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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 that returns true, if a source expression returns null,
* else false.
* Created: 08.10.2010 23:04:01
* @since 0.5.4
* @author Volker Bergmann
*/
public class IsNullExpression extends UnaryExpression {
public IsNullExpression(Expression term) {
super("", term);
}
public Boolean evaluate(Context context) {
return term.evaluate(context) == null;
}
@Override
public String toString() {
return "(" + term + "IS NULL)";
}
}