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| 1 | /* | ||
| 2 | * Copyright (c) 2003, 2004, 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 java.lang.management; | ||
| 27 | |||
| 28 | import javax.management.openmbean.CompositeData; | ||
| 29 | import sun.management.MemoryUsageCompositeData; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * A <tt>MemoryUsage</tt> object represents a snapshot of memory usage. | ||
| 33 | * Instances of the <tt>MemoryUsage</tt> class are usually constructed | ||
| 34 | * by methods that are used to obtain memory usage | ||
| 35 | * information about individual memory pool of the Java virtual machine or | ||
| 36 | * the heap or non-heap memory of the Java virtual machine as a whole. | ||
| 37 | * | ||
| 38 | * <p> A <tt>MemoryUsage</tt> object contains four values: | ||
| 39 | * <ul> | ||
| 40 | * <table> | ||
| 41 | * <tr> | ||
| 42 | * <td valign=top> <tt>init</tt> </td> | ||
| 43 | * <td valign=top> represents the initial amount of memory (in bytes) that | ||
| 44 | * the Java virtual machine requests from the operating system | ||
| 45 | * for memory management during startup. The Java virtual machine | ||
| 46 | * may request additional memory from the operating system and | ||
| 47 | * may also release memory to the system over time. | ||
| 48 | * The value of <tt>init</tt> may be undefined. | ||
| 49 | * </td> | ||
| 50 | * </tr> | ||
| 51 | * <tr> | ||
| 52 | * <td valign=top> <tt>used</tt> </td> | ||
| 53 | * <td valign=top> represents the amount of memory currently used (in bytes). | ||
| 54 | * </td> | ||
| 55 | * </tr> | ||
| 56 | * <tr> | ||
| 57 | * <td valign=top> <tt>committed</tt> </td> | ||
| 58 | * <td valign=top> represents the amount of memory (in bytes) that is | ||
| 59 | * guaranteed to be available for use by the Java virtual machine. | ||
| 60 | * The amount of committed memory may change over time (increase | ||
| 61 | * or decrease). The Java virtual machine may release memory to | ||
| 62 | * the system and <tt>committed</tt> could be less than <tt>init</tt>. | ||
| 63 | * <tt>committed</tt> will always be greater than | ||
| 64 | * or equal to <tt>used</tt>. | ||
| 65 | * </td> | ||
| 66 | * </tr> | ||
| 67 | * <tr> | ||
| 68 | * <td valign=top> <tt>max</tt> </td> | ||
| 69 | * <td valign=top> represents the maximum amount of memory (in bytes) | ||
| 70 | * that can be used for memory management. Its value may be undefined. | ||
| 71 | * The maximum amount of memory may change over time if defined. | ||
| 72 | * The amount of used and committed memory will always be less than | ||
| 73 | * or equal to <tt>max</tt> if <tt>max</tt> is defined. | ||
| 74 | * A memory allocation may fail if it attempts to increase the | ||
| 75 | * used memory such that <tt>used > committed</tt> even | ||
| 76 | * if <tt>used <= max</tt> would still be true (for example, | ||
| 77 | * when the system is low on virtual memory). | ||
| 78 | * </td> | ||
| 79 | * </tr> | ||
| 80 | * </table> | ||
| 81 | * </ul> | ||
| 82 | * | ||
| 83 | * Below is a picture showing an example of a memory pool: | ||
| 84 | * <p> | ||
| 85 | * <pre> | ||
| 86 | * +----------------------------------------------+ | ||
| 87 | * +//////////////// | + | ||
| 88 | * +//////////////// | + | ||
| 89 | * +----------------------------------------------+ | ||
| 90 | * | ||
| 91 | * |--------| | ||
| 92 | * init | ||
| 93 | * |---------------| | ||
| 94 | * used | ||
| 95 | * |---------------------------| | ||
| 96 | * committed | ||
| 97 | * |----------------------------------------------| | ||
| 98 | * max | ||
| 99 | * </pre> | ||
| 100 | * | ||
| 101 | * <h4>MXBean Mapping</h4> | ||
| 102 | * <tt>MemoryUsage</tt> is mapped to a {@link CompositeData CompositeData} | ||
| 103 | * with attributes as specified in the {@link #from from} method. | ||
| 104 | * | ||
