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Data Mapper package is a high-performance data binding package built on Jackson JSON processor

There is a newer version: 1.9.13

package org.codehaus.jackson.map.ser;

import java.util.*;

import org.codehaus.jackson.map.JsonSerializer;

/**
 * Simple cache object that allows for doing 2-level lookups: first level is
 * by "local" read-only lookup Map (used without locking)
 * and second backup level is by a shared modifiable HashMap.
 * The idea is that after a while, most serializers are found from the
 * local Map (to optimize performance, reduce lock contention),
 * but that during buildup we can use a shared map to reduce both
 * number of distinct read-only maps constructed, and number of
 * serializers constructed.
 */
public final class SerializerCache
{
    /**
     * Shared, modifiable map; all access needs to be through synchronized blocks.
     */
    private HashMap> _sharedMap = new HashMap>(64);

    /**
     * Most recent read-only instance, created from _sharedMap, if any.
     */
    private ReadOnlyClassToSerializerMap _readOnlyMap = null;

    public SerializerCache() {
    }

    /**
     * Method that can be called to get a read-only instance populated from the
     * most recent version of the shared lookup Map.
     */
    public ReadOnlyClassToSerializerMap getReadOnlyLookupMap()
    {
        synchronized (this) {
            if (_readOnlyMap == null) {
                _readOnlyMap = ReadOnlyClassToSerializerMap.from(_sharedMap);
            }
            return _readOnlyMap.instance();
        }
    }

    /**
     * Method that checks if the shared (and hence, synchronized) lookup Map might have
     * the serializer already.
     */
    public JsonSerializer