Add check that PdfAPage can be flushed

Add PdfAPage class.
Use page factories to create pages.
Add check that PdfAPage object is ready to be flushed and if no don't call flushing.

DEVSIX-2645

Author: ar3em

kernel/src/main/java/com/itextpdf/kernel/pdf/IPdfPageFactory.java

@@ -0,0 +1,66 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    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.pdf;
+
+import com.itextpdf.kernel.geom.PageSize;
+
+/**
+ * Interface used to create instances of {@link PdfPage}.
+ */
+public interface IPdfPageFactory {
+
+    /**
+     * Create {@link PdfPage} on the base of the page {@link PdfDictionary}.
+     * @param pdfObject the {@link PdfDictionary} object on which the {@link PdfPage} will be based
+     * @return created {@link PdfPage}
+     */
+    PdfPage createPdfPage(PdfDictionary pdfObject);
+
+    /**
+     * Create {@link PdfPage} with given page size and add it to the {@link PdfDocument}.
+     * @param pdfDocument  {@link PdfDocument} to add page
+     * @param pageSize {@link PageSize} of the created page
+     * @return created {@link PdfPage}
+     */
+    PdfPage createPdfPage(PdfDocument pdfDocument, PageSize pageSize);
+}

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfDocument.java

@@ -110,6 +110,8 @@ public class PdfDocument implements IEventDispatcher, Closeable, Serializable {
 
     private static final long serialVersionUID = -7041578979319799646L;
 
+    private static IPdfPageFactory pdfPageFactory = new PdfPageFactory();
+
     /**
      * Currently active page.
      * @deprecated Will be removed in iText 7.2
@@ -191,7 +193,6 @@ public class PdfDocument implements IEventDispatcher, Closeable, Serializable {
 
     protected boolean closed = false;
 
-
     /**
      * flag determines whether to write unused objects to result document
      */
@@ -454,7 +455,7 @@ public PdfPage addNewPage() {
      */
     public PdfPage addNewPage(PageSize pageSize) {
         checkClosingStatus();
-        PdfPage page = new PdfPage(this, pageSize);
+        PdfPage page = getPageFactory().createPdfPage(this, pageSize);
         checkAndAddPage(page);
         dispatchEvent(new PdfDocumentEvent(PdfDocumentEvent.START_PAGE, page));
         dispatchEvent(new PdfDocumentEvent(PdfDocumentEvent.INSERT_PAGE, page));
@@ -482,7 +483,7 @@ public PdfPage addNewPage(int index) {
      */
     public PdfPage addNewPage(int index, PageSize pageSize) {
         checkClosingStatus();
-        PdfPage page = new PdfPage(this, pageSize);
+        PdfPage page = getPageFactory().createPdfPage(this, pageSize);
         checkAndAddPage(index, page);
         currentPage = page;
         dispatchEvent(new PdfDocumentEvent(PdfDocumentEvent.START_PAGE, page));
@@ -2098,6 +2099,15 @@ protected List<ICounter> getCounters() {
         return CounterManager.getInstance().getCounters(PdfDocument.class);
     }
 
+    /**
+     * Returns the factory for creating page instances.
+     *
+     * @return implementation of {@link IPdfPageFactory} for current document
+     */
+    protected IPdfPageFactory getPageFactory() {
+        return pdfPageFactory;
+    }
+
     /**
      * Gets iText version info.
      *

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfPage.java

@@ -399,7 +399,7 @@ public PdfPage copyTo(PdfDocument toDocument) {
      */
     public PdfPage copyTo(PdfDocument toDocument, IPdfPageExtraCopier copier) {
         PdfDictionary dictionary = getPdfObject().copyTo(toDocument, PAGE_EXCLUDED_KEYS, true);
-        PdfPage page = new PdfPage(dictionary);
+        PdfPage page = getDocument().getPageFactory().createPdfPage(dictionary);
         copyInheritedProperties(page, toDocument);
         for (PdfAnnotation annot : getAnnotations()) {
             if (annot.getSubtype().equals(PdfName.Link)) {
@@ -506,7 +506,6 @@ public void flush() {
      *                                     will be flushed.
      */
     public void flush(boolean flushResourcesContentStreams) {
-        // TODO log warning in case of failed flush in pdfa document case
         if (isFlushed()) {
             return;
         }

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfPageFactory.java

@@ -0,0 +1,58 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    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.pdf;
+
+import com.itextpdf.kernel.geom.PageSize;
+
+class PdfPageFactory implements IPdfPageFactory {
+
+    @Override
+    public PdfPage createPdfPage(PdfDictionary pdfObject) {
+        return new PdfPage(pdfObject);
+    }
+
+    @Override
+    public PdfPage createPdfPage(PdfDocument pdfDocument, PageSize pageSize) {
+        return new PdfPage(pdfDocument, pageSize);
+    }
+}

