Added supported for template attributes.

Templates instantiated through the engine's Context, will have the context set as an attribute by default.

lib/src/main/java/rife/engine/Context.java

@@ -511,7 +511,9 @@ public class Context {
         if (null == name) throw new IllegalArgumentException("name can't be null.");
         if (0 == name.length()) throw new IllegalArgumentException("name can't be empty.");
 
-        return TemplateFactory.HTML.get(name, encoding);
+        var template = TemplateFactory.HTML.get(name, encoding);
+        template.setAttribute(Context.class.getName(), this);
+        return template;
     }
 
     /**
@@ -563,7 +565,9 @@ public class Context {
         if (null == name) throw new IllegalArgumentException("name can't be null.");
         if (0 == name.length()) throw new IllegalArgumentException("name can't be empty.");
 
-        return TemplateFactory.TXT.get(name, encoding);
+        var template = TemplateFactory.TXT.get(name, encoding);
+        template.setAttribute(Context.class.getName(), this);
+        return template;
     }
 
     /**
@@ -615,7 +619,9 @@ public class Context {
         if (null == name) throw new IllegalArgumentException("name can't be null.");
         if (0 == name.length()) throw new IllegalArgumentException("name can't be empty.");
 
-        return TemplateFactory.XML.get(name, encoding);
+        var template = TemplateFactory.XML.get(name, encoding);
+        template.setAttribute(Context.class.getName(), this);
+        return template;
     }
 
     /**
@@ -667,7 +673,9 @@ public class Context {
         if (null == name) throw new IllegalArgumentException("name can't be null.");
         if (0 == name.length()) throw new IllegalArgumentException("name can't be empty.");
 
-        return TemplateFactory.JSON.get(name, encoding);
+        var template = TemplateFactory.JSON.get(name, encoding);
+        template.setAttribute(Context.class.getName(), this);
+        return template;
     }
 
     /**
@@ -719,7 +727,9 @@ public class Context {
         if (null == name) throw new IllegalArgumentException("name can't be null.");
         if (0 == name.length()) throw new IllegalArgumentException("name can't be empty.");
 
-        return TemplateFactory.SVG.get(name, encoding);
+        var template = TemplateFactory.SVG.get(name, encoding);
+        template.setAttribute(Context.class.getName(), this);
+        return template;
     }
 
     /**

lib/src/main/java/rife/template/AbstractTemplate.java

@@ -26,6 +26,7 @@ public abstract class AbstractTemplate implements Template {
     protected TemplateEncoder encoder_ = EncoderDummy.instance();
     protected List<ResourceBundle> defaultResourceBundles_ = null;
     protected List<ResourceBundle> resourceBundles_ = null;
+    protected Map<String, Object> attributes_ = null;
     protected String language_ = null;
     protected String defaultContentType_ = null;
 
@@ -874,6 +875,52 @@ public abstract class AbstractTemplate implements Template {
         return language_;
     }
 
+    public void setAttribute(String name, Object value) {
+        if (null == attributes_) {
+            attributes_ = new HashMap<>();
+        }
+
+        attributes_.put(name, value);
+    }
+
+    public void setAttributes(Map<String, Object> map) {
+        if (null == attributes_) {
+            attributes_ = new HashMap<>();
+        }
+
+        attributes_.putAll(map);
+    }
+
+    public void removeAttribute(String name) {
+        if (null == attributes_) {
+            return;
+        }
+
+        attributes_.remove(name);
+    }
+
+    public boolean hasAttribute(String name) {
+        if (null == attributes_) {
+            return false;
+        }
+        return attributes_.containsKey(name);
+    }
+
+    public Object getAttribute(String name) {
+        if (null == attributes_) {
+            return null;
+        }
+        return attributes_.get(name);
+    }
+
+    public Map<String, Object> getAttributes() {
+        if (attributes_ == null) {
+            return Collections.emptyMap();
+        }
+
+        return Collections.unmodifiableMap(attributes_);
+    }
+
     final void initialize()
     throws TemplateException {
         evaluateL10nTags();
@@ -959,6 +1006,10 @@ public abstract class AbstractTemplate implements Template {
             new_template.constructedValues_.put(constructed_value_id, constructedValues_.get(constructed_value_id));
         }
 
+        if (attributes_ != null) {
+            new_template.attributes_ = new HashMap<>(attributes_);
+        }
+
         return new_template;
     }
 }

lib/src/main/java/rife/template/Template.java

@@ -1493,6 +1493,92 @@ public interface Template extends Cloneable {
      */
     String getLanguage();
 