| 105 | * @author Mandy Chung | ||
| 106 | * @since 1.5 | ||
| 107 | */ | ||
| 108 | public class MemoryUsage { | ||
| 109 | private final long init; | ||
| 110 | private final long used; | ||
| 111 | private final long committed; | ||
| 112 | private final long max; | ||
| 113 | |||
| 114 | /** | ||
| 115 | * Constructs a <tt>MemoryUsage</tt> object. | ||
| 116 | * | ||
| 117 | * @param init the initial amount of memory in bytes that | ||
| 118 | * the Java virtual machine allocates; | ||
| 119 | * or <tt>-1</tt> if undefined. | ||
| 120 | * @param used the amount of used memory in bytes. | ||
| 121 | * @param committed the amount of committed memory in bytes. | ||
| 122 | * @param max the maximum amount of memory in bytes that | ||
| 123 | * can be used; or <tt>-1</tt> if undefined. | ||
| 124 | * | ||
| 125 | * @throws IllegalArgumentException if | ||
| 126 | * <ul> | ||
| 127 | * <li> the value of <tt>init</tt> or <tt>max</tt> is negative | ||
| 128 | * but not <tt>-1</tt>; or</li> | ||
| 129 | * <li> the value of <tt>used</tt> or <tt>committed</tt> is negative; | ||
| 130 | * or</li> | ||
| 131 | * <li> <tt>used</tt> is greater than the value of <tt>committed</tt>; | ||
| 132 | * or</li> | ||
| 133 | * <li> <tt>committed</tt> is greater than the value of <tt>max</tt> | ||
| 134 | * <tt>max</tt> if defined.</li> | ||
| 135 | * </ul> | ||
| 136 | */ | ||
| 137 | public MemoryUsage(long init, | ||
| 138 | long used, | ||
| 139 | long committed, | ||
| 140 | long max) { | ||
| 141 | if (init < -1) { | ||
| 142 | throw new IllegalArgumentException( "init parameter = " + | ||
| 143 | init + " is negative but not -1."); | ||
| 144 | } | ||
| 145 | if (max < -1) { | ||
| 146 | throw new IllegalArgumentException( "max parameter = " + | ||
| 147 | max + " is negative but not -1."); | ||
| 148 | } | ||
| 149 | if (used < 0) { | ||
| 150 | throw new IllegalArgumentException( "used parameter = " + | ||
| 151 | used + " is negative."); | ||
| 152 | } | ||
| 153 | if (committed < 0) { | ||
| 154 | throw new IllegalArgumentException( "committed parameter = " + | ||
| 155 | committed + " is negative."); | ||
| 156 | } | ||
| 157 | if (used > committed) { | ||
| 158 | throw new IllegalArgumentException( "used = " + used + | ||
| 159 | " should be <= committed = " + committed); | ||
| 160 | } | ||
| 161 | if (max >= 0 && committed > max) { | ||
| 162 | throw new IllegalArgumentException( "committed = " + committed + | ||
| 163 | " should be < max = " + max); | ||
| 164 | } | ||
| 165 | |||
| 166 | this.init = init; | ||
| 167 | this.used = used; | ||
| 168 | this.committed = committed; | ||
| 169 | this.max = max; | ||
| 170 | } | ||
| 171 | |||
| 172 | /** | ||
| 173 | * Constructs a <tt>MemoryUsage</tt> object from a | ||
| 174 | * {@link CompositeData CompositeData}. | ||
| 175 | */ | ||
| 176 | private MemoryUsage(CompositeData cd) { | ||
| 177 | // validate the input composite data | ||
| 178 | MemoryUsageCompositeData.validateCompositeData(cd); | ||
| 179 | |||
| 180 | this.init = MemoryUsageCompositeData.getInit(cd); | ||
| 181 | this.used = MemoryUsageCompositeData.getUsed(cd); | ||
| 182 | this.committed = MemoryUsageCompositeData.getCommitted(cd); | ||
| 183 | this.max = MemoryUsageCompositeData.getMax(cd); | ||
| 184 | } | ||
| 185 | |||
| 186 | /** | ||
| 187 | * Returns the amount of memory in bytes that the Java virtual machine | ||
| 188 | * initially requests from the operating system for memory management. | ||
| 189 | * This method returns <tt>-1</tt> if the initial memory size is undefined. | ||
| 190 | * | ||
| 191 | * @return the initial size of memory in bytes; | ||
| 192 | * <tt>-1</tt> if undefined. | ||
| 193 | */ | ||
| 194 | public long getInit() { | ||
| 195 | return init; | ||
| 196 | } | ||
| 197 | |||
| 198 | /** | ||
| 199 | * Returns the amount of used memory in bytes. | ||
