1/* 2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package jdk.jshell; 27 28import jdk.jshell.Snippet.Status; 29 30/** 31 * A description of a change to a Snippet. These are generated by direct changes 32 * to state with {@link JShell#eval(java.lang.String) JShell.eval(String)} or 33 * {@link JShell#drop(jdk.jshell.Snippet) JShell.drop(Snippet)}, 34 * or indirectly by these same methods as 35 * dependencies change or Snippets are overwritten. For direct changes, the 36 * {@link SnippetEvent#causeSnippet()} is {@code null}. 37 * <p> 38 * {@code SnippetEvent} is immutable: an access to 39 * any of its methods will always return the same result. 40 * and thus is thread-safe. 41 * 42 * @author Robert Field 43 * @since 9 44 */ 45public class SnippetEvent { 46 47 SnippetEvent(Snippet snippet, Status previousStatus, Status status, 48 boolean isSignatureChange, Snippet causeSnippet, 49 String value, JShellException exception) { 50 this.snippet = snippet; 51 this.previousStatus = previousStatus; 52 this.status = status; 53 this.isSignatureChange = isSignatureChange; 54 this.causeSnippet = causeSnippet; 55 this.value = value; 56 this.exception = exception; 57 } 58 59 private final Snippet snippet; 60 private final Status previousStatus; 61 private final Status status; 62 private final boolean isSignatureChange; 63 private final Snippet causeSnippet; 64 private final String value; 65 private final JShellException exception; 66 67 /** 68 * The Snippet which has changed 69 * @return the return the Snippet whose {@code Status} has changed. 70 */ 71 public Snippet snippet() { 72 return snippet; 73 } 74 75 /** 76 * The status before the transition. If this event describes a Snippet 77 * creation return {@link Snippet.Status#NONEXISTENT NONEXISTENT}. 78 * @return the previousStatus 79 */ 80 public Status previousStatus() { 81 return previousStatus; 82 } 83 84 /** 85 * The after status. Note: this may be the same as the previous status (not 86 * all changes cause a {@code Status} change. 87 * @return the status 88 */ 89 public Status status() { 90 return status; 91 } 92 93 /** 94 * Indicates whether the signature has changed. Coming in or out of 95 * {@linkplain Status#isDefined() definition} is always a signature change. 96 * An overwritten Snippet 97 * {@link jdk.jshell.Snippet.Status#OVERWRITTEN (status == OVERWRITTEN)} 98 * is always {@code false} as responsibility for the 99 * definition has passed to the overwriting definition. 100 * 101 * @return {@code true} if the signature changed; otherwise {@code false} 102 */ 103 public boolean isSignatureChange() { 104 return isSignatureChange; 105 } 106 107 /** 108 * Either the snippet whose change caused this update or 109 * {@code null}. This returns {@code null} if this change is the 110 * creation of a new Snippet via 111 * {@link jdk.jshell.JShell#eval(java.lang.String) eval} or it is the 112 * explicit drop of a Snippet with 113 * {@link jdk.jshell.JShell#drop(jdk.jshell.Snippet) drop}. 114 * 115 * @return the Snippet which caused this change or {@code null} if 116 * directly caused by an API action. 117 */ 118 public Snippet causeSnippet() { 119 return causeSnippet; 120 } 121 122 /** 123 * An instance of {@link jdk.jshell.UnresolvedReferenceException}, if an unresolved reference was 124 * encountered, or an instance of {@link jdk.jshell.EvalException} if an exception was thrown 125 * during execution, otherwise {@code null}. 126 * @return the exception or {@code null}. 127 */ 128 public JShellException exception() { 129 return exception; 130 } 131 132 /** 133 * The result value of successful run. The value is null if not executed 134 * or an exception was thrown. 135 * @return the value or {@code null}. 136 */ 137 public String value() { 138 return value; 139 } 140 141 /** 142 * Return a string representation of the event 143 * @return a descriptive representation of the SnippetEvent 144 */ 145 @Override 146 public String toString() { 147 return "SnippetEvent(snippet=" + snippet + 148 ",previousStatus=" + previousStatus + 149 ",status=" + status + 150 ",isSignatureChange=" + isSignatureChange + 151 ",causeSnippet" + causeSnippet + 152 (value == null? "" : "value=" + value) + 153 (exception == null? "" : "exception=" + exception) + 154 ")"; 155 } 156} 157