value = get(key, null);
        if (value != null) {
            if (value.equalsIgnoreCase("true"))
                result = true;
            else if (value.equalsIgnoreCase("false"))
                result = false;
        }

        return result;
    }

    /**
     * Implements the <tt>putFloat</tt> method as per the specification in
     * {@link Preferences#putFloat(String,float)}.
     *
     * <p>This implementation translates <tt>value</tt> to a string with
     * {@link Float#toString(float)} and invokes {@link #put(String,String)}
     * on the result.
     *
     * @param key key with which the string form of value is to be associated.
     * @param value value whose string form is to be associated with key.
     * @throws NullPointerException if key is <tt>null</tt>.
     * @throws IllegalArgumentException if <tt>key.length()</tt> exceeds
     *         <tt>MAX_KEY_LENGTH</tt>.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void putFloat(String key, float value) {
        put(key, Float.toString(value));
    }

    /**
     * Implements the <tt>getFloat</tt> method as per the specification in
     * {@link Preferences#getFloat(String,float)}.
     *
     * <p>This implementation invokes {@link #get(String,String) <tt>get(key,
     * null)</tt>}.  If the return value is non-null, the implementation
     * attempts to translate it to an <tt>float</tt> with
     * {@link Float#parseFloat(String)}.  If the attempt succeeds, the return
     * value is returned by this method.  Otherwise, <tt>def</tt> is returned.
     *
     * @param key key whose associated value is to be returned as a float.
     * @param def the value to be returned in the event that this
     *        preference node has no value associated with <tt>key</tt>
     *        or the associated value cannot be interpreted as a float.
     * @return the float value represented by the string associated with
     *         <tt>key</tt> in this preference node, or <tt>def</tt> if the
     *         associated value does not exist or cannot be interpreted as
     *         a float.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>.
     */
    public float getFloat(String key, float def) {
        float result = def;
        try {
            String value = get(key, null);
            if (value != null)
                result = Float.parseFloat(value);
        } catch (NumberFormatException e) {
            // Ignoring exception causes specified default to be returned
        }

        return result;
    }

    /**
     * Implements the <tt>putDouble</tt> method as per the specification in
     * {@link Preferences#putDouble(String,double)}.
     *
     * <p>This implementation translates <tt>value</tt> to a string with
     * {@link Double#toString(double)} and invokes {@link #put(String,String)}
     * on the result.
     *
     * @param key key with which the string form of value is to be associated.
     * @param value value whose string form is to be associated with key.
     * @throws NullPointerException if key is <tt>null</tt>.
     * @throws IllegalArgumentException if <tt>key.length()</tt> exceeds
     *         <tt>MAX_KEY_LENGTH</tt>.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     */
    public void putDouble(String key, double value) {
        put(key, Double.toString(value));
    }

    /**
     * Implements the <tt>getDouble</tt> method as per the specification in
     * {@link Preferences#getDouble(String,double)}.
     *
     * <p>This implementation invokes {@link #get(String,String) <tt>get(key,
     * null)</tt>}.  If the return value is non-null, the implementation
     * attempts to translate it to an <tt>double</tt> with
     * {@link Double#parseDouble(String)}.  If the attempt succeeds, the return
     * value is returned by this method.  Otherwise, <tt>def</tt> is returned.
     *
     * @param key key whose associated value is to be returned as a double.
     * @param def the value to be returned in the event that this
     *        preference node has no value associated with <tt>key</tt>
     *        or the associated value cannot be interpreted as a double.
     * @return the double value represented by the string associated with
     *         <tt>key</tt> in this preference node, or <tt>def</tt> if the
     *         associated value does not exist or cannot be interpreted as
     *         a double.
     * @throws IllegalStateException if this node (or an ancestor) has been
     *         removed with the {@link #removeNode()} method.
     * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>.
     */
    public double getDouble(String key, double def) {
        double result = def;