org.eclipse.jface.commands.PersistentState.java Source code

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Here is the source code for org.eclipse.jface.commands.PersistentState.java

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/*******************************************************************************
 * Copyright (c) 2005, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jface.commands;

import org.eclipse.core.commands.State;
import org.eclipse.jface.preference.IPreferenceStore;

/**
 * <p>
 * This is a state that can be made persistent. A state is persisted to a
 * preference store.
 * </p>
 * <p>
 * Clients may extend this class.
 * </p>
 *
 * @since 3.2
 */
public abstract class PersistentState extends State {

    /**
     * Whether this state should be persisted.
     */
    private boolean persisted;

    /**
     * Loads this state from the preference store, given the location at which
     * to look. This method must be symmetric with a call to
     * {@link #save(IPreferenceStore, String)}.
     *
     * @param store
     *            The store from which to read; must not be <code>null</code>.
     * @param preferenceKey
     *            The key at which the state is stored; must not be
     *            <code>null</code>.
     */
    public abstract void load(final IPreferenceStore store, final String preferenceKey);

    /**
     * Saves this state to the preference store, given the location at which to
     * write. This method must be symmetric with a call to
     * {@link #load(IPreferenceStore, String)}.
     *
     * @param store
     *            The store to which the state should be written; must not be
     *            <code>null</code>.
     * @param preferenceKey
     *            The key at which the state should be stored; must not be
     *            <code>null</code>.
     */
    public abstract void save(final IPreferenceStore store, final String preferenceKey);

    /**
     * Sets whether this state should be persisted.
     *
     * @param persisted
     *            Whether this state should be persisted.
     */
    public void setShouldPersist(final boolean persisted) {
        this.persisted = persisted;
    }

    /**
     * Whether this state should be persisted. Subclasses should check this
     * method before loading or saving.
     *
     * @return <code>true</code> if this state should be persisted;
     *         <code>false</code> otherwise.
     */
    public boolean shouldPersist() {
        return persisted;
    }
}