here we go again...
Index: ConstructorUtils.java
===================================================================
RCS file:
/home/cvspublic/jakarta-commons/beanutils/src/java/org/apache/commons/beanutils/ConstructorUtils.java,v
retrieving revision 1.2
diff -u -r1.2 ConstructorUtils.java
--- ConstructorUtils.java 15 Jan 2003 21:59:38 -0000 1.2
+++ ConstructorUtils.java 3 Feb 2003 14:38:06 -0000
@@ -63,6 +63,21 @@
/**
* @version $Revision: 1.2 $ $Date: 2003/01/15 21:59:38 $
+ *
+ * <p> Utility reflection methods focussed on constructors, modelled after {@link
+MethodUtils}. </p>
+ *
+ * <h3>Known Limitations</h3>
+ * <h4>Accessing Public Constructors In A Default Access Superclass</h4>
+ * <p>There is an issue when invoking public constructors contained in a default
+access superclass.
+ * Reflection locates these constructors fine and correctly assigns them as public.
+ * However, an <code>IllegalAccessException</code> is thrown if the constructors is
+invoked.</p>
+ *
+ * <p><code>ConstructorUtils</code> contains a workaround for this situation.
+ * It will attempt to call <code>setAccessible</code> on this constructor.
+ * If this call succeeds, then the method can be invoked as normal.
+ * This call will only succeed when the application has sufficient security
+privilages.
+ * If this call fails then a warning will be logged and the method may fail.</p>
+ *
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
@@ -82,6 +97,19 @@
// --------------------------------------------------------- Public Methods
+ /**
+ * <p>Convenience method returning new instance of <code>klazz</code> using a
+single argument constructor.
+ * The formal parameter type is inferred from the actual values of
+<code>arg</code>.
+ * See {@link #invokeExactConstructor(Class, Object[], Class[])} for more
+details.</p>
+ *
+ * <p>The signatures should be assignment compatible.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param arg the actual argument
+ * @return new instance of <code>klazz</code>
+ *
+ * @see #invokeConstructor(java.lang.Class, java.lang.Object[], java.lang.Class[])
+ */
public static Object invokeConstructor(Class klass, Object arg)
throws
NoSuchMethodException,
@@ -94,6 +122,19 @@
}
+ /**
+ * <p>Returns new instance of <code>klazz</code> created using the actual
+arguments <code>args</code>.
+ * The formal parameter types are inferred from the actual values of
+<code>args</code>.
+ * See {@link #invokeExactConstructor(Class, Object[], Class[])} for more
+details.</p>
+ *
+ * <p>The signatures should be assignment compatible.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param args actual argument array
+ * @return new instance of <code>klazz</code>
+ *
+ * @see #invokeConstructor(java.lang.Class, java.lang.Object[], java.lang.Class[])
+ */
public static Object invokeConstructor(Class klass, Object[] args)
throws
NoSuchMethodException,
@@ -113,6 +154,23 @@
}
+ /**
+ * <p>Returns new instance of <code>klazz</code> created using constructor
+ * with signature <code>parameterTypes</code> and actual arguments
+<code>args</code>.</p>
+ *
+ * <p>The signatures should be assignment compatible.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param args actual argument array
+ * @param parameterTypes parameter types array
+ * @return new instance of <code>klazz</code>
+ *
+ * @throws NoSuchMethodException if matching constructor cannot be found
+ * @throws IllegalAccessException thrown on the constructor's invocation
+ * @throws InvocationTargetException thrown on the constructor's invocation
+ * @throws InstantiationException thrown on the constructor's invocation
+ * @see Constructor#newInstance
+ */
public static Object invokeConstructor(
Class klass,
Object[] args,
@@ -139,6 +197,20 @@
return ctor.newInstance(args);
}
+
+ /**
+ * <p>Convenience method returning new instance of <code>klazz</code> using a
+single argument constructor.
+ * The formal parameter type is inferred from the actual values of
+<code>arg</code>.
