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package org.hsqldb.lib;

The default HSQLDB thread factory implementation.  This factory can be
used to wrap other thread factories using the setImpl method, but, by
default simply produces new, vanilla thread objects constructed with
the supplied runnable object.
Author:
Campbell Burnet (campbell-burnet@users dot sourceforge.net)
Version:
1.7.2
Since:
1.7.2/**
 * The default HSQLDB thread factory implementation.  This factory can be
 * used to wrap other thread factories using the setImpl method, but, by
 * default simply produces new, vanilla thread objects constructed with
 * the supplied runnable object.
 *
 * @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
 * @version 1.7.2
 * @since 1.7.2
 */
class HsqlThreadFactory implements ThreadFactory {

    
The factory implementation.  Typically, this will be the
HsqlThreadFactory object itself.
/**
     * The factory implementation.  Typically, this will be the
     * HsqlThreadFactory object itself.
     */
    protected ThreadFactory factory;

    
Constructs a new HsqlThreadFactory that uses itself as the factory
implementation.
/**
     * Constructs a new HsqlThreadFactory that uses itself as the factory
     * implementation.
     */
    public HsqlThreadFactory() {
        this(null);
    }

    
Constructs a new HsqlThreadFactory whose retrieved threads come from the
specified ThreadFactory object or from this factory implementation, if'
the specified implementation is null.
Params:
f – the factory implementation this factory uses/**
     * Constructs a new HsqlThreadFactory whose retrieved threads come from the
     * specified ThreadFactory object or from this factory implementation, if'
     * the specified implementation is null.
     *
     * @param f the factory implementation this factory uses
     */
    public HsqlThreadFactory(ThreadFactory f) {
        setImpl(f);
    }

    
Retrieves a thread instance for running the specified Runnable
Params:
r – The runnable that the retrieved thread handles
Returns:
the requested thread instance/**
     * Retrieves a thread instance for running the specified Runnable
     * @param r The runnable that the retrieved thread handles
     * @return the requested thread instance
     */
    public Thread newThread(Runnable r) {
        return factory == this ? new Thread(r)
                               : factory.newThread(r);
    }

    
Sets the factory implementation that this factory will use to
produce threads.  If the specified argument, f, is null, then
this factory uses itself as the implementation.
Params:
f – the factory implementation that this factory will use
     to produce threads
Returns:
the previously installed factory implementation/**
     * Sets the factory implementation that this factory will use to
     * produce threads.  If the specified argument, f, is null, then
     * this factory uses itself as the implementation.
     *
     * @param f the factory implementation that this factory will use
     *      to produce threads
     * @return the previously installed factory implementation
     */
    public synchronized ThreadFactory setImpl(ThreadFactory f) {

        ThreadFactory old;

        old     = factory;
        factory = (f == null) ? this
                              : f;

        return old;
    }

    
Retrieves the factory implementation that this factory is using
to produce threads.
Returns:
the factory implementation that this factory is using to produce
threads./**
     * Retrieves the factory implementation that this factory is using
     * to produce threads.
     *
     * @return the factory implementation that this factory is using to produce
     * threads.
     */
    public synchronized ThreadFactory getImpl() {
        return factory;
    }
}