From 8e3b22b3e36c0ba3962022765a5f9b69a8e18c27 Mon Sep 17 00:00:00 2001
From: Robert von Burg <eitch@eitchnet.ch>
Date: Wed, 16 Jan 2019 17:25:57 +0100
Subject: [PATCH] [New] Added PolicyHandler.isPolicyDefAvailable()

---
 .../strolch/policy/DefaultPolicyHandler.java  | 14 ++++++++
 .../java/li/strolch/policy/PolicyHandler.java | 34 ++++++++++++-------
 2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/li.strolch.agent/src/main/java/li/strolch/policy/DefaultPolicyHandler.java b/li.strolch.agent/src/main/java/li/strolch/policy/DefaultPolicyHandler.java
index 2b5340d1d..fe4ad8d68 100644
--- a/li.strolch.agent/src/main/java/li/strolch/policy/DefaultPolicyHandler.java
+++ b/li.strolch.agent/src/main/java/li/strolch/policy/DefaultPolicyHandler.java
@@ -81,6 +81,7 @@ public class DefaultPolicyHandler extends StrolchComponent implements PolicyHand
 
 	@Override
 	public <T extends StrolchPolicy> T getPolicy(PolicyDef policyDef, StrolchTransaction tx) {
+		DBC.PRE.assertNotNull("policyDef must not be null!", policyDef);
 		DBC.PRE.assertNotNull("tx must not be null!", tx);
 		try {
 
@@ -94,6 +95,19 @@ public class DefaultPolicyHandler extends StrolchComponent implements PolicyHand
 		}
 	}
 
+	@Override
+	public boolean isPolicyDefAvailable(PolicyDef policyDef) {
+		DBC.PRE.assertNotNull("policyDef must not be null!", policyDef);
+
+		if (policyDef instanceof KeyPolicyDef)
+			return this.classByTypeMap.containsElement(policyDef.getType(), policyDef.getValue());
+
+		if (policyDef instanceof JavaPolicyDef)
+			return true;
+
+		throw new IllegalArgumentException("Unhandled PolicyDev instance " + policyDef.getClass());
+	}
+
 	@Override
 	public <T> Class<T> visit(JavaPolicyDef policyDef) throws ClassNotFoundException {
 		String value = policyDef.getValue();
diff --git a/li.strolch.agent/src/main/java/li/strolch/policy/PolicyHandler.java b/li.strolch.agent/src/main/java/li/strolch/policy/PolicyHandler.java
index a7713d896..2e728d9e7 100644
--- a/li.strolch.agent/src/main/java/li/strolch/policy/PolicyHandler.java
+++ b/li.strolch.agent/src/main/java/li/strolch/policy/PolicyHandler.java
@@ -1,12 +1,12 @@
 /*
  * Copyright 2015 Robert von Burg <eitch@eitchnet.ch>
- * 
+ *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -23,35 +23,45 @@ import li.strolch.persistence.api.StrolchTransaction;
  * <p>
  * The {@link PolicyHandler} is Strolch's mechanism of dependency injection
  * </p>
- * 
+ *
  * <p>
  * Objects which require delegation can use a {@link PolicyConfiguration} element and then retrieve a StrolchPolicy
  * instance from this {@link PolicyHandler}.
  * </p>
- * 
+ *
  * <p>
  * {@link PolicyConfiguration} have a mapping of a policy type, i.e. an interface for a specific delegation. This
  * interface has concrete implementations which are then returned by the {@link PolicyHandler} depending on the current
  * configuration
  * </p>
- * 
+ *
  * <p>
  * The resolving of a policy instance is handled by a {@link PolicyDefVisitor}
  * <p>
- * 
+ *
  * @author Robert von Burg <eitch@eitchnet.ch>
  */
 public interface PolicyHandler {
 
 	/**
 	 * Instantiates the actual policy by resolving the {@link PolicyDef} using a {@link PolicyDefVisitor}
-	 * 
+	 *
 	 * @param policyDef
-	 *            the {@link PolicyDef} referencing a concrete policy
+	 * 		the {@link PolicyDef} referencing a concrete policy
 	 * @param tx
-	 *            the current transaction for which the policy is instantiated
-	 * 
+	 * 		the current transaction for which the policy is instantiated
+	 *
 	 * @return the instantiated instance of the referenced policy
 	 */
-	public <T extends StrolchPolicy> T getPolicy(PolicyDef policyDef, StrolchTransaction tx);
+	<T extends StrolchPolicy> T getPolicy(PolicyDef policyDef, StrolchTransaction tx);
+
+	/**
+	 * Returns true, if the policy definition is known
+	 *
+	 * @param policyDef
+	 * 		the policy definition to check for
+	 *
+	 * @return true if the policy definition is known, false otherwise
+	 */
+	boolean isPolicyDefAvailable(PolicyDef policyDef);
 }