org.apache.apex.malhar.lib.state.managed.TimeBucketAssigner.java Source code

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Here is the source code for org.apache.apex.malhar.lib.state.managed.TimeBucketAssigner.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.apex.malhar.lib.state.managed;

import javax.validation.constraints.NotNull;

import org.joda.time.Duration;

import org.apache.apex.malhar.lib.state.spillable.WindowListener;

import com.esotericsoftware.kryo.serializers.FieldSerializer;
import com.esotericsoftware.kryo.serializers.JavaSerializer;
import com.google.common.base.Preconditions;

import com.datatorrent.api.Context;

/**
 * Abstract class to extract a bucket for a given time
 *
 * @since 3.7.0
 */
public abstract class TimeBucketAssigner implements ManagedStateComponent, WindowListener {
    private transient PurgeListener purgeListener;

    private boolean initialized;

    @FieldSerializer.Bind(JavaSerializer.class)
    private Duration bucketSpan;

    @Override
    public void setup(@NotNull ManagedStateContext managedStateContext) {
        Context.OperatorContext context = managedStateContext.getOperatorContext();
        if (!initialized && bucketSpan == null) {
            setBucketSpan(Duration.millis(context.getValue(Context.OperatorContext.APPLICATION_WINDOW_COUNT)
                    * context.getValue(Context.DAGContext.STREAMING_WINDOW_SIZE_MILLIS)));
        }
    }

    /**
     * Get the time bucket for any given time
     * @param time
     * @return
     */
    public abstract long getTimeBucket(long time);

    /**
     * Get possible number of buckets
     * @return
     */
    public abstract long getNumBuckets();

    /**
     * @return time-bucket span
     */
    public Duration getBucketSpan() {
        return bucketSpan;
    }

    /**
     * Sets the length of a time bucket.
     * @param bucketSpan length of time bucket
     */
    public void setBucketSpan(Duration bucketSpan) {
        this.bucketSpan = bucketSpan;
    }

    public boolean isInitialized() {
        return initialized;
    }

    public void setInitialized(boolean initialized) {
        this.initialized = initialized;
    }

    /**
     * Sets the purge listener.
     * @param purgeListener purge listener
     */
    public void setPurgeListener(@NotNull PurgeListener purgeListener) {
        this.purgeListener = Preconditions.checkNotNull(purgeListener, "purge listener");
    }

    public PurgeListener getPurgeListener() {
        return purgeListener;
    }

    /**
     * The listener is informed when the time slides and time buckets which are older than the smallest time bucket
     * (changed because of time slide) can be purged.
     */
    public interface PurgeListener {
        void purgeTimeBucketsLessThanEqualTo(long timeBucket);
    }
}