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[patch] java.beans.Statement - Take 3
Michael Koch writes:
> Have you actually tested to compile it with this change ? This looks
> like hand edited and one or two changes are missing. Please use
> automake-gcj to regenerate Makefile.in.
OK, I think I've got it right this time. Makefile.in is regenerated
with the appropriate automake.
Jerry
2004-06-20 Jerry Quinn <jlquinn@optonline.net>
* Makefile.am (awt_java_source_files): Add Statement.java.
* Makefile.in: Regenerate.
* java/beans/Statement.java: New file.
===================================================================
RCS file: /cvs/gcc/gcc/libjava/Makefile.am,v
retrieving revision 1.381
diff -u -r1.381 Makefile.am
--- Makefile.am 28 May 2004 18:53:04 -0000 1.381
+++ Makefile.am 20 Jun 2004 17:18:52 -0000
@@ -1299,6 +1300,7 @@
java/beans/PropertyEditorManager.java \
java/beans/PropertyEditorSupport.java \
java/beans/PropertyVetoException.java \
+java/beans/Statement.java \
java/beans/SimpleBeanInfo.java \
java/beans/VetoableChangeListener.java \
java/beans/VetoableChangeListenerProxy.java \
Index: Makefile.in
===================================================================
RCS file: /cvs/gcc/gcc/libjava/Makefile.in,v
retrieving revision 1.405
diff -u -r1.405 Makefile.in
--- Makefile.in.~1.405.~ 2004-06-01 21:54:47.000000000 -0400
+++ Makefile.in 2004-06-20 17:27:10.000000000 -0400
@@ -978,6 +979,7 @@
java/beans/PropertyEditorManager.java \
java/beans/PropertyEditorSupport.java \
java/beans/PropertyVetoException.java \
+java/beans/Statement.java \
java/beans/SimpleBeanInfo.java \
java/beans/VetoableChangeListener.java \
java/beans/VetoableChangeListenerProxy.java \
@@ -3730,7 +3731,7 @@
.deps/java/beans/PropertyEditorManager.P \
.deps/java/beans/PropertyEditorSupport.P \
.deps/java/beans/PropertyVetoException.P \
-.deps/java/beans/SimpleBeanInfo.P \
+.deps/java/beans/SimpleBeanInfo.P .deps/java/beans/Statement.P \
.deps/java/beans/VetoableChangeListener.P \
.deps/java/beans/VetoableChangeListenerProxy.P \
.deps/java/beans/VetoableChangeSupport.P .deps/java/beans/Visibility.P \
diff -u /dev/null java/beans/Statement.java
--- /dev/null 2004-06-16 22:59:06.000000000 -0400
+++ java/beans/Statement.java 2004-06-20 11:15:54.000000000 -0400
@@ -0,0 +1,307 @@
+/* java.beans.Statement
+ Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.beans;
+
+import java.lang.reflect.Array;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+/**
+ * class Statement
+ *
+ * A Statement captures the execution of an object method. It stores
+ * the object, the method to call, and the arguments to the method and
+ * provides the ability to execute the method on the object, using the
+ * provided arguments.
+ *
+ * @since 1.4
+ */
+public class Statement
+{
+ private Object target;
+ private String methodName;
+ private Object[] arguments;
+
+ // One or the other of these will get a value after execute is
+ // called once, but not both.
+ private transient Method method;
+ private transient Constructor ctor;
+
+ /**
+ * Constructs a statement representing the invocation of
+ * object.methodName(arg[0], arg[1], ...);
+ *
+ * @param target The object to invoke the method on.
+ * @param methodName The object method to invoke.
+ * @param arguments An array of arguments to pass to the method.
+ */
+ public Statement(Object target, String methodName, Object[] arguments)
+ {
+ this.target = target;
+ this.methodName = methodName;
+ this.arguments = arguments;
+ }
+
+ /**
+ * Execute the statement.
+ *
+ * Finds the specified method in the target object and calls it with
+ * the arguments given in the constructor.
+ *
+ * The most specific method according to the JLS(15.11) is used when
+ * there are multiple methods with the same name.
+ *
+ * Execute performs some special handling for methods and
+ * parameters:
+ *
+ * Static methods can be executed by providing the class as a
+ * target.
+ *
+ * The method name new is reserved to call the constructor
+ * new() will construct an object and return it. Not useful unless
+ * an expression :-)
+ *
+ * If the target is an array, get and set as defined in
+ * java.util.List are recognized as valid methods and mapped to the
+ * methods of the same name in java.lang.reflect.Array.
+ *
+ * The native datatype wrappers Boolean, Byte, Character, Double,
+ * Float, Integer, Long, and Short will map to methods that have
+ * native datatypes as parameters, in the same way as Method.invoke.
+ * However, these wrappers also select methods that actually take
+ * the wrapper type as an argument.
+ *
+ * The Sun spec doesn't deal with overloading between int and
+ * Integer carefully. If there are two methods, one that takes an
+ * Integer and the other taking an int, the method chosen is not
+ * specified, and can depend on the order in which the methods are
+ * declared in the source file.
+ *
+ * @throws Exception if an exception occurs while locating or
+ * invoking the method.
+ */
+ public void execute() throws Exception { doExecute(); }
+
+ private static Class wrappers[] =
+ {
+ Boolean.class, Byte.class, Character.class, Double.class, Float.class,
+ Integer.class, Long.class, Short.class
+ };
+
+ private static Class natives[] =
+ {
+ Boolean.TYPE, Byte.TYPE, Character.TYPE, Double.TYPE, Float.TYPE,
+ Integer.TYPE, Long.TYPE, Short.TYPE
+ };
+
+ // Given a wrapper class, return the native class for it. For
+ // example, if c is Integer, Integer.TYPE is returned.
