Extracted ISBN class

JabRef · Jul 18, 2016 · 6900dff · 6900dff
1 parent db7e213
commit 6900dff
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diff --git a/src/main/java/net/sf/jabref/logic/integrity/ISBNChecker.java b/src/main/java/net/sf/jabref/logic/integrity/ISBNChecker.java
@@ -2,68 +2,35 @@
 
 import java.util.Collections;
 import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 import net.sf.jabref.logic.integrity.IntegrityCheck.Checker;
 import net.sf.jabref.logic.l10n.Localization;
+import net.sf.jabref.logic.util.ISBN;
 import net.sf.jabref.model.entry.BibEntry;
 
 
 public class ISBNChecker implements Checker {
 
-    private static final Pattern ISBN_PATTERN = Pattern.compile("^(\\d{9}[\\dxX]|\\d{13})$");
 
     @Override
     public List<IntegrityMessage> check(BibEntry entry) {
         if (!entry.hasField("isbn")) {
             return Collections.emptyList();
         }
 
-        // Check that the ISSN is on the correct form
-        String isbn = entry.getFieldOptional("isbn").get().trim().replace("-", "");
-        Matcher isbnMatcher = ISBN_PATTERN.matcher(isbn);
+        // Check that the ISBN is on the correct form
+        ISBN isbn = new ISBN(entry.getFieldOptional("isbn").get());
 
-        if (!isbnMatcher.matches()) {
+        if (!isbn.isValidFormat()) {
             return Collections.singletonList(
                     new IntegrityMessage(Localization.lang("incorrect format"), entry, "isbn"));
         }
 
-        boolean valid;
-        if (isbn.length() == 10) {
-            valid = isbn10check(isbn);
-        } else {
-            // length is either 10 or 13 based on regexp so will be 13 here
-            valid = isbn13check(isbn);
-        }
-        if (valid) {
-            return Collections.emptyList();
-        } else {
+        if (!isbn.isValidChecksum()) {
             return Collections
                     .singletonList(new IntegrityMessage(Localization.lang("incorrect control digit"), entry, "isbn"));
         }
-    }
 
-    // Check that the control digit is correct, see e.g. https://en.wikipedia.org/wiki/International_Standard_Book_Number#Check_digits
-    private boolean isbn10check(String isbn) {
-        int sum = 0;
-        for (int pos = 0; pos <= 8; pos++) {
-            sum += (isbn.charAt(pos) - '0') * ((10 - pos));
-        }
-        char control = isbn.charAt(9);
-        if ((control == 'x') || (control == 'X')) {
-            control = '9' + 1;
-        }
-        sum += (control - '0');
-        return (sum % 11) == 0;
+        return Collections.emptyList();
     }
 
-    // Check that the control digit is correct, see e.g. https://en.wikipedia.org/wiki/International_Standard_Book_Number#Check_digits
-    private boolean isbn13check(String isbn) {
-        int sum = 0;
-        for (int pos = 0; pos <= 12; pos++) {
-            sum += (isbn.charAt(pos) - '0') * ((pos % 2) == 0 ? 1 : 3);
-        }
-        return (sum % 10) == 0;
-    }
 }
diff --git a/src/main/java/net/sf/jabref/logic/util/ISBN.java b/src/main/java/net/sf/jabref/logic/util/ISBN.java
@@ -0,0 +1,76 @@
+package net.sf.jabref.logic.util;
+
+import java.util.Objects;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ISBN {
+
+    private static final Pattern ISBN_PATTERN = Pattern.compile("^(\\d{9}[\\dxX]|\\d{13})$");
+
+    private final String isbn;
+
+
+    public ISBN(String isbnString) {
+        this.isbn = Objects.requireNonNull(isbnString).trim().replace("-", "");
+    }
+
+    public boolean isValidFormat() {
+        Matcher isbnMatcher = ISBN_PATTERN.matcher(isbn);
+        if (isbnMatcher.matches()) {
+            return true;
+        }
+        return false;
+    }
+
+    public boolean isValidChecksum() {
+        boolean valid;
+        if (isbn.length() == 10) {
+            valid = isbn10check();
+        } else {
+            // length is either 10 or 13 based on regexp so will be 13 here
+            valid = isbn13check();
+        }
+        return valid;
+    }
+
+    public boolean isIsbn10() {
+        return isbn10check();
+    }
+
+    public boolean isIsbn13() {
+        return isbn13check();
+    }
+
+    // Check that the control digit is correct, see e.g. https://en.wikipedia.org/wiki/International_Standard_Book_Number#Check_digits
+    private boolean isbn10check() {
+        if ((isbn == null) || (isbn.length() != 10)) {
+            return false;
+        }
+
+        int sum = 0;
+        for (int pos = 0; pos <= 8; pos++) {
+            sum += (isbn.charAt(pos) - '0') * ((10 - pos));
+        }
+        char control = isbn.charAt(9);
+        if ((control == 'x') || (control == 'X')) {
+            control = '9' + 1;
+        }
+        sum += (control - '0');
+        return (sum % 11) == 0;
+    }
+
+    // Check that the control digit is correct, see e.g. https://en.wikipedia.org/wiki/International_Standard_Book_Number#Check_digits
+    private boolean isbn13check() {
+        if ((isbn == null) || (isbn.length() != 13)) {
+            return false;
+        }
+
+        int sum = 0;
+        for (int pos = 0; pos <= 12; pos++) {
+            sum += (isbn.charAt(pos) - '0') * ((pos % 2) == 0 ? 1 : 3);
+        }
+        return (sum % 10) == 0;
+    }
+
+}