com.blacklocus.qs.aws.s3.AmazonS3QueueItemProvider.java Source code

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Here is the source code for com.blacklocus.qs.aws.s3.AmazonS3QueueItemProvider.java

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/**
 * Copyright 2013 BlackLocus
 *
 * 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.blacklocus.qs.aws.s3;

import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import com.blacklocus.qs.QueueItemProvider;

import java.util.Collection;
import java.util.Iterator;

/**
 * @author Jason Dunkelberger (dirkraft)
 */
public class AmazonS3QueueItemProvider implements QueueItemProvider<S3ObjectSummary> {

    private final String bucket;
    private final String prefix;
    private final String delimiter;
    private final AmazonS3 s3;

    private ObjectListing page;

    public AmazonS3QueueItemProvider(String bucket, AmazonS3 s3) {
        this(bucket, null, null, s3);
    }

    public AmazonS3QueueItemProvider(String bucket, String prefix, String delimiter, AmazonS3 s3) {
        this.bucket = bucket;
        this.prefix = prefix;
        this.delimiter = delimiter;
        this.s3 = s3;
    }

    @Override
    public Iterator<Collection<S3ObjectSummary>> iterator() {
        return this;
    }

    @Override
    public boolean hasNext() {
        return page == null || page.isTruncated();
    }

    @Override
    public Collection<S3ObjectSummary> next() {
        if (page == null) {
            page = s3.listObjects(new ListObjectsRequest(bucket, prefix, null, delimiter, 1000));
        } else {
            assert page.isTruncated();
            page = s3.listNextBatchOfObjects(page);
        }
        return page.getObjectSummaries();
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException();
    }
}