org.electrologic.convergence.server.cache.CacheEntry.java Source code

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Here is the source code for org.electrologic.convergence.server.cache.CacheEntry.java

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/*****************************************************************************
 * Copyright 2013 Tobias Wich
 *
 * 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 org.electrologic.convergence.server.cache;

import java.text.DateFormat;
import java.util.Date;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import javax.annotation.concurrent.ThreadSafe;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Base class for a cache entry representing one distinct timeframe a certificate on a remote server remained constant.
 * Implementations of this interface must be immutable, so that results returned by the {@link Cache} implementation can
 * not change in the time between the cache query and the response delivery.
 *
 * @author Tobias Wich <tobias.wich@ecsec.de>
 */
@Immutable
@ThreadSafe
public abstract class CacheEntry {

    /**
     * Gets the time in UNIX time format since when the certificate represented by this instance has been seen by this
     * server.
     *
     * @return Time since when the certificate has been seen.
     */
    @Nonnegative
    public abstract long getStart();

    /**
     * Gets the time in UNIX time format until when the certificate represented by this instance has been seen by this
     * server.
     * This value also marks the last query made to the remote server. This means the time value does not indicate that
     * the certificate has changed on the server. This information is available implicitly through the list of cache
     * entries.
     *
     * @return Time until when the certificate has been seen.
     */
    @Nonnegative
    public abstract long getFinish();

    /**
     * Gets the fingerprint identifying the certificate represented by this entry.
     *
     * @return Fingerprint identifying the certificate.
     */
    @Nonnull
    public abstract String getFingerprint();

    /**
     * Converts the entry to a JSON object suitable for inclusion in the fingerprint list returned in the response.
     *
     * @return JSON object with the values represented by this instance.
     * @throws JSONException Thrown in case the entry contains invalid elements.
     */
    @Nonnull
    public JSONObject toJSON() throws JSONException {
        JSONObject obj = new JSONObject();
        JSONObject timestamp = new JSONObject();
        timestamp.put("start", getStart());
        timestamp.put("finish", getFinish());
        obj.put("timestamp", timestamp);
        obj.put("fingerprint", getFingerprint());
        return obj;
    }

    @Override
    public String toString() {
        StringBuilder b = new StringBuilder(50);
        DateFormat dateFormatter = DateFormat.getInstance();
        Date startDate = new Date(getStart());
        Date finishDate = new Date(getFinish());
        b.append(dateFormatter.format(startDate));
        b.append(" -> ");
        b.append(dateFormatter.format(finishDate));
        b.append(" :: [");
        b.append(getFingerprint());
        b.append("]");
        return b.toString();
    }

}