org.trancecode.xproc.step.CompareStepProcessor.java Source code

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Here is the source code for org.trancecode.xproc.step.CompareStepProcessor.java

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/*
 * Copyright (C) 2008 Herve Quiroz
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
 *
 * $Id$
 */
package org.trancecode.xproc.step;

import com.google.common.collect.Iterables;
import net.sf.saxon.s9api.Processor;
import net.sf.saxon.s9api.QName;
import net.sf.saxon.s9api.SaxonApiException;
import net.sf.saxon.s9api.XPathCompiler;
import net.sf.saxon.s9api.XPathSelector;
import net.sf.saxon.s9api.XdmAtomicValue;
import net.sf.saxon.s9api.XdmItem;
import net.sf.saxon.s9api.XdmNode;
import net.sf.saxon.s9api.XdmValue;
import org.trancecode.logging.Logger;
import org.trancecode.xproc.XProcExceptions;
import org.trancecode.xproc.port.XProcPorts;
import org.trancecode.xproc.variable.XProcOptions;

/**
 * {@code p:compare}.
 * 
 * @author Herve Quiroz
 * @see <a href="http://www.w3.org/TR/xproc/#c.compare">p:compare</a>
 */
@ExternalResources(read = false, write = false)
public final class CompareStepProcessor extends AbstractStepProcessor {
    private static final Logger LOG = Logger.getLogger(CompareStepProcessor.class);

    @Override
    public QName getStepType() {
        return XProcSteps.COMPARE;
    }

    @Override
    protected void execute(final StepInput input, final StepOutput output) {
        final XdmNode sourceNode = input.readNode(XProcPorts.SOURCE);
        final XdmNode alternateNode = input.readNode(XProcPorts.ALTERNATE);
        final boolean result = compare(input.getPipelineContext().getProcessor(), sourceNode, alternateNode);
        LOG.trace("  result = {}", result);
        final boolean failIfNotEqual = Boolean.parseBoolean(input.getOptionValue(XProcOptions.FAIL_IF_NOT_EQUAL));
        LOG.trace("  failIfNotEqual = {}", failIfNotEqual);
        if (!result && failIfNotEqual) {
            throw XProcExceptions.xc0019(input.getStep());
        }

        output.writeNodes(XProcPorts.RESULT, input.newResultElement(Boolean.toString(result)));
    }

    private static boolean compare(final Processor processor, final XdmNode sourceNode,
            final XdmNode alternateNode) {
        try {
            final XPathCompiler xpathCompiler = processor.newXPathCompiler();
            final QName node1 = new QName("node1");
            final QName node2 = new QName("node2");
            xpathCompiler.declareVariable(node1);
            xpathCompiler.declareVariable(node2);

            final XPathSelector selector = xpathCompiler.compile("deep-equal($node1, $node2)").load();
            selector.setVariable(node1, sourceNode);
            selector.setVariable(node2, alternateNode);

            final XdmValue result = selector.evaluate();
            final XdmItem resultNode = Iterables.getOnlyElement(result);
            assert resultNode.isAtomicValue() : resultNode;
            return ((XdmAtomicValue) resultNode).getBooleanValue();
        } catch (final SaxonApiException e) {
            throw new IllegalStateException(e);
        }
    }
}