com.allogy.couch.filter.ExcludeRevisionExistsDocumentFilter.java Source code

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Here is the source code for com.allogy.couch.filter.ExcludeRevisionExistsDocumentFilter.java

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/*
 * Copyright (c) 2012 David Venable.
 *
 * 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.allogy.couch.filter;

import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import org.ektorp.CouchDbConnector;
import org.ektorp.Revision;

import javax.annotation.Nullable;
import java.util.List;

/**
 * A DocumentFilter which excludes documents which exist, or have existed, on
 * the destination Couch database.
 * Thus, if the document does not exist the filter will always include it. If
 * the document exists, but does not have the import revision in its history the
 * filter will include it.
 */
public class ExcludeRevisionExistsDocumentFilter implements DocumentFilter {
    public boolean includeDocument(CouchDbConnector couchDbConnector, String documentId, final String revision) {
        if (!couchDbConnector.contains(documentId))
            return true;

        List<Revision> revisions = couchDbConnector.getRevisions(documentId);

        return !Iterables.any(revisions, new Predicate<Revision>() {
            public boolean apply(@Nullable Revision existingRevision) {
                if (existingRevision == null)
                    return false;
                return revision.equals(existingRevision.getRev());
            }
        });
    }
}