com.hula.lang.util.DotNotationUtil.java Source code

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Here is the source code for com.hula.lang.util.DotNotationUtil.java

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/**
 * Copyright 2013 Simon Curd <simoncurd@gmail.com>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.hula.lang.util;

import org.apache.commons.beanutils.PropertyUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DotNotationUtil {
    private static Logger logger = LoggerFactory.getLogger(DotNotationUtil.class);

    /**
     * Checks if a String is a property path. Returns true if at least
     * one dot (.) is present
     * 
     * @param propertyPath the String to inspect
     * @return boolean indicating whether this is a property path
     */
    public static boolean isPath(String propertyPath) {
        return propertyPath.indexOf(".") != -1;
    }

    /**
     * Get the first property in a property path
     * 
     * @param propertyPath the property path to inspect
     * @return the first property in the property path
     */
    public static String getFirstItem(String propertyPath) {
        if (isPath(propertyPath)) {
            String[] path = getPath(propertyPath);
            return path[0];
        }
        return propertyPath;
    }

    /**
     * Split a dot notation property path into it's constitute parts
     * 
     * @param propertyPath The property path to inspect
     * @return A String[] of nested properties
     */
    public static String[] getPath(String propertyPath) {
        String[] path = new String[] { propertyPath };
        if (isPath(propertyPath)) {
            path = propertyPath.split("\\.");
        }
        return path;
    }

    /**
     * Get the last item in a property path
     * 
     * @param propertyPath the property path to inspect
     * @return the last property in the property path
     */
    public static String getLastItem(String propertyPath) {
        if (isPath(propertyPath)) {
            String[] path = getPath(propertyPath);
            return path[path.length - 1];
        }
        return propertyPath;
    }

    public static void setProperty(String name, Object source, Object value, int index) {
        // last item in the path is the target property name
        //
        // i.e. script.description
        //
        // we're looking up to script, then to description
        String targetProperty = getLastItem(name);

        String[] path = getPath(name);

        // refine the source down to the correct object
        for (int i = index; index != path.length - 1; index++) {
            String item = path[i];

            source = reflect(source, item);

        }

        // now do the set
        try {
            PropertyUtils.setProperty(source, targetProperty, value);
        } catch (Throwable t) {
            t.printStackTrace();
        }

    }

    /**
     * This inspects the property path of an object graph to return the value
     * of a property. Uses a dot notation based path.
     * 
     * @param propertyPath The path to the property
     * @param root The root of the object graph
     * @return The property value
     */
    public static Object getProperty(String propertyPath, Object root) {
        return getProperty(propertyPath, root, 0);
    }

    /**
     * This inspects the property path of an object graph to return the value
     * of a property. Uses a dot notation based path.
     * 
     * @param propertyPath The path to the property
     * @param root The root of the object graph
     * @param index The path item to start from
     * @return The property result
     */
    public static Object getProperty(String propertyPath, Object root, int index) {
        Object value = root;
        if (value == null) {
            // no point in traversing any further
            return null;
        }
        String[] path = getPath(propertyPath);

        // traverse path items
        for (int i = index; i != path.length; i++) {
            String par = path[i];

            value = reflect(value, par);

            if (value == null) {
                // no point in traversing any further
                return null;
            }
        }
        return value;

    }

    /**
     * Uses beanutils to reflect the value of a property
     * 
     * @param obj the object to inspect
     * @param property the property to reflect
     * @return the value of the property
     */
    private static Object reflect(Object obj, String property) {
        try {
            return PropertyUtils.getProperty(obj, property);
        } catch (Throwable t) {
            logger.error("error getting property [" + t.getClass().getSimpleName() + "]", t);
            return null;
        }
    }

}