J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2004 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.jvmstat.monitor; |
| 27 | |
| 28 | import java.util.List; |
| 29 | |
| 30 | import sun.jvmstat.monitor.event.VmListener; |
| 31 | |
| 32 | /** |
| 33 | * Interface for interacting with a monitorable Java Virtual Machine. |
| 34 | * The MonitoredVm interface provides methods for discovery of exported |
| 35 | * instrumentation, for attaching event listeners, and for overall |
| 36 | * maintenance of the connection to the target. |
| 37 | * |
| 38 | * @author Brian Doherty |
| 39 | * @since 1.5 |
| 40 | */ |
| 41 | public interface MonitoredVm { |
| 42 | |
| 43 | /** |
| 44 | * Get the VmIdentifier associated with this MonitoredVm |
| 45 | * |
| 46 | * @return VmIdentifier - the fully resolved Vm identifier associated |
| 47 | * with this MonitoredVm. |
| 48 | */ |
| 49 | VmIdentifier getVmIdentifier(); |
| 50 | |
| 51 | /** |
| 52 | * Find a named Instrumentation object. |
| 53 | * |
| 54 | * This method will look for the named instrumentation object in the |
| 55 | * instrumentation exported by this Java Virtual Machine. If an |
| 56 | * instrumentation object with the given name exists, a Monitor interface |
| 57 | * to that object will be return. Otherwise, the method returns |
| 58 | * <tt>null</tt>. |
| 59 | * |
| 60 | * @param name the name of the Instrumentation object to find. |
| 61 | * @return Monitor - the {@link Monitor} object that can be used to |
| 62 | * monitor the the named instrumentation object, or |
| 63 | * <tt>null</tt> if the named object doesn't exist. |
| 64 | * @throws MonitorException Thrown if an error occurs while communicating |
| 65 | * with the target Java Virtual Machine. |
| 66 | */ |
| 67 | Monitor findByName(String name) throws MonitorException; |
| 68 | |
| 69 | /** |
| 70 | * Find all Instrumentation objects with names matching the given pattern. |
| 71 | * |
| 72 | * This method returns a {@link List} of Monitor objects such that |
| 73 | * the name of each object matches the given pattern. |
| 74 | * |
| 75 | * @param patternString a string containing a pattern as described in |
| 76 | * {@link java.util.regex.Pattern}. |
| 77 | * @return List<Monitor> - a List of {@link Monitor} objects that can be used to |
| 78 | * monitor the instrumentation objects whose names match |
| 79 | * the given pattern. If no instrumentation objects have` |
| 80 | * names matching the given pattern, then an empty List |
| 81 | * is returned. |
| 82 | * @throws MonitorException Thrown if an error occurs while communicating |
| 83 | * with the target Java Virtual Machine. |
| 84 | * @see java.util.regex.Pattern |
| 85 | */ |
| 86 | List<Monitor> findByPattern(String patternString) throws MonitorException; |
| 87 | |
| 88 | /** |
| 89 | * Detach from target Java Virtual Machine. |
| 90 | * |
| 91 | * After calling this method, updates of the instrumentation data values |
| 92 | * may be halted. All event notifications are halted. Further interactions |
| 93 | * with this object should be avoided. |
| 94 | */ |
| 95 | void detach(); |
| 96 | |
| 97 | |
| 98 | /* ---- Methods to support polled MonitoredVm Implementations ---- */ |
| 99 | |
| 100 | /** |
| 101 | * Set the polling interval to <code>interval</code> milliseconds. |
| 102 | * |
| 103 | * Polling based monitoring implementations need to refresh the |
| 104 | * instrumentation data on a periodic basis. This interface allows |
| 105 | * the interval to override the implementation specific default |
| 106 | * interval. |
| 107 | * |
| 108 | * @param interval the polling interval in milliseconds |
| 109 | */ |
| 110 | void setInterval(int interval); |
| 111 | |
| 112 | /** |
| 113 | * Get the polling interval. |
| 114 | * |
| 115 | * @return int - the current polling interval in milliseconds. |
| 116 | * @see #setInterval |
| 117 | */ |
| 118 | int getInterval(); |
| 119 | |
| 120 | /** |
| 121 | * Set the last exception encountered while polling this MonitoredVm. |
| 122 | * |
| 123 | * Polling implementations may choose to poll asynchronously. This |
| 124 | * method allows an asynchronous task to communicate any polling related |
| 125 | * exceptions with the application. When an a non-null exception is reported |
| 126 | * through this interface, the MonitoredVm instance is considered to |
| 127 | * be in the <em>errored</em> state. |
| 128 | * |
| 129 | * @param cause the exception to record. |
| 130 | * @see #isErrored |
| 131 | */ |
| 132 | void setLastException(Exception cause); |
| 133 | |
| 134 | /** |
| 135 | * Get the last exception encountered while polling this MonitoredVm. |
| 136 | * |
| 137 | * Returns the last exception observed by the implementation dependent |
| 138 | * polling task or <tt>null</tt> if no such error has occurred. |
| 139 | * |
| 140 | * @return Exception - the last exception that occurred during polling |
| 141 | * or <tt>null</tt> if no error condition exists. |
| 142 | * @see #isErrored |
| 143 | * @see #setLastException |
| 144 | */ |
| 145 | Exception getLastException(); |
| 146 | |
| 147 | /** |
| 148 | * Clear the last exception. |
| 149 | * |
| 150 | * Calling this method will clear the <em>errored</em> state of this |
| 151 | * MonitoredVm. However, there is no guarantee that clearing the |
| 152 | * the errored state return the asynchronous polling task to an |
| 153 | * operational state. |
| 154 | * |
| 155 | */ |
| 156 | void clearLastException(); |
| 157 | |
| 158 | /** |
| 159 | * Test if this MonitoredVm is in the errored state. |
| 160 | * The errored state exists only if an error was reported with |
| 161 | * call to {@link #setLastException} and only if the parameter to |
| 162 | * that call was non-null and no subsequent calls are made to |
| 163 | * {@link #clearLastException}. |
| 164 | * |
| 165 | * @return boolean - true if the instance has a non-null error condition |
| 166 | * set, false otherwise. |
| 167 | * |
| 168 | * @see #setLastException |
| 169 | * @see #getLastException |
| 170 | */ |
| 171 | boolean isErrored(); |
| 172 | |
| 173 | /** |
| 174 | * Add a VmListener. The given listener is added to the list of |
| 175 | * VmListener objects to be notified of MonitoredVm related events. |
| 176 | * |
| 177 | * @param listener the VmListener to add. |
| 178 | * @throws MonitorException Thrown if any problems occur while attempting |
| 179 | * to add this listener. |
| 180 | */ |
| 181 | void addVmListener(VmListener listener) throws MonitorException; |
| 182 | |
| 183 | /** |
| 184 | * Remove a VmListener. The given listener is removed from the list of |
| 185 | * VmListener objects to be notified of MonitoredVm related events. |
| 186 | * |
| 187 | * @param listener the VmListener to be removed. |
| 188 | * @throws MonitorException Thrown if any problems occur while attempting |
| 189 | * to remove this listener. |
| 190 | */ |
| 191 | void removeVmListener(VmListener listener) throws MonitorException; |
| 192 | } |