001: /*
002: * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
003: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004: *
005: * This code is free software; you can redistribute it and/or modify it
006: * under the terms of the GNU General Public License version 2 only, as
007: * published by the Free Software Foundation. Sun designates this
008: * particular file as subject to the "Classpath" exception as provided
009: * by Sun in the LICENSE file that accompanied this code.
010: *
011: * This code is distributed in the hope that it will be useful, but WITHOUT
012: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014: * version 2 for more details (a copy is included in the LICENSE file that
015: * accompanied this code).
016: *
017: * You should have received a copy of the GNU General Public License version
018: * 2 along with this work; if not, write to the Free Software Foundation,
019: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020: *
021: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022: * CA 95054 USA or visit www.sun.com if you need additional information or
023: * have any questions.
024: */
025:
026: package com.sun.management;
027:
028: import sun.management.VMOptionCompositeData;
029: import javax.management.openmbean.CompositeData;
030:
031: /**
032: * Information about a VM option including its value and
033: * where the value came from which is referred as its
034: * {@link VMOption.Origin <i>origin</i>}.
035: * <p>
036: * Each VM option has a default value. A VM option can
037: * be set at VM creation time typically as a command line
038: * argument to the launcher or an argument passed to the
039: * VM created using the JNI invocation interface.
040: * In addition, a VM option may be set via an environment
041: * variable or a configuration file. A VM option can also
042: * be set dynamically via a management interface after
043: * the VM was started.
044: *
045: * A <tt>VMOption</tt> contains the value of a VM option
046: * and the origin of that value at the time this <tt>VMOption</tt>
047: * object was constructed. The value of the VM option
048: * may be changed after the <tt>VMOption</tt> object was constructed,
049: *
050: * @see <a href="{@docRoot}/../../../../technotes/guides/vm/index.html">
051: * Java Virtual Machine</a>
052: * @author Mandy Chung
053: * @since 1.6
054: */
055: public class VMOption {
056: private String name;
057: private String value;
058: private boolean writeable;
059: private Origin origin;
060:
061: /**
062: * Origin of the value of a VM option. It tells where the
063: * value of a VM option came from.
064: *
065: * @since 1.6
066: */
067: public enum Origin {
068: /**
069: * The VM option has not been set and its value
070: * is the default value.
071: */
072: DEFAULT,
073: /**
074: * The VM option was set at VM creation time typically
075: * as a command line argument to the launcher or
076: * an argument passed to the VM created using the
077: * JNI invocation interface.
078: */
079: VM_CREATION,
080: /**
081: * The VM option was set via an environment variable.
082: */
083: ENVIRON_VAR,
084: /**
085: * The VM option was set via a configuration file.
086: */
087: CONFIG_FILE,
088: /**
089: * The VM option was set via the management interface after the VM
090: * was started.
091: */
092: MANAGEMENT,
093: /**
094: * The VM option was set via the VM ergonomic support.
095: */
096: ERGONOMIC,
097: /**
098: * The VM option was set via some other mechanism.
099: */
100: OTHER
101: }
102:
103: /**
104: * Constructs a <tt>VMOption</tt>.
105: *
106: * @param name Name of a VM option.
107: * @param value Value of a VM option.
108: * @param writeable <tt>true</tt> if a VM option can be set dynamically,
109: * or <tt>false</tt> otherwise.
110: * @param origin where the value of a VM option came from.
111: *
112: * @throws NullPointerException if the name or value is <tt>null</tt>
113: */
114: public VMOption(String name, String value, boolean writeable,
115: Origin origin) {
116: this .name = name;
117: this .value = value;
118: this .writeable = writeable;
119: this .origin = origin;
120: }
121:
122: /**
123: * Constructs a <tt>VMOption</tt> object from a
124: * {@link CompositeData CompositeData}.
125: */
126: private VMOption(CompositeData cd) {
127: // validate the input composite data
128: VMOptionCompositeData.validateCompositeData(cd);
129:
130: this .name = VMOptionCompositeData.getName(cd);
131: this .value = VMOptionCompositeData.getValue(cd);
132: this .writeable = VMOptionCompositeData.isWriteable(cd);
133: this .origin = VMOptionCompositeData.getOrigin(cd);
134: }
135:
136: /**
137: * Returns the name of this VM option.
138: *
139: * @return the name of this VM option.
140: */
141: public String getName() {
142: return name;
143: }
144:
145: /**
146: * Returns the value of this VM option at the time when
147: * this <tt>VMOption</tt> was created. The value could have been changed.
148: *
149: * @return the value of the VM option at the time when
150: * this <tt>VMOption</tt> was created.
151: */
152: public String getValue() {
153: return value;
154: }
155:
156: /**
157: * Returns the origin of the value of this VM option. That is,
158: * where the value of this VM option came from.
159: *
160: * @return where the value of this VM option came from.
161: */
162: public Origin getOrigin() {
163: return origin;
164: }
165:
166: /**
167: * Tests if this VM option is writeable. If this VM option is writeable,
168: * it can be set by the {@link HotSpotDiagnosticMXBean#setVMOption
169: * HotSpotDiagnosticMXBean.setVMOption} method.
170: *
171: * @return <tt>true</tt> if this VM option is writeable; <tt>false</tt>
172: * otherwise.
173: */
174: public boolean isWriteable() {
175: return writeable;
176: }
177:
178: public String toString() {
179: return "VM option: " + getName() + " value: " + value + " "
180: + " origin: " + origin + " "
181: + (writeable ? "(read-only)" : "(read-write)");
182: }
183:
184: /**
185: * Returns a <tt>VMOption</tt> object represented by the
186: * given <tt>CompositeData</tt>. The given <tt>CompositeData</tt>
187: * must contain the following attributes:
188: * <p>
189: * <blockquote>
190: * <table border>
191: * <tr>
192: * <th align=left>Attribute Name</th>
193: * <th align=left>Type</th>
194: * </tr>
195: * <tr>
196: * <td>name</td>
197: * <td><tt>java.lang.String</tt></td>
198: * </tr>
199: * <tr>
200: * <td>value</td>
201: * <td><tt>java.lang.String</tt></td>
202: * </tr>
203: * <tr>
204: * <td>origin</td>
205: * <td><tt>java.lang.String</tt></td>
206: * </tr>
207: * <tr>
208: * <td>writeable</td>
209: * <td><tt>java.lang.Boolean</tt></td>
210: * </tr>
211: * </table>
212: * </blockquote>
213: *
214: * @param cd <tt>CompositeData</tt> representing a <tt>VMOption</tt>
215: *
216: * @throws IllegalArgumentException if <tt>cd</tt> does not
217: * represent a <tt>VMOption</tt> with the attributes described
218: * above.
219: *
220: * @return a <tt>VMOption</tt> object represented by <tt>cd</tt>
221: * if <tt>cd</tt> is not <tt>null</tt>;
222: * <tt>null</tt> otherwise.
223: */
224: public static VMOption from(CompositeData cd) {
225: if (cd == null) {
226: return null;
227: }
228:
229: if (cd instanceof VMOptionCompositeData) {
230: return ((VMOptionCompositeData) cd).getVMOption();
231: } else {
232: return new VMOption(cd);
233: }
234:
235: }
236:
237: }
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