Java tutorial
/* * Copyright (c) 2002-2015 JGoodies Software GmbH. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * o Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * o Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * o Neither the name of JGoodies Software GmbH nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package com.jgoodies.binding.adapter; import static com.jgoodies.common.base.Preconditions.checkArgument; import static com.jgoodies.common.base.Preconditions.checkNotNull; import java.util.prefs.Preferences; import com.jgoodies.binding.value.AbstractValueModel; /** * A ValueModel implementation that reads and writes values from/to a key * of a given {@code Preferences} node under a specified key. * Write changes fire value changes.<p> * * <strong>Example:</strong><pre> * String prefsKey = "isShowing"; * Boolean defaultValue = Boolean.TRUE; * Preferences prefs = Workbench.userPreferences(); * ValueModel model = new PreferencesAdapter(prefs, prefsKey, defaultValue); * JCheckBox showingBox = new JCheckBox("Show tips"); * showingBox.setModel(new ToggleButtonAdapter(model)); * </pre> * * @author Karsten Lentzsch * @version $Revision: 1.11 $ * * @see java.util.prefs.Preferences */ public final class PreferencesAdapter extends AbstractValueModel { private static final String ERROR_MSG = "Value must be a Boolean, Double, Float, Integer, Long, or String."; /** * Refers to the preferences node that is used to persist the bound data. */ private final Preferences prefs; /** * Holds the preferences key that is used to access the stored value. */ private final String key; /** * Refers to the type of accepted values. */ private final Class<?> type; /** * Holds the default value that is used if the preferences * do not yet store a value. */ private final Object defaultValue; //Instance Creation ******************************************************* /** * Constructs a PreferencesAdapter on the given {@code Preferences} * using the specified key and default value, all which must be * non-{@code null}. * * @param prefs the {@code Preferences} used to store and retrieve * @param key the key used to get and set values in the Preferences * @param defaultValue the default value * * @throws NullPointerException if the Preferences, key, or default value * is {@code null} * @throws IllegalArgumentException if the default value is of a type other * than Boolean, Double, Float, Integer, Long, or String. */ public PreferencesAdapter(Preferences prefs, String key, Object defaultValue) { this.prefs = checkNotNull(prefs, "The Preferences must not be null."); this.key = checkNotNull(key, "The key must not be null."); this.defaultValue = checkNotNull(defaultValue, "The default value must not be null."); checkArgument(isBackedType(defaultValue), "The Default " + ERROR_MSG); this.type = defaultValue.getClass(); } // ValueModel Implementation ********************************************** /** * Looks up and returns the value from the preferences. The value is * look up under this adapter's key. It will be converted before it is * returned. * * @return the retrieved and converted value * @throws ClassCastException if the type of the default value * cannot be read from the preferences */ @Override public Object getValue() { if (type == Boolean.class) { return Boolean.valueOf(getBoolean()); } else if (type == Double.class) { return Double.valueOf(getDouble()); } else if (type == Float.class) { return Float.valueOf(getFloat()); } else if (type == Integer.class) { return Integer.valueOf(getInt()); } else if (type == Long.class) { return Long.valueOf(getLong()); } else if (type == String.class) { return getString(); } else { throw new ClassCastException(ERROR_MSG); } } /** * Converts the given value to a string and puts it into the preferences. * * @param newValue the object to be stored * @throws IllegalArgumentException if the new value cannot be stored * in the preferences due to an illegal type */ @Override public void setValue(Object newValue) { checkNotNull(newValue, "The value must not be null."); // Class valueType = newValue.getClass(); // if (type != valueType) // throw new IllegalArgumentException( // "The type of the value set must be consistent " // + "with the default value type " + type); // if (newValue instanceof Boolean) { setBoolean(((Boolean) newValue).booleanValue()); } else if (newValue instanceof Double) { setDouble(((Double) newValue).doubleValue()); } else if (newValue instanceof Float) { setFloat(((Float) newValue).floatValue()); } else if (newValue instanceof Integer) { setInt(((Integer) newValue).intValue()); } else if (newValue instanceof Long) { setLong(((Long) newValue).longValue()); } else if (newValue instanceof String) { setString((String) newValue); } } // Convenience Accessors ************************************************** /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ public boolean getBoolean() { return prefs.getBoolean(key, ((Boolean) defaultValue).booleanValue()); } /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ public double getDouble() { return prefs.getDouble(key, ((Double) defaultValue).doubleValue()); } /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ public float getFloat() { return prefs.getFloat(key, ((Float) defaultValue).floatValue()); } /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ public int getInt() { return prefs.getInt(key, ((Integer) defaultValue).intValue()); } /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ public long getLong() { return prefs.getLong(key, ((Long) defaultValue).longValue()); } /** * Looks up, converts and returns the stored value from the preferences. * Returns the default value if no value has been stored before. * * @return the stored value or the default */ @Override public String getString() { return prefs.get(key, (String) defaultValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not a Boolean */ public void setBoolean(boolean newValue) { boolean oldValue = getBoolean(); prefs.putBoolean(key, newValue); fireValueChange(oldValue, newValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not a Double */ public void setDouble(double newValue) { double oldValue = getDouble(); prefs.putDouble(key, newValue); fireValueChange(oldValue, newValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not a Float */ public void setFloat(float newValue) { float oldValue = getFloat(); prefs.putFloat(key, newValue); fireValueChange(oldValue, newValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not an Integer */ public void setInt(int newValue) { int oldValue = getInt(); prefs.putInt(key, newValue); fireValueChange(oldValue, newValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not a Long */ public void setLong(long newValue) { long oldValue = getLong(); prefs.putLong(key, newValue); fireValueChange(oldValue, newValue); } /** * Converts the given value to an Object and stores it in this * adapter's Preferences under this adapter's preferences key. * * @param newValue the value to put into the Preferences * * @throws ClassCastException if the default value is not a String */ public void setString(String newValue) { String oldValue = getString(); prefs.put(key, newValue); fireValueChange(oldValue, newValue); } // Helper Code ************************************************************ /** * Used to check the default value type during construction. */ private static boolean isBackedType(Object value) { Class<?> aClass = value.getClass(); return aClass == Boolean.class || aClass == Double.class || aClass == Float.class || aClass == Integer.class || aClass == Long.class || aClass == String.class; } }