/*******************************************************************************
* Copyright (c) 2000, 2005 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.preference;
import org.eclipse.jface.util.IPropertyChangeListener;
/**
* The <code>IPreferenceStore</code> interface represents a table mapping
* named preferences to values. If there is no value for a given name,
* then that preferences's default value is returned; and if there is no
* default value for that preference, then a default-default value is returned.
* The default-default values for the primitive types are as follows:
* <ul>
* <li><code>boolean</code> = <code>false</code></li>
* <li><code>double</code> = <code>0.0</code></li>
* <li><code>float</code> = <code>0.0f</code></li>
* <li><code>int</code> = <code>0</code></li>
* <li><code>long</code> = <code>0</code></li>
* <li><code>String</code> = <code>""</code> (the empty string)</li>
* </ul>
* <p>
* Thus a preference store maintains two values for each of a set of
* names: a current value and a default value.
* The typical usage is to establish the defaults for all known preferences
* and then restore previously stored values for preferences whose values
* were different from their defaults. After the current values of
* the preferences have been modified, it is a simple matter to write
* out only those preferences whose values are different from their defaults.
* This two-tiered approach to saving and restoring preference setting
* minimized the number of preferences that need to be persisted; indeed,
* the normal starting state does not require storing any preferences
* at all.
* </p>
* <p>
* A property change event is reported whenever a preferences current
* value actually changes (whether through <code>setValue</code>,
* <code>setToDefault</code>, or other unspecified means). Note, however,
* that manipulating default values (with <code>setDefault</code>)
* does not cause such events to be reported.
* </p>
* <p>
* Clients who need a preference store may implement this interface or
* instantiate the standard implementation <code>PreferenceStore</code>.
* </p>
*
* @see PreferenceStore
*/
public interface IPreferenceStore {
/**
* The default-default value for boolean preferences (<code>false</code>).
*/
public static final boolean BOOLEAN_DEFAULT_DEFAULT = false;
/**
* The default-default value for double preferences (<code>0.0</code>).
*/
public static final double DOUBLE_DEFAULT_DEFAULT = 0.0;
/**
* The default-default value for float preferences (<code>0.0f</code>).
*/
public static final float FLOAT_DEFAULT_DEFAULT = 0.0f;
/**
* The default-default value for int preferences (<code>0</code>).
*/
public static final int INT_DEFAULT_DEFAULT = 0;
/**
* The default-default value for long preferences (<code>0L</code>).
*/
public static final long LONG_DEFAULT_DEFAULT = 0L;
/**
* The default-default value for String preferences (<code>""</code>).
*/
public static final String STRING_DEFAULT_DEFAULT = ""; //$NON-NLS-1$
/**
* The string representation used for <code>true</code> (<code>"true"</code>).
*/
public static final String TRUE = "true"; //$NON-NLS-1$
/**
* The string representation used for <code>false</code> (<code>"false"</code>).
*/
public static final String FALSE = "false"; //$NON-NLS-1$
/**
* <p>
* Adds a property change listener to this preference store.
* </p>
* <p>
* <b>Note</b> The types of the oldValue and newValue of the
* generated PropertyChangeEvent are determined by whether
* or not the typed API in IPreferenceStore was called.
* If values are changed via setValue(name,type) the
* values in the PropertyChangedEvent will be of that type.
* If they are set using a non typed API (i.e. #setToDefault
* or using the OSGI Preferences) the values will be unconverted
* Strings.
* </p>
* <p>
* A listener will be called in the same Thread
* that it is invoked in. Any Thread dependant listeners (such as
* those who update an SWT widget) will need to update in the
* correct Thread. In the case of an SWT update you can update
* using Display#syncExec(Runnable) or Display#asyncExec(Runnable).
* </p>
* <p>
* Likewise any application that updates an IPreferenceStore
* from a Thread other than the UI Thread should be aware of
* any listeners that require an update in the UI Thread.
* </p>
*
* @param listener a property change listener
* @see org.eclipse.jface.util.PropertyChangeEvent
* @see #setToDefault(String)
* @see #setValue(String, boolean)
* @see #setValue(String, double)
* @see #setValue(String, float)
* @see #setValue(String, int)
* @see #setValue(String, long)
* @see #setValue(String, String)
* @see org.osgi.service.prefs.Preferences
*/
public void addPropertyChangeListener(IPropertyChangeListener listener);
/**
* Returns whether the named preference is known to this preference
* store.
*
* @param name the name of the preference
* @return <code>true</code> if either a current value or a default
* value is known for the named preference, and <code>false</code>otherwise
*/
public boolean contains(String name);
/**
* Fires a property change event corresponding to a change to the
* current value of the preference with the given name.
* <p>
* This method is provided on this interface to simplify the implementation
* of decorators. There is normally no need to call this method since
* <code>setValue</code> and <code>setToDefault</code> report such
* events in due course. Implementations should funnel all preference
* changes through this method.
* </p>
*
* @param name the name of the preference, to be used as the property
* in the event object
* @param oldValue the old value
* @param newValue the new value
*/
public void firePropertyChangeEvent(String name, Object oldValue,
Object newValue);
/**
* Returns the current value of the boolean-valued preference with the
* given name.
* Returns the default-default value (<code>false</code>) if there
* is no preference with the given name, or if the current value
* cannot be treated as a boolean.
*
* @param name the name of the preference
* @return the boolean-valued preference
*/
public boolean getBoolean(String name);
/**
* Returns the default value for the boolean-valued preference
* with the given name.
* Returns the default-default value (<code>false</code>) if there
* is no default preference with the given name, or if the default
* value cannot be treated as a boolean.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public boolean getDefaultBoolean(String name);
/**
* Returns the default value for the double-valued preference
* with the given name.
