Add meta info to the event counting API

This meta info will be passed with the event during counting and can
be used to determine the event origin. It can be also used in event
processing API since it is passed to IEventDataFactory.

DEVSIX-1958

Author: IdamkinI

kernel/src/main/java/com/itextpdf/kernel/counter/ContextManager.java

@@ -95,82 +95,25 @@ public static ContextManager getInstance() {
     }
 
     /**
-     * Gets the top {@link IContext} based on the stack trace.
+     * Gets the context associated with the passed class object.
+     * The context is determined by class namespace.
      *
-     * For example if the {@link PdfDocument} was created inside pdfHtml,
-     * and the pdfHtml was called directly,
-     * then calling this method from {@link PdfDocument} will retrieve pdfHtml context.
-     *
-     * @return the top {@link IContext} instance, or {@code null} if the context is unknown
+     * @param clazz the class for which the context will be determined.
+     * @return the {@link IContext} associated with the class, or {@code null} if the class is unknown.
      */
-    public IContext getTopContext() {
-        return getTopContext(null);
+    public IContext getContext(Class<?> clazz) {
+        return clazz != null ? getContext(clazz.getName()) : null;
     }
 
     /**
-     * Gets the top {@link IContext} based on the stack trace.
-     *
-     * For example if the {@link PdfDocument} was created inside pdfHtml,
-     * and the pdfHtml was called directly,
-     * then calling this method from {@link PdfDocument} will retrieve pdfHtml context.
+     * Gets the context associated with the passed class object.
+     * The context is determined by class namespace.
      *
-     * @param stop  if this class is encountered during stack trace analysis,
-     *              then the process is stopped and {@code null} is returned
-     * @return      the top {@link IContext} instance, or {@code null}
-     *              if the context is unknown or {@code stop} is encountered
+     * @param className the class name with the namespace for which the context will be determined.
+     * @return the {@link IContext} associated with the class, or {@code null} if the class is unknown.
      */
-    public IContext getTopContext(Class<?> stop) {
-        return getNamespaceMapping(getTopRecognisedNamespace(stop));
-    }
-
-    /**
-     * Gets the top recognised namespace based on the stack trace.
-     *
-     * For example if the {@link PdfDocument} was created inside pdfHtml,
-     * and the pdfHtml was called directly,
-     * then calling this method from {@link PdfDocument} will retrieve pdfHtml namespace.
-     *
-     * @return the top recognised namespace, or {@code null} if it is unrecognised
-     */
-    public String getTopRecognisedNamespace() {
-        return getTopRecognisedNamespace(null);
-    }
-
-    /**
-     * Gets the top recognised namespace based on the stack trace.
-     *
-     * For example if the {@link PdfDocument} was created inside pdfHtml,
-     * and the pdfHtml was called directly,
-     * then calling this method from {@link PdfDocument} will retrieve pdfHtml namespace.
-     *
-     * @param stop  if this class is encountered during stack trace analysis,
-     *              then the process is stopped and {@code null} is returned
-     * @return the top recognised namespace, or {@code null} if the context is unknown
-     */
-    public String getTopRecognisedNamespace(Class<?> stop) {
-        if (stop == null) {
-            stop = getClass();
-        }
-        try {
-            StackTraceElement[] trace = Thread.currentThread().getStackTrace();
-            String result;
-            for(int i=trace.length-1; i>=0; --i){
-                if (stop.getName().equals(trace[i].getClassName())) {
-                    return null;
-                }
-                result = getRecognisedNamespace(trace[i].getClassName());
-                if (result != null) {
-                    return result;
-                }
-            }
-        } catch (SecurityException e) {
-            long current = SystemUtil.getRelativeTimeMillis();
-            if (current - securityErrorLastLogged > SECURITY_ERROR_LOGGING_INTERVAL) {
-                LoggerFactory.getLogger(getClass()).error(LogMessageConstant.UNABLE_TO_SEARCH_FOR_EVENT_CONTEXT);
-                securityErrorLastLogged = current;
-            }
-        }
-        return null;
+    public IContext getContext(String className) {
+        return getNamespaceMapping(getRecognisedNamespace(className));
     }
 
     private String getRecognisedNamespace(String className) {

kernel/src/main/java/com/itextpdf/kernel/counter/DataHandlerCounter.java

@@ -49,6 +49,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.counter.data.EventDataHandlerUtil;
 import com.itextpdf.kernel.counter.data.EventData;
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
 /**
  * Counter based on {@link EventDataHandler}.
@@ -73,7 +74,7 @@ public DataHandlerCounter(EventDataHandler<T, V> dataHandler, IContext fallback)
     }
 
