org.xmlpull.infoset.xpath.jaxen.function.BooleanFunction Maven / Gradle / Ivy
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/*
* $Header: /l/extreme/cvs/codes/xpp5/xis5/infoset_xpath_jaxen/org/xmlpull/infoset/xpath/jaxen/function/BooleanFunction.java,v 1.1 2005/05/16 23:59:24 aslom Exp $
* $Revision: 1.1 $
* $Date: 2005/05/16 23:59:24 $
*
* ====================================================================
*
* Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions, and the disclaimer that follows
* these conditions in the documentation and/or other materials
* provided with the distribution.
*
* 3. The name "Jaxen" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [email protected].
*
* 4. Products derived from this software may not be called "Jaxen", nor
* may "Jaxen" appear in their name, without prior written permission
* from the Jaxen Project Management ([email protected]).
*
* In addition, we request (but do not require) that you include in the
* end-user documentation provided with the redistribution and/or in the
* software itself an acknowledgement equivalent to the following:
* "This product includes software developed by the
* Jaxen Project (http://www.jaxen.org/)."
* Alternatively, the acknowledgment may be graphical using the logos
* available at http://www.jaxen.org/
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 Jaxen AUTHORS OR THE PROJECT
* 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.
*
* ====================================================================
* This software consists of voluntary contributions made by many
* individuals on behalf of the Jaxen Project and was originally
* created by bob mcwhirter and
* James Strachan . For more information on the
* Jaxen Project, please see 4.3 boolean boolean(object)
*
* @author bob mcwhirter (bob @ werken.com)
*/
public class BooleanFunction implements Function
{
public Object call(Context context,
List args) throws FunctionCallException
{
if ( args.size() == 1 )
{
return evaluate( args.get(0), context.getNavigator() );
}
throw new FunctionCallException("boolean() requires one argument");
}
public static Boolean evaluate(Object obj, Navigator nav)
{
if ( obj instanceof List )
{
List list = (List) obj;
// if it's an empty list, then we have a null node-set -> false
if (list.size() == 0)
{
return Boolean.FALSE;
}
// otherwise, unwrap the list and check the primitive
obj = list.get(0);
}
// now check for primitive types
// otherwise a non-empty nodeset is true
// if it's a Boolean, let it decide
if ( obj instanceof Boolean )
{
return (Boolean) obj;
}
// if it's a Number, != 0 -> true
else if ( obj instanceof Number )
{
double d = ((Number) obj).doubleValue();
if ( d == 0 || d == Double.NaN )
{
return Boolean.FALSE;
}
return Boolean.TRUE;
}
// if it's a String, "" -> false
else if ( obj instanceof String )
{
return ( ((String)obj).length() > 0
? Boolean.TRUE
: Boolean.FALSE );
}
else
{
// assume its a node so that this nodeset is non-empty
// and so its true
return ( obj != null ) ? Boolean.TRUE : Boolean.FALSE;
}
/*
This is the old way to test nodes
- don't think this is correct and its certainly less efficient
else {
// convert to String if it's a special object type
if ( nav.isElement( obj ) )
{
obj = nav.getElementStringValue( obj );
}
else if ( nav.isAttribute( obj ) )
{
obj = nav.getAttributeStringValue( obj );
}
else if ( nav.isText( obj ) )
{
obj = nav.getTextStringValue( obj );
}
else if ( obj instanceof String )
{
return ( ((String)obj).length() > 0
? Boolean.TRUE
: Boolean.FALSE );
}
return Boolean.FALSE;
}
*/
}
}