jdk/src/share/classes/com/sun/jmx/mbeanserver/MBeanAnalyzer.java
changeset 2 90ce3da70b43
child 287 bff5501b2a02
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/com/sun/jmx/mbeanserver/MBeanAnalyzer.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,268 @@
+/*
+ * Copyright 2005-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package com.sun.jmx.mbeanserver;
+
+import static com.sun.jmx.mbeanserver.Util.*;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import javax.management.NotCompliantMBeanException;
+
+/**
+ * <p>An analyzer for a given MBean interface.  The analyzer can
+ * be for Standard MBeans or MXBeans, depending on the MBeanIntrospector
+ * passed at construction.
+ *
+ * <p>The analyzer can
+ * visit the attributes and operations of the interface, calling
+ * a caller-supplied visitor method for each one.</p>
+ *
+ * @param <M> Method or ConvertingMethod according as this is a
+ * Standard MBean or an MXBean.
+ *
+ * @since 1.6
+ */
+class MBeanAnalyzer<M> {
+
+    static interface MBeanVisitor<M> {
+        public void visitAttribute(String attributeName,
+                M getter,
+                M setter);
+        public void visitOperation(String operationName,
+                M operation);
+    }
+
+    void visit(MBeanVisitor<M> visitor) {
+        // visit attributes
+        for (Map.Entry<String, AttrMethods<M>> entry : attrMap.entrySet()) {
+            String name = entry.getKey();
+            AttrMethods<M> am = entry.getValue();
+            visitor.visitAttribute(name, am.getter, am.setter);
+        }
+
+        // visit operations
+        for (Map.Entry<String, List<M>> entry : opMap.entrySet()) {
+            for (M m : entry.getValue())
+                visitor.visitOperation(entry.getKey(), m);
+        }
+    }
+
+    /* Map op name to method */
+    private Map<String, List<M>> opMap = newInsertionOrderMap();
+    /* Map attr name to getter and/or setter */
+    private Map<String, AttrMethods<M>> attrMap = newInsertionOrderMap();
+
+    private static class AttrMethods<M> {
+        M getter;
+        M setter;
+    }
+
+    /**
+     * <p>Return an MBeanAnalyzer for the given MBean interface and
+     * MBeanIntrospector.  Calling this method twice with the same
+     * parameters may return the same object or two different but
+     * equivalent objects.
+     */
+    // Currently it's two different but equivalent objects.  This only
+    // really impacts proxy generation.  For MBean creation, the
+    // cached PerInterface object for an MBean interface means that
+    // an analyzer will not be recreated for a second MBean using the
+    // same interface.
+    static <M> MBeanAnalyzer<M> analyzer(Class<?> mbeanInterface,
+            MBeanIntrospector<M> introspector)
+            throws NotCompliantMBeanException {
+        return new MBeanAnalyzer<M>(mbeanInterface, introspector);
+    }
+
+    private MBeanAnalyzer(Class<?> mbeanInterface,
+            MBeanIntrospector<M> introspector)
+            throws NotCompliantMBeanException {
+        if (!mbeanInterface.isInterface()) {
+            throw new NotCompliantMBeanException("Not an interface: " +
+                    mbeanInterface.getName());
+        }
+
+        try {
+            initMaps(mbeanInterface, introspector);
+        } catch (Exception x) {
+            throw Introspector.throwException(mbeanInterface,x);
+        }
+    }
+
+    // Introspect the mbeanInterface and initialize this object's maps.
