1 files changed, 153 insertions, 0 deletions
diff --git a/libjava/classpath/javax/swing/text/EmptyAttributeSet.java b/libjava/classpath/javax/swing/text/EmptyAttributeSet.java
new file mode 100644
index 000000000..92263bc1a
--- /dev/null
+++ b/libjava/classpath/javax/swing/text/EmptyAttributeSet.java
@@ -0,0 +1,153 @@
+/* EmptyAttributeSet.java -- An empty attribute set
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package javax.swing.text;
+
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+
+/**
+ * An immutable, empty attribute set.
+ *
+ * @see SimpleAttributeSet#EMPTY
+ *
+ * @author Roman Kennke (kennke@aicas.com)
+ */
+final class EmptyAttributeSet
+  implements AttributeSet
+{
+
+  /**
+   * Always return false as this AttributeSet doesn't contain any attributes.
+   */
+  public boolean containsAttribute(Object name, Object value)
+  {
+    return false;
+  }
+
+  /**
+   * Return true only if the attributes argument also contains no attributes.
+   */
+  public boolean containsAttributes(AttributeSet attributes)
+  {
+    return attributes.getAttributeCount() == 0;
+  }
+
+  /**
+   * Return this, as this is immutable.
+   */
+  public AttributeSet copyAttributes()
+  {
+    return this;
+  }
+
+  /**
+   * Always return null as this AttributeSet doesn't contain any attributes.
+   */
+  public Object getAttribute(Object key)
+  {
+    return null;
+  }
+
+  /**
+   * Always return 0.
+   */
+  public int getAttributeCount()
+  {
+    return 0;
+  }
+
+  /**
+   * Returns an empty Enumeration.
+   */
+  public Enumeration getAttributeNames()
+  {
+    return new Enumeration()
+    {
+      public boolean hasMoreElements()
+      {
+        return false;
+      }
+
+      public Object nextElement()
+      {
+        throw new NoSuchElementException("No more elements");
+      }
+
+    };
+  }
+
+  /**
+   * Always return null as this has no resolve parent.
+   */
+  public AttributeSet getResolveParent()
+  {
+    return null;
+  }
+
+  /**
+   * Always return false as this AttributeSet doesn't contain any attributes.
+   */
+  public boolean isDefined(Object attrName)
+  {
+    return false;
+  }
+
+  /**
+   * Other attribute sets are equal if they are empty too.
+   */
+  public boolean isEqual(AttributeSet attr)
+  {
+    return attr.getAttributeCount() == 0;
+  }
+
+  /**
+   * Other objects are equal if it's the same instance as this, or if
+   * it's another attribute set without attributes.
+   */
+  public boolean equals(Object o)
+  {
+    boolean eq = o == this;
+    if (! eq)
+      {
+        eq = (o instanceof AttributeSet)
+             && ((AttributeSet) o).getAttributeCount() == 0;
+      }
+    return eq;
+  }
+}