1 /*
   2  * Copyright (c) 2016, 2019, 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.io.IOException;
  29 import java.io.Reader;
  30 import java.nio.file.Files;
  31 import java.nio.file.Path;
  32 import java.text.ParseException;
  33 import java.util.ArrayList;
  34 import java.util.Collections;
  35 import java.util.LinkedHashMap;
  36 import java.util.List;
  37 import java.util.Map;
  38 import java.util.Objects;
  39 
  40 import jdk.jfr.internal.JVMSupport;
  41 import jdk.jfr.internal.jfc.JFC;
  42 
  43 /**
  44  * A collection of settings and metadata describing the configuration.
  45  *
  46  * @since 8
  47  */
  48 public final class Configuration {
  49     private final Map<String, String> settings;
  50     private final String label;
  51     private final String description;
  52     private final String provider;
  53     private final String contents;
  54     private final String name;
  55 
  56     // package private
  57     Configuration(String name, String label, String description, String provider, Map<String, String> settings, String contents) {
  58         this.name = name;
  59         this.label = label;
  60         this.description = description;
  61         this.provider = provider;
  62         this.settings = settings;
  63         this.contents = contents;
  64     }
  65 
  66     /**
  67      * Returns the settings that specifies how a recording is configured.
  68      * <p>
  69      * Modifying the returned {@code Map} object doesn't change the
  70      * configuration.
  71      *
  72      * @return settings, not {@code null}
  73      */
  74     public Map<String, String> getSettings() {
  75         return new LinkedHashMap<String, String>(settings);
  76     }
  77 
  78     /**
  79      * Returns an identifying name (for example, {@code "default" or "profile")}.
  80      *
  81      * @return the name, or {@code null} if it doesn't exist
  82      */
  83     public String getName() {
  84         return this.name;
  85     }
  86 
  87     /**
  88      * Returns a human-readable name (for example, {@code "Continuous" or "Profiling"}}.
  89      *
  90      * @return the label, or {@code null} if it doesn't exist
  91      */
  92     public String getLabel() {
  93         return this.label;
  94     }
  95 
  96     /**
  97      * Returns a short sentence that describes the configuration (for example
  98      * {@code "Low
  99      * overhead configuration safe for continuous use in production
 100      * environments"})
 101      *
 102      * @return the description, or {@code null} if it doesn't exist
 103      */
 104     public String getDescription() {
 105         return description;
 106     }
 107 
 108     /**
 109      * Returns who created the configuration (for example {@code "OpenJDK"}).
 110      *
 111      * @return the provider, or {@code null} if it doesn't exist
 112      */
 113     public String getProvider() {
 114         return provider;
 115     }
 116 
 117     /**
 118      * Returns a textual representation of the configuration (for example, the
 119      * contents of a JFC file).
 120      *
 121      * @return contents, or {@code null} if it doesn't exist
 122      *
 123      * @see Configuration#getContents()
 124      */
 125     public String getContents() {
 126         return contents;
 127     }
 128 
 129     /**
 130      * Reads a configuration from a file.
 131      *
 132      * @param path the file that contains the configuration, not {@code null}
 133      * @return the read {@link Configuration}, not {@code null}
 134      * @throws ParseException if the file can't be parsed
 135      * @throws IOException if the file can't be read
 136      * @throws SecurityException if a security manager exists and its
 137      *         {@code checkRead} method denies read access to the file.
 138      *
 139      * @see java.io.File#getPath()
 140      * @see java.lang.SecurityManager#checkRead(java.lang.String)
 141      */
 142     public static Configuration create(Path path) throws IOException, ParseException {
 143         Objects.requireNonNull(path);
 144         JVMSupport.ensureWithIOException();
 145         try (Reader reader = Files.newBufferedReader(path)) {
 146             return JFC.create(JFC.nameFromPath(path), reader);
 147         }
 148     }
 149 
 150     /**
 151      * Reads a configuration from a character stream.
 152      *
 153      * @param reader a {@code Reader} that provides the configuration contents, not
 154      *        {@code null}
 155      * @return a configuration, not {@code null}
 156      * @throws IOException if an I/O error occurs while trying to read contents
 157      *         from the {@code Reader}
 158      * @throws ParseException if the file can't be parsed
 159      */
 160     public static Configuration create(Reader reader) throws IOException, ParseException {
 161         Objects.requireNonNull(reader);
 162         JVMSupport.ensureWithIOException();
 163         return JFC.create(null, reader);
 164     }
 165 
 166     /**
 167      * Returns a predefined configuration.
 168      * <p>
 169      * See {@link Configuration#getConfigurations()} for available configuration
 170      * names.
 171      *
 172      * @param name the name of the configuration (for example, {@code "default"} or
 173      *        {@code "profile"})
 174      * @return a configuration, not {@code null}
 175      *
 176      * @throws IOException if a configuration with the given name does not
 177      *         exist, or if an I/O error occurs while reading the
 178      *         configuration file
 179      * @throws ParseException if the configuration file can't be parsed
 180      */
 181     public static Configuration getConfiguration(String name) throws IOException, ParseException {
 182         JVMSupport.ensureWithIOException();
 183         return JFC.getPredefined(name);
 184     }
 185 
 186     /**
 187      * Returns an immutable list of predefined configurations for this Java Virtual Machine (JVM).
 188      *
 189      * @return the list of predefined configurations, not {@code null}
 190      */
 191     public static List<Configuration> getConfigurations() {
 192         if (JVMSupport.isNotAvailable()) {
 193             return new ArrayList<>();
 194         }
 195         return Collections.unmodifiableList(JFC.getConfigurations());
 196     }
 197 }