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The basic runtime tools and interfaces for intarsys components.

There is a newer version: 4.11

/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of intarsys 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 de.intarsys.tools.expression;

import de.intarsys.tools.functor.IArgs;
import de.intarsys.tools.preferences.IPreferences;

/**
 * An {@link IStringEvaluator} accessing preferences values.
 * 
 */
public class PreferencesResolver implements IStringEvaluator {

	private IPreferences preferences;

	public PreferencesResolver(IPreferences preferences) {
		super();
		this.preferences = preferences;
	}

	public Object evaluate(String expression, IArgs pArgs)
			throws EvaluationException {
		IPreferences current = preferences;
		String[] names = expression.split("\\.", 0); //$NON-NLS-1$
		for (int i = 0; i < names.length; i++) {
			String name = names[i];
			if (i == names.length - 1) {
				return current.get(name);
			} else {
				current = current.node(name);
			}
			if (current == null) {
				return null;
			}
		}
		return null;
	}
}