/*

 * Copyright (c) 2005, 2008, 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 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 returnMapping.getOpenType();

    }

    OpenType<?>[] getOpenParameterTypes() {

        final OpenType<?>[] types = new OpenType<?>[paramMappings.length];

        for (int i = 0; i < paramMappings.length; i++)

            types[i] = paramMappings[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() {

        try {

            for (MXBeanMapping paramConverter : paramMappings)

                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() {

        try {

            returnMapping.checkReconstructible();

        } catch (InvalidObjectException e) {

            throw new IllegalArgumentException(e);

        }

    }

    String[] getOpenSignature() {

        if (paramMappings.length == 0)

            return noStrings;

        String[] sig = new String[paramMappings.length];

        for (int i = 0; i < paramMappings.length; i++)

            sig[i] = paramMappings[i].getOpenClass().getName();

        return sig;

    }

    final Object toOpenReturnValue(MXBeanLookup lookup, Object ret)

            throws OpenDataException {

        return returnMapping.toOpenValue(ret);

    }

    final Object fromOpenReturnValue(MXBeanLookup lookup, Object ret)

            throws InvalidObjectException {

        return returnMapping.fromOpenValue(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] = paramMappings[i].toOpenValue(params[i]);

        return oparams;

    }

    final Object[] fromOpenParameters(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] = paramMappings[i].fromOpenValue(params[i]);

        return jparams;

    }

    final Object toOpenParameter(MXBeanLookup lookup,

                                 Object param,

                                 int paramNo)

        throws OpenDataException {

        return paramMappings[paramNo].toOpenValue(param);

    }

    final Object fromOpenParameter(MXBeanLookup lookup,

                                   Object param,

                                   int paramNo)

        throws InvalidObjectException {

        return paramMappings[paramNo].fromOpenValue(param);

    }

    Object invokeWithOpenReturn(MXBeanLookup lookup,

                                Object obj, Object[] params)

            throws MBeanException, IllegalAccessException,

                   InvocationTargetException {

        MXBeanLookup old = MXBeanLookup.getLookup();

        try {

            MXBeanLookup.setLookup(lookup);

            return invokeWithOpenReturn(obj, params);

        } finally {

            MXBeanLookup.setLookup(old);

        }

    }

    private Object invokeWithOpenReturn(Object obj, Object[] params)

            throws MBeanException, IllegalAccessException,

                   InvocationTargetException {

        final Object[] javaParams;

        try {

            javaParams = fromOpenParameters(params);

        } catch (InvalidObjectException e) {

            // probably can't happen

            final String msg = methodName() + ": cannot convert parameters " +

                "from open values: " + e;

            throw new MBeanException(e, msg);

        }

        try {

            return returnMapping.toOpenValue(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;

        MXBeanMappingFactory mappingFactory = MXBeanMappingFactory.DEFAULT;

        returnMapping =

                mappingFactory.mappingForType(m.getGenericReturnType(), mappingFactory);

        Type[] params = m.getGenericParameterTypes();

        paramMappings = new MXBeanMapping[params.length];

        boolean identity = true;

        for (int i = 0; i < params.length; i++) {

            paramMappings[i] = mappingFactory.mappingForType(params[i], mappingFactory);

            identity &= DefaultMXBeanMappingFactory.isIdentity(paramMappings[i]);

        }

        paramConversionIsIdentity = identity;

    }

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

    private final Method method;

    private final MXBeanMapping returnMapping;

    private final MXBeanMapping[] paramMappings;

    private final boolean paramConversionIsIdentity;

}