     @Override
-    protected void process(IEvent event) {
-        dataHandler.register(event);
+    protected void onEvent(IEvent event, IMetaInfo metaInfo) {
+        dataHandler.register(event, metaInfo);
     }
 }

kernel/src/main/java/com/itextpdf/kernel/counter/DefaultEventCounter.java

@@ -47,6 +47,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.Version;
 import com.itextpdf.kernel.counter.context.UnknownContext;
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -102,7 +103,7 @@ public DefaultEventCounter() {
                     "yBvdXIgc2FsZXMgZGVwYXJ0bWVudC4=");
 
     @Override
-    protected void process(IEvent event) {
+    protected void onEvent(IEvent event, IMetaInfo metaInfo) {
         if (count.incrementAndGet() > repeatLevel) {
             if (Version.isAGPLVersion() || Version.isExpired() ) {
                 String message =  new String(message_1);

kernel/src/main/java/com/itextpdf/kernel/counter/EventCounter.java

@@ -46,6 +46,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.counter.context.IContext;
 import com.itextpdf.kernel.counter.context.UnknownContext;
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
 /**
  * Class that can be extended if you want to count iText events, for example the number of documents
@@ -56,7 +57,7 @@ This file is part of the iText (R) project.
  */
 public abstract class EventCounter {
 
-    private final IContext fallback;
+    final IContext fallback;
 
     /**
      * Creates instance of this class that allows all events from unknown {@link IContext}.
@@ -70,27 +71,17 @@ public EventCounter() {
      * @param fallback the {@link IContext} that will be used in case the event context is unknown
      */
     public EventCounter(IContext fallback) {
-        this.fallback = fallback;
-    }
-
-    /**
-     * Entry point for event processing. Some events may be discarded based on the event context.
-     *
-     * @param event {@link IEvent} to count
-     * @param context event's {@link IContext}
-     */
-    public final void onEvent(IEvent event, IContext context) {
-        if (context == null) {
-            context = fallback;
-        }
-        if (context.allow(event)) {
-            process(event);
+        if (fallback == null) {
+            throw new IllegalArgumentException("The fallback context in EventCounter constructor cannot be null");
         }
+        this.fallback = fallback;
     }
 
     /**
      * The method that should be overridden for actual event processing
+     *
      * @param event {@link IEvent} to count
+     * @param metaInfo the {@link IMetaInfo} that can hold information about event origin
      */
-    abstract protected void process(IEvent event);
+    protected abstract void onEvent(IEvent event, IMetaInfo metaInfo);
 }

kernel/src/main/java/com/itextpdf/kernel/counter/EventCounterHandler.java

@@ -45,15 +45,14 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.kernel.counter.context.IContext;
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
-import java.util.Collections;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Manager that works with {@link IEventCounterFactory}. Create {@link EventCounter} for each registered {@link IEventCounterFactory}
- * and send corresponding events when calling {@link #onEvent(IEvent, Class)} method.
+ * and send corresponding events when calling {@link #onEvent(IEvent, IMetaInfo, Class)} method.
  * <br/>
  * You can implement your own {@link IEventCounterFactory} and register them with {@link EventCounterHandler#register(IEventCounterFactory)}
  * Or implement {@link EventCounter} and register it with {@link SimpleEventCounterFactory} like this:
@@ -89,17 +88,27 @@ public static EventCounterHandler getInstance() {
      * Triggers all registered {@link IEventCounterFactory} to produce {@link EventCounter} instance
      * and count the event.
      */
-    public void onEvent(IEvent event, Class<?> caller) {
+    public void onEvent(IEvent event, IMetaInfo metaInfo, Class<?> caller) {
         IContext context = null;
         boolean contextInitialized = false;
         for (IEventCounterFactory factory : factories.keySet()) {
             EventCounter counter = factory.getCounter(caller);
             if (counter != null) {
                 if (!contextInitialized) {
-                    context = ContextManager.getInstance().getTopContext(getClass());
+                    if (metaInfo != null) {
+                        context = ContextManager.getInstance().getContext(metaInfo.getClass());
+                    }
+                    if (context == null) {
+                        context = ContextManager.getInstance().getContext(caller);
+                    }
+                    if (context == null) {
+                        context = ContextManager.getInstance().getContext(event.getClass());
+                    }
                     contextInitialized = true;
                 }
-                counter.onEvent(event, context);
+                if ((context != null && context.allow(event)) || (context == null && counter.fallback.allow(event))) {
+                    counter.onEvent(event, metaInfo);
+                }
             }
         }
     }

