1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18package java.util.logging;
19
20/**
21 * An error reporting facility for {@link Handler} implementations to record any
22 * error that may happen during logging. {@code Handlers} should report errors
23 * to an {@code ErrorManager}, instead of throwing exceptions, which would
24 * interfere with the log issuer's execution.
25 */
26public class ErrorManager {
27
28    /**
29     * The error code indicating a failure that does not fit in any of the
30     * specific types of failures that follow.
31     */
32    public static final int GENERIC_FAILURE = 0;
33
34    /**
35     * The error code indicating a failure when writing to an output stream.
36     */
37    public static final int WRITE_FAILURE = 1;
38
39    /**
40     * The error code indicating a failure when flushing an output stream.
41     */
42    public static final int FLUSH_FAILURE = 2;
43
44    /**
45     * The error code indicating a failure when closing an output stream.
46     */
47    public static final int CLOSE_FAILURE = 3;
48
49    /**
50     * The error code indicating a failure when opening an output stream.
51     */
52    public static final int OPEN_FAILURE = 4;
53
54    /**
55     * The error code indicating a failure when formatting the error messages.
56     */
57    public static final int FORMAT_FAILURE = 5;
58
59    private static final String[] FAILURES = new String[] { "GENERIC_FAILURE",
60            "WRITE_FAILURE", "FLUSH_FAILURE", "CLOSE_FAILURE", "OPEN_FAILURE",
61            "FORMAT_FAILURE" };
62
63    /**
64     * An indicator for determining if the error manager has been called at
65     * least once before.
66     */
67    private boolean called;
68
69    /**
70     * Constructs an instance of {@code ErrorManager}.
71     */
72    public ErrorManager() {
73    }
74
75    /**
76     * Reports an error using the given message, exception and error code. This
77     * implementation will write out the message to {@link System#err} on the
78     * first call and all subsequent calls are ignored. A subclass of this class
79     * should override this method.
80     *
81     * @param message
82     *            the error message, which may be {@code null}.
83     * @param exception
84     *            the exception associated with the error, which may be
85     *            {@code null}.
86     * @param errorCode
87     *            the error code that identifies the type of error; see the
88     *            constant fields of this class for possible values.
89     */
90    public void error(String message, Exception exception, int errorCode) {
91        synchronized (this) {
92            if (called) {
93                return;
94            }
95            called = true;
96        }
97        System.err.println(this.getClass().getName() + ": " + FAILURES[errorCode]);
98        if (message != null) {
99            System.err.println("Error message - " + message);
100        }
101        if (exception != null) {
102            System.err.println("Exception - " + exception);
103        }
104    }
105}
106