[camel] 01/01: CAMEL-17307: Add exception factory for predicate validation. WIP.

[da...@apache.org]

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davsclaus pushed a commit to branch throw-predicate
in repository https://gitbox.apache.org/repos/asf/camel.git

commit 3ad876a5816a0eef4add96f9fe3ae325cdaad071
Author: Claus Ibsen <cl...@gmail.com>
AuthorDate: Mon Jan 10 09:15:18 2022 +0100

    CAMEL-17307: Add exception factory for predicate validation. WIP.
---
 .../camel/spi/PredicateExceptionFactory.java       | 38 ++++++++++++++++++++++
 .../processor/PredicateValidatingProcessor.java    | 25 +++++++++++++-
 2 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/core/camel-api/src/main/java/org/apache/camel/spi/PredicateExceptionFactory.java b/core/camel-api/src/main/java/org/apache/camel/spi/PredicateExceptionFactory.java
new file mode 100644
index 0000000..df5711ff
--- /dev/null
+++ b/core/camel-api/src/main/java/org/apache/camel/spi/PredicateExceptionFactory.java
@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.spi;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.Predicate;
+
+/**
+ * A factory that can be used to create a specific exception when a {@link Predicate} returning false, which can be used
+ * by camel-validator and other components.
+ */
+public interface PredicateExceptionFactory {
+
+    /**
+     * Allows to return a specific exception for the given predicate in case it failed
+     *
+     * @param  exchange  the current exchange
+     * @param  predicate the predicate that returned false
+     * @return           the exception, or <tt>null</tt> to not use a specific exception but let Camel use a standard
+     *                   exception such as PredicateValidationException.
+     */
+    Exception newPredicateException(Exchange exchange, Predicate predicate);
+
+}
diff --git a/core/camel-support/src/main/java/org/apache/camel/support/processor/PredicateValidatingProcessor.java b/core/camel-support/src/main/java/org/apache/camel/support/processor/PredicateValidatingProcessor.java
index c318869..02c64d2 100644
--- a/core/camel-support/src/main/java/org/apache/camel/support/processor/PredicateValidatingProcessor.java
+++ b/core/camel-support/src/main/java/org/apache/camel/support/processor/PredicateValidatingProcessor.java
@@ -20,6 +20,7 @@ import org.apache.camel.Exchange;
 import org.apache.camel.Predicate;
 import org.apache.camel.Processor;
 import org.apache.camel.Traceable;
+import org.apache.camel.spi.PredicateExceptionFactory;
 import org.apache.camel.support.service.ServiceSupport;
 import org.apache.camel.util.ObjectHelper;
 import org.slf4j.Logger;
@@ -33,6 +34,7 @@ public class PredicateValidatingProcessor extends ServiceSupport implements Proc
     private static final Logger LOG = LoggerFactory.getLogger(PredicateValidatingProcessor.class);
 
     private final Predicate predicate;
+    private PredicateExceptionFactory predicateExceptionFactory;
 
     public PredicateValidatingProcessor(Predicate predicate) {
         ObjectHelper.notNull(predicate, "predicate", this);
@@ -48,7 +50,14 @@ public class PredicateValidatingProcessor extends ServiceSupport implements Proc
         }
 
         if (!matches) {
-            throw new PredicateValidationException(exchange, predicate);
+            Exception cause = null;
+            if (predicateExceptionFactory != null) {
+                cause = predicateExceptionFactory.newPredicateException(exchange, predicate);
+            }
+            if (cause == null) {
+                cause = new PredicateValidationException(exchange, predicate);
+            }
+            throw cause;
         }
     }
 
@@ -56,6 +65,20 @@ public class PredicateValidatingProcessor extends ServiceSupport implements Proc
         return predicate;
     }
 
+    /**
+     * To use a custom factory for creating the exception to throw if predicate does not match
+     */
+    public PredicateExceptionFactory getPredicateExceptionFactory() {
+        return predicateExceptionFactory;
+    }
+
+    /**
+     * To use a custom factory for creating the exception to throw if predicate does not match
+     */
+    public void setPredicateExceptionFactory(PredicateExceptionFactory predicateExceptionFactory) {
+        this.predicateExceptionFactory = predicateExceptionFactory;
+    }
+
     @Override
     public String toString() {
         return "validate(" + predicate + ")";