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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 | +} | |