src/PlatformSupport/XalanDOMStringCache.hpp

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2000 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.ibm.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
#if !defined(XALAN_DOMSTRINGCACHE_HEADER_GUARD)
#define XALAN_DOMSTRINGCACHE_HEADER_GUARD



// Base include file.  Must be first.
#include <PlatformSupport/PlatformSupportDefinitions.hpp>



#include <deque>
#include <vector>



#include <XalanDOM/XalanDOMString.hpp>



class XALAN_PLATFORMSUPPORT_EXPORT XalanDOMStringCache
{
public:

	enum { eDefaultMaximumSize = 100 };

#if defined(XALAN_NO_NAMESPACES)
	typedef vector<XalanDOMString*>			StringListType;
#else
	typedef std::vector<XalanDOMString*>	StringListType;
#endif

	explicit
	XalanDOMStringCache(unsigned int	theMaximumSize = eDefaultMaximumSize);

	~XalanDOMStringCache();

	unsigned int
	getMaximumSize() const
	{
		return m_maximumSize;
	}

	void
	setMaximumSize(unsigned int		theSize)
	{
		m_maximumSize = theSize;
	}

	XalanDOMString&
	get();

	bool
	release(XalanDOMString&		theString);

	/*
	 * Clear all of the strings in the cache.  This
	 * destroys all of the strings.
	 *
	 */
	void
	clear();

	/*
	 * Reset the cache so that all strings that are
	 * currently in use are available.
	 */
	void
	reset();

	class GetAndRelease
	{
	public:

		GetAndRelease(XalanDOMStringCache&	theCache) :
			m_cache(theCache),
			m_string(&theCache.get())
		{
		}

		~GetAndRelease()
		{
			m_cache.release(*m_string);
		}

		XalanDOMString&
		get() const
		{
			return *m_string;
		}

	private:

		XalanDOMStringCache&	m_cache;

		XalanDOMString* const	m_string;
	};

private:

	// not implemented
	XalanDOMStringCache(const XalanDOMStringCache&);

	bool
	operator==(const XalanDOMStringCache&) const;

	XalanDOMStringCache&
	operator=(const XalanDOMStringCache&);

	/**
	 * A list to hold the strings that are available...
	 */
	StringListType	m_availableList;

	/**
	 * A list to hold the strings that are busy...
	 */
	StringListType	m_busyList;

	unsigned int	m_maximumSize;
};



#endif	// XALAN_RESULTNAMESPACESSTACK_HEADER_GUARD