+ private Class unwrap(Class c)
+ {
+ for (int i = 0; i < wrappers.length; i++)
+ if (c == wrappers[i])
+ return natives[i];
+ return null;
+ }
+
+ // Return true if all args can be assigned to params, false
+ // otherwise. Arrays are guaranteed to be the same length.
+ private boolean compatible(Class[] params, Class[] args)
+ {
+ for (int i = 0; i < params.length; i++)
+ {
+ // Treat Integer like int if appropriate
+ Class nativeType = unwrap(args[i]);
+ if (nativeType != null && params[i].isPrimitive()
+ && params[i].isAssignableFrom(nativeType))
+ continue;
+ if (params[i].isAssignableFrom(args[i]))
+ continue;
+
+ return false;
+ }
+ return true;
+ }
+
+ /**
+ * Return true if the method arguments in first are more specific
+ * than the method arguments in second, i.e. all args in first can
+ * be assigned to those in second.
+ *
+ * A method is more specific if all parameters can also be fed to
+ * the less specific method, because, e.g. the less specific method
+ * accepts a base class of the equivalent argument for the more
+ * specific one.
+ *
+ * @param first a <code>Class[]</code> value
+ * @param second a <code>Class[]</code> value
+ * @return a <code>boolean</code> value
+ */
+ private boolean moreSpecific(Class[] first, Class[] second)
+ {
+ for (int j=0; j < first.length; j++)
+ {
+ if (second[j].isAssignableFrom(first[j]))
+ continue;
+ return false;
+ }
+ return true;
+ }
+
+ final Object doExecute() throws Exception
+ {
+ Class klazz = target.getClass();
+ Class argTypes[] = new Class[arguments.length];
+ for (int i = 0; i < arguments.length; i++)
+ argTypes[i] = arguments[i].getClass();
+
+ if (target.getClass().isArray())
+ {
+ // FIXME: invoke may have to be used. For now, cast to Number
+ // and hope for the best. If caller didn't behave, we go boom
+ // and throw the exception.
+ if (methodName.equals("get") && argTypes.length == 1)
+ return Array.get(target, ((Number)arguments[0]).intValue());
+ if (methodName.equals("set") && argTypes.length == 2)
+ {
+ Object obj = Array.get(target, ((Number)arguments[0]).intValue());
+ Array.set(target, ((Number)arguments[0]).intValue(), arguments[1]);
+ return obj;
+ }
+ throw new NoSuchMethodException("No matching method for statement " + toString());
+ }
+
+ // If we already cached the method, just use it.
+ if (method != null)
+ return method.invoke(target, arguments);
+ else if (ctor != null)
+ return ctor.newInstance(arguments);
+
+ // Find a matching method to call. JDK seems to go through all
+ // this to find the method to call.
+
+ // if method name or length don't match, skip
+ // Need to go through each arg
+ // If arg is wrapper - check if method arg is matchable builtin
+ // or same type or super
+ // - check that method arg is same or super
+
+ if (methodName.equals("new"))
+ {
+ Constructor ctors[] = klazz.getConstructors();
+ for (int i = 0; i < ctors.length; i++)
+ {
+ // Skip methods with wrong number of args.
+ Class ptypes[] = ctors[i].getParameterTypes();
+ if (ptypes.length != arguments.length) continue;
+
+ // Check if method matches
+ if (!compatible(ptypes, argTypes)) continue;
+
+ // Use method[i] if it is more specific.
+ // FIXME: should this check both directions and throw if
+ // neither is more specific?
+ if (ctor == null)
+ {
+ ctor = ctors[i];
+ continue;
+ }
+ Class mptypes[] = ctor.getParameterTypes();
+ if (moreSpecific(ptypes, mptypes))
+ ctor = ctors[i];
+ }
+ if (ctor == null)
+ throw new InstantiationException("No matching constructor for statement " + toString());
+ return ctor.newInstance(arguments);
+ }
+
+ Method methods[] = klazz.getMethods();
+
+ for (int i = 0; i < methods.length; i++)
+ {
+ // Skip methods with wrong name or number of args.
+ if (!methods[i].getName().equals(methodName)) continue;
+ Class ptypes[] = methods[i].getParameterTypes();
+ if (ptypes.length != arguments.length) continue;
+
+ // Check if method matches
+ if (!compatible(ptypes, argTypes)) continue;
+
+ // Use method[i] if it is more specific.
+ // FIXME: should this check both directions and throw if
+ // neither is more specific?
+ if (method == null)
+ {
+ method = methods[i];
+ continue;
+ }
+ Class mptypes[] = method.getParameterTypes();
+ if (moreSpecific(ptypes, mptypes))
+ method = methods[i];
+ }
+ if (method == null)
+ throw new NoSuchMethodException("No matching method for statement " + toString());
+ return method.invoke(target, arguments);
+ }
+
+
+
+ /** Return the statement arguments. */
+ public Object[] getArguments() { return arguments; }
+
+ /** Return the statement method name. */
+ public String getMethodName() { return methodName; }
+
+ /** Return the statement object. */
+ public Object getTarget() { return target; }
+
+ /** Return a string representation. */
+ public String toString()
+ {
+ String result = target.getClass().getName() + "." + methodName + "(";
+ String sep = "";
+ for (int i = 0; i < arguments.length; i++)
+ {
+ result = result + sep + arguments[i].getClass().getName();
+ sep = ", ";
+ }
+ result = result + ")";
+ return result;
+ }
+}