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diff --git a/libjava/classpath/java/lang/management/MemoryUsage.java b/libjava/classpath/java/lang/management/MemoryUsage.java
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+/* MemoryUsage.java - Information on the usage of a memory pool.
+   Copyright (C) 2006 Free Software Foundation
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.lang.management;
+
+import javax.management.openmbean.CompositeData;
+import javax.management.openmbean.CompositeType;
+import javax.management.openmbean.SimpleType;
+/**
+ * <p>
+ * Retains information on the usage of a particular memory
+ * pool, or heap/non-heap memory as a whole.  Memory usage
+ * is represented by four values (all in bytes):
+ * </p>
+ * <ul>
+ * <li><strong>Initial Level</strong>: This is the initial
+ * amount of memory allocated for the pool by the operating
+ * system.  This value may be undefined.</li>
+ * <li><strong>Used Level</strong>: This is the amount of
+ * memory currently in use.</li>
+ * <li><strong>Committed Level</strong>: This is the current
+ * amount of memory allocated for the pool by the operating
+ * system.  This value will always be equal to or greater than
+ * the current amount of memory in use.  It may drop below
+ * the initial amount, if the virtual machine judges this to
+ * be practical.</li>
+ * <li><strong>Maximum Level</strong>: This is the maximum
+ * amount of memory that may be allocated for the pool by
+ * the operating system.  Like the initial amount, it may
+ * be undefined.  If it is defined, it will be greater than
+ * or equal to the used and committed amounts and may change
+ * over time.  It is not guaranteed that the maximum amount
+ * of memory may actually be allocated to the pool.  For
+ * example, a request for an amount of memory greater than
+ * the current committed level, but less than the maximum,
+ * may still fail due to resources at the operating system
+ * level not being sufficient to fulfill the demand.</li>
+ * </ul>
+ *
+ * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
+ * @since 1.5
+ * @see MemoryMXBean
+ * @see MemoryPoolMXBean
+ */
+public class MemoryUsage
+{
+
+  /**
+   * The initial amount of memory allocated.
+   */
+  private long init;
+
+  /**
+   * The amount of memory used.
+   */
+  private long used;
+
+  /**
+   * The amount of memory committed for use.
+   */
+  private long committed;
+
+  /**
+   * The maximum amount of memory available.
+   */
+  private long maximum;
+
+  /**
+   * Constructs a new {@link MemoryUsage} object with
+   * the specified allocation levels.
+   *
+   * @param init the initial amount of memory allocated,
+   *             or -1 if this value is undefined.  Must
+   *             be >= -1.
+   * @param used the amount of memory used.  Must be >= 0,
+   *             and <= committed.
+   * @param committed the amount of memory committed for use
+   *                  at present.  Must be >= 0 and <=
+   *                  maximum (if defined).
+   * @param maximum the maximum amount of memory that may be
+   *                used, or -1 if this value is undefined.
+   *                Must be >= -1.
+   * @throws IllegalArgumentException if the values break any
+   *                                  of the limits specified
+   *                                  above.
+   */
+  public MemoryUsage(long init, long used, long committed,
+                     long maximum)
+  {
+    if (init < -1)
+      throw new IllegalArgumentException("Initial value of "
+                                         + init + " is too small.");
+    if (used < 0)
+      throw new IllegalArgumentException("Used value of "
+                                         + used + " is too small.");
+    if (committed < 0)
+      throw new IllegalArgumentException("Committed value of "
+                                         + committed + " is too small.");
+    if (committed < used)
+      throw new IllegalArgumentException("Committed value of "
+                                         + committed + " is below "
+                                         + used + ", the amount used.");
+    if (maximum < -1)
+      throw new IllegalArgumentException("Maximum value of "
+                                         + maximum + " is too small.");
+    if (maximum != -1 && maximum < committed)
+      throw new IllegalArgumentException("Maximum value of "
+                                         + maximum + " is below "
+                                         + committed + ", the amount "
+                                         + "committed.");
+    this.init = init;
+    this.used = used;
+    this.committed = committed;
+    this.maximum = maximum;
+  }
+
+  /**
+   * <p>
+   * Returns a {@link MemoryUsage} instance using the values
+   * given in the supplied
+   * {@link javax.management.openmbean.CompositeData} object.
