com.iorga.iraj.json.ObjectContextCaller.java Source code

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Here is the source code for com.iorga.iraj.json.ObjectContextCaller.java

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/*
 * Copyright (C) 2013 Iorga Group
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see [http://www.gnu.org/licenses/].
 */
package com.iorga.iraj.json;

import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

import org.apache.commons.lang3.StringUtils;

import com.iorga.iraj.annotation.ContextParam;
import com.iorga.iraj.annotation.ContextPath;

public class ObjectContextCaller implements ContextCaller {
    private Method getter;
    private final ContextCaller nextContextCaller;

    public ObjectContextCaller(final String elementName, final AnnotatedElement annotatedElement,
            final ContextParam contextParam) {
        this(contextParam.value(), getContextPath(elementName, annotatedElement));
    }

    private static String getContextPath(final String elementName, final AnnotatedElement annotatedElement) {
        final ContextPath contextPathAnnotation = annotatedElement.getAnnotation(ContextPath.class);
        if (contextPathAnnotation != null) {
            return contextPathAnnotation.value();
        } else {
            return elementName;
        }
    }

    public ObjectContextCaller(final Class<?> currentClass, final String currentContextPath)
            throws SecurityException {
        final String firstContextPathPart = StringUtils.substringBefore(currentContextPath, ".");

        try {
            getter = currentClass.getMethod("get" + StringUtils.capitalize(firstContextPathPart));
        } catch (final NoSuchMethodException e) {
            try {
                getter = currentClass.getMethod("is" + StringUtils.capitalize(firstContextPathPart));
            } catch (final NoSuchMethodException e1) {
                throw new IllegalArgumentException("No getter for " + firstContextPathPart + " on " + currentClass);
            }
        }

        if (!firstContextPathPart.equals(currentContextPath)) {
            // the path is not finished to handle
            nextContextCaller = new ObjectContextCaller(getter.getReturnType(),
                    StringUtils.substringAfter(currentContextPath, "."));
        } else {
            nextContextCaller = null;
        }
    }

    @Override
    public Object callContext(final Object context) {
        try {
            if (context != null) {
                final Object nextContext = getter.invoke(context);
                if (nextContext != null && nextContextCaller != null) {
                    return nextContextCaller.callContext(nextContext);
                } else {
                    return nextContext;
                }
            } else {
                // If the current object is null, let's return null in order to avoid NPE
                return null;
            }
        } catch (final Exception e) {
            throw new IllegalStateException("Couldn't call " + getter, e);
        }
    }

    @Override
    public Type getReturnType() {
        return nextContextCaller != null ? nextContextCaller.getReturnType() : getter.getGenericReturnType();
    }

}