The new helper class itself.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@267767 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/EnumeratedAttribute.java

@@ -0,0 +1,112 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2000 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant;
+
+/**
+ * Helper class for attributes that can only take one of a fixed list
+ * of values.
+ *
+ * <p>See {@link org.apache.tools.ant.taskdefs.FixCRLF FixCRLF} for an
+ * example.
+ *
+ * @author Stefan Bodewig <a href="mailto:stefan.bodewig@megabit.net">stefan.bodewig@megabit.net</a> 
+ */
+public abstract class EnumeratedAttribute {
+
+    protected String value;
+
+    /**
+     * This is the only method a subclass needs to implement.
+     *
+     * @return an array holding all possible values of the enumeration.
+     */
+    public abstract String[] getValues();
+
+    public EnumeratedAttribute() {}
+
+    /**
+     * Invoked by {@link IntrospectionHelper IntrospectionHelper}.
+     */
+    public final void setValue(String value) throws BuildException {
+        if (!containsValue(value)) {
+            throw new BuildException(value+" is not a legal value for this attribute");
+        }
+        this.value = value;
+    }
+
+    /**
+     * Is this value included in the enumeration?
+     */
+    public final boolean containsValue(String value) {
+        String[] values = getValues();
+        if (values == null || value == null) {
+            return false;
+        }
+        
+        for (int i=0; i<values.length; i++) {
+            if (value.equals(values[i])) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Retrieves the value.
+     */
+    public final String getValue() {
+        return value;
+    }
+}