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/*
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* Copyright 1996-2003 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package java.beans;
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import java.lang.ref.Reference;
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import java.lang.ref.WeakReference;
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import java.lang.reflect.Method;
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import java.util.List;
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import java.util.ArrayList;
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/**
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* A MethodDescriptor describes a particular method that a Java Bean
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* supports for external access from other components.
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*/
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public class MethodDescriptor extends FeatureDescriptor {
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private Reference<Method> methodRef;
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private String[] paramNames;
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private List params;
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private ParameterDescriptor parameterDescriptors[];
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/**
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* Constructs a <code>MethodDescriptor</code> from a
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* <code>Method</code>.
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*
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* @param method The low-level method information.
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*/
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public MethodDescriptor(Method method) {
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this(method, null);
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}
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/**
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* Constructs a <code>MethodDescriptor</code> from a
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* <code>Method</code> providing descriptive information for each
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* of the method's parameters.
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*
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* @param method The low-level method information.
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* @param parameterDescriptors Descriptive information for each of the
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* method's parameters.
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*/
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public MethodDescriptor(Method method,
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ParameterDescriptor parameterDescriptors[]) {
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setName(method.getName());
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setMethod(method);
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this.parameterDescriptors = parameterDescriptors;
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}
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/**
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* Gets the method that this MethodDescriptor encapsualtes.
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*
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* @return The low-level description of the method
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*/
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public synchronized Method getMethod() {
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Method method = getMethod0();
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if (method == null) {
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Class cls = getClass0();
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if (cls != null) {
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Class[] params = getParams();
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if (params == null) {
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for (int i = 0; i < 3; i++) {
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// Find methods for up to 2 params. We are guessing here.
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// This block should never execute unless the classloader
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// that loaded the argument classes disappears.
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method = Introspector.findMethod(cls, getName(), i, null);
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if (method != null) {
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break;
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}
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}
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} else {
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method = Introspector.findMethod(cls, getName(),
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params.length, params);
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}
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setMethod(method);
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}
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}
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return method;
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}
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private synchronized void setMethod(Method method) {
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if (method == null) {
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return;
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}
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if (getClass0() == null) {
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setClass0(method.getDeclaringClass());
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}
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setParams(getParameterTypes(getClass0(), method));
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this.methodRef = getSoftReference(method);
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}
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private Method getMethod0() {
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return (this.methodRef != null)
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? this.methodRef.get()
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: null;
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}
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private synchronized void setParams(Class[] param) {
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if (param == null) {
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return;
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}
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paramNames = new String[param.length];
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params = new ArrayList(param.length);
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for (int i = 0; i < param.length; i++) {
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paramNames[i] = param[i].getName();
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params.add(new WeakReference(param[i]));
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}
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}
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// pp getParamNames used as an optimization to avoid method.getParameterTypes.
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String[] getParamNames() {
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return paramNames;
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}
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private synchronized Class[] getParams() {
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Class[] clss = new Class[params.size()];
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for (int i = 0; i < params.size(); i++) {
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Reference ref = (Reference)params.get(i);
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Class cls = (Class)ref.get();
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if (cls == null) {
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return null;
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} else {
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clss[i] = cls;
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}
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}
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return clss;
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}
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/**
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* Gets the ParameterDescriptor for each of this MethodDescriptor's
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* method's parameters.
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*
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* @return The locale-independent names of the parameters. May return
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* a null array if the parameter names aren't known.
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*/
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public ParameterDescriptor[] getParameterDescriptors() {
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return parameterDescriptors;
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}
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/*
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public String toString() {
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String message = "name=" + getName();
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Class cls = getClass0();
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if (cls != null) {
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message += ", class=";
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message += cls.getName();
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}
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String[] names = getParamNames();
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if (names != null) {
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for (int i = 0; i < names.length; i++) {
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message += ", param=" + names[i];
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}
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}
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return message;
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} */
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/*
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* Package-private constructor
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* Merge two method descriptors. Where they conflict, give the
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* second argument (y) priority over the first argument (x).
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* @param x The first (lower priority) MethodDescriptor
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* @param y The second (higher priority) MethodDescriptor
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*/
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MethodDescriptor(MethodDescriptor x, MethodDescriptor y) {
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super(x,y);
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methodRef = x.methodRef;
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if (y.methodRef != null) {
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methodRef = y.methodRef;
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}
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params = x.params;
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if (y.params != null) {
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params = y.params;
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}
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paramNames = x.paramNames;
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if (y.paramNames != null) {
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paramNames = y.paramNames;
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}
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parameterDescriptors = x.parameterDescriptors;
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if (y.parameterDescriptors != null) {
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parameterDescriptors = y.parameterDescriptors;
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}
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}
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/*
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* Package-private dup constructor
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* This must isolate the new object from any changes to the old object.
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*/
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MethodDescriptor(MethodDescriptor old) {
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super(old);
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methodRef = old.methodRef;
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params = old.params;
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paramNames = old.paramNames;
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if (old.parameterDescriptors != null) {
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int len = old.parameterDescriptors.length;
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parameterDescriptors = new ParameterDescriptor[len];
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for (int i = 0; i < len ; i++) {
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parameterDescriptors[i] = new ParameterDescriptor(old.parameterDescriptors[i]);
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}
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}
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}
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}
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