io.druid.data.input.impl.prefetch.OpenedObject.java Source code

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Here is the source code for io.druid.data.input.impl.prefetch.OpenedObject.java

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/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.data.input.impl.prefetch;

import org.apache.commons.io.FileUtils;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;

/**
 * A class containing meta information about an opened object.  This class is used to put related objects together.  It
 * contains an original object, an objectStream from the object, and a resourceCloser which knows how to release
 * associated resources on closing.
 *
 * {@link PrefetchableTextFilesFirehoseFactory.ResourceCloseableLineIterator} consumes the objectStream and closes
 * it with the resourceCloser.
 */
class OpenedObject<T> {
    // Original object
    private final T object;
    // Input stream from the object
    private final InputStream objectStream;
    // Closer which is called when the file is not needed anymore. Usually this deletes the file except for cached files.
    private final Closeable resourceCloser;

    OpenedObject(FetchedFile<T> fetchedFile) throws IOException {
        this(fetchedFile.getObject(), FileUtils.openInputStream(fetchedFile.getFile()),
                fetchedFile.getResourceCloser());
    }

    OpenedObject(T object, InputStream objectStream, Closeable resourceCloser) {
        this.object = object;
        this.objectStream = objectStream;
        this.resourceCloser = resourceCloser;
    }

    T getObject() {
        return object;
    }

    InputStream getObjectStream() {
        return objectStream;
    }

    Closeable getResourceCloser() {
        return resourceCloser;
    }
}