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Utility classes for Jetty

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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//

package org.eclipse.jetty.util.compression;

import java.util.zip.Deflater;

import org.eclipse.jetty.util.component.Container;
import org.eclipse.jetty.util.thread.ThreadPool;

public class DeflaterPool extends CompressionPool
{
    private final int compressionLevel;
    private final boolean nowrap;

    /**
     * Create a Pool of {@link Deflater} instances.
     * 
     * If given a capacity equal to zero the Deflaters will not be pooled
     * and will be created on acquire and ended on release.
     * If given a negative capacity equal to zero there will be no size restrictions on the DeflaterPool
     *
     * @param capacity maximum number of Deflaters which can be contained in the pool
     * @param compressionLevel the default compression level for new Deflater objects
     * @param nowrap if true then use GZIP compatible compression for all new Deflater objects
     */
    public DeflaterPool(int capacity, int compressionLevel, boolean nowrap)
    {
        super(capacity);
        this.compressionLevel = compressionLevel;
        this.nowrap = nowrap;
    }

    @Override
    protected Deflater newPooled()
    {
        return new Deflater(compressionLevel, nowrap);
    }

    @Override
    protected void end(Deflater deflater)
    {
        deflater.end();
    }

    @Override
    protected void reset(Deflater deflater)
    {
        deflater.reset();
    }

    public static DeflaterPool ensurePool(Container container)
    {
        DeflaterPool pool = container.getBean(DeflaterPool.class);
        if (pool != null)
            return pool;

        int capacity = CompressionPool.DEFAULT_CAPACITY;
        ThreadPool.SizedThreadPool threadPool = container.getBean(ThreadPool.SizedThreadPool.class);
        if (threadPool != null)
            capacity = threadPool.getMaxThreads();

        pool = new DeflaterPool(capacity, Deflater.DEFAULT_COMPRESSION, true);
        container.addBean(pool, true);
        return pool;
    }
}