/*
* Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.beans;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.Method;
import java.util.List;
import java.util.ArrayList;
/**
* A MethodDescriptor describes a particular method that a Java Bean
* supports for external access from other components.
*/
public class MethodDescriptor extends FeatureDescriptor {
private Reference<Method> methodRef;
private String[] paramNames;
private List<WeakReference<Class<?>>> params;
private ParameterDescriptor parameterDescriptors[];
/**
* Constructs a <code>MethodDescriptor</code> from a
* <code>Method</code>.
*
* @param method The low-level method information.
*/
public MethodDescriptor(Method method) {
this(method, null);
}
/**
* Constructs a <code>MethodDescriptor</code> from a
* <code>Method</code> providing descriptive information for each
* of the method's parameters.
*
* @param method The low-level method information.
* @param parameterDescriptors Descriptive information for each of the
* method's parameters.
*/
public MethodDescriptor(Method method,
ParameterDescriptor parameterDescriptors[]) {
setName(method.getName());
setMethod(method);
this.parameterDescriptors = (parameterDescriptors != null)
? parameterDescriptors.clone()
: null;
}
/**
* Gets the method that this MethodDescriptor encapsualtes.
*
* @return The low-level description of the method
*/
public synchronized Method getMethod() {
Method method = getMethod0();
if (method == null) {
Class<?> cls = getClass0();
String name = getName();
if ((cls != null) && (name != null)) {
Class<?>[] params = getParams();
if (params == null) {
for (int i = 0; i < 3; i++) {
// Find methods for up to 2 params. We are guessing here.
// This block should never execute unless the classloader
// that loaded the argument classes disappears.
method = Introspector.findMethod(cls, name, i, null);
if (method != null) {
break;
}
}
} else {
method = Introspector.findMethod(cls, name, params.length, params);
}
setMethod(method);
}
}
return method;
}
private synchronized void setMethod(Method method) {
if (method == null) {
return;
}
if (getClass0() == null) {
setClass0(method.getDeclaringClass());
}
setParams(getParameterTypes(getClass0(), method));
this.methodRef = getSoftReference(method);
}
private Method getMethod0() {
return (this.methodRef != null)
? this.methodRef.get()
: null;
}
private synchronized void setParams(Class<?>[] param) {
if (param == null) {
return;
}
paramNames = new String[param.length];
params = new ArrayList<>(param.length);
for (int i = 0; i < param.length; i++) {
paramNames[i] = param[i].getName();
params.add(new WeakReference<Class<?>>(param[i]));
}
}
// pp getParamNames used as an optimization to avoid method.getParameterTypes.
String[] getParamNames() {
return paramNames;
}
private synchronized Class<?>[] getParams() {
Class<?>[] clss = new Class<?>[params.size()];
for (int i = 0; i < params.size(); i++) {
Reference<? extends Class<?>> ref = (Reference<? extends Class<?>>)params.get(i);
Class<?> cls = ref.get();
if (cls == null) {
return null;
} else {
clss[i] = cls;
}
}
return clss;
}
/**
* Gets the ParameterDescriptor for each of this MethodDescriptor's
* method's parameters.
*
* @return The locale-independent names of the parameters. May return
* a null array if the parameter names aren't known.
*/
public ParameterDescriptor[] getParameterDescriptors() {
return (this.parameterDescriptors != null)
? this.parameterDescriptors.clone()
: null;
}
/*
* Package-private constructor
* Merge two method descriptors. Where they conflict, give the
* second argument (y) priority over the first argument (x).
* @param x The first (lower priority) MethodDescriptor
* @param y The second (higher priority) MethodDescriptor
*/
MethodDescriptor(MethodDescriptor x, MethodDescriptor y) {
super(x,y);
methodRef = x.methodRef;
if (y.methodRef != null) {
methodRef = y.methodRef;
}
params = x.params;
if (y.params != null) {
params = y.params;
}
paramNames = x.paramNames;
if (y.paramNames != null) {
paramNames = y.paramNames;
}
parameterDescriptors = x.parameterDescriptors;
if (y.parameterDescriptors != null) {
parameterDescriptors = y.parameterDescriptors;
}
}
/*
* Package-private dup constructor
* This must isolate the new object from any changes to the old object.
*/
MethodDescriptor(MethodDescriptor old) {
super(old);
methodRef = old.methodRef;
params = old.params;
paramNames = old.paramNames;
if (old.parameterDescriptors != null) {
int len = old.parameterDescriptors.length;
parameterDescriptors = new ParameterDescriptor[len];
for (int i = 0; i < len ; i++) {
parameterDescriptors[i] = new ParameterDescriptor(old.parameterDescriptors[i]);
}
}
}
void appendTo(StringBuilder sb) {
appendTo(sb, "method", this.methodRef);
if (this.parameterDescriptors != null) {
sb.append("; parameterDescriptors={");
for (ParameterDescriptor pd : this.parameterDescriptors) {
sb.append(pd).append(", ");
}
sb.setLength(sb.length() - 2);
sb.append("}");
}
}
}