PropertyMap.java

package org.yajul.reflection;

import org.yajul.collections.CollectionUtil;
import org.yajul.reflection.BeanProperties;
import org.yajul.reflection.PropertyAccessors;

import java.util.*;

/**
 * Provides a Map view of a JavaBean's properties.
 *
 * @author josh Apr 4, 2004 10:48:27 AM
 */
public class PropertyMap extends AbstractMap implements Map {
    /**
     * The meta-data for the bean's properties.
     */
    private BeanProperties properties;
    /**
     * The bean.
     */
    private Object bean;

    /**
     * Constructs a map view of the bean.
     *
     * @param bean the bean to create a map view of.
     */
    public PropertyMap(Object bean) {
        this(new BeanProperties(bean.getClass()), bean);
    }

    /**
     * Constructs a map view of the bean, with the given BeanProperties meta-data.
     *
     * @param beanProperties The property properties
     * @param bean           the bean to create a map view of.
     */
    private PropertyMap(BeanProperties beanProperties, Object bean) {
        this.bean = bean;
        this.properties = beanProperties;
    }

    public void clear() {
        throw new UnsupportedOperationException("PropertyMap does not support the clear() method.");
    }

    public Object put(Object key, Object value) {
        String propertyName = (key instanceof String) ? (String) key : key.toString();
        return properties.setProperty(bean, propertyName, value);
    }

    public Set<Entry> entrySet() {
        // Create a hash set of entries.
        Set<Entry> set = CollectionUtil.newHashSet();
        Iterator iter = properties.accessorMethods();
        while (iter.hasNext()) {
            PropertyAccessors accessorMethods = (PropertyAccessors) iter.next();
            Entry entry = new Entry(properties, bean, accessorMethods.getName());
            set.add(entry);
        }
        return Collections.unmodifiableSet(set);
    }

    /**
     * Represents a property name / value pair in the Map view of a bean.
     */
    public static class Entry implements Map.Entry {
        private BeanProperties accessor;
        private Object bean;
        private String propertyName;

        /**
         * Creates a new name / value pair in the map view of a bean.
         *
         * @param accessor     The property properties (from the bean's class).
         * @param bean         The bean
         * @param propertyName The name of the property.
         */
        