* Returns the default-default value (<code>0.0</code>) if there
* is no default preference with the given name, or if the default
* value cannot be treated as a double.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public double getDefaultDouble(String name);
/**
* Returns the default value for the float-valued preference
* with the given name.
* Returns the default-default value (<code>0.0f</code>) if there
* is no default preference with the given name, or if the default
* value cannot be treated as a float.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public float getDefaultFloat(String name);
/**
* Returns the default value for the integer-valued preference
* with the given name.
* Returns the default-default value (<code>0</code>) if there
* is no default preference with the given name, or if the default
* value cannot be treated as an integer.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public int getDefaultInt(String name);
/**
* Returns the default value for the long-valued preference
* with the given name.
* Returns the default-default value (<code>0L</code>) if there
* is no default preference with the given name, or if the default
* value cannot be treated as a long.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public long getDefaultLong(String name);
/**
* Returns the default value for the string-valued preference
* with the given name.
* Returns the default-default value (the empty string <code>""</code>)
* is no default preference with the given name, or if the default
* value cannot be treated as a string.
*
* @param name the name of the preference
* @return the default value of the named preference
*/
public String getDefaultString(String name);
/**
* Returns the current value of the double-valued preference with the
* given name.
* Returns the default-default value (<code>0.0</code>) if there
* is no preference with the given name, or if the current value
* cannot be treated as a double.
*
* @param name the name of the preference
* @return the double-valued preference
*/
public double getDouble(String name);
/**
* Returns the current value of the float-valued preference with the
* given name.
* Returns the default-default value (<code>0.0f</code>) if there
* is no preference with the given name, or if the current value
* cannot be treated as a float.
*
* @param name the name of the preference
* @return the float-valued preference
*/
public float getFloat(String name);
/**
* Returns the current value of the integer-valued preference with the
* given name.
* Returns the default-default value (<code>0</code>) if there
* is no preference with the given name, or if the current value
* cannot be treated as an integter.
*
* @param name the name of the preference
* @return the int-valued preference
*/
public int getInt(String name);
/**
* Returns the current value of the long-valued preference with the
* given name.
* Returns the default-default value (<code>0L</code>) if there
* is no preference with the given name, or if the current value
* cannot be treated as a long.
*
* @param name the name of the preference
* @return the long-valued preference
*/
public long getLong(String name);
/**
* Returns the current value of the string-valued preference with the
* given name.
* Returns the default-default value (the empty string <code>""</code>)
* if there is no preference with the given name, or if the current value
* cannot be treated as a string.
*
* @param name the name of the preference
* @return the string-valued preference
*/
public String getString(String name);
/**
* Returns whether the current value of the preference with the given name
* has the default value.
*
* @param name the name of the preference
* @return <code>true</code> if the preference has a known default value
* and its current value is the same, and <code>false</code> otherwise
* (including the case where the preference is unknown to this store)
*/
public boolean isDefault(String name);
/**
* Returns whether the current values in this property store
* require saving.
*
* @return <code>true</code> if at least one of values of
* the preferences known to this store has changed and
* requires saving, and <code>false</code> otherwise.
*/
public boolean needsSaving();
/**
* Sets the current value of the preference with the given name to
* the given string value without sending a property change.
* <p>
* This method does not fire a property change event and
* should only be used for setting internal preferences
* that are not meant to be processed by listeners.
* Normal clients should instead call #setValue.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void putValue(String name, String value);
/**
* Removes the given listener from this preference store.
* Has no affect if the listener is not registered.
*
* @param listener a property change listener
*/
public void removePropertyChangeListener(IPropertyChangeListener listener);
/**
* Sets the default value for the double-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param value the new default value for the preference
*/
public void setDefault(String name, double value);
/**
* Sets the default value for the float-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param value the new default value for the preference
*/
public void setDefault(String name, float value);
/**
* Sets the default value for the integer-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param value the new default value for the preference
*/
public void setDefault(String name, int value);
/**
* Sets the default value for the long-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param value the new default value for the preference
*/
public void setDefault(String name, long value);
/**
* Sets the default value for the string-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param defaultObject the new default value for the preference
*/
public void setDefault(String name, String defaultObject);
/**
* Sets the default value for the boolean-valued preference with the
* given name.
* <p>
* Note that the current value of the preference is affected if
* the preference's current value was its old default value, in which
* case it changes to the new default value. If the preference's current
* is different from its old default value, its current value is
* unaffected. No property change events are reported by changing default
* values.
* </p>
*
* @param name the name of the preference
* @param value the new default value for the preference
*/
public void setDefault(String name, boolean value);
/**
* Sets the current value of the preference with the given name back
* to its default value.
* <p>
* Note that the preferred way of re-initializing a preference to the
* appropriate default value is to call <code>setToDefault</code>.
* This is implemented by removing the named value from the store,
* thereby exposing the default value.
* </p>
*
* @param name the name of the preference
*/
public void setToDefault(String name);
/**
* Sets the current value of the double-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, double value);
/**
* Sets the current value of the float-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, float value);
/**
* Sets the current value of the integer-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, int value);
/**
* Sets the current value of the long-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, long value);
/**
* Sets the current value of the string-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, String value);
/**
* Sets the current value of the boolean-valued preference with the
* given name.
* <p>
* A property change event is reported if the current value of the
* preference actually changes from its previous value. In the event
* object, the property name is the name of the preference, and the
* old and new values are wrapped as objects.
* </p>
* <p>
* Note that the preferred way of re-initializing a preference to its
* default value is to call <code>setToDefault</code>.
* </p>
*
* @param name the name of the preference
* @param value the new current value of the preference
*/
public void setValue(String name, boolean value);
}
