jdk/src/share/classes/com/sun/jmx/mbeanserver/ConvertingMethod.java

/*
 * Copyright 2005-2007 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 java.io.InvalidObjectException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

import javax.management.Descriptor;
import javax.management.MBeanException;
import javax.management.openmbean.OpenDataException;
import javax.management.openmbean.OpenType;

final class ConvertingMethod {
    static ConvertingMethod from(Method m) {
        try {
            return new ConvertingMethod(m);
        } catch (OpenDataException ode) {
            final String msg = "Method " + m.getDeclaringClass().getName() +
                "." + m.getName() + " has parameter or return type that " +
                "cannot be translated into an open type";
            throw new IllegalArgumentException(msg, ode);
        }
    }

    Method getMethod() {
        return method;
    }

    Descriptor getDescriptor() {
        return Introspector.descriptorForElement(method);
    }

    Type getGenericReturnType() {
        return method.getGenericReturnType();
    }

    Type[] getGenericParameterTypes() {
        return method.getGenericParameterTypes();
    }

    String getName() {
        return method.getName();
    }

    OpenType getOpenReturnType() {
        return returnConverter.getOpenType();
    }

    OpenType[] getOpenParameterTypes() {
        final OpenType[] types = new OpenType[paramConverters.length];
        for (int i = 0; i < paramConverters.length; i++)
            types[i] = paramConverters[i].getOpenType();
        return types;
    }

    /* Check that this method will be callable when we are going from
     * open types to Java types, for example when we are going from
     * an MXBean wrapper to the underlying resource.
     * The parameters will be converted to
     * Java types, so they must be "reconstructible".  The return
     * value will be converted to an Open Type, so if it is convertible
     * at all there is no further check needed.
     */
    void checkCallFromOpen() throws IllegalArgumentException {
        try {
            for (OpenConverter paramConverter : paramConverters)
                paramConverter.checkReconstructible();
        } catch (InvalidObjectException e) {
            throw new IllegalArgumentException(e);
        }
    }

    /* Check that this method will be callable when we are going from
     * Java types to open types, for example when we are going from
     * an MXBean proxy to the open types that it will be mapped to.
     * The return type will be converted back to a Java type, so it
     * must be "reconstructible".  The parameters will be converted to
     * open types, so if it is convertible at all there is no further
     * check needed.
     */
    void checkCallToOpen() throws IllegalArgumentException {
        try {
            returnConverter.checkReconstructible();
        } catch (InvalidObjectException e) {
            throw new IllegalArgumentException(e);
        }
    }

    String[] getOpenSignature() {
        if (paramConverters.length == 0)
            return noStrings;

        String[] sig = new String[paramConverters.length];
        for (int i = 0; i < paramConverters.length; i++)
            sig[i] = paramConverters[i].getOpenClass().getName();
        return sig;
    }

    final Object toOpenReturnValue(MXBeanLookup lookup, Object ret)
            throws OpenDataException {
        return returnConverter.toOpenValue(lookup, ret);
    }

    final Object fromOpenReturnValue(MXBeanLookup lookup, Object ret)
            throws InvalidObjectException {
        return returnConverter.fromOpenValue(lookup, ret);
    }

    final Object[] toOpenParameters(MXBeanLookup lookup, Object[] params)
            throws OpenDataException {
        if (paramConversionIsIdentity || params == null)
            return params;
        final Object[] oparams = new Object[params.length];
        for (int i = 0; i < params.length; i++)
            oparams[i] = paramConverters[i].toOpenValue(lookup, params[i]);
        return oparams;
    }

    final Object[] fromOpenParameters(MXBeanLookup lookup, Object[] params)
            throws InvalidObjectException {
        if (paramConversionIsIdentity || params == null)
            return params;
        final Object[] jparams = new Object[params.length];
        for (int i = 0; i < params.length; i++)
            jparams[i] = paramConverters[i].fromOpenValue(lookup, params[i]);
        return jparams;
    }

    final Object toOpenParameter(MXBeanLookup lookup,
                                 Object param,
                                 int paramNo)
        throws OpenDataException {
        return paramConverters[paramNo].toOpenValue(lookup, param);
    }

    final Object fromOpenParameter(MXBeanLookup lookup,
                                   Object param,
                                   int paramNo)
        throws InvalidObjectException {
        return paramConverters[paramNo].fromOpenValue(lookup, param);
    }

    Object invokeWithOpenReturn(MXBeanLookup lookup,
                                Object obj, Object[] params)
            throws MBeanException, IllegalAccessException,
                   InvocationTargetException {
        final Object[] javaParams;
        try {
            javaParams = fromOpenParameters(lookup, params);
        } catch (InvalidObjectException e) {
            // probably can't happen
            final String msg = methodName() + ": cannot convert parameters " +
                "from open values: " + e;
            throw new MBeanException(e, msg);
        }
        final Object javaReturn = method.invoke(obj, javaParams);
        try {
            return returnConverter.toOpenValue(lookup, javaReturn);
        } catch (OpenDataException e) {
            // probably can't happen
            final String msg = methodName() + ": cannot convert return " +
                "value to open value: " + e;
            throw new MBeanException(e, msg);
        }
    }

    private String methodName() {
        return method.getDeclaringClass() + "." + method.getName();
    }

    private ConvertingMethod(Method m) throws OpenDataException {
        this.method = m;
        returnConverter = OpenConverter.toConverter(m.getGenericReturnType());
        Type[] params = m.getGenericParameterTypes();
        paramConverters = new OpenConverter[params.length];
        boolean identity = true;
        for (int i = 0; i < params.length; i++) {
            paramConverters[i] = OpenConverter.toConverter(params[i]);
            identity &= paramConverters[i].isIdentity();
        }
        paramConversionIsIdentity = identity;
    }

    private static final String[] noStrings = new String[0];

    private final Method method;
    private final OpenConverter returnConverter;
    private final OpenConverter[] paramConverters;
    private final boolean paramConversionIsIdentity;
}