javax.management.openmbean: public class: CompositeDataInvocationHandler

javax.management.openmbean
public class: CompositeDataInvocationHandler [javadoc | source]

java.lang.Object
   javax.management.openmbean.CompositeDataInvocationHandler

All Implemented Interfaces:
InvocationHandler

An InvocationHandler that forwards getter methods to a CompositeData . If you have an interface that contains only getter methods (such as {@code String getName()} or {@code boolean isActive()}) then you can use this class in conjunction with the Proxy class to produce an implementation of the interface where each getter returns the value of the corresponding item in a {@code CompositeData}.

For example, suppose you have an interface like this:

public interface NamedNumber {
public int getNumber();
public String getName();
}

and a {@code CompositeData} constructed like this:

CompositeData cd =
new CompositeDataSupport (
someCompositeType,
new String[] {"number", "name"},
new Object[] {5, "five"}
);

then you can construct an object implementing {@code NamedNumber} and backed by the object {@code cd} like this:

InvocationHandler handler =
new CompositeDataInvocationHandler(cd);
NamedNumber nn = (NamedNumber)
Proxy.newProxyInstance(NamedNumber.class.getClassLoader(),
new Class[] {NamedNumber.class},
handler);

A call to {@code nn.getNumber()} will then return 5.

If the first letter of the property defined by a getter is a capital, then this handler will look first for an item in the {@code CompositeData} beginning with a capital, then, if that is not found, for an item beginning with the corresponding lowercase letter or code point. For a getter called {@code getNumber()}, the handler will first look for an item called {@code Number}, then for {@code number}. If the getter is called {@code getnumber()}, then the item must be called {@code number}.

If the method given to invoke is the method {@code boolean equals(Object)} inherited from {@code Object}, then it will return true if and only if the argument is a {@code Proxy} whose {@code InvocationHandler} is also a {@code CompositeDataInvocationHandler} and whose backing {@code CompositeData} is equal (not necessarily identical) to this object's. If the method given to {@code invoke} is the method {@code int hashCode()} inherited from {@code Object}, then it will return a value that is consistent with this definition of {@code equals}: if two objects are equal according to {@code equals}, then they will have the same {@code hashCode}.

since: 1.6 -

Constructor:

Constructor:
public CompositeDataInvocationHandler(CompositeData compositeData) { this(compositeData, null); } Construct a handler backed by the given {@code CompositeData}. Parameters: `compositeData` - the {@code CompositeData} that will supply information to getters. Throws: `IllegalArgumentException` - if {@code compositeData} is null.
CompositeDataInvocationHandler(CompositeData compositeData, MXBeanLookup lookup) { if (compositeData == null) throw new IllegalArgumentException("compositeData"); this.compositeData = compositeData; this.lookup = lookup; } Construct a handler backed by the given {@code CompositeData}. Parameters: `mbsc` - the {@code MBeanServerConnection} related to this {@code CompositeData}. This is only relevant if a method in the interface for which this is an invocation handler returns a type that is an MXBean interface. Otherwise, it can be null. `compositeData` - the {@code CompositeData} that will supply information to getters. Throws: `IllegalArgumentException` - if {@code compositeData} is null.

 public CompositeDataInvocationHandler(CompositeData compositeData) {
        this(compositeData, null);
}

Construct a handler backed by the given {@code CompositeData}.

Parameters:

compositeData - the {@code CompositeData} that will supply information to getters.

Throws:

IllegalArgumentException - if {@code compositeData} is null.

 CompositeDataInvocationHandler(CompositeData compositeData,
    MXBeanLookup lookup) {
        if (compositeData == null)
            throw new IllegalArgumentException("compositeData");
        this.compositeData = compositeData;
        this.lookup = lookup;
}

Construct a handler backed by the given {@code CompositeData}.

Parameters:

mbsc - the {@code MBeanServerConnection} related to this {@code CompositeData}. This is only relevant if a method in the interface for which this is an invocation handler returns a type that is an MXBean interface. Otherwise, it can be null.

compositeData - the {@code CompositeData} that will supply information to getters.

