/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the 
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 
 * which accompanies this distribution. 
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
 *     08/23/2010-2.2 Michael O'Brien 
 *        - 323043: application.xml module ordering may cause weaving not to occur causing an NPE.
 *                       warn if expected "_persistence_*_vh" method not found
 *                       instead of throwing NPE during deploy validation.
 *                       Note: SDO overrides this class so an override of getMethodReturnType
 *                       will also need an override in SDO.
 ******************************************************************************/  
package org.eclipse.persistence.internal.descriptors;

import java.lang.reflect.*;
import java.security.AccessController;
import java.security.PrivilegedActionException;

import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.logging.AbstractSessionLog;
import org.eclipse.persistence.logging.SessionLog;
import org.eclipse.persistence.mappings.AttributeAccessor;
import org.eclipse.persistence.internal.security.*;

/**
 * <p><b>Purpose</b>: A wrapper class for handling cases when the domain object attributes are
 * to be accessed thru the accessor methods. This could happen if the variables are not defined
 * public in the domain object.
 *
 * @author Sati
 * @since TOPLink/Java 1.0
 */
public class MethodAttributeAccessor extends AttributeAccessor {
    protected String setMethodName = "";
    protected String getMethodName;
    protected transient Method setMethod;
    protected transient Method getMethod;
    
    /**
     * Return the return type of the method accessor.
     */
    public Class getAttributeClass() {
        if (getGetMethod() == null) {
            return null;
        }

        return getGetMethodReturnType();
    }

    /**
     * Gets the value of an instance variable in the object.
     */
    public Object getAttributeValueFromObject(Object anObject) throws DescriptorException {
        return getAttributeValueFromObject(anObject, (Object[]) null);
    }
    
    /**
     * Gets the value of an instance variable in the object.
     */
    protected Object getAttributeValueFromObject(Object anObject, Object[] parameters) throws DescriptorException {
        try {
            if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                try {
                    return AccessController.doPrivileged(new PrivilegedMethodInvoker(getGetMethod(), anObject, parameters));
                } catch (PrivilegedActionException exception) {
                    Exception throwableException = exception.getException();
                    if (throwableException instanceof IllegalAccessException) {
                        throw DescriptorException.illegalAccessWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), throwableException);
                    } else {
                        throw DescriptorException.targetInvocationWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), throwableException);
                     }
                }
            } else {
                // PERF: Direct-var access.
                return this.getMethod.invoke(anObject, parameters);    
            }
        } catch (IllegalArgumentException exception) {
            throw DescriptorException.illegalArgumentWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), exception);
        } catch (IllegalAccessException exception) {
            throw DescriptorException.illegalAccessWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), exception);
        } catch (InvocationTargetException exception) {
            throw DescriptorException.targetInvocationWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), exception);
        } catch (NullPointerException exception) {
            // Some JVM's throw this exception for some very odd reason
            throw DescriptorException.nullPointerWhileGettingValueThruMethodAccessor(getGetMethodName(), anObject.getClass().getName(), exception);
        }
    }

    /**
     * Return the accessor method for the attribute accessor.
     * 266912: For Metamodel API - change visibility from protected
     */
    public Method getGetMethod() {
        return getMethod;
    }

    /**
     * Return the name of the accessor method for the attribute accessor.
     */
    public String getGetMethodName() {
        return getMethodName;
    }

    /**
     * INTERNAL:
     * Return the GetMethod return type for this MethodAttributeAccessor.
     * A special check is made to determine if a missing method is a result of failed weaving.
     * @return
     */
    // Note: SDO overrides this method and will handle a null GetMethod
    public Class getGetMethodReturnType() throws DescriptorException {
        // 323403: If the getMethod is missing - check for "_persistence_*_vh" to see if weaving was expected 
        if(null == getGetMethod() && null != getGetMethodName() 
            && (getGetMethodName().indexOf(Helper.PERSISTENCE_FIELDNAME_PREFIX) > -1)) {
            // warn before a possible NPE on accessing a weaved method that does not exist
            AbstractSessionLog.getLog().log(SessionLog.FINEST, "no_weaved_vh_method_found_verify_weaving_and_module_order",
                getGetMethodName(), null, this);
            // 323403: We cannot continue to process objects that are not weaved - if weaving is enabled
            // If we allow the getMethodReturnType to continue - we will throw an obscure NullPointerException
            throw DescriptorException.nullPointerWhileGettingValueThruMethodAccessorCausedByWeavingNotOccurringBecauseOfModuleOrder(getGetMethodName(), "", null);
        }
        if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
            try {
                return AccessController.doPrivileged(new PrivilegedGetMethodReturnType(getGetMethod()));
            } catch (PrivilegedActionException exception) {
                // we should not get here since this call does not throw any checked exceptions
               return null;
            }
        } else {
            return PrivilegedAccessHelper.getMethodReturnType(getGetMethod());
        }
    }