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfPagesTree.java

@@ -117,7 +117,7 @@ public PdfPage getPage(int pageNum) {
                 int parentIndex = findPageParent(pageNum);
                 PdfObject pageObject = pageRefs.get(pageNum).getRefersTo();
                 if (pageObject instanceof PdfDictionary) {
-                    pdfPage = new PdfPage((PdfDictionary) pageObject);
+                    pdfPage = document.getPageFactory().createPdfPage((PdfDictionary) pageObject);
                     pdfPage.parentPages = parents.get(parentIndex);
                 } else {
                     LOGGER.error(MessageFormatUtil.format(LogMessageConstant.PAGE_TREE_IS_BROKEN_FAILED_TO_RETRIEVE_PAGE, pageNum + 1));

pdfa/src/main/java/com/itextpdf/pdfa/PdfADocument.java

@@ -43,11 +43,11 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.pdfa;
 
-import com.itextpdf.io.LogMessageConstant;
 import com.itextpdf.kernel.font.PdfFont;
 import com.itextpdf.kernel.log.CounterManager;
 import com.itextpdf.kernel.log.ICounter;
 import com.itextpdf.kernel.pdf.DocumentProperties;
+import com.itextpdf.kernel.pdf.IPdfPageFactory;
 import com.itextpdf.kernel.pdf.IsoKey;
 import com.itextpdf.kernel.pdf.PdfAConformanceLevel;
 import com.itextpdf.kernel.pdf.PdfDictionary;
@@ -94,8 +94,15 @@ This file is part of the iText (R) project.
 public class PdfADocument extends PdfDocument {
 
     private static final long serialVersionUID = -5908390625367471894L;
+
+    private static IPdfPageFactory pdfAPageFactory = new PdfAPageFactory();
+
     protected PdfAChecker checker;
 
+    private boolean alreadyLoggedThatObjectFlushingWasNotPerformed = false;
+
+    private boolean alreadyLoggedThatPageFlushingWasNotPerformed = false;
+
     /**
      * Constructs a new PdfADocument for writing purposes, i.e. from scratch. A
      * PDF/A file has a conformance level, and must have an explicit output
@@ -228,6 +235,14 @@ public PdfAConformanceLevel getConformanceLevel() {
         return checker.getConformanceLevel();
     }
 
+    void logThatPdfAPageFlushingWasNotPerformed() {
+        if (!alreadyLoggedThatPageFlushingWasNotPerformed) {
+            alreadyLoggedThatPageFlushingWasNotPerformed = true;
+            // This log message will be printed once for one instance of the document.
+            LoggerFactory.getLogger(PdfADocument.class).warn(PdfALogMessageConstant.PDFA_PAGE_FLUSHING_WAS_NOT_PERFORMED);
+        }
+    }
+
     @Override
     protected void addCustomMetadataExtensions(XMPMeta xmpMeta) {
         if (this.isTagged()) {
@@ -238,7 +253,7 @@ protected void addCustomMetadataExtensions(XMPMeta xmpMeta) {
                 }
             } catch (XMPException exc) {
                 Logger logger = LoggerFactory.getLogger(PdfADocument.class);
-                logger.error(LogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA, exc);
+                logger.error(com.itextpdf.io.LogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA, exc);
             }
         }
     }
@@ -253,7 +268,7 @@ protected void updateXmpMetadata() {
             setXmpMetadata(xmpMeta);
         } catch (XMPException e) {
             Logger logger = LoggerFactory.getLogger(PdfADocument.class);
-            logger.error(LogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA, e);
+            logger.error(com.itextpdf.io.LogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA, e);
         }
     }
 
@@ -267,9 +282,10 @@ protected void flushObject(PdfObject pdfObject, boolean canBeInObjStm) throws IO
         markObjectAsMustBeFlushed(pdfObject);
         if (isClosing || checker.objectIsChecked(pdfObject)) {
             super.flushObject(pdfObject, canBeInObjStm);
-        } else {
-            //suppress the call
-            //TODO log unsuccessful call
+        } else if (!alreadyLoggedThatObjectFlushingWasNotPerformed) {
+            alreadyLoggedThatObjectFlushingWasNotPerformed = true;
+            // This log message will be printed once for one instance of the document.
+            LoggerFactory.getLogger(PdfADocument.class).warn(PdfALogMessageConstant.PDFA_OBJECT_FLUSHING_WAS_NOT_PERFORMED);
         }
     }
 
@@ -305,6 +321,15 @@ protected List<ICounter> getCounters() {
         return CounterManager.getInstance().getCounters(PdfADocument.class);
     }
 
+    @Override
+    protected IPdfPageFactory getPageFactory() {
+        return pdfAPageFactory;
+    }
+
+    boolean isClosing() {
+        return isClosing;
+    }
+
     private static PdfVersion getPdfVersionForPdfA(PdfAConformanceLevel conformanceLevel) {
         PdfVersion version;
         switch (conformanceLevel.getPart()) {

pdfa/src/main/java/com/itextpdf/pdfa/PdfALogMessageConstant.java

@@ -0,0 +1,52 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    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.pdfa;
+
+/**
+ * Class containing constants to be used in logging.
+ */
+public class PdfALogMessageConstant {
+    public static final String PDFA_PAGE_FLUSHING_WAS_NOT_PERFORMED = "Page flushing was not performed. Pages flushing in PDF/A mode works only with explicit calls to PdfPage#flush(boolean) with flushResourcesContentStreams argument set to true";
+
+    public static final String PDFA_OBJECT_FLUSHING_WAS_NOT_PERFORMED = "Object flushing was not performed. Object in PDF/A mode can only be flushed if the document is closed or if this object has already been checked for compliance with PDF/A rules.";
+}