org.trancecode.xml.catalog.Catalogs.java Source code

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Here is the source code for org.trancecode.xml.catalog.Catalogs.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.xml.catalog;

import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

import java.net.URI;

import org.trancecode.api.Nullable;
import org.trancecode.collection.TcIterables;
import org.trancecode.function.TcFunctions;
import org.trancecode.io.UriFunctions;
import org.trancecode.io.Uris;

/**
 * Utility methods related to {@link Catalog}.
 * 
 * @author Herve Quiroz
 */
public final class Catalogs {
    private Catalogs() {
        // No instantiation
    }

    public static Function<CatalogQuery, URI> defaultCatalog() {
        return DefaultCatalog.INSTANCE;
    }

    private static final class DefaultCatalog implements Function<CatalogQuery, URI> {
        public static DefaultCatalog INSTANCE = new DefaultCatalog();

        @Override
        public URI apply(final CatalogQuery query) {
            if (query.systemId() != null) {
                return Uris.createUri(query.systemId());
            }

            assert query.uri() != null;
            return query.uri();
        }
    }

    public static Function<CatalogQuery, URI> routingCatalog(final Function<CatalogQuery, URI>... catalogEntries) {
        return routingCatalog(ImmutableList.copyOf(catalogEntries));
    }

    public static Function<CatalogQuery, URI> routingCatalog(
            final Iterable<Function<CatalogQuery, URI>> catalogEntries) {
        return new RoutingCatalog(catalogEntries);
    }

    private static class RoutingCatalog implements Function<CatalogQuery, URI> {
        private final Iterable<Function<CatalogQuery, URI>> catalogEntries;

        public RoutingCatalog(final Iterable<Function<CatalogQuery, URI>> catalogEntries) {
            this.catalogEntries = Preconditions.checkNotNull(catalogEntries);
        }

        @Override
        public URI apply(final CatalogQuery query) {
            return Iterables.find(TcIterables.applyFunctions(catalogEntries, query), Predicates.notNull());
        }
    }

    public static Function<CatalogQuery, URI> setBaseUri(final URI baseUri,
            @Nullable final Function<CatalogQuery, URI> catalog) {
        if (baseUri == null) {
            return catalog;
        }

        return Functions.compose(UriFunctions.resolveUri(baseUri), catalog);
    }

    public static Function<CatalogQuery, URI> addCache(final Function<CatalogQuery, URI> catalog) {
        return TcFunctions.memoize(catalog);
    }

    public static Function<CatalogQuery, URI> rewriteSystem(final String systemIdStartString,
            final String rewritePrefix) {
        return new RewriteSystem(systemIdStartString, rewritePrefix);
    }

    private static final class RewriteSystem implements Function<CatalogQuery, URI> {
        private final String systemIdStartString;
        private final String rewritePrefix;

        public RewriteSystem(final String systemIdStartString, final String rewritePrefix) {
            this.systemIdStartString = systemIdStartString;
            this.rewritePrefix = rewritePrefix;
        }

        @Override
        public URI apply(final CatalogQuery query) {
            if (query.systemId() != null && query.systemId().startsWith(systemIdStartString)) {
                final String suffix = query.systemId().substring(systemIdStartString.length());
                return Uris.createUri(rewritePrefix + suffix);
            }

            return null;
        }
    }

    public static Function<CatalogQuery, URI> rewriteUri(final String uriStartString, final String rewritePrefix) {
        return new RewriteUri(uriStartString, rewritePrefix);
    }

    private static final class RewriteUri implements Function<CatalogQuery, URI> {
        private final String uriStartString;
        private final String rewritePrefix;

        public RewriteUri(final String uriStartString, final String rewritePrefix) {
            this.uriStartString = uriStartString;
            this.rewritePrefix = rewritePrefix;
        }

        @Override
        public URI apply(final CatalogQuery query) {
            final String uriString = query.uriAsString();
            if (uriString != null && uriString.startsWith(uriStartString)) {
                final String suffix = uriString.substring(uriStartString.length());
                return Uris.createUri(rewritePrefix + suffix);
            }

            return null;
        }
    }

    public static Function<CatalogQuery, URI> group(final URI baseUri,
            final Iterable<Function<CatalogQuery, URI>> catalogs) {
        return setBaseUri(baseUri, routingCatalog(catalogs));
    }
}