    /**
     * Return the set method for the attribute accessor.
     */
    protected Method getSetMethod() {
        return setMethod;
    }

    /**
     * Return the name of the set method for the attribute accessor.
     */
    public String getSetMethodName() {
        return setMethodName;
    }

    public Class getSetMethodParameterType() {
        return getSetMethodParameterType(0);
    }
    
    protected Class getSetMethodParameterType(int index) {
        if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
            try {
                return AccessController.doPrivileged(new PrivilegedGetMethodParameterTypes(getSetMethod()))[index];
            } catch (PrivilegedActionException exception) {
                // we should not get here since this call does not throw any checked exceptions
                return null;
            }
        } else {
            return PrivilegedAccessHelper.getMethodParameterTypes(getSetMethod())[index];
        }
    }

    protected Class[] getSetMethodParameterTypes() { 
        return new Class[] {getGetMethodReturnType()};
    }
    
    /**
     * Set get and set method after creating these methods by using
     * get and set method names
     */
    public void initializeAttributes(Class theJavaClass) throws DescriptorException {
        initializeAttributes(theJavaClass, (Class[]) null);
    }
    
    /**
     * Set get and set method after creating these methods by using
     * get and set method names
     */
    protected void initializeAttributes(Class theJavaClass, Class[] getParameterTypes) throws DescriptorException {
        if (getAttributeName() == null) {
            throw DescriptorException.attributeNameNotSpecified();
        }
        try {
            setGetMethod(Helper.getDeclaredMethod(theJavaClass, getGetMethodName(), getParameterTypes));
            
            // The parameter type for the set method must always be the return type of the get method.
            if(!isWriteOnly()) {
                setSetMethod(Helper.getDeclaredMethod(theJavaClass, getSetMethodName(), getSetMethodParameterTypes()));
            }
        } catch (NoSuchMethodException ex) {
            DescriptorException descriptorException = DescriptorException.noSuchMethodWhileInitializingAttributesInMethodAccessor(getSetMethodName(), getGetMethodName(), theJavaClass.getName());
            descriptorException.setInternalException(ex);
            throw descriptorException;
        } catch (SecurityException exception) {
            DescriptorException descriptorException = DescriptorException.securityWhileInitializingAttributesInMethodAccessor(getSetMethodName(), getGetMethodName(), theJavaClass.getName());
            descriptorException.setInternalException(exception);
            throw descriptorException;
        }
    }

    /**
     * Returns true if this attribute accessor has been initialized and now stores a reference to the
     * class's attribute.  An attribute accessor can become uninitialized on serialization.
     */
    public boolean isInitialized(){
        return (this.getMethod !=  null || isReadOnly()) && (this.setMethod != null || isWriteOnly());
    }

    public boolean isMethodAttributeAccessor() {
        return true;
    }

    /**
     * Sets the value of the instance variable in the object to the value.
     */
    public void setAttributeValueInObject(Object domainObject, Object attributeValue) throws DescriptorException {
        setAttributeValueInObject(domainObject, attributeValue, new Object[] {attributeValue});
    }
    