| 200 | * | ||
| 201 | * @return the amount of used memory in bytes. | ||
| 202 | * | ||
| 203 | */ | ||
| 204 | public long getUsed() { | ||
| 205 | return used; | ||
| 206 | }; | ||
| 207 | |||
| 208 | /** | ||
| 209 | * Returns the amount of memory in bytes that is committed for | ||
| 210 | * the Java virtual machine to use. This amount of memory is | ||
| 211 | * guaranteed for the Java virtual machine to use. | ||
| 212 | * | ||
| 213 | * @return the amount of committed memory in bytes. | ||
| 214 | * | ||
| 215 | */ | ||
| 216 | public long getCommitted() { | ||
| 217 | return committed; | ||
| 218 | }; | ||
| 219 | |||
| 220 | /** | ||
| 221 | * Returns the maximum amount of memory in bytes that can be | ||
| 222 | * used for memory management. This method returns <tt>-1</tt> | ||
| 223 | * if the maximum memory size is undefined. | ||
| 224 | * | ||
| 225 | * <p> This amount of memory is not guaranteed to be available | ||
| 226 | * for memory management if it is greater than the amount of | ||
| 227 | * committed memory. The Java virtual machine may fail to allocate | ||
| 228 | * memory even if the amount of used memory does not exceed this | ||
| 229 | * maximum size. | ||
| 230 | * | ||
| 231 | * @return the maximum amount of memory in bytes; | ||
| 232 | * <tt>-1</tt> if undefined. | ||
| 233 | */ | ||
| 234 | public long getMax() { | ||
| 235 | return max; | ||
| 236 | }; | ||
| 237 | |||
| 238 | /** | ||
| 239 | * Returns a descriptive representation of this memory usage. | ||
| 240 | */ | ||
| 241 | public String toString() { | ||
| 242 | StringBuffer buf = new StringBuffer(); | ||
| 243 | buf.append("init = " + init + "(" + (init >> 10) + "K) "); | ||
| 244 | buf.append("used = " + used + "(" + (used >> 10) + "K) "); | ||
| 245 | buf.append("committed = " + committed + "(" + | ||
| 246 | (committed >> 10) + "K) " ); | ||
| 247 | buf.append("max = " + max + "(" + (max >> 10) + "K)"); | ||
| 248 | return buf.toString(); | ||
| 249 | } | ||
| 250 | |||
| 251 | /** | ||
| 252 | * Returns a <tt>MemoryUsage</tt> object represented by the | ||
| 253 | * given <tt>CompositeData</tt>. The given <tt>CompositeData</tt> | ||
| 254 | * must contain the following attributes: | ||
| 255 | * <p> | ||
| 256 | * <blockquote> | ||
| 257 | * <table border> | ||
| 258 | * <tr> | ||
| 259 | * <th align=left>Attribute Name</th> | ||
| 260 | * <th align=left>Type</th> | ||
| 261 | * </tr> | ||
| 262 | * <tr> | ||
| 263 | * <td>init</td> | ||
| 264 | * <td><tt>java.lang.Long</tt></td> | ||
| 265 | * </tr> | ||
| 266 | * <tr> | ||
| 267 | * <td>used</td> | ||
| 268 | * <td><tt>java.lang.Long</tt></td> | ||
| 269 | * </tr> | ||
| 270 | * <tr> | ||
| 271 | * <td>committed</td> | ||
| 272 | * <td><tt>java.lang.Long</tt></td> | ||
| 273 | * </tr> | ||
| 274 | * <tr> | ||
| 275 | * <td>max</td> | ||
| 276 | * <td><tt>java.lang.Long</tt></td> | ||
| 277 | * </tr> | ||
| 278 | * </table> | ||
| 279 | * </blockquote> | ||
| 280 | * | ||
| 281 | * @param cd <tt>CompositeData</tt> representing a <tt>MemoryUsage</tt> | ||
| 282 | * | ||
| 283 | * @throws IllegalArgumentException if <tt>cd</tt> does not | ||
| 284 | * represent a <tt>MemoryUsage</tt> with the attributes described | ||
| 285 | * above. | ||
| 286 | * | ||
| 287 | * @return a <tt>MemoryUsage</tt> object represented by <tt>cd</tt> | ||
| 288 | * if <tt>cd</tt> is not <tt>null</tt>; | ||
| 289 | * <tt>null</tt> otherwise. | ||
| 290 | */ | ||
| 291 | public static MemoryUsage from(CompositeData cd) { | ||
| 292 | if (cd == null) { | ||
| 293 | return null; | ||
| 294 | } | ||
| 295 | |||
| 296 | if (cd instanceof MemoryUsageCompositeData) { | ||
| 297 | return ((MemoryUsageCompositeData) cd).getMemoryUsage(); | ||
| 298 | } else { | ||
| 299 | return new MemoryUsage(cd); | ||
| 300 | } | ||
| 301 | |||
| 302 | } | ||
| 303 | } | ||