/**
* Modification from original by Gist Labs, LLC (http://gistlabs.com)
*
* Copyright (c) 2009-2012, Christer Sandberg
*
* Licensed 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.
*
*/
package com.gistlabs.mechanize.util.css_query;
import java.util.Collection;
import java.util.LinkedHashSet;
import se.fishtank.css.selectors.dom.internal.NodeTraversalChecker;
import se.fishtank.css.selectors.specifier.PseudoNthSpecifier;
import se.fishtank.css.util.Assert;
import com.gistlabs.mechanize.util.css_query.NodeHelper.Index;
/**
* A {@link NodeTraversalChecker} that check if a node matches
* the {@code nth-*} {@linkplain PseudoNthSpecifier pseudo-class specifier} set.
*
* @author Christer Sandberg
*/
public class PseudoNthSpecifierChecker<Node> extends AbstractChecker<Node> {
/** The {@code nth-*} pseudo-class specifier to check against. */
private final PseudoNthSpecifier specifier;
/**
* Create a new instance.
*
* @param specifier The {@code nth-*} pseudo-class specifier to check against.
*/
public PseudoNthSpecifierChecker(final NodeHelper<Node> helper, final PseudoNthSpecifier specifier) {
super(helper);
Assert.notNull(specifier, "specifier is null!");
this.specifier = specifier;
}
/**
* {@inheritDoc}
*/
@Override
public Collection<Node> check(final Collection<Node> nodes) {
Assert.notNull(nodes, "nodes is null!");
this.nodes = nodes;
result = new LinkedHashSet<Node>();
String value = specifier.getValue();
if ("nth-child".equals(value))
addNthChild(false);
else if ("nth-last-child".equals(value))
addNthLastChild(false);
else if ("nth-of-type".equals(value))
addNthChild(true);
else if ("nth-last-of-type".equals(value))
addNthLastChild(false);
else
throw new RuntimeException("Unknown pseudo nth class: " + value);
return result;
}
/**
* Add the {@code :nth-child} elements.
*
* @see <a href="http://www.w3.org/TR/css3-selectors/#nth-child-pseudo"><code>:nth-child</code> pseudo-class</a>
*/
private void addNthChild(final boolean byType) {
for (Node node : nodes) {
Index index = helper.getIndexInParent(node, byType);
if (specifier.isMatch(index.index+1))
result.add(node);
}
}
/**
* Add {@code :nth-last-child} elements.
*
* @see <a href="http://www.w3.org/TR/css3-selectors/#nth-last-child-pseudo"><code>:nth-last-child</code> pseudo-class</a>
*/
private void addNthLastChild(final boolean byType) {
for (Node node : nodes) {
Index index = helper.getIndexInParent(node, byType);
if (specifier.isMatch(index.size - index.index+1))
result.add(node);
}
}
}