All Downloads are FREE. Search and download functionalities are using the official Maven repository.

io.netty.handler.codec.CodecOutputList Maven / Gradle / Ivy

Go to download

This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

There is a newer version: 34.0.0.Final
Show newest version
/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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.netty.handler.codec;

import io.netty.util.concurrent.FastThreadLocal;
import io.netty.util.internal.MathUtil;

import java.util.AbstractList;
import java.util.RandomAccess;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

/**
 * Special {@link AbstractList} implementation which is used within our codec base classes.
 */
final class CodecOutputList extends AbstractList implements RandomAccess {

    private static final CodecOutputListRecycler NOOP_RECYCLER = new CodecOutputListRecycler() {
        @Override
        public void recycle(CodecOutputList object) {
            // drop on the floor and let the GC handle it.
        }
    };

    private static final FastThreadLocal CODEC_OUTPUT_LISTS_POOL =
            new FastThreadLocal() {
                @Override
                protected CodecOutputLists initialValue() throws Exception {
                    // 16 CodecOutputList per Thread are cached.
                    return new CodecOutputLists(16);
                }
            };

    private interface CodecOutputListRecycler {
        void recycle(CodecOutputList codecOutputList);
    }

    private static final class CodecOutputLists implements CodecOutputListRecycler {
        private final CodecOutputList[] elements;
        private final int mask;

        private int currentIdx;
        private int count;

        CodecOutputLists(int numElements) {
            elements = new CodecOutputList[MathUtil.safeFindNextPositivePowerOfTwo(numElements)];
            for (int i = 0; i < elements.length; ++i) {
                // Size of 16 should be good enough for the majority of all users as an initial capacity.
                elements[i] = new CodecOutputList(this, 16);
            }
            count = elements.length;
            currentIdx = elements.length;
            mask = elements.length - 1;
        }

        public CodecOutputList getOrCreate() {
            if (count == 0) {
                // Return a new CodecOutputList which will not be cached. We use a size of 4 to keep the overhead
                // low.
                return new CodecOutputList(NOOP_RECYCLER, 4);
            }
            --count;

            int idx = (currentIdx - 1) & mask;
            CodecOutputList list = elements[idx];
            currentIdx = idx;
            return list;
        }

        @Override
        public void recycle(CodecOutputList codecOutputList) {
            int idx = currentIdx;
            elements[idx] = codecOutputList;
            currentIdx = (idx + 1) & mask;
            ++count;
            assert count <= elements.length;
        }
    }

    static CodecOutputList newInstance() {
        return CODEC_OUTPUT_LISTS_POOL.get().getOrCreate();
    }

    private final CodecOutputListRecycler recycler;
    private int size;
    private Object[] array;
    private boolean insertSinceRecycled;

    private CodecOutputList(CodecOutputListRecycler recycler, int size) {
        this.recycler = recycler;
        array = new Object[size];
    }

    @Override
    public Object get(int index) {
        checkIndex(index);
        return array[index];
    }

    @Override
    public int size() {
        return size;
    }

    @Override
    public boolean add(Object element) {
        checkNotNull(element, "element");
        try {
            insert(size, element);
        } catch (IndexOutOfBoundsException ignore) {
            // This should happen very infrequently so we just catch the exception and try again.
            expandArray();
            insert(size, element);
        }
        ++ size;
        return true;
    }

    @Override
    public Object set(int index, Object element) {
        checkNotNull(element, "element");
        checkIndex(index);

        Object old = array[index];
        insert(index, element);
        return old;
    }

    @Override
    public void add(int index, Object element) {
        checkNotNull(element, "element");
        checkIndex(index);

        if (size == array.length) {
            expandArray();
        }

        if (index != size) {
            System.arraycopy(array, index, array, index + 1, size - index);
        }

        insert(index, element);
        ++ size;
    }

    @Override
    public Object remove(int index) {
        checkIndex(index);
        Object old = array[index];

        int len = size - index - 1;
        if (len > 0) {
            System.arraycopy(array, index + 1, array, index, len);
        }
        array[-- size] = null;

        return old;
    }

    @Override
    public void clear() {
        // We only set the size to 0 and not null out the array. Null out the array will explicit requested by
        // calling recycle()
        size = 0;
    }

    /**
     * Returns {@code true} if any elements where added or set. This will be reset once {@link #recycle()} was called.
     */
    boolean insertSinceRecycled() {
        return insertSinceRecycled;
    }

    /**
     * Recycle the array which will clear it and null out all entries in the internal storage.
     */
    void recycle() {
        for (int i = 0 ; i < size; i ++) {
            array[i] = null;
        }
        size = 0;
        insertSinceRecycled = false;

        recycler.recycle(this);
    }

    /**
     * Returns the element on the given index. This operation will not do any range-checks and so is considered unsafe.
     */
    Object getUnsafe(int index) {
        return array[index];
    }

    private void checkIndex(int index) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("expected: index < ("
                    + size + "),but actual is (" + size + ")");
        }
    }

    private void insert(int index, Object element) {
        array[index] = element;
        insertSinceRecycled = true;
    }

    private void expandArray() {
        // double capacity
        int newCapacity = array.length << 1;

        if (newCapacity < 0) {
            throw new OutOfMemoryError();
        }

        Object[] newArray = new Object[newCapacity];
        System.arraycopy(array, 0, newArray, 0, array.length);

        array = newArray;
    }
}
    

    

    

            

    

            



    
    






    
© 2015 - 2024 Weber Informatics LLC | Privacy Policy