LMS-257 new method for Template: attemptToBind()

SVN: 4521

common/source/java/ch/systemsx/cisd/common/utilities/Template.java

@@ -29,6 +29,7 @@ import java.util.Map;
  * String text = template.createText();
  * </pre>
  * The method {@link #bind(String, String)} throws an exception if the placeholder name is unknown.
+ * The method {@link #attemptToBind(String, String)} returns <code>false</code> if the placeholder name is unknown.
  * The method {@link #createText()} throws an exception if not all placeholders have been bound.
  * <p>
  * Since placeholder bindings change the state of an instance of this class there is method {@link #createFreshCopy()}
@@ -273,6 +274,20 @@ public class Template
      * @throws IllegalArgumentException if placeholder is not known.
      */
     public void bind(String placeholderName, String value)
+    {
+        boolean successful = attemptToBind(placeholderName, value);
+        if (successful == false)
+        {
+            throw new IllegalArgumentException("Unknown variable '" + placeholderName + "'."); 
+        }
+    }
+
+    /**
+     * Attempts to bind the specified value to the specified placeholder name.
+     * 
+     * @return <code>true</code> if successful.
+     */
+    public boolean attemptToBind(String placeholderName, String value)
     {
         assert placeholderName != null : "Unspecified placeholder name.";
         assert value != null : "Unspecified value for '" + placeholderName + "'";
@@ -280,9 +295,10 @@ public class Template
         VariableToken variableToken = variableTokens.get(placeholderName);
         if (variableToken == null)
         {
-            throw new IllegalArgumentException("Unknown variable '" + placeholderName + "'."); 
+            return false;
         }
         variableToken.bind(value);
+        return true;
     }
     
     /**

common/sourceTest/java/ch/systemsx/cisd/common/utilities/TemplateTest.java

@@ -128,6 +128,15 @@ public class TemplateTest
         }
     }
     
+    @Test
+    public void testAttemptToBind()
+    {
+        Template template = new Template("${greeting} ${name}!");
+        assertEquals(true, template.attemptToBind("greeting", "Hi"));
+        assertEquals(false, template.attemptToBind("blabla", "blub"));
+        assertEquals("Hi ${name}!", template.createText(false));
+    }
+    
     @Test
     public void testIncompleteBinding()
     {