kernel/src/main/java/com/itextpdf/kernel/counter/SystemOutEventCounter.java

@@ -45,6 +45,7 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.io.util.MessageFormatUtil;
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
 /**
  * A {@link EventCounter} implementation that outputs event type to {@link System#out}
@@ -70,7 +71,7 @@ public SystemOutEventCounter(Class<?> cls) {
     }
 
     @Override
-    protected void process(IEvent event) {
+    protected void onEvent(IEvent event, IMetaInfo metaInfo) {
         System.out.println(MessageFormatUtil.format("[{0}] {1} event", name, event.getEventType()));
     }
 }

kernel/src/main/java/com/itextpdf/kernel/counter/data/EventDataHandler.java

@@ -45,7 +45,7 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.io.util.SystemUtil;
 import com.itextpdf.kernel.counter.event.IEvent;
-import org.slf4j.LoggerFactory;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
 import java.util.Collections;
 import java.util.List;
@@ -95,11 +95,11 @@ public List<V> clear() {
         return all != null ? all : Collections.<V>emptyList();
     }
 
-    public void register(IEvent event) {
+    public void register(IEvent event, IMetaInfo metaInfo) {
         V data;
         //Synchronization is left here mostly in consistency with cache and process, but factories are usually not thread safe anyway.
         synchronized (factory) {
-            data = factory.create(event);
+            data = factory.create(event, metaInfo);
         }
         if (data != null) {
             synchronized (cache) {

kernel/src/main/java/com/itextpdf/kernel/counter/data/IEventDataFactory.java

@@ -44,6 +44,7 @@ This file is part of the iText (R) project.
 package com.itextpdf.kernel.counter.data;
 
 import com.itextpdf.kernel.counter.event.IEvent;
+import com.itextpdf.kernel.counter.event.IMetaInfo;
 
 /**
  * Interface that is responsible for creating new instance of {@link EventData}.
@@ -54,5 +55,5 @@ This file is part of the iText (R) project.
  */
 public interface IEventDataFactory<T, V extends EventData<T>> {
 
-    V create(IEvent event);
+    V create(IEvent event, IMetaInfo metaInfo);
 }

kernel/src/main/java/com/itextpdf/kernel/counter/event/IMetaInfo.java

@@ -0,0 +1,52 @@
+/*
+
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2018 iText Group NV
+    Authors: Bruno Lowagie, Paulo Soares, et al.
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License version 3
+    as published by the Free Software Foundation with the addition of the
+    following permission added to Section 15 as permitted in Section 7(a):
+    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
+    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
+    OF THIRD PARTY RIGHTS
+
+    This program is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE.
+    See the GNU Affero General Public License for more details.
+    You should have received a copy of the GNU Affero General Public License
+    along with this program; if not, see http://www.gnu.org/licenses or write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA, 02110-1301 USA, or download the license from the following URL:
+    http://itextpdf.com/terms-of-use/
+
+    The interactive user interfaces in modified source and object code versions
+    of this program must display Appropriate Legal Notices, as required under
+    Section 5 of the GNU Affero General Public License.
+
+    In accordance with Section 7(b) of the GNU Affero General Public License,
+    a covered work must retain the producer line in every PDF that is created
+    or manipulated using iText.
+
+    You can be released from the requirements of the license by purchasing
+    a commercial license. Buying such a license is mandatory as soon as you
+    develop commercial activities involving the iText software without
+    disclosing the source code of your own applications.
+    These activities include: offering paid services to customers as an ASP,
+    serving PDFs on the fly in a web application, shipping iText with a closed
+    source product.
+
+    For more information, please contact iText Software Corp. at this
+    address: [email protected]
+ */
+package com.itextpdf.kernel.counter.event;
+
+import java.io.Serializable;
+
+/**
+ * The meta info that can holds information about instance that throws the event
+ */
+public interface IMetaInfo extends Serializable {
+}