Styles.java

/*
 * Copyright 2013-2015 Skynav, Inc. 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 following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY SKYNAV, INC. AND ITS 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 SKYNAV, INC. OR ITS 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,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package com.skynav.ttv.verifier.util;

import java.util.List;
import java.util.Set;

import javax.xml.namespace.QName;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

import com.skynav.ttv.util.Location;
import com.skynav.ttv.util.Reporter;
import com.skynav.ttv.verifier.VerifierContext;
import com.skynav.xml.helpers.Nodes;

public class Styles {

    public static boolean isStyleReference(Node node, Object value, Location location, VerifierContext context, Class<?> targetClass, List<List<QName>> ancestors) {
        if (!targetClass.isInstance(value))
            return false;
        if (!isSignificantStyle(node, value, ancestors))
            return false;
        if (hasStyleChainLoop(node))
            return false;
        return true;
    }

    public static void badStyleReference(Node node, Object value, Location location, VerifierContext context, QName referencingAttribute,
        QName targetName, Class<?> targetClass, List<List<QName>> ancestors) {
        if (!targetClass.isInstance(value))
            IdReferences.badReference(value, location, context, referencingAttribute, targetName);
        else {
            if (!isSignificantStyle(node, value, ancestors))
                badStyleSignificance(node, value, location, context, referencingAttribute, targetName, ancestors);
            if (hasStyleChainLoop(node))
                badStyleChainLoop(node, value, location, context);
        }
    }

    private static boolean isSignificantStyle(Node node, Object value, List<List<QName>> ancestors) {
        return Nodes.hasAncestors(node, ancestors);
    }

    private static boolean hasStyleChainLoop(Node node) {
        assert node instanceof Element;
        return hasStyleChainLoop((Element) node, new java.util.HashSet<String>());
    }

    private static boolean hasStyleChainLoop(Element elt, Set<String> encounteredStyles) {
        Document document = elt.getOwnerDocument();
        String style = elt.getAttributeNS(null, "style");
        if (style.length() != 0) {
            String[] styleRefs = style.split("\\s+");
            for (String styleRef : styleRefs) {
                assert document.getElementById(styleRef) != null;
                if (encounteredStyles.contains(styleRef))
                    return true;
                else
                    encounteredStyles.add(styleRef);
                if (hasStyleChainLoop(document.getElementById(styleRef), encounteredStyles))
                    return true;
            }
        }
        return false;
    }

    private static void badStyleSignificance(Node node, Object value, Location location, VerifierContext context, QName referencingAttribute,
        QName targetName, List<List<QName>> ancestors) {
        Reporter reporter = context.getReporter();
        reporter.logInfo(reporter.message(location.getLocator(), "*KEY*",
            "Bad IDREF ''{0}'', must reference significant ''{1}'' which ancestors are one of {2}.",
            IdReferences.getId(value), targetName, ancestors));
    }

    private static void badStyleChainLoop(Node node, Object value, Location location, VerifierContext context) {
        Reporter reporter = context.getReporter();
        reporter.logInfo(reporter.message(location.getLocator(), "*KEY*", "Loop in style chain from IDREF ''{0}''.", IdReferences.getId(value)));
    }

}