org.databene.script.expression.FallbackExpression Maven / Gradle / Ivy
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'DatabeneScript' is an open source software library for resolving Java-like script expressions, written by Volker Bergmann.
/*
* (c) Copyright 2010-2011 by Volker Bergmann. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted under the terms of the
* GNU General Public License (GPL).
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
* REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
* HEREBY EXCLUDED. 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 org.databene.script.expression;
import org.databene.commons.Context;
import org.databene.script.Expression;
/**
* Expression which evaluates a list of expressions and returns the first result which is not null.
* Created: 16.06.2010 07:39:20
* @since 0.5.3
* @author Volker Bergmann
*/
public class FallbackExpression extends CompositeExpression {
public FallbackExpression(Expression... terms) {
super(terms);
}
public E evaluate(Context context) {
for (Expression term : terms) {
E result = (term != null ? term.evaluate(context) : null);
if (result != null)
return result;
}
return null;
}
}