net.hillsdon.reviki.wiki.graph.WikiGraphImpl.java Source code

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Here is the source code for net.hillsdon.reviki.wiki.graph.WikiGraphImpl.java

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/**
 * Copyright 2008 Matthew Hillsdon
 *
 * 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 net.hillsdon.reviki.wiki.graph;

import java.io.IOException;
import java.util.LinkedHashSet;
import java.util.Set;

import net.hillsdon.reviki.search.SearchEngine;
import net.hillsdon.reviki.vc.PageReference;
import net.hillsdon.reviki.vc.PageStore;
import net.hillsdon.reviki.vc.PageStoreException;
import net.hillsdon.reviki.vc.impl.CachingPageStore;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;

public class WikiGraphImpl implements WikiGraph {

    private final SearchEngine _searchEngine;
    private final PageStore _pageStore;

    public WikiGraphImpl(final CachingPageStore pageStore, final SearchEngine searchEngine) {
        _pageStore = pageStore;
        _searchEngine = searchEngine;
    }

    public Set<String> incomingLinks(final String page) throws IOException, PageStoreException {
        Set<String> incoming = _searchEngine.incomingLinks(page);
        return onlyExistingPages(incoming);
    }

    public Set<String> outgoingLinks(final String page) throws IOException, PageStoreException {
        Set<String> outgoing = _searchEngine.outgoingLinks(page);
        return onlyExistingPages(outgoing);
    }

    public Set<String> isolatedPages() throws IOException, PageStoreException {
        final Set<String> isolated = new LinkedHashSet<String>();
        for (PageReference page : _pageStore.list()) {
            final String name = page.getPath();
            if (incomingLinks(name).isEmpty()) {
                isolated.add(name);
            }
        }
        return isolated;
    }

    /**
     * The search index will only update its record of outgoing links
     * when pages are edited so we compensate by filtering.
     *
     * @param pages Incoming.
     * @throws PageStoreException If we can't get the page list.
     */
    private Set<String> onlyExistingPages(final Set<String> pages) throws PageStoreException {
        Set<String> allExisting = ImmutableSet
                .copyOf(Iterables.transform(_pageStore.list(), PageReference.TO_NAME));
        return Sets.intersection(pages, allExisting);
    }

}