    /**
     * Sets the value of the instance variable in the object to the value.
     */
    protected void setAttributeValueInObject(Object domainObject, Object attributeValue, Object[] parameters) throws DescriptorException {
        try {
            if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                try {
                    AccessController.doPrivileged(new PrivilegedMethodInvoker(getSetMethod(), domainObject, parameters));
                } catch (PrivilegedActionException exception) {
                    Exception throwableException = exception.getException();
                    if (throwableException instanceof IllegalAccessException) {
                        throw DescriptorException.illegalAccessWhileSettingValueThruMethodAccessor(getSetMethodName(), attributeValue, throwableException);
                    } else {
                        throw DescriptorException.targetInvocationWhileSettingValueThruMethodAccessor(getSetMethodName(), attributeValue, throwableException);
                     }
                }
            } else {
                // PERF: Direct-var access.
                this.setMethod.invoke(domainObject, parameters);
            }
        } catch (IllegalAccessException exception) {
            throw DescriptorException.illegalAccessWhileSettingValueThruMethodAccessor(getSetMethodName(), attributeValue, exception);
        } catch (IllegalArgumentException exception) {
            // TODO: This code should be removed, it should not be required and may cause unwanted sideeffects.
            // Allow XML change set to merge correctly since new value in XML change set is always String
            try {
                if (attributeValue instanceof String) {
                    Object newValue = ConversionManager.getDefaultManager().convertObject(attributeValue, getAttributeClass());
                    Object[] newParameters = new Object[1];
                    newParameters[0] = newValue;
                    if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                        try {
                            AccessController.doPrivileged(new PrivilegedMethodInvoker(getSetMethod(), domainObject, newParameters));
                        } catch (PrivilegedActionException exc) {
                            // Do nothing and move on to throw the original exception
                        }
                    } else {
                        PrivilegedAccessHelper.invokeMethod(getSetMethod(), domainObject, newParameters);
                    }
                    return;
                }
            } catch (Exception e) {
                // Do nothing and move on to throw the original exception
            }
            throw DescriptorException.illegalArgumentWhileSettingValueThruMethodAccessor(getSetMethodName(), attributeValue, exception);
        } catch (InvocationTargetException exception) {
            throw DescriptorException.targetInvocationWhileSettingValueThruMethodAccessor(getSetMethodName(), attributeValue, exception);
        } catch (NullPointerException exception) {
            try {
                // TODO: This code should be removed, it should not be required and may cause unwanted side effects.
                // cr 3737  If a null pointer was thrown because EclipseLink attempted to set a null reference into a
                // primitive creating a primitive of value 0 to set in the object.
                // Is this really the best place for this? is this not why we have null-value and conversion-manager?
                Class fieldClass = getSetMethodParameterType();

                //Found when fixing Bug2910086
                if (fieldClass.isPrimitive() && (attributeValue == null)) {
                    parameters[parameters.length-1] = ConversionManager.getDefaultManager().convertObject(Integer.valueOf(0), fieldClass);
                    if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
                        try {
                            AccessController.doPrivileged(new PrivilegedMethodInvoker(getSetMethod(), domainObject, parameters));
                        } catch (PrivilegedActionException exc) {
                            Exception throwableException = exc.getException();
                            if (throwableException instanceof IllegalAccessException) {
                                throw DescriptorException.nullPointerWhileSettingValueThruInstanceVariableAccessor(getAttributeName(), attributeValue, throwableException);
                            } else {
                                throw DescriptorException.nullPointerWhileSettingValueThruInstanceVariableAccessor(getAttributeName(), attributeValue, throwableException);
                             }
                        }
                    } else {
                        PrivilegedAccessHelper.invokeMethod(getSetMethod(), domainObject, parameters);
                    }
                } else {
                    // Some JVM's throw this exception for some very odd reason
                    // See 
                    throw DescriptorException.nullPointerWhileSettingValueThruInstanceVariableAccessor(getAttributeName(), attributeValue, exception);
                }
            } catch (IllegalAccessException accessException) {
                throw DescriptorException.nullPointerWhileSettingValueThruInstanceVariableAccessor(getAttributeName(), attributeValue, exception);
            } catch (InvocationTargetException invocationException) {
                throw DescriptorException.nullPointerWhileSettingValueThruInstanceVariableAccessor(getAttributeName(), attributeValue, exception);
            }
        }
    }

    /**
     * Set the accessor method for the attribute accessor.
     */
    protected void setGetMethod(Method getMethod) {
        this.getMethod = getMethod;
    }

    /**
     * Set the name of the accessor method for the attribute accessor.
     */
    public void setGetMethodName(String getMethodName) {
        this.getMethodName = getMethodName;
    }

    /**
     * Set the set method for the attribute accessor.
     */
    protected void setSetMethod(Method setMethod) {
        this.setMethod = setMethod;
    }

    /**
     * Set the name of the set method for the attribute accessor.
     */
    public void setSetMethodName(String setMethodName) {
        this.setMethodName = setMethodName;
    }
}
