org.pepstock.jem.annotations.SetFields.java Source code

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Here is the source code for org.pepstock.jem.annotations.SetFields.java

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/**
JEM, the BEE - Job Entry Manager, the Batch Execution Environment
Copyright (C) 2012-2015   Andrea "Stock" Stocchero
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
any later version.
    
This program 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 for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package org.pepstock.jem.annotations;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;

import javax.naming.InitialContext;
import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;

import org.apache.commons.lang3.reflect.FieldUtils;
import org.pepstock.jem.jppf.DataStreamNameClassPair;
import org.pepstock.jem.jppf.UniqueInitialContext;
import org.pepstock.jem.node.tasks.jndi.ContextUtils;

/**
 * Utility to set method value using the annotations toassign data sources and data description
 * 
 * @see AssignDataDescription
 * @see AssignDataSource
 * 
 * @author Andrea "Stock" Stocchero
 * @version 2.2
 */
public final class SetFields {

    /**
     * To avoid any instantiation
     */
    private SetFields() {

    }

    /**
     * Assigns the value of data description and data source starting from a class. This is used when you have to set fields of java main class.
     * @param clazz java main class
     * @throws NamingException if any error occurs
     * @throws IllegalAccessException if any error occurs
     */
    public static void applyByAnnotation(Class<?> clazz) throws NamingException, IllegalAccessException {
        applyByAnnotation(null, clazz, false);
    }

    /**
     * Assigns the value of data description and data source to a object.
     * @param object instance of object to set fields
     * @throws NamingException if any error occurs
     * @throws IllegalAccessException if any error occurs
     */
    public static void applyByAnnotation(Object object) throws NamingException, IllegalAccessException {
        applyByAnnotation(object, false);
    }

    /**
     * Assigns the value of data description and data source to a object, checking if for JPPF integration or not
     * @param object instance of object to set fields
     * @param isUsingUniqueInitialContext if is JPPF integration
     * @throws NamingException if any error occurs
     * @throws IllegalAccessException if any error occurs
     */
    public static void applyByAnnotation(Object object, boolean isUsingUniqueInitialContext)
            throws NamingException, IllegalAccessException {
        applyByAnnotation(object, object.getClass(), false);
    }

    /**
     * Assigns the value of data description and data source to a object, checking if for JPPF integration or not
     * @param object instance of object to set fields (can be null for java main class call)
     * @param clazz class for reflection
     * @param isUsingUniqueInitialContext if is JPPF integration
     * @throws NamingException if any error occurs
     * @throws IllegalAccessException if any error occurs
     */
    private static void applyByAnnotation(Object object, Class<?> clazz, boolean isUsingUniqueInitialContext)
            throws NamingException, IllegalAccessException {
        // new initial context to access by JNDI to COMMAND DataDescription
        InitialContext ic = null;

        // scans all declared fields
        for (Field field : clazz.getDeclaredFields()) {
            // if has got data description annotation
            if (field.isAnnotationPresent(AssignDataDescription.class)) {
                // check initial context to instantiate once
                if (ic == null) {
                    // checks if is JPPF integration which used another context
                    ic = (isUsingUniqueInitialContext) ? UniqueInitialContext.getContext()
                            : ContextUtils.getContext();
                }
                // gets annotation
                AssignDataDescription annotation = (AssignDataDescription) field
                        .getAnnotation(AssignDataDescription.class);

                checkIfIsRightObject(annotation.value(), true);

                // sets field
                setFieldByAnnotation(ic, object, annotation.value(), field);
            } else if (field.isAnnotationPresent(AssignDataSource.class)) {
                // check initial context to instantiate once
                if (ic == null) {
                    // checks if is JPPF integration which used another context
                    ic = (isUsingUniqueInitialContext) ? UniqueInitialContext.getContext()
                            : ContextUtils.getContext();
                }
                // gets annotation
                AssignDataSource annotation = (AssignDataSource) field.getAnnotation(AssignDataSource.class);

                checkIfIsRightObject(annotation.value(), false);

                // sets field
                setFieldByAnnotation(ic, object, annotation.value(), field);
            }
        }
    }

    private static void setFieldByAnnotation(InitialContext ic, Object object, String name, Field field)
            throws NamingException, IllegalAccessException {
        // gets object via JNDI
        Object objectJNDI = (Object) ic.lookup(name);
        // if is static or it's a java main class (object = null) sets statically
        if (Modifier.isStatic(field.getModifiers()) || object == null) {
            FieldUtils.writeStaticField(field, objectJNDI, true);
        } else {
            // sets field
            FieldUtils.writeField(field, object, objectJNDI, true);
        }
    }

    private static void checkIfIsRightObject(String name, boolean isDD) throws NamingException {
        InitialContext ic = ContextUtils.getContext();
        NamingEnumeration<NameClassPair> list = ic.list(name);
        boolean isDataDescription = false;
        while (list.hasMore()) {
            NameClassPair pair = list.next();
            // checks if is datastream
            // only datastreams are changed
            if (pair instanceof DataStreamNameClassPair) {
                isDataDescription = true;
            }
        }
        if (isDD && !isDataDescription) {
            throw new NamingException(name + " is not a data description");
        }
        if (!isDD && isDataDescription) {
            throw new NamingException(name + " is not a data source");
        }
    }

}