+ * See {@link #invokeExactConstructor(Class, Object[], Class[])} for more
+details.</p>
+ *
+ * <p>The signatures should match exactly.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param arg the actual argument
+ * @return new instance of <code>klazz</code>
+ *
+ * @see #invokeExactConstructor(java.lang.Class, java.lang.Object[],
+java.lang.Class[])
+ */
public static Object invokeExactConstructor(Class klass, Object arg)
throws
NoSuchMethodException,
@@ -150,6 +222,20 @@
return invokeExactConstructor(klass, args);
}
+
+ /**
+ * <p>Returns new instance of <code>klazz</code> created using the actual
+arguments <code>args</code>.
+ * The formal parameter types are inferred from the actual values of
+<code>args</code>.
+ * See {@link #invokeExactConstructor(Class, Object[], Class[])} for more
+details.</p>
+ *
+ * <p>The signatures should match exactly.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param args actual argument array
+ * @return new instance of <code>klazz</code>
+ *
+ * @see #invokeExactConstructor(java.lang.Class, java.lang.Object[],
+java.lang.Class[])
+ */
public static Object invokeExactConstructor(Class klass, Object[] args)
throws
NoSuchMethodException,
@@ -168,6 +254,24 @@
}
+ /**
+ * <p>Returns new instance of <code>klazz</code> created using constructor
+ * with signature <code>parameterTypes</code> and actual arguments
+ * <code>args</code>.</p>
+ *
+ * <p>The signatures should match exactly.</p>
+ *
+ * @param klass the class to be constructed.
+ * @param args actual argument array
+ * @param parameterTypes parameter types array
+ * @return new instance of <code>klazz</code>
+ *
+ * @throws NoSuchMethodException if matching constructor cannot be found
+ * @throws IllegalAccessException thrown on the constructor's invocation
+ * @throws InvocationTargetException thrown on the constructor's invocation
+ * @throws InstantiationException thrown on the constructor's invocation
+ * @see Constructor#newInstance
+ */
public static Object invokeExactConstructor(
Class klass,
Object[] args,
@@ -195,6 +299,13 @@
}
+ /**
+ * Returns a constructor with single argument.
+ * @param klass the class to be constructed
+ * @return null if matching accessible constructor can not be found.
+ * @see Class#getConstructor
+ * @see #getAccessibleConstructor(java.lang.reflect.Constructor)
+ */
public static Constructor getAccessibleConstructor(
Class klass,
Class parameterType) {
@@ -204,6 +315,14 @@
}
+ /**
+ * Returns a constructor given a class and signature.
+ * @param klass the class to be constructed
+ * @param parameterTypes the parameter array
+ * @return null if matching accessible constructor can not be found
+ * @see Class#getConstructor
+ * @see #getAccessibleConstructor(java.lang.reflect.Constructor)
+ */
public static Constructor getAccessibleConstructor(
Class klass,
Class[] parameterTypes) {
@@ -217,6 +336,12 @@
}
+ /**
+ * Returns accessible version of the given constructor.
+ * @param ctor prototype constructor object.
+ * @return <code>null</code> if accessible constructor can not be found.
+ * @see java.lang.SecurityManager
+ */
public static Constructor getAccessibleConstructor(Constructor ctor) {
// Make sure we have a method to check
@@ -241,7 +366,21 @@
}
// -------------------------------------------------------- Private Methods
-
+ /**
+ * <p>Find an accessible constructor with compatible parameters.
+ * Compatible parameters mean that every method parameter is assignable from
+ * the given parameters. In other words, it finds constructor that will take
+ * the parameters given.</p>
+ *
+ * <p>First it checks if there is constructor matching the exact signature.
+ * If no such, all the constructors of the class are tested if their signatures
+ * are assignment compatible with the parameter types.
+ * The first matching constructor is returned.</p>
+ *
+ * @param clazz find constructor for this class
+ * @param parameterTypes find method with compatible parameters
+ * @return a valid Constructor object. If there's no matching constructor,
+returns <code>null</code>.
+ */
private static Constructor getMatchingAccessibleConstructor(
Class clazz,
Class[] parameterTypes) {
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