exception_handling.patch

Index: src/main/java/com/handson/basic/util/RestErrorMessage.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/main/java/com/handson/basic/util/RestErrorMessage.java b/src/main/java/com/handson/basic/util/RestErrorMessage.java
new file mode 100644
--- /dev/null	(date 1643232603469)
+++ b/src/main/java/com/handson/basic/util/RestErrorMessage.java	(date 1643232603469)
@@ -0,0 +1,65 @@
+package com.handson.basic.util;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import java.util.Objects;
+
+@JsonAutoDetect
+@JsonInclude(JsonInclude.Include.NON_EMPTY)
+public class RestErrorMessage {
+    private String error;
+
+
+
+    @JsonProperty
+    public String getError() {
+        return error;
+    }
+
+
+    @Override
+    public String toString() {
+        return "RestErrorMessage{" +
+                "error='" + error + '\'' +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        RestErrorMessage that = (RestErrorMessage) o;
+        return Objects.equals(error, that.error) ;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(error);
+    }
+
+
+    public static final class RestErrorMessageBuilder {
+        private String error;
+
+        private RestErrorMessageBuilder() {
+        }
+
+        public static RestErrorMessageBuilder aRestErrorMessage() {
+            return new RestErrorMessageBuilder();
+        }
+
+        public RestErrorMessageBuilder error(String error) {
+            this.error = error;
+            return this;
+        }
+
+
+        public RestErrorMessage build() {
+            RestErrorMessage restErrorMessage = new RestErrorMessage();
+            restErrorMessage.error = this.error;
+            return restErrorMessage;
+        }
+    }
+}
Index: src/main/java/com/handson/basic/util/GlobalDefaultExceptionHandler.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/main/java/com/handson/basic/util/GlobalDefaultExceptionHandler.java b/src/main/java/com/handson/basic/util/GlobalDefaultExceptionHandler.java
new file mode 100644
--- /dev/null	(date 1643232603463)
+++ b/src/main/java/com/handson/basic/util/GlobalDefaultExceptionHandler.java	(date 1643232603463)
@@ -0,0 +1,73 @@
+package com.handson.basic.util;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.dao.DuplicateKeyException;
+import org.springframework.dao.EmptyResultDataAccessException;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MissingServletRequestParameterException;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+import javax.servlet.http.HttpServletRequest;
+import java.nio.file.AccessDeniedException;
+
+
+@ControllerAdvice
+class GlobalDefaultExceptionHandler {
+
+    private static final Logger logger = LoggerFactory.getLogger(GlobalDefaultExceptionHandler.class);
+
+    @Autowired
+    ObjectMapper om;
+
+    @ExceptionHandler(value = Exception.class)
+    public ResponseEntity<String> defaultErrorHandler(HttpServletRequest req, Exception e) throws Exception {
+        logger.error("exception:" + e.getMessage() + ", class:" + e.getClass().getName());
+        // If the exception is annotated with @ResponseStatus rethrow it and let
+        // the framework handle it - like the OrderNotFoundException example
+        // at the start of this post.
+        // AnnotationUtils is a Spring Framework utility class.
+        if (AnnotationUtils.findAnnotation
+                (e.getClass(), ResponseStatus.class) != null) {
+            logger.error(e.getMessage(), e);
+            throw e;
+        }
+        if (e instanceof DuplicateKeyException) {
+            return new ResponseEntity<>(anErrorResponse("Duplicate Id"), HttpStatus.CONFLICT);
+        } else if (e instanceof EmptyResultDataAccessException) {
+            return new ResponseEntity<>(anErrorResponse("Not Found"), HttpStatus.NOT_FOUND);
+            // we raise runtime exceptions for business issues.
+        } else if (e instanceof MissingServletRequestParameterException) {
+            String res = anErrorResponse(e.getMessage());
+            return new ResponseEntity<>(res, HttpStatus.BAD_REQUEST);
+        } else if (e instanceof AccessDeniedException) {
+            String res = anErrorResponse(e.getMessage());
+            return new ResponseEntity<>(res, HttpStatus.FORBIDDEN);
+        } else if (e instanceof HandsonException) {
+            String res = anErrorResponse(e.getMessage());
+            return new ResponseEntity<>(res, HttpStatus.FORBIDDEN);
+        }
+        logger.error(e.getMessage(), e);
+        // Otherwise it is unexpected
+        return new ResponseEntity<>(anErrorResponse("unexpected problem"), HttpStatus.CONFLICT);
+    }
+
+    private String anErrorResponse(String s) {
+        RestErrorMessage em = RestErrorMessage.RestErrorMessageBuilder.aRestErrorMessage().error(s).build();
+        String res = null;
+        try {
+            res = om.writeValueAsString(em);
+            return res;
+        } catch (JsonProcessingException e) {
+            logger.error(e.getMessage(), e);
+            return "";
+        }
+    }
+}
Index: src/main/java/com/handson/basic/util/HandsonException.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/main/java/com/handson/basic/util/HandsonException.java b/src/main/java/com/handson/basic/util/HandsonException.java
new file mode 100644
--- /dev/null	(date 1643232603466)
+++ b/src/main/java/com/handson/basic/util/HandsonException.java	(date 1643232603466)
@@ -0,0 +1,16 @@
+package com.handson.basic.util;
+
+import java.util.function.Supplier;
+
+public class HandsonException extends RuntimeException implements Supplier<HandsonException> {
+
+    public HandsonException(String message) {
+        super(message);
+    }
+
+
+    @Override
+    public HandsonException get() {
+        return this;
+    }
+}