de.intarsys.tools.expression.PushScopeStringEvaluator Maven / Gradle / Ivy

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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.Args;
import de.intarsys.tools.functor.IArgs;

/**
 * 
 */
public class PushScopeStringEvaluator implements IStringEvaluator {

	static public class Resolver implements IStringEvaluator {
		@Override
		public Object evaluate(String expression, IArgs args)
				throws EvaluationException {
			ScopedResolver resolver = (ScopedResolver) args
					.get(ARG_DYNAMIC_SCOPE);
			if (resolver == null) {
				throw new EvaluationException(
						"can't evaluate '" + expression + "'"); //$NON-NLS-1$ //$NON-NLS-2$
			}
			return resolver.evaluate(expression, args);
		}
	}

	protected static final String ARG_DYNAMIC_SCOPE = "_dynamic_scope";

	final private IStringEvaluator wrappedEvaluator;

	final private IStringEvaluator scope;

	public PushScopeStringEvaluator(IStringEvaluator wrappedEvaluator,
			IStringEvaluator scope) {
		super();
		this.wrappedEvaluator = wrappedEvaluator;
		this.scope = scope;
	}

	public Object evaluate(String expression, IArgs args)
			throws EvaluationException {
		if (args == null) {
			args = Args.create();
		}
		ScopedResolver resolver = (ScopedResolver) args.get(ARG_DYNAMIC_SCOPE);
		if (resolver == null) {
			resolver = new ScopedResolver();
			args.put(ARG_DYNAMIC_SCOPE, resolver);
		}
		resolver.addResolver(scope);
		return wrappedEvaluator.evaluate(expression, args);
	}
}