Throws:

IllegalArgumentException - if {@code compositeData} is null.

Method from javax.management.openmbean.CompositeDataInvocationHandler Summary:
getCompositeData, invoke

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.management.openmbean.CompositeDataInvocationHandler Detail:
public CompositeData getCompositeData() { assert compositeData != null; return compositeData; } Return the {@code CompositeData} that was supplied to the constructor.
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { final String methodName = method.getName(); // Handle the methods from java.lang.Object if (method.getDeclaringClass() == Object.class) { if (methodName.equals("toString") && args == null) return "Proxy[" + compositeData + "]"; else if (methodName.equals("hashCode") && args == null) return compositeData.hashCode() + 0x43444948; else if (methodName.equals("equals") && args.length == 1 && method.getParameterTypes()[0] == Object.class) return equals(proxy, args[0]); else { /* Either someone is calling invoke by hand, or it is a non-final method from Object overriden by the generated Proxy. At the time of writing, the only non-final methods in Object that are not handled above are finalize and clone, and these are not overridden in generated proxies. */ return method.invoke(this, args); } } String propertyName = DefaultMXBeanMappingFactory.propertyName(method); if (propertyName == null) { throw new IllegalArgumentException("Method is not getter: " + method.getName()); } Object openValue; if (compositeData.containsKey(propertyName)) openValue = compositeData.get(propertyName); else { String decap = DefaultMXBeanMappingFactory.decapitalize(propertyName); if (compositeData.containsKey(decap)) openValue = compositeData.get(decap); else { final String msg = "No CompositeData item " + propertyName + (decap.equals(propertyName) ? "" : " or " + decap) + " to match " + methodName; throw new IllegalArgumentException(msg); } } MXBeanMapping mapping = MXBeanMappingFactory.DEFAULT.mappingForType(method.getGenericReturnType(), MXBeanMappingFactory.DEFAULT); return mapping.fromOpenValue(openValue); }

Method from javax.management.openmbean.CompositeDataInvocationHandler Detail:

 public CompositeData getCompositeData() {
        assert compositeData != null;
        return compositeData;
}

Return the {@code CompositeData} that was supplied to the constructor.

 public Object invoke(Object proxy,
    Method method,
    Object[] args) throws Throwable {
        final String methodName = method.getName();
        // Handle the methods from java.lang.Object
        if (method.getDeclaringClass() == Object.class) {
            if (methodName.equals("toString") && args == null)
                return "Proxy[" + compositeData + "]";
            else if (methodName.equals("hashCode") && args == null)
                return compositeData.hashCode() + 0x43444948;
            else if (methodName.equals("equals") && args.length == 1
                && method.getParameterTypes()[0] == Object.class)
                return equals(proxy, args[0]);
            else {
                /* Either someone is calling invoke by hand, or
                   it is a non-final method from Object overriden
                   by the generated Proxy.  At the time of writing,
                   the only non-final methods in Object that are not
                   handled above are finalize and clone, and these
                   are not overridden in generated proxies.  */
                return method.invoke(this, args);
            }
        }
        String propertyName = DefaultMXBeanMappingFactory.propertyName(method);
        if (propertyName == null) {
            throw new IllegalArgumentException("Method is not getter: " +
                                               method.getName());
        }
        Object openValue;
        if (compositeData.containsKey(propertyName))
            openValue = compositeData.get(propertyName);
        else {
            String decap = DefaultMXBeanMappingFactory.decapitalize(propertyName);
            if (compositeData.containsKey(decap))
                openValue = compositeData.get(decap);
            else {
                final String msg =
                    "No CompositeData item " + propertyName +
                    (decap.equals(propertyName) ? "" : " or " + decap) +
                    " to match " + methodName;
                throw new IllegalArgumentException(msg);
            }
        }
        MXBeanMapping mapping =
            MXBeanMappingFactory.DEFAULT.mappingForType(method.getGenericReturnType(),
                                   MXBeanMappingFactory.DEFAULT);
        return mapping.fromOpenValue(openValue);
}