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package javax.management.openmbean;
A Java class can implement this interface to indicate how it is to be converted into a CompositeData by the MXBean framework.
A typical way to use this class is to add extra items to the CompositeData in addition to the ones that are declared in the CompositeType supplied by the MXBean framework. To do this, you must create another CompositeType that has all the same items, plus your extra items.
For example, suppose you have a class Measure that consists of a String called units and a value that is either a long or a double. It might look like this:
public class Measure implements CompositeDataView { private String units; private Number value; // a Long or a Double public Measure(String units, Number value) { this.units = units; this.value = value; } public static Measure from(CompositeData cd) { return new Measure((String) cd.get("units"), (Number) cd.get("value")); } public String getUnits() { return units; } // Can't be called getValue(), because Number is not a valid type // in an MXBean, so the implied "value" property would be rejected. public Number _getValue() { return value; } public CompositeData toCompositeData(CompositeType ct) { try { List<String> itemNames = new ArrayList<String>(ct.keySet()); List<String> itemDescriptions = new ArrayList<String>(); List<OpenType<?>> itemTypes = new ArrayList<OpenType<?>>(); for (String item : itemNames) { itemDescriptions.add(ct.getDescription(item)); itemTypes.add(ct.getType(item)); } itemNames.add("value"); itemDescriptions.add("long or double value of the measure"); itemTypes.add((value instanceof Long) ? SimpleType.LONG : SimpleType.DOUBLE); CompositeType xct = new CompositeType(ct.getTypeName(), ct.getDescription(), itemNames.toArray(new String[0]), itemDescriptions.toArray(new String[0]), itemTypes.toArray(new OpenType<?>[0])); CompositeData cd = new CompositeDataSupport(xct, new String[] {"units", "value"}, new Object[] {units, value}); assert ct.isValue(cd); // check we've done it right return cd; } catch (Exception e) { throw new RuntimeException(e); } } }
The CompositeType that will appear in the openType field of the Descriptor for an attribute or operation of this type will show only the units item, but the actual CompositeData that is generated will have both units and value.
See Also: Since: 1.6
/**
* <p>A Java class can implement this interface to indicate how it is
* to be converted into a {@code CompositeData} by the MXBean framework.</p>
*
* <p>A typical way to use this class is to add extra items to the
* {@code CompositeData} in addition to the ones that are declared in the
* {@code CompositeType} supplied by the MXBean framework. To do this,
* you must create another {@code CompositeType} that has all the same items,
* plus your extra items.</p>
*
* <p>For example, suppose you have a class {@code Measure} that consists of
* a String called {@code units} and a {@code value} that is either a
* {@code long} or a {@code double}. It might look like this:</p>
*
* <pre>
* public class Measure implements CompositeDataView {
* private String units;
* private Number value; // a Long or a Double
*
* public Measure(String units, Number value) {
* this.units = units;
* this.value = value;
* }
*
* public static Measure from(CompositeData cd) {
* return new Measure((String) cd.get("units"),
* (Number) cd.get("value"));
* }
*
* public String getUnits() {
* return units;
* }
*
* // Can't be called getValue(), because Number is not a valid type
* // in an MXBean, so the implied "value" property would be rejected.
* public Number _getValue() {
* return value;
* }
*
* public CompositeData toCompositeData(CompositeType ct) {
* try {
* {@code List<String> itemNames = new ArrayList<String>(ct.keySet());}
* {@code List<String> itemDescriptions = new ArrayList<String>();}
* {@code List<OpenType<?>> itemTypes = new ArrayList<OpenType<?>>();}
* for (String item : itemNames) {
* itemDescriptions.add(ct.getDescription(item));
* itemTypes.add(ct.getType(item));
* }
* itemNames.add("value");
* itemDescriptions.add("long or double value of the measure");
* itemTypes.add((value instanceof Long) ? SimpleType.LONG :
* SimpleType.DOUBLE);
* CompositeType xct =
* new CompositeType(ct.getTypeName(),
* ct.getDescription(),
* itemNames.toArray(new String[0]),
* itemDescriptions.toArray(new String[0]),
* itemTypes.toArray(new OpenType<?>[0]));
* CompositeData cd =
* new CompositeDataSupport(xct,
* new String[] {"units", "value"},
* new Object[] {units, value});
* assert ct.isValue(cd); // check we've done it right
* return cd;
* } catch (Exception e) {
* throw new RuntimeException(e);
* }
* }
* }
* </pre>
*
* <p>The {@code CompositeType} that will appear in the {@code openType} field
* of the {@link javax.management.Descriptor Descriptor} for an attribute or
* operation of this type will show only the {@code units} item, but the actual
* {@code CompositeData} that is generated will have both {@code units} and
* {@code value}.</p>
*
* @see javax.management.MXBean
*
* @since 1.6
*/
public interface CompositeDataView {
Return a CompositeData corresponding to the values in this object. The returned value should usually be an instance of CompositeDataSupport, or a class that serializes as a CompositeDataSupport via a writeReplace method. Otherwise, a remote client that receives the object might not be able to reconstruct it.
Params: - ct – The expected
CompositeType of the returned value. If the returned value is cd, then cd.getCompositeType().equals(ct) should be true. Typically this will be because cd is a CompositeDataSupport constructed with ct as its CompositeType.
Returns: the CompositeData.
/**
* <p>Return a {@code CompositeData} corresponding to the values in
* this object. The returned value should usually be an instance of
* {@link CompositeDataSupport}, or a class that serializes as a
* {@code CompositeDataSupport} via a {@code writeReplace} method.
* Otherwise, a remote client that receives the object might not be
* able to reconstruct it.
*
* @param ct The expected {@code CompositeType} of the returned
* value. If the returned value is {@code cd}, then
* {@code cd.getCompositeType().equals(ct)} should be true.
* Typically this will be because {@code cd} is a
* {@link CompositeDataSupport} constructed with {@code ct} as its
* {@code CompositeType}.
*
* @return the {@code CompositeData}.
*/
public CompositeData toCompositeData(CompositeType ct);
}