• Returning to the example, the next step is to configure the arguments for the invocation. The -setArgument:atIndex: method of NSInvocation is used for this.The messages being sent can have 0, 1, or 2 ...
The NSInvocation class is designed to represent an Objective-C message. NSInovation instances encapsulates all the attributes of an Objective-C message. They know the message's receive, the message name (both the selector and method signature), and all the message's arguments. After invoking an NSInvocation, the message's return value may be retrieved from the NSInvocations.
One point of confusion for many developers is how messages are named. Each name has two parts, the selector and the method signature. A selector is the message's name without any type information, for example "countOfObjectsOfType:" is a selector. To build a complete message, the types of each argument and return value's type need to be known. This type information is known as a method signature. The class NSMethodSignature encapsulates this information.

// if you must use an id type, then use a cast when sending the message
id myObject;
value = [(ClassA *)myObject countOfObjectsOfType:aType];
// otherwise, use static typing instead of a generic id to disambiguate
ClassA *myObject;
value = [myObject countOfObjectsOfType:aType];

At runtime, however, the receiver is known, and it is possible to simply ask it for the correct message signature, like this:

NSMethodSignature* mySignature = [myObject
methodSignatureForSelector:@selector(countOfObjectsOfType:)];

a sample,

NSString *messageString = [message titleOfSelectedItem];
SEL selector = NSSelectorFromString(messageString);
NSMethodSignature *methodSignature = [receivingString
methodSignatureForSelector:selector];
NSInvocation *invocation = [NSInvocation
invocationWithMethodSignature:methodSignature];

Every Objective-C method has two hidden arguments. The first and most commonly used arguments is self. The second, containing the selector that invoked the method, is called _cmd.

[invocation setTarget:receivingString]; // argument 0 is "self"
[invocation setSelector:selector]; // argument 1 is "_cmd"

Returning to the example, the next step is to configure the arguments for the invocation.The -setArgument:atIndex: method of NSInvocation is used for this.The messagesbeing sent can have 0, 1, or 2 arguments, and the tag of the selected pop-up buttonitem tells how many arguments to set up. Because the hidden arguments self and _cmdtake up spots 0 and 1 in the argument list, the first argument to the method is actually argument 2.Also when using the -setArgument:atIndex: method, pointers to objectpointers must be used instead of just a pointer to the object. Here’s the code:

int numberOfArguments = [[message selectedItem] tag];
if (numberOfArguments > 0)
{
NSString *argumentString1 = [argument1 stringValue];
[invocation setArgument:&argumentString1 atIndex:2];
if (numberOfArguments > 1)
{
NSString *argumentString2 = [argument2 stringValue];
[invocation setArgument:&argumentString2 atIndex:3];
}
}

Here is the code to invoke the message and interpret the return value:

[invocation invoke];
void *returnValue = NULL;
[invocation getReturnValue:&returnValue];
const char *returnType = [methodSignature methodReturnType];

转载于:https://www.cnblogs.com/grep/archive/2012/07/08/2581545.html
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• m trying to create a <code>IFunctionInvocationFilter</code> but I want to be able to safely short circuit the invocation of the function from a filter and pass back a return value. <p>It's ...
• 1 package method.invocation; 2 3 public class MethodInvocation { 4 public static void main(String[] args) { 5 boolean b = compare(10, 20); 6 System.out.println(b); ...

1 package method.invocation;
2
3 public class MethodInvocation {
4     public static void main(String[] args) {
5         boolean b = compare(10, 20);
6         System.out.println(b);
7     }
8
9     public static boolean compare(byte a, byte b) {
10         System.out.println("byte");
11         return a == b;
12     }
13     public static boolean compare(short a, short b) {
14         System.out.println("short");
15         return a == b;
16     }
17     public static boolean compare(int a, int b) {
18         System.out.println("int");
19         return a == b;
20     }
21     public static boolean compare(long a, long b) {
22         System.out.println("long");
23         return a == b;
24     }
25 }

