1 /* 2 * Copyright (c) 2016, 2018, 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 26 package jdk.jfr; 27 28 import java.lang.annotation.Annotation; 29 import java.util.Collections; 30 import java.util.List; 31 import java.util.Objects; 32 33 import jdk.jfr.internal.AnnotationConstruct; 34 import jdk.jfr.internal.Type; 35 36 /** 37 * Describes an event setting. 38 * 39 * @since 9 40 */ 41 public final class SettingDescriptor { 42 43 private final AnnotationConstruct annotationConstruct; 44 private final Type type; 45 private final String name; 46 private final String defaultValue; 47 48 // package private, invoked by jdk.internal. SettingDescriptor(Type type, String name, String defaultValue, List<AnnotationElement> annotations)49 SettingDescriptor(Type type, String name, String defaultValue, List<AnnotationElement> annotations) { 50 Objects.requireNonNull(annotations); 51 this.name = Objects.requireNonNull(name, "Name of value descriptor can't be null"); 52 this.type = Objects.requireNonNull(type); 53 this.annotationConstruct = new AnnotationConstruct(annotations); 54 this.defaultValue = Objects.requireNonNull(defaultValue); 55 } 56 57 // package private setAnnotations(List<AnnotationElement> as)58 void setAnnotations(List<AnnotationElement> as) { 59 annotationConstruct.setAnnotationElements(as); 60 } 61 62 /** 63 * Returns the name of the setting (for example, {@code "threshold"}). 64 * 65 * @return the name, not {@code null} 66 */ getName()67 public String getName() { 68 return name; 69 } 70 71 /** 72 * Returns a human-readable name that describes the setting (for example, 73 * {@code "Threshold"}). 74 * <p> 75 * If the setting lacks a label, the label for the type that is associated with this 76 * setting is returned, or {@code null} if doesn't exist 77 * 78 * @return a human-readable name, or {@code null} if doesn't exist 79 */ getLabel()80 public String getLabel() { 81 String label = annotationConstruct.getLabel(); 82 if (label == null) { 83 label = type.getLabel(); 84 } 85 return label; 86 } 87 88 /** 89 * Returns a sentence that describes the setting (for example 90 * {@code "Record event with duration 91 * above or equal to threshold"}). 92 * <p> 93 * If the setting lacks a description, the description for the type that is 94 * associated with this setting is returned, or {@code null} if doesn't exist. 95 * 96 * @return the description, or {@code null} if doesn't exist 97 */ getDescription()98 public String getDescription() { 99 String description = annotationConstruct.getDescription(); 100 if (description == null) { 101 description = type.getDescription(); 102 } 103 return description; 104 } 105 106 /** 107 * Returns a textual identifier that specifies how a value that is represented by 108 * this {@code SettingDescriptor} object is interpreted or formatted. 109 * <p> 110 * For example, if the setting descriptor represents a percentage, then 111 * {@code "jdk.jfr.Percentage"} hints to a client that a value of "0.5" 112 * is formatted as "50%". 113 * <p> 114 * The JDK provides the following predefined content types: 115 * <ul> 116 * <li>jdk.jfr.Percentage</li> 117 * <li>jdk.jfr.Timespan</li> 118 * <li>jdk.jfr.Timestamp</li> 119 * <li>jdk.jfr.Frequency</li> 120 * <li>jdk.jfr.Flag</li> 121 * <li>jdk.jfr.MemoryAddress</li> 122 * <li>jdk.jfr.DataAmount</li> 123 * <li>jdk.jfr.NetworkAddress</li> 124 * </ul> 125 * <p> 126 * User-defined content types can be created by using {@link ContentType}. 127 * <p> 128 * If the setting lacks a content type, the content type for the type 129 * that is associated with this setting is returned, or {@code null} if not 130 * available. 131 * 132 * @return the content type, or {@code null} if doesn't exist 133 * 134 * @see ContentType 135 */ getContentType()136 public String getContentType() { 137 for (AnnotationElement anno : getAnnotationElements()) { 138 for (AnnotationElement meta : anno.getAnnotationElements()) { 139 if (meta.getTypeName().equals(ContentType.class.getName())) { 140 return anno.getTypeName(); 141 } 142 } 143 } 144 for (AnnotationElement anno : type.getAnnotationElements()) { 145 for (AnnotationElement meta : anno.getAnnotationElements()) { 146 if (meta.getTypeName().equals(ContentType.class.getName())) { 147 return anno.getTypeName(); 148 } 149 } 150 } 151 return null; 152 } 153 154 /** 155 * Returns the fully qualified class name of the type that is associated with this 156 * setting descriptor. 157 * 158 * @return the type name, not {@code null} 159 * 160 * @see SettingDescriptor#getTypeId() 161 */ getTypeName()162 public String getTypeName() { 163 return type.getName(); 164 } 165 166 /** 167 * Returns a unique ID for the type in the Java Virtual Machine (JVM). 168 * <p> 169 * The ID might not be the same between JVM instances. 170 * 171 * @return the type ID, not negative 172 */ getTypeId()173 public long getTypeId() { 174 return type.getId(); 175 } 176 177 /** 178 * Returns the first annotation for the specified type if an annotation 179 * element with the same name is available, {@code null} otherwise. 180 * 181 * @param <A> the type of the annotation to query for and return if available 182 * @param annotationType the Class object that corresponds to the annotation 183 * type, not {@code null} 184 * @return this element's annotation for the specified annotation type if 185 * available, {@code null} otherwise 186 */ getAnnotation(Class<A> annotationType)187 public <A extends Annotation> A getAnnotation(Class<A> annotationType) { 188 Objects.requireNonNull(annotationType); 189 return annotationConstruct.getAnnotation(annotationType); 190 } 191 192 /** 193 * Returns an immutable list of annotation elements for this value 194 * descriptor. 195 * 196 * @return a list of annotations, not {@code null} 197 */ getAnnotationElements()198 public List<AnnotationElement> getAnnotationElements() { 199 return Collections.unmodifiableList(annotationConstruct.getUnmodifiableAnnotationElements()); 200 } 201 202 /** 203 * Returns the default value for this setting descriptor. 204 * 205 * @return the default value, not {@code null} 206 */ getDefaultValue()207 public String getDefaultValue() { 208 return defaultValue; 209 } 210 211 // package private getType()212 Type getType() { 213 return type; 214 } 215 } 216