1 /** 2 * Copyright (C) 2006 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.inject.spi; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.common.base.Objects; 22 import com.google.common.collect.ImmutableList; 23 import com.google.inject.Binder; 24 import com.google.inject.internal.Errors; 25 import com.google.inject.internal.util.SourceProvider; 26 27 import java.io.ObjectStreamException; 28 import java.io.Serializable; 29 import java.util.List; 30 31 /** 32 * An error message and the context in which it occured. Messages are usually created internally by 33 * Guice and its extensions. Messages can be created explicitly in a module using {@link 34 * com.google.inject.Binder#addError(Throwable) addError()} statements: 35 * <pre> 36 * try { 37 * bindPropertiesFromFile(); 38 * } catch (IOException e) { 39 * addError(e); 40 * }</pre> 41 * 42 * @author crazybob@google.com (Bob Lee) 43 */ 44 public final class Message implements Serializable, Element { 45 private final String message; 46 private final Throwable cause; 47 private final List<Object> sources; 48 49 /** 50 * @since 2.0 51 */ Message(List<Object> sources, String message, Throwable cause)52 public Message(List<Object> sources, String message, Throwable cause) { 53 this.sources = ImmutableList.copyOf(sources); 54 this.message = checkNotNull(message, "message"); 55 this.cause = cause; 56 } 57 58 /** 59 * @since 4.0 60 */ Message(String message, Throwable cause)61 public Message(String message, Throwable cause) { 62 this(ImmutableList.of(), message, cause); 63 } 64 Message(Object source, String message)65 public Message(Object source, String message) { 66 this(ImmutableList.of(source), message, null); 67 } 68 Message(String message)69 public Message(String message) { 70 this(ImmutableList.of(), message, null); 71 } 72 getSource()73 public String getSource() { 74 return sources.isEmpty() 75 ? SourceProvider.UNKNOWN_SOURCE.toString() 76 : Errors.convert(sources.get(sources.size() - 1)).toString(); 77 } 78 79 /** @since 2.0 */ getSources()80 public List<Object> getSources() { 81 return sources; 82 } 83 84 /** 85 * Gets the error message text. 86 */ getMessage()87 public String getMessage() { 88 return message; 89 } 90 91 /** @since 2.0 */ acceptVisitor(ElementVisitor<T> visitor)92 public <T> T acceptVisitor(ElementVisitor<T> visitor) { 93 return visitor.visit(this); 94 } 95 96 /** 97 * Returns the throwable that caused this message, or {@code null} if this 98 * message was not caused by a throwable. 99 * 100 * @since 2.0 101 */ getCause()102 public Throwable getCause() { 103 return cause; 104 } 105 toString()106 @Override public String toString() { 107 return message; 108 } 109 hashCode()110 @Override public int hashCode() { 111 return message.hashCode(); 112 } 113 equals(Object o)114 @Override public boolean equals(Object o) { 115 if (!(o instanceof Message)) { 116 return false; 117 } 118 Message e = (Message) o; 119 return message.equals(e.message) && Objects.equal(cause, e.cause) && sources.equals(e.sources); 120 } 121 122 /** @since 2.0 */ applyTo(Binder binder)123 public void applyTo(Binder binder) { 124 binder.withSource(getSource()).addError(this); 125 } 126 127 /** 128 * When serialized, we eagerly convert sources to strings. This hurts our formatting, but it 129 * guarantees that the receiving end will be able to read the message. 130 */ writeReplace()131 private Object writeReplace() throws ObjectStreamException { 132 Object[] sourcesAsStrings = sources.toArray(); 133 for (int i = 0; i < sourcesAsStrings.length; i++) { 134 sourcesAsStrings[i] = Errors.convert(sourcesAsStrings[i]).toString(); 135 } 136 return new Message(ImmutableList.copyOf(sourcesAsStrings), message, cause); 137 } 138 139 private static final long serialVersionUID = 0; 140 } 141