LUCENE-2088: AttributeSource.addAttribute should only accept interfaces, the missing test leads to problems with Token.TOKEN_ATTRIBUTE_FACTORY

This also fixes the package.html error Shai mentioned.

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@883074 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -184,6 +184,9 @@ Bug fixes
 * LUCENE-2013: SpanRegexQuery does not work with QueryScorer.
   (Benjamin Keil via Mark Miller)
 
+* LUCENE-2088: addAttribute() should only accept interfaces that
+  extend Attribute. (Shai Erera, Uwe Schindler)
+
 New features
 
 * LUCENE-1933: Provide a convenience AttributeFactory that creates a

src/java/org/apache/lucene/analysis/package.html

@@ -140,7 +140,6 @@ There are many post tokenization steps that can be done, including (but not limi
       TokenStream ts = analyzer.tokenStream("myfield",new StringReader("some text goes here"));
       while (ts.incrementToken()) {
         System.out.println("token: "+ts));
-        t = ts.next();
       }
   </PRE>
 </p>

src/java/org/apache/lucene/util/AttributeSource.java

@@ -224,6 +224,12 @@ public class AttributeSource {
   public <A extends Attribute> A addAttribute(Class<A> attClass) {
     AttributeImpl attImpl = attributes.get(attClass);
     if (attImpl == null) {
+      if (!(attClass.isInterface() && Attribute.class.isAssignableFrom(attClass))) {
+        throw new IllegalArgumentException(
+          "addAttribute() only accepts an interface that extends Attribute, but " +
+          attClass.getName() + " does not fulfil this contract."
+        );
+      }
       addAttributeImpl(attImpl = this.factory.createAttributeInstance(attClass));
     }
     return attClass.cast(attImpl);

src/test/org/apache/lucene/util/TestAttributeSource.java

@@ -141,4 +141,18 @@ public class TestAttributeSource extends LuceneTestCase {
     assertTrue("TypeAttribute is not implemented by TypeAttributeImpl",
       src.addAttribute(TypeAttribute.class) instanceof TypeAttributeImpl);
   }
+  
+  public void testInvalidArguments() throws Exception {
+    try {
+      AttributeSource src = new AttributeSource();
+      src.addAttribute(Token.class);
+      fail("Should throw IllegalArgumentException");
+    } catch (IllegalArgumentException iae) {}
+    
+    try {
+      AttributeSource src = new AttributeSource(Token.TOKEN_ATTRIBUTE_FACTORY);
+      src.addAttribute(Token.class);
+      fail("Should throw IllegalArgumentException");
+    } catch (IllegalArgumentException iae) {}
+  }
 }