1 files changed, 217 insertions, 0 deletions
diff --git a/container-core/src/main/java/com/yahoo/processing/request/ErrorMessage.java b/container-core/src/main/java/com/yahoo/processing/request/ErrorMessage.java
new file mode 100644
index 00000000000..0ced664bfdc
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/processing/request/ErrorMessage.java
@@ -0,0 +1,217 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.processing.request;
+
+/**
+ * An error encountered while processing a request.
+ * This can be subclassed to add error messages containing more information.
+ * <p>
+ * Error messages are immutable.
+ *
+ * @author bratseth
+ */
+public class ErrorMessage implements Cloneable {
+
+    private final int code;
+    private final String message;
+    private final String detailedMessage;
+    private final Throwable cause;
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     */
+    public ErrorMessage(String message) {
+        this(0, message, null, null);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     * @param code an error code. If this is bound to HTTP request/responses and
+     *             this error code is a HTTP status code, this code will be returned as the HTTP status
+     */
+    public ErrorMessage(int code, String message) {
+        this(code, message, null, null);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     * @param details a longer detail description of this condition
+     */
+    public ErrorMessage(String message, String details) {
+        this(0, message, details, null);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     * @param code an error code. If this is bound to HTTP request/responses and
+     *             this error code is a HTTP status code, this code will be returned as the HTTP status
+     * @param details a longer detail description of this condition
+     */
+    public ErrorMessage(int code, String message, String details) {
+        this(code, message, details, null);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     * @param cause the cause of this error
+     */
+    public ErrorMessage(String message, Throwable cause) {
+        this(0, message, null, cause);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param code an error code. If this is bound to HTTP request/responses and
+     *             this error code is a HTTP status code, this code will be returned as the HTTP status
+     * @param message the textual message describing this condition tersely
+     * @param cause the cause of this error
+     */
+    public ErrorMessage(int code, String message, Throwable cause) {
+        this(code, message, null, cause);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param message the textual message describing this condition tersely
+     * @param details a longer detail description of this condition
+     * @param cause the cause of this error
+     */
+    public ErrorMessage(String message, String details, Throwable cause) {
+        this(0, message, details, cause);
+    }
+
+    /**
+     * Creates an error
+     *
+     * @param code an error code. If this is bound to HTTP request/responses and
+     *             this error code is a HTTP status code, this code will be returned as the HTTP status
+     * @param message the textual message describing this condition tersely
+     * @param details a longer detail description of this condition
+     * @param cause the cause of this error
+     */
+    public ErrorMessage(int code, String message, String details, Throwable cause) {
+        if (message == null) throw new NullPointerException("Message cannot be null");
+        this.code = code;
+        this.message = message;
+        this.detailedMessage = details;
+        this.cause = cause;
+    }
+
+    /**
+     * Returns the code of this message, or 0 if no code is set
+     */
+    public int getCode() {
+        return code;
+    }
+
+    /**
+     * Returns the error message, never null
+     */
+    public String getMessage() {
+        return message;
+    }
+
+    /**
+     * Returns detailed information about this error, or null if there is no detailed message
+     */
+    public String getDetailedMessage() {
+        return detailedMessage;
+    }
+
+    /**
+     * Returns the throwable associated with this error, or null if none
+     */
+    public Throwable getCause() {
+        return cause;
+    }
+
+    /**
+     * Returns a formatted message containing the information in this
+     */
+    @Override
+    public String toString() {
+        if (code == 0 && detailedMessage == null && cause == null) return message; // shortcut
+        StringBuilder b = new StringBuilder();
+        if (code != 0)
+            b.append(code).append(": ");
+        b.append(message);
+        if (detailedMessage != null)
+            b.append(": ").append(detailedMessage);
+        if (cause != null)
+            append(cause, b);
+        return b.toString();
+    }
+
+    private void append(Throwable t, StringBuilder b) {
+        String lastMessage = null;
+        String message;
+        for (; t != null; t = t.getCause(), lastMessage = message) {
+            message = getMessage(t);
+            if (message == null) continue;
+            if (lastMessage != null && lastMessage.equals(message)) continue;
+            if (b.length() > 0)
+                b.append(": ");
+            b.append(message);
+        }
+    }
+
+    /**
+     * Returns a useful message from *this* exception, or null if none
+     */
+    private static String getMessage(Throwable t) {
+        String message = t.getMessage();
+        if (t.getCause() == null) {
+            if (message == null) return t.getClass().getSimpleName();
+        } else {
+            if (message == null) return null;
+            if (message.equals(t.getCause().getClass().getName() + ": " + t.getCause().getMessage())) return null;
+        }
+        return message;
+    }
+
+    @Override
+    public int hashCode() {
+        return code * 7 + message.hashCode() + (detailedMessage == null ? 0 : 17 * detailedMessage.hashCode());
+    }
+
+    /**
+     * Two error messages are equal if they have the same code and message.
+     * The cause is ignored in the comparison.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof ErrorMessage)) return false;
+
+        ErrorMessage other = (ErrorMessage) o;
+
+        if (this.code != other.code) return false;
+
+        if (!this.message.equals(other.message)) return false;
+
+        if (this.detailedMessage == null) return other.detailedMessage == null;
+        if (other.detailedMessage == null) return false;
+
+        return this.detailedMessage.equals(other.detailedMessage);
+    }
+
+    @Override
+    public ErrorMessage clone() {
+        try {
+            return (ErrorMessage) super.clone();
+        } catch (CloneNotSupportedException e) {
+            throw new RuntimeException("Programming error");
+        }
+    }
+
+}