Fix javadoc warnings in sign module

DEVSIX-5133

Author: nikitakovaliov92

sign/src/main/java/com/itextpdf/signatures/PdfPKCS7.java

@@ -609,7 +609,10 @@ public int getSigningInfoVersion() {
     private PdfName filterSubtype;
 
     /**
-     * Getter for the ID of the digest algorithm, e.g. "2.16.840.1.101.3.4.2.1"
+     * Getter for the ID of the digest algorithm, e.g. "2.16.840.1.101.3.4.2.1".
+     * See ISO-32000-1, section 12.8.3.3 PKCS#7 Signatures as used in ISO 32000
+     *
+     * @return the ID of the digest algorithm
      */
     public String getDigestAlgorithmOid() {
         return digestAlgorithmOid;
@@ -632,14 +635,18 @@ public String getHashAlgorithm() {
     private String digestEncryptionAlgorithmOid;
 
     /**
-     * Getter for the digest encryption algorithm
+     * Getter for the digest encryption algorithm.
+     * See ISO-32000-1, section 12.8.3.3 PKCS#7 Signatures as used in ISO 32000
+     *
+     * @return the encryption algorithm
      */
     public String getDigestEncryptionAlgorithmOid() {
         return digestEncryptionAlgorithmOid;
     }
 
     /**
      * Get the algorithm used to calculate the message digest, e.g. "SHA1withRSA".
+     * See ISO-32000-1, section 12.8.3.3 PKCS#7 Signatures as used in ISO 32000
      *
      * @return the algorithm used to calculate the message digest
      */
@@ -973,7 +980,6 @@ private ASN1EncodableVector buildUnauthenticatedAttributes(byte[] timeStampToken
      * exactly the same as in {@link #getEncodedPKCS7(byte[])}.
      * <p>
      * A simple example:
-     * <p>
      * <pre>
      * Calendar cal = Calendar.getInstance();
      * PdfPKCS7 pk7 = new PdfPKCS7(key, chain, null, "SHA1", null, false);
@@ -1009,7 +1015,6 @@ public byte[] getAuthenticatedAttributeBytes(byte[] secondDigest, byte[] ocsp, C
      * exactly the same as in {@link #getEncodedPKCS7(byte[])}.
      * <p>
      * A simple example:
-     * <p>
      * <pre>
      * Calendar cal = Calendar.getInstance();
      * PdfPKCS7 pk7 = new PdfPKCS7(key, chain, null, "SHA1", null, false);
@@ -1486,7 +1491,9 @@ public Calendar getTimeStampDate() {
     }
 
     /**
-     * Returns the filter subtype.
+     * Getter for the filter subtype.
+     *
+     * @return the filter subtype
      */
     public PdfName getFilterSubtype() {
         return filterSubtype;

sign/src/main/java/com/itextpdf/signatures/PdfSignature.java

@@ -141,6 +141,9 @@ public void setContents(byte[] contents) {
 
     /**
      * Gets the /Contents entry value.
+     * See ISO 32000-1 12.8.1, Table 252 – Entries in a signature dictionary.
+     *
+     * @return the signature content
      */
     public PdfString getContents() {
         return getPdfObject().getAsString(PdfName.Contents);
@@ -157,6 +160,9 @@ public void setCert(byte[] cert) {
 
     /**
      * Gets the /Cert entry value of this signature.
+     * See ISO 32000-1 12.8.1, Table 252 – Entries in a signature dictionary.
+     *
+     * @return the signature cert
      */
     public PdfString getCert() {
         return getPdfObject().getAsString(PdfName.Cert);

sign/src/main/java/com/itextpdf/signatures/PdfSignatureAppearance.java

@@ -634,8 +634,8 @@ public boolean isInvisible() {
      *
      * @return a top-level signature appearance
      * @throws IOException if font cannot be created
-     * @see <a href="https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PPKAppearances.pdf">
-     *      Adobe Pdf Digital Signature Appearances</a> for further details
+     * @see <a href="https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PPKAppearances.pdf">Adobe Pdf Digital
+     * Signature Appearances</a>
      */
     protected PdfFormXObject getAppearance() throws IOException {
         PdfCanvas canvas;

sign/src/main/java/com/itextpdf/signatures/SignaturePermissions.java

@@ -66,14 +66,30 @@ public class FieldLock {
         PdfName action;
         /** An array of PdfString values with fieldnames */
         PdfArray fields;
-        /** Creates a FieldLock instance */
+
+        /**
+         * Creates a FieldLock instance.
+         *
+         * @param action indicates the set of fields that should be locked
+         * @param fields an array of text strings containing field names
+         */
         public FieldLock(PdfName action, PdfArray fields) {
             this.action = action;
             this.fields = fields;
         }
-        /** Getter for the field lock action. */
+
+        /**
+         * Getter for the field lock action.
+         *
+         * @return the action of field lock dictionary
+         */
         public PdfName getAction() { return action; }
-        /** Getter for the fields involved in the lock action. */
+
+        /**
+         * Getter for the fields involved in the lock action.
+         *
+         * @return the fields of field lock dictionary
+         */
         public PdfArray getFields() { return fields; }
         /** toString method */
         public String toString() {
@@ -94,6 +110,9 @@ public String toString() {
      * Creates an object that can inform you about the type of signature
      * in a signature dictionary as well as some of the permissions
      * defined by the signature.
+     *
+     * @param sigDict the signature dictionary
+     * @param previous the signature permissions
      */
     public SignaturePermissions(PdfDictionary sigDict, SignaturePermissions previous) {
         if (previous != null) {

sign/src/main/java/com/itextpdf/signatures/SignatureUtil.java

@@ -340,7 +340,7 @@ public String getTranslatedFieldName(String name) {
      *
      * @param field the signature field name
      * @return an InputStream covering the revision. Returns null if it's not a signature field
-     * @throws IOException
+     * @throws IOException signals that an I/O exception has occurred.
      */
     public InputStream extractRevision(String field) throws IOException {
         getSignatureNames();