+    /**
+     * Sets an attribute that will be associated with this template instance.
+     * <p>
+     * For general purpose attributes of object instances, it's recommended to
+     * use the fully qualified classname of the object as the attribute name.
+     *
+     * @param name  the name of the attribute
+     * @param value the value of the attribute
+     * @see #setAttributes
+     * @see #removeAttribute
+     * @see #hasAttribute
+     * @see #getAttribute
+     * @see #getAttributes
+     * @since 1.5
+     */
+    void setAttribute(String name, Object value);
+
+    /**
+     * Sets the given attributes to the corresponding values.
+     * Calling this method is equivalent to calling {@link #setAttribute
+     * setAttribute} for each entry in the given map.
+     *
+     * @param map a map of attribute name and values
+     * @see #setAttribute
+     * @see #removeAttribute
+     * @see #hasAttribute
+     * @see #getAttribute
+     * @see #getAttributes
+     * @since 1.5
+     */
+    void setAttributes(Map<String, Object> map);
+
+    /**
+     * Removes an attribute from this template instance.
+     *
+     * @param name  the name of the attribute
+     * @see #setAttribute
+     * @see #setAttributes
+     * @see #hasAttribute
+     * @see #getAttribute
+     * @see #getAttributes
+     * @since 1.5
+     */
+    void removeAttribute(String name);
+
+    /**
+     * Checks whether an attribute exists in this template instance.
+     *
+     * @return {@code true} if the attribute exists; {@code false} otherwise
+     * @see #setAttribute
+     * @see #removeAttribute
+     * @see #setAttributes
+     * @see #getAttribute
+     * @see #getAttributes
+     * @since 1.5
+     */
+    boolean hasAttribute(String name);
+
+    /**
+     * Returns the value of an attribute that was {@linkplain #setAttribute set}
+     * in this template instance.
+     *
+     * @return the attributes value; or {@code null} of no such attribute could be found
+     * @see #setAttribute
+     * @see #removeAttribute
+     * @see #setAttributes
+     * @see #hasAttribute
+     * @see #getAttributes
+     * @since 1.5
+     */
+    Object getAttribute(String name);
+
+    /**
+     * Returns the name and value of all attributes that
+     * have been {@linkplain #setAttribute set} in this template instance.
+     *
+     * @return the attributes currently set in this template
+     * @see #setAttribute
+     * @see #removeAttribute
+     * @see #setAttributes
+     * @see #hasAttribute
+     * @see #getAttribute
+     * @since 1.5
+     */
+    Map<String, Object> getAttributes();
+
     /**
      * Returns a list of URL's that this template depends on, and their last
      * modification dates (in milliseconds since the Unix epoch). This method

lib/src/test/java/rife/template/TestTemplate.java

@@ -13,9 +13,7 @@ import rife.tools.ExceptionUtils;
 import rife.tools.StringUtils;
 import rife.validation.ConstrainedProperty;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collection;
-import java.util.List;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -1080,4 +1078,58 @@ public class TestTemplate {
             fail(ExceptionUtils.getExceptionStackTrace(e));
         }
     }
+
+    @Test
+    void testAttributes() {
+        var template = TemplateFactory.HTML.get("empty");
+        assertNotNull(template.getAttributes());
+        assertEquals(0, template.getAttributes().size());
+
+        assertNull(template.getAttribute("date"));
+        assertNull(template.getAttribute("template"));
+        assertFalse(template.hasAttribute("date"));
+        assertFalse(template.hasAttribute("template"));
+        var date = new Date();
+        template.setAttribute("date", date);
+        template.setAttribute("template", template);
+
+        assertSame(date, template.getAttribute("date"));
+        assertSame(template, template.getAttribute("template"));
+        assertTrue(template.hasAttribute("date"));
+        assertTrue(template.hasAttribute("template"));
+
+        assertEquals(2, template.getAttributes().size());
+        assertSame(date, template.getAttributes().get("date"));
+        assertSame(template, template.getAttributes().get("template"));
+
+        template.removeAttribute("date");
+        assertNull(template.getAttribute("date"));
+        assertSame(template, template.getAttribute("template"));
+
+        assertFalse(template.hasAttribute("date"));
+        assertTrue(template.hasAttribute("template"));
+
+        assertEquals(1, template.getAttributes().size());
+        assertNull(template.getAttributes().get("date"));
+        assertSame(template, template.getAttributes().get("template"));
+
+        var map = new HashMap<String, Object>();
+        var date2 = new Date();
+        var cal = Calendar.getInstance();
+        map.put("date", date2);
+        map.put("cal", cal);
+
+        assertFalse(template.hasAttribute("date"));
+        assertTrue(template.hasAttribute("template"));
+        assertFalse(template.hasAttribute("cal"));
+
+        template.setAttributes(map);
+        assertEquals(3, template.getAttributes().size());
+        assertTrue(template.hasAttribute("date"));
+        assertTrue(template.hasAttribute("template"));
+        assertTrue(template.hasAttribute("cal"));
+        assertSame(date2, template.getAttributes().get("date"));
+        assertSame(template, template.getAttributes().get("template"));
+        assertSame(cal, template.getAttributes().get("cal"));
+    }
 }