/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* $Id: TrueCheck.java 426576 2006-07-28 15:44:37Z jeremias $ */
package org.apache.fop.layoutengine;
import javax.xml.transform.TransformerException;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.PrefixResolverDefault;
import org.apache.xpath.XPathAPI;
import org.apache.xpath.objects.XBoolean;
import org.apache.xpath.objects.XObject;
import org.w3c.dom.Node;
/**
* Simple check that requires an XPath expression to evaluate to true.
*/
public class TrueCheck implements LayoutEngineCheck {
private String xpath;
private String failureMessage;
private PrefixResolver prefixResolver;
/**
* Creates a new instance
* @param xpath XPath statement that needs to be evaluated
*/
public TrueCheck(String xpath) {
this.xpath = xpath;
}
/**
* Creates a new instance from a DOM node.
* @param node DOM node that defines this check
*/
public TrueCheck(Node node) {
this.xpath = node.getAttributes().getNamedItem("xpath").getNodeValue();
Node nd = node.getAttributes().getNamedItem("fail-msg");
if (nd != null) {
this.failureMessage = nd.getNodeValue();
}
this.prefixResolver = new PrefixResolverDefault(node);
}
/** @see org.apache.fop.layoutengine.LayoutEngineCheck */
public void check(LayoutResult result) {
XObject res;
try {
res = XPathAPI.eval(result.getAreaTree(), xpath, prefixResolver);
} catch (TransformerException e) {
throw new RuntimeException("XPath evaluation failed: " + e.getMessage());
}
if (!XBoolean.S_TRUE.equals(res)) {
if (failureMessage != null) {
throw new RuntimeException(failureMessage);
} else {
throw new RuntimeException(
"Expected XPath expression to evaluate to 'true', but got '"
+ res + "' (" + this + ")");
}
}
}
/** @see java.lang.Object#toString() */
public String toString() {
return "XPath: " + xpath;
}
}