+   * The composite data instance should contain the following
+   * attributes:
+   * </p>
+   * <ul>
+   * <li>init</li>
+   * <li>used</li>
+   * <li>committed</li>
+   * <li>max</li>
+   * </ul>
+   * <p>
+   * All should have the type, <code>java.lang.Long</code>.
+   * </p>
+   *
+   * @param data the composite data structure to take values from.
+   * @return a new instance containing the values from the
+   *         composite data structure, or <code>null</code>
+   *         if the data structure was also <code>null</code>.
+   * @throws IllegalArgumentException if the composite data structure
+   *                                  does not match the structure
+   *                                  outlined above, or the values
+   *                                  are invalid.
+   */
+  public static MemoryUsage from(CompositeData data)
+  {
+    if (data == null)
+      return null;
+    CompositeType type = data.getCompositeType();
+    ThreadInfo.checkAttribute(type, "Init", SimpleType.LONG);
+    ThreadInfo.checkAttribute(type, "Used", SimpleType.LONG);
+    ThreadInfo.checkAttribute(type, "Committed", SimpleType.LONG);
+    ThreadInfo.checkAttribute(type, "Max", SimpleType.LONG);
+    return new MemoryUsage(((Long) data.get("Init")).longValue(),
+                           ((Long) data.get("Used")).longValue(),
+                           ((Long) data.get("Committed")).longValue(),
+                           ((Long) data.get("Max")).longValue());
+  }
+
+  /**
+   * Returns the amount of memory committed for use by this
+   * memory pool (in bytes).  This amount is guaranteed to
+   * be available, unlike the maximum.
+   *
+   * @return the committed amount of memory.
+   */
+  public long getCommitted()
+  {
+    return committed;
+  }
+
+  /**
+   * Returns the initial amount of memory allocated to the
+   * pool (in bytes).  This method may return -1, if the
+   * value is undefined.
+   *
+   * @return the initial amount of memory allocated, or -1
+   *         if this value is undefined.
+   */
+  public long getInit()
+  {
+    return init;
+  }
+
+  /**
+   * Returns the maximum amount of memory available for this
+   * pool (in bytes).  This amount is not guaranteed to
+   * actually be usable.  This method may return -1, if the
+   * value is undefined.
+   *
+   * @return the maximum amount of memory available, or -1
+   *         if this value is undefined.
+   */
+  public long getMax()
+  {
+    return maximum;
+  }
+
+  /**
+   * Returns the amount of memory used (in bytes).
+   *
+   * @return the amount of used memory.
+   */
+  public long getUsed()
+  {
+    return used;
+  }
+
+  /**
+   * Returns a {@link java.lang.String} representation of
+   * this {@link MemoryUsage} object.  This takes the form
+   * <code>java.lang.management.MemoryUsage[init=i, used=u,
+   * committed=c, maximum=m]</code>, where <code>i</code>
+   * is the initial level, <code>u</code> is the used level,
+   * <code>c</code> is the committed level and <code>m</code>
+   * is the maximum level.
+   *
+   * @return the string specified above.
+   */
+  public String toString()
+  {
+    int megabyte = 1024 * 1024;
+    return getClass().getName() +
+      "[init=" + init + " bytes (~" + (init / megabyte) +
+      "MB), used=" + used + " bytes (~" + (used / megabyte) +
+      "MB), committed=" + committed + " bytes (~" + (committed / megabyte) +
+      "MB), maximum=" + maximum + " bytes (~" + (maximum / megabyte) +
+      "MB)]";
+  }
+
+}