输出int,false。
转载于:https://www.cnblogs.com/lzp123456-/p/9692179.html
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• <div><p>Allow for multiple invocation images to be defined in a bundle, e.g. one for docker and another for VMs. The first invocation image that is compatible with the current driver is used for the ...
• <div><p>This PR adds PHPCSFixer with <code>native_function_invocation</code> which can improve performance a little bit - <code>Add leading \ before function invocation to speed up resolving.</code>....
• <div><p>Reasoning behind this enhancement is to be able to make non-blocking invocation inside PartitionThreads. Currently all invocations which are targeted to different partition-threads (partition ...
• As it is now, the replacement looks correct after a transformation, but the new class is not imported to file where the invocation is made. This even though the new class should have been loaded by ...
• t have their own zone or invocation code. <p>We've removed most of them but left one for examination. The OpenX script for some MPU zones appears to be adding a 10px margin and then something is ...
• <div><p>Implement client, target, invocation.builder, invocation, configuration</p><p>该提问来源于开源项目：jersey/jersey</p></div>
• </code> yielded only our manual invocation (and not the 9am EST one). No exception info in our Slack invoicing webhooks channel. So it seems like maybe the Lambda invocation failed, but wasn't ...
• <div><p>Currently, we take all the targets in context and then do a junit/pytest invoke - this needs to be isolated into a per target invocation so that we can break down the work involved in a test ...
• At third run, failed config generated invocation-number set 0, but we count on keeping track of failed case in data-provider, so test run with wrong case data. <h3>TestNG Version 6.11 <h3>Expected ...
• <div><p>I visited methodInvocation. But some method invocations are missed. <p>For example: Missed: public static final String LOG_TAG = ACRA.class.getSimpleName(); ErrorReporter ...
• <p>It is quite normal to have access to Java invocation metadata, such as the method invoked and Java parameters. This is easily the case in AOP, such as AspectJ, but it is also readily available in ...
• : Illegal invocation</code></p> <p>on Firefox <code>TypeError: 'getUserMedia' called on an object that does not implement interface MediaDevices</code></p>该提问来源于开源项目：danrouse/...
• at com.hazelcast.spi.impl.operationservice.impl.Invocation_NetworkSplitTest.testWaitNotifyService_whenNodeSplitFromCluster(Invocation_NetworkSplitTest.java:178) at ...
• <div><p>When Invocation does not get a response, we should handle it by retrying the invocation if necessary.</p><p>该提问来源于开源项目：hazelcast/hazelcast-nodejs-client</p></div>
• d be happy to remove the Configurable support from Invocation.Builder and Invocation. After working with the API for quite some time now my feeling is that in these two cases we went just too far. I ...
• java.lang.IllegalStateException: No MethodInvocation found: Check that an AOP invocation is in progress, and that the ExposeInvocationInterceptor is upfront in the interceptor chain. Specifically, ...
java.lang.IllegalStateException: No MethodInvocation found: Check that an AOP invocation is in progress, and that the ExposeInvocationInterceptor is upfront in the interceptor chain. Specifically, note that advices with order HIGHEST_PRECEDENCE will execute before ExposeInvocationInterceptor!
这是springmvc.xml中AOP expression表达式语法错了，改一下就行了。
参考改法：


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• s invocation code. <p>When I go to: <p>http://mysite.com/ads/www/admin/zone-invocation.php?affiliateid=1&zoneid=1, there are no options to select under "Please choose the type of ...
• <div><p>When writing an invocation tag plugin, realized there was partial code already to allow variables to be defined easily with $defaultOptionValues member array, but it wasn't complete. Think... • <div><p>Our team needs a means to launch a JVM from Rust (in C JNI interface that functionality is provided by <a href="https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/invocation.... • <div><p>There is no way to sort the interceptors of a methodinvocation; ... • javax.servlet.ServletException: java.lang.reflect.InvocationTargetException while attempting to process a 'beforeCreate' event for 'event573'. root cause java.lang.RuntimeException: ... • <div><p>Using the old approach without active check needed, assuming only cross invocation can be between onSubscribe and onNext/Complete/Success/Error</p><p>该提问来源于开源项目：micronaut-... • java.lang.reflect.InvocationTargetException Exception in thread "main" java.lang.OutOfMemoryError: PermGen space Exception in thread "ContainerBackgroundProcessor[StandardEngine[Catalina]]" java.lang.... 信息: Starting Coyote HTTP/1.1 on http-80 java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413) Caused by: java.lang.OutOfMemoryError: PermGen space at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631) at java.lang.ClassLoader.defineClass(ClassLoader.java:615) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.security.AccessController.doPrivileged(Native Method)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2436)
at java.lang.Class.privateGetPublicMethods(Class.java:2556)
at java.lang.Class.getMethods(Class.java:1412)
at org.apache.tomcat.util.modeler.modules.MbeansDescriptorsIntrospectionSource.createManagedBean(MbeansDescriptorsIntrospectionSource.java:304)
at org.apache.tomcat.util.modeler.modules.MbeansDescriptorsIntrospectionSource.execute(MbeansDescriptorsIntrospectionSource.java:84)
at org.apache.tomcat.util.modeler.Registry.findManagedBean(Registry.java:650)
at org.apache.tomcat.util.modeler.Registry.findManagedBean(Registry.java:962)
at org.apache.tomcat.util.modeler.Registry.registerComponent(Registry.java:793)
at org.apache.catalina.connector.Connector.start(Connector.java:1152)
at org.apache.catalina.core.StandardService.start(StandardService.java:531)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)




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• not of the Invocation. This change pushes the ExecutionCallback registration into the future using an andThen; just as any normal call.</p><p>该提问来源于开源项目：hazelcast/hazelcast</p></div>
• yahoo pipes invocation http://pipes.yahoo.com posted on 2012-03-11 13:57lexus 阅...
• <div><p>类似于 org.apache.servicecomb.swagger.invocation.context.ContextUtils#getInvocationContext</p><p>该提问来源于开源项目：apache/servicecomb-java-chassis</p></div>
• at com.hazelcast.spi.impl.operationservice.impl.Invocation_DetectHeartbeatTimeoutTest.assertDetectHeartbeatTimeoutEventually(Invocation_DetectHeartbeatTimeoutTest.java:131) at ...

...