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Diffstat (limited to 'jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java')
| -rw-r--r-- | jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java | 346 |
1 files changed, 0 insertions, 346 deletions
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java deleted file mode 100644 index 5314bb9250..0000000000 --- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java +++ /dev/null @@ -1,346 +0,0 @@ -/******************************************************************************* - * Copyright (c) 2007, 2009 Oracle. All rights reserved. - * This program and the accompanying materials are made available under the - * terms of the Eclipse Public License v1.0, which accompanies this distribution - * and is available at http://www.eclipse.org/legal/epl-v10.html. - * - * Contributors: - * Oracle - initial API and implementation - ******************************************************************************/ -package org.eclipse.jpt.utility.internal.model.value.prefs; - -import java.util.EventListener; -import java.util.prefs.PreferenceChangeEvent; -import java.util.prefs.PreferenceChangeListener; -import java.util.prefs.Preferences; - -import org.eclipse.jpt.utility.internal.BidiStringConverter; -import org.eclipse.jpt.utility.internal.model.value.AspectAdapter; -import org.eclipse.jpt.utility.internal.model.value.StaticPropertyValueModel; -import org.eclipse.jpt.utility.model.listener.PropertyChangeListener; -import org.eclipse.jpt.utility.model.value.PropertyValueModel; -import org.eclipse.jpt.utility.model.value.WritablePropertyValueModel; - -/** - * This adapter wraps a Preference and converts it into a PropertyValueModel. - * It listens for the appropriate "preference" changes and converts them into - * VALUE property changes. It also allows the specification of a default value - * for the Preference, which, by default, is null (and is probably *not* a very - * good default). - * - * You can configure whether the preference's value is returned, - * unchanged, as a string or as some other object (e.g. an Integer) by - * setting the adapter's converter. Internally, the preference's value - * is stored as the converted object; and the conversions take place - * when reading or writing from the preferences node or retrieving the - * value from an event fired by the preferences node. - * - * This adapter is a bit different from most other adapters because the - * change events fired off by a Preferences node are asynchronous from - * the change itself. (AbstractPreferences uses an event dispatch daemon.) - * As a result, a client can set our value with #setValue(Object) and we - * will return from that method before we ever receive notification from - * the Preferences node that *it* has changed. This means we cannot - * rely on that event to keep our internally cached value in synch. - */ -public class PreferencePropertyValueModel<P> - extends AspectAdapter<Preferences> - implements WritablePropertyValueModel<P> -{ - /** The key to the preference we use for the value. */ - protected final String key; - - /** - * Cache the current (object) value of the preference so we - * can pass an "old value" when we fire a property change event. - */ - protected P value; - - /** - * The default (object) value returned if there is no value - * associated with the preference. - */ - protected final P defaultValue; - - /** - * This converter is used to convert the preference's - * string value to and from an object. - */ - protected final BidiStringConverter<P> converter; - - /** A listener that listens to the appropriate preference. */ - protected final PreferenceChangeListener preferenceChangeListener; - - - // ********** constructors ********** - - /** - * Construct an adapter for the specified preference. - * The default value of the preference will be null. - */ - public PreferencePropertyValueModel(Preferences preferences, String key) { - this(preferences, key, null); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public PreferencePropertyValueModel(Preferences preferences, String key, P defaultValue) { - this(preferences, key, defaultValue, BidiStringConverter.Default.<P>instance()); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public PreferencePropertyValueModel(Preferences preferences, String key, P defaultValue, BidiStringConverter<P> converter) { - this(new StaticPropertyValueModel<Preferences>(preferences), key, defaultValue, converter); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public static PreferencePropertyValueModel<Boolean> forBoolean(Preferences preferences, String key, boolean defaultValue) { - return new PreferencePropertyValueModel<Boolean>( - preferences, - key, - defaultValue ? Boolean.TRUE : Boolean.FALSE, - BidiStringConverter.BooleanConverter.instance() - ); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public static PreferencePropertyValueModel<Integer> forInteger(Preferences preferences, String key, int defaultValue) { - return new PreferencePropertyValueModel<Integer>( - preferences, - key, - Integer.valueOf(defaultValue), - BidiStringConverter.IntegerConverter.instance() - ); - } - - /** - * Construct an adapter for the specified preference. - * The default value of the preference will be null. - */ - public PreferencePropertyValueModel(PropertyValueModel<? extends Preferences> preferencesHolder, String key) { - this(preferencesHolder, key, null); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public PreferencePropertyValueModel(PropertyValueModel<? extends Preferences> preferencesHolder, String key, P defaultValue) { - this(preferencesHolder, key, defaultValue, BidiStringConverter.Default.