com.eucalyptus.ws.protocol.RequestLoggingFilters.java Source code

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Here is the source code for com.eucalyptus.ws.protocol.RequestLoggingFilters.java

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/*************************************************************************
 * Copyright 2009-2014 Eucalyptus Systems, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3 of the License.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
 * CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
 * additional information or have any questions.
 ************************************************************************/
package com.eucalyptus.ws.protocol;

import java.util.Collection;
import java.util.concurrent.atomic.AtomicReference;
import com.google.common.base.Function;
import com.google.common.base.Functions;

/**
 *
 */
public class RequestLoggingFilters {

    private static final AtomicReference<RequestLoggingFilter> filter = new AtomicReference<>(
            forFunction(Functions.<Collection<String>>identity()));

    public static RequestLoggingFilter get() {
        return filter.get();
    }

    public static void register(final RequestLoggingFilter requestLoggingFilter) {
        RequestLoggingFilter current;
        RequestLoggingFilter chained;
        do {
            current = filter.get();
            chained = forFunction(Functions.compose(requestLoggingFilter, current));
        } while (!filter.compareAndSet(current, chained));
    }

    public static RequestLoggingFilter forFunction(
            Function<? super Collection<String>, Collection<String>> filter) {
        return new RequestLoggingFilterFunction(filter);
    }

    private static final class RequestLoggingFilterFunction implements RequestLoggingFilter {
        private final Function<? super Collection<String>, Collection<String>> filter;

        private RequestLoggingFilterFunction(
                final Function<? super Collection<String>, Collection<String>> filter) {
            this.filter = filter;
        }

        @Override
        public Collection<String> apply(final Collection<String> parametersOrBody) {
            return filter.apply(parametersOrBody);
        }
    }
}