MediaReduceStrategy.java

/*
 * Copyright 2010 Ronnie Kolehmainen
 *
 * 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.github.cssxfire.filter;

import com.github.cssxfire.StringUtils;
import com.github.cssxfire.tree.CssDeclarationPath;
import com.intellij.openapi.diagnostic.Logger;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * <p>Reduces the candidates down to the elements (selectors) which matches the media query.
 * If the collection is empty this reducer does nothing.
 * <p><p>
 * Created by IntelliJ IDEA.
 * User: Ronnie
 */
public class MediaReduceStrategy implements ReduceStrategy<CssDeclarationPath> {
    private static final Logger LOG = Logger.getInstance(MediaReduceStrategy.class.getName());

    @NotNull
    private String media;

    public MediaReduceStrategy(@NotNull String media) {
        this.media = media;
    }

    public void reduce(@NotNull Collection<CssDeclarationPath> candidates) {
        if (LOG.isDebugEnabled()) {
            LOG.debug("Reducing " + candidates.size() + " candidates for media: " + media);
        }
        if (candidates.isEmpty()) {
            // nothing to do here
            return;
        }

        List<CssDeclarationPath> matches = new ArrayList<CssDeclarationPath>();
        for (CssDeclarationPath candidate : candidates) {
            String candidateMedia = candidate.getSelectorNode().getMedia();
            if (StringUtils.equalsNormalizeWhitespace(media, candidateMedia)) {
                // media query matches candidate selector
                matches.add(candidate);
            }
        }

        candidates.retainAll(matches);
    }
}