+    //
+    private void initMaps(Class<?> mbeanInterface,
+            MBeanIntrospector<M> introspector) throws Exception {
+        final Method[] methodArray = mbeanInterface.getMethods();
+
+        final List<Method> methods = eliminateCovariantMethods(methodArray);
+
+        /* Run through the methods to detect inconsistencies and to enable
+           us to give getter and setter together to visitAttribute. */
+        for (Method m : methods) {
+            String name = m.getName();
+
+            final M cm = introspector.mFrom(m);
+
+            String attrName = "";
+            if (name.startsWith("get"))
+                attrName = name.substring(3);
+            else if (name.startsWith("is")
+            && m.getReturnType() == boolean.class)
+                attrName = name.substring(2);
+
+            if (attrName.length() != 0 && m.getParameterTypes().length == 0
+                    && m.getReturnType() != void.class) {
+                // It's a getter
+                // Check we don't have both isX and getX
+                AttrMethods<M> am = attrMap.get(attrName);
+                if (am == null)
+                    am = new AttrMethods<M>();
+                else {
+                    if (am.getter != null) {
+                        final String msg = "Attribute " + attrName +
+                                " has more than one getter";
+                        throw new NotCompliantMBeanException(msg);
+                    }
+                }
+                am.getter = cm;
+                attrMap.put(attrName, am);
+            } else if (name.startsWith("set") && name.length() > 3
+                    && m.getParameterTypes().length == 1 &&
+                    m.getReturnType() == void.class) {
+                // It's a setter
+                attrName = name.substring(3);
+                AttrMethods<M> am = attrMap.get(attrName);
+                if (am == null)
+                    am = new AttrMethods<M>();
+                else if (am.setter != null) {
+                    final String msg = "Attribute " + attrName +
+                            " has more than one setter";
+                    throw new NotCompliantMBeanException(msg);
+                }
+                am.setter = cm;
+                attrMap.put(attrName, am);
+            } else {
+                // It's an operation
+                List<M> cms = opMap.get(name);
+                if (cms == null)
+                    cms = newList();
+                cms.add(cm);
+                opMap.put(name, cms);
+            }
+        }
+        /* Check that getters and setters are consistent. */
+        for (Map.Entry<String, AttrMethods<M>> entry : attrMap.entrySet()) {
+            AttrMethods<M> am = entry.getValue();
+            if (!introspector.consistent(am.getter, am.setter)) {
+                final String msg = "Getter and setter for " + entry.getKey() +
+                        " have inconsistent types";
+                throw new NotCompliantMBeanException(msg);
+            }
+        }
+    }
+
+    /**
+     * A comparator that defines a total order so that methods have the
+     * same name and identical signatures appear next to each others.
+     * The methods are sorted in such a way that methods which
+     * override each other will sit next to each other, with the
+     * overridden method first - e.g. Object getFoo() is placed before
+     * Integer getFoo(). This makes it possible to determine whether
+     * a method overrides another one simply by looking at the method(s)
+     * that precedes it in the list. (see eliminateCovariantMethods).
+     **/
+    private static class MethodOrder implements Comparator<Method> {
+        public int compare(Method a, Method b) {
+            final int cmp = a.getName().compareTo(b.getName());
+            if (cmp != 0) return cmp;
+            final Class<?>[] aparams = a.getParameterTypes();
+            final Class<?>[] bparams = b.getParameterTypes();
+            if (aparams.length != bparams.length)
+                return aparams.length - bparams.length;
+            if (!Arrays.equals(aparams, bparams)) {
+                return Arrays.toString(aparams).
+                        compareTo(Arrays.toString(bparams));
+            }
+            final Class<?> aret = a.getReturnType();
+            final Class<?> bret = b.getReturnType();
+            if (aret == bret) return 0;
+
+            // Super type comes first: Object, Number, Integer
+            if (aret.isAssignableFrom(bret))
+                return -1;
+            return +1;      // could assert bret.isAssignableFrom(aret)
+        }
+        public final static MethodOrder instance = new MethodOrder();
+    }
+
+
+    /* Eliminate methods that are overridden with a covariant return type.
+       Reflection will return both the original and the overriding method
+       but only the overriding one is of interest.  We return the methods
+       in the same order they arrived in.  This isn't required by the spec
+       but existing code may depend on it and users may be used to seeing
+       operations or attributes appear in a particular order.  */
+    static List<Method>
+            eliminateCovariantMethods(Method[] methodArray) {
+        // We are assuming that you never have very many methods with the
+        // same name, so it is OK to use algorithms that are quadratic
+        // in the number of methods with the same name.
+
+        final int len = methodArray.length;
+        final Method[] sorted = methodArray.clone();
+        Arrays.sort(sorted,MethodOrder.instance);
+        final Set<Method> overridden = newSet();
+        for (int i=1;i<len;i++) {
+            final Method m0 = sorted[i-1];
+            final Method m1 = sorted[i];
+
+            // Methods that don't have the same name can't override each others
+            if (!m0.getName().equals(m1.getName())) continue;
+
+            // Methods that have the same name and same signature override
+            // each other. In that case, the second method overrides the first,
+            // due to the way we have sorted them in MethodOrder.
+            if (Arrays.equals(m0.getParameterTypes(),
+                    m1.getParameterTypes())) {
+                overridden.add(m0);
+            }
+        }
+
+        final List<Method> methods = newList(Arrays.asList(methodArray));
+        methods.removeAll(overridden);
+        return methods;
+    }
+
+
+}