Implement #equals() and #hashCode() methods for PDF primitive objects.

DEVSIX-851

Author: pavel-alay

io/src/main/java/com/itextpdf/io/LogMessageConstant.java

@@ -66,6 +66,7 @@ public final class LogMessageConstant {
     public static final String IMAGE_SIZE_CANNOT_BE_MORE_4KB = "Inline image size cannot be more than 4KB. It will be added as an ImageXObject";
     public static final String INVALID_INDIRECT_REFERENCE = "Invalid indirect reference";
     public static final String INVALID_KEY_VALUE_KEY_0_HAS_NULL_VALUE = "Invalid key value: key {0} has null value.";
+    public static final String CALCULATE_HASHCODE_FOR_MODIFIED_PDFNUMBER = "Calculate hashcode for modified PdfNumber.";
     public static final String MAKE_COPY_OF_CATALOG_DICTIONARY_IS_FORBIDDEN = "Make copy of Catalog dictionary is forbidden.";
     public static final String NOT_TAGGED_PAGES_IN_TAGGED_DOCUMENT = "Not tagged pages are copied to the tagged document. Destination document now may contain not tagged content.";
     public static final String PDF_READER_CLOSING_FAILED = "PdfReader closing failed due to the error occurred!";

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

@@ -152,4 +152,15 @@ protected void copyContent(PdfObject from, PdfDocument document) {
         PdfBoolean bool = (PdfBoolean)from;
         value = bool.value;
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        return this == obj ||
+                !(obj == null || getClass() != obj.getClass()) && value == ((PdfBoolean) obj).value;
+    }
+
+    @Override
+    public int hashCode() {
+        return (value ? 1 : 0);
+    }
 }

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

@@ -102,6 +102,17 @@ protected void generateContent() {
 
     }
 
+    @Override
+    public boolean equals(Object o) {
+        return this == o ||
+                !(o == null || getClass() != o.getClass()) && Arrays.equals(content, ((PdfLiteral) o).content);
+    }
+
+    @Override
+    public int hashCode() {
+        return content == null ? 0 : Arrays.hashCode(content);
+    }
+
     @Override
     protected PdfLiteral newInstance() {
         return new PdfLiteral();

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

@@ -144,4 +144,14 @@ protected PdfNull newInstance() {
     protected void copyContent(PdfObject from, PdfDocument document) {
 
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        return this == obj || !(obj == null || getClass() != obj.getClass());
+    }
+
+    @Override
+    public int hashCode() {
+        return 0;
+    }
 }

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

@@ -43,14 +43,18 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.kernel.pdf;
 
+import com.itextpdf.io.LogMessageConstant;
 import com.itextpdf.io.source.ByteUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class PdfNumber extends PdfPrimitiveObject {
 
     private static final long serialVersionUID = -250799718574024246L;
 
     private double value;
     private boolean isDouble;
+    private boolean changed = false;
 
     public PdfNumber(double value) {
         super();
@@ -103,6 +107,7 @@ public void setValue(int value) {
         this.value = value;
         this.isDouble = false;
         this.content = null;
+        this.changed = true;
     }
 
     public void setValue(double value) {
@@ -183,6 +188,24 @@ public String toString() {
         }
     }
 
+    @Override
+    public boolean equals(Object o) {
+        return this == o ||
+                !(o == null || getClass() != o.getClass()) && Double.compare(((PdfNumber) o).value, value) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        if (changed) {
+            //if the instance was modified, hashCode also will be changed, it may cause inconsistency.
+            Logger logger = LoggerFactory.getLogger(PdfReader.class);
+            logger.warn(LogMessageConstant.CALCULATE_HASHCODE_FOR_MODIFIED_PDFNUMBER);
+            changed = false;
+        }
+        long hash = Double.doubleToLongBits(value);
+        return (int) (hash ^ (hash >>> 32));
+    }
+
     @Override
     protected PdfNumber newInstance() {
         return new PdfNumber();

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

@@ -69,8 +69,6 @@ public class PdfString extends PdfPrimitiveObject {
 
     private static final long serialVersionUID = 390789504287887010L;
 
-	private static String defaultCharset = "UTF-8";
-
     protected String value;
     protected String encoding;
     protected boolean hexWriting = false;
@@ -97,8 +95,8 @@ public PdfString(byte[] content) {
         super();
         if (content != null && content.length > 0) {
             StringBuilder str = new StringBuilder(content.length);
-            for (byte b: content) {
-                str.append((char)(b & 0xff));
+            for (byte b : content) {
+                str.append((char) (b & 0xff));
             }
             this.value = str.toString();
         } else {
@@ -152,10 +150,15 @@ public String getEncoding() {
     /**
      * Sets the encoding of this string.
      * NOTE. Byte content will be removed.
+     * @deprecated Create a new instance with {@link PdfString#PdfString(String, String)} instead.
      */
+    @Deprecated
     public void setEncoding(String encoding) {
+        if (value == null) {
+            generateValue();
+            this.content = null;
+        }
         this.encoding = encoding;
-        this.content = null;
     }
 
     /**
@@ -170,7 +173,7 @@ public String toUnicodeString() {
             generateContent();
         }
         byte[] b = PdfTokenizer.decodeStringContent(content, hexWriting);
-        if (b.length >= 2 && b[0] == (byte)0xFE && b[1] == (byte)0xFF) {
+        if (b.length >= 2 && b[0] == (byte) 0xFE && b[1] == (byte) 0xFF) {
             return PdfEncodings.convertToString(b, PdfEncodings.UNICODE_BIG);
         } else {
             return PdfEncodings.convertToString(b, PdfEncodings.PDF_DOC_ENCODING);
@@ -245,6 +248,26 @@ public PdfString copyTo(PdfDocument document, boolean allowDuplicating) {
         return (PdfString) super.copyTo(document, allowDuplicating);
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        PdfString that = (PdfString) o;
+        String v1 = getValue();
+        String v2 = that.getValue();
+        if (v1 != null && v1.equals(v2)) {
+            String e1 = getEncoding();
+            String e2 = that.getEncoding();
+            if ((e1 == null && e2 == null)
+                    || (e1 != null && e1.equals(e2))) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @Override
     public String toString() {
         if (value == null) {
@@ -254,6 +277,14 @@ public String toString() {
         }
     }
 
+    @Override
+    public int hashCode() {
+        String v = getValue();
+        String e = getEncoding();
+        int result = v != null ? v.hashCode() : 0;
+        return 31 * result + (e != null ? e.hashCode() : 0);
+    }
+
     protected void generateValue() {
         assert content != null : "No byte[] content to generate value";
         value = PdfEncodings.convertToString(PdfTokenizer.decodeStringContent(content, hexWriting), null);