Imporvement of performance : Reduce the Java running count

# What is it
- #6465 is the first reqeust.  So I followed up the albert advice.
	- in case of debug you use printf statements, I think that here there better options would be
		- create an -d flag (e.g. -d plantuml) that gives the information, so no need for using the configuration option
		- Follow up : create -d plantuml [debug.h, debug.cpp]
	- usage of printf
		- printf should not be used,all output is steered over calls to routines as defined in message.cpp,
		- Follow up : use Debug::Print(Debug::Plantuml, ...    and msg()
	- usage of std::string / std::map
		- in doxygen the string manipulation is. mostly, done by means of Qt classes (e.g. classes QCString, QString). For consistency these classes should be used.
		- map manipulation is also done by means of Qt classes (dictionary and list classes)
		- Follow up : use QDict QList QCString [plantuml.h, plantuml.cpp]
	- dirent / opendir /readdir
		- when browsing through directories the routines line readFileOrDirectory should probably be used or the techniques used in this routine
		- Follow up : I will follow when I try to reduce redundancy of creating plantuml image.

- Run java minimally
	- Test Case : 4 plantuml
	- Original Run without PLANTUML_RUN_JAVA_ONCE
		- 8.2 sec = 4 times * ( 1.6(java vm) + 0.1 * 1(load multiple file) + process each plantuml (0.35) *1 ) <- prediction
	- New with PLANTUML_RUN_JAVA_ONCE
		- 3.499 sec = 1.6(java vm) + 0.1 * 4(load multiple file) + process each plantuml (0.35) *4 <- prediction
	- Creating Java Virtual Machine has a big portion.

- Result
	- Improving Performance : 8.2 -> 3.499  (in case of 4 plantuml)

# Configuration
- add configuration value in Doxyfile
	- PLANTUML_RUN_JAVA_ONCE = YES

# Debugging
- doxygen -d plantuml
- doxygen -d time -d plantuml

# Tested with following options
- source code of 3 plantuml
- PLANTUML_RUN_JAVA_ONCE = YES  or    NO
- DOT_IMAGE_FORMAT       = png  or    svg
- DOT_CLEANUP            = YES  or    NO
- -d plantuml

1 files changed, 22 insertions, 0 deletions

diff --git a/src/plantuml.h b/src/plantuml.h
index 54ab8a2..b931e70 100644
--- a/src/plantuml.h
+++ b/src/plantuml.h
@@ -16,6 +16,9 @@
 #ifndef PLANTUML_H
 #define PLANTUML_H
 
+#include <qdict.h>
+#include <qlist.h>
+
 class QCString;
 
 /** Plant UML output image formats */
@@ -36,5 +39,24 @@ QCString writePlantUMLSource(const QCString &outDir,const QCString &fileName,con
  */
 void generatePlantUMLOutput(const char *baseName,const char *outDir,PlantUMLOutputFormat format);
 
+/** Singleton that manages plantuml relation actions */
+class PlantumlManager
+{
+  public:
+    static PlantumlManager *instance();
+    void run();
+	void insert(const QCString key , const QCString value,PlantUMLOutputFormat format);
+  private:
+    PlantumlManager();
+    virtual ~PlantumlManager();
+	void addPlantumlFiles(QDict< QList <QCString> > &PlantumlFiles,const QCString key , const QCString value);
+	void print(QDict< QList <QCString> > &PlantumlFiles);
+	void runPlantumlFiles(QDict< QList <QCString> > &PlantumlFiles,const char *type);
+    static PlantumlManager     *m_theInstance;
+    QDict< QList<QCString> >       m_pngPlantumlFiles;
+    QDict< QList<QCString> >       m_svgPlantumlFiles;
+    QDict< QList<QCString> >       m_epsPlantumlFiles;
+};
+
 #endif