<P>instance()); - } - - /** - * Construct an adapter for the specified preference with - * the specified default value for the preference. - */ - public PreferencePropertyValueModel(PropertyValueModel<? extends Preferences> preferencesHolder, String key, P defaultValue, BidiStringConverter<P> converter) { - super(preferencesHolder); - this.key = key; - this.defaultValue = defaultValue; - this.converter = converter; - this.preferenceChangeListener = this.buildPreferenceChangeListener(); - // our value is null when we are not listening to the preference - this.value = null; - } - - - // ********** initialization ********** - - /** - * A preference has changed, notify the listeners if necessary. - */ - protected PreferenceChangeListener buildPreferenceChangeListener() { - // transform the preference change events into VALUE property change events - return new PreferenceChangeListener() { - public void preferenceChange(PreferenceChangeEvent event) { - PreferencePropertyValueModel.this.preferenceChanged(event.getKey(), event.getNewValue()); - } - @Override - public String toString() { - return "preference change listener"; //$NON-NLS-1$ - } - }; - } - - - // ********** ValueModel implementation ********** - - /** - * Return the cached (converted) value. - */ - @Override - public synchronized P getValue() { - return this.value; - } - - - // ********** PropertyValueModel implementation ********** - - /** - * Set the cached value, then set the appropriate preference value. - */ - public synchronized void setValue(P value) { - if (this.hasNoListeners()) { - return; // no changes allowed when we have no listeners - } - - Object old = this.value; - this.value = value; - this.fireAspectChanged(old, value); - - if ((this.subject != null) && this.shouldSetPreference(old, value)) { - this.setValue_(value); - } - } - - - // ********** AspectAdapter implementation ********** - - @Override - protected Class<? extends EventListener> getListenerClass() { - return PropertyChangeListener.class; - } - - @Override - protected String getListenerAspectName() { - return VALUE; - } - - @Override - protected boolean hasListeners() { - return this.hasAnyPropertyChangeListeners(VALUE); - } - - @Override - protected void fireAspectChanged(Object oldValue, Object newValue) { - this.firePropertyChanged(VALUE, oldValue, newValue); - } - - @Override - protected synchronized void engageSubject_() { - this.subject.addPreferenceChangeListener(this.preferenceChangeListener); - this.value = this.buildValue(); - } - - @Override - protected synchronized void disengageSubject_() { - try { - this.subject.removePreferenceChangeListener(this.preferenceChangeListener); - } catch (IllegalStateException ex) { - // for some odd reason, we are not allowed to remove a listener from a "dead" - // preferences node; so handle the exception that gets thrown here - if ( ! ex.getMessage().equals("Node has been removed.")) { //$NON-NLS-1$ - // if it is not the expected exception, re-throw it - throw ex; - } - } - this.value = null; - } - - - // ********** AbstractModel implementation ********** - - @Override - public void toString(StringBuilder sb) { - sb.append(this.key); - sb.append(" => "); //$NON-NLS-1$ - sb.append(this.value); - } - - - // ********** public API ********** - - /** - * Return the preference's key. - */ - public String getKey() { - return this.key; - } - - - // ********** internal methods ********** - - /** - * Return the preference's value. - * At this point the subject may be null. - */ - protected P buildValue() { - return (this.subject == null) ? null : this.buildValue_(); - } - - /** - * Return the appropriate preference, converted to the appropriate object. - * At this point we can be sure that the subject is not null. - */ - protected P buildValue_() { - return this.convertToObject(this.subject.get(this.key, this.convertToString(this.defaultValue))); - } - - /** - * Set the appropriate preference after converting the value to a string. - * At this point we can be sure that the subject is not null. - */ - protected void setValue_(P value) { - this.subject.put(this.key, this.convertToString(value)); - } - - /** - * Return whether the specified new value should be passed - * through to the preference. By default, only if the value has changed, - * will it be passed through to the preference. This also has the - * effect of not creating new preferences in the "backing store" - * if the new value is the same as the default value. - * - * Subclasses can override this method to return true if they - * would like to ALWAYS pass through the new value to the preference. - */ - protected boolean shouldSetPreference(Object oldValue, Object newValue) { - return this.attributeValueHasChanged(oldValue, newValue); - } - - /** - * Convert the specified object to a string that can be stored as - * the value of the preference. - */ - protected String convertToString(P o) { - return this.converter.convertToString(o); - } - - /** - * Convert the specified preference value string to an - * appropriately-typed object to be returned to the client. - */ - protected P convertToObject(String s) { - return this.converter.convertToObject(s); - } - - protected void preferenceChanged(String prefKey, @SuppressWarnings("unused") String newValue) { - if (prefKey.equals(this.key)) { - this.preferenceChanged(); - } - } - - /** - * The underlying preference changed; either because we changed it - * in #setValue_(Object) or a third-party changed it. - * If this is called because of our own change, the event will be - * swallowed because the old and new values are the same. - */ - protected synchronized void preferenceChanged() { - Object old = this.value; - this.value = this.buildValue(); - this.fireAspectChanged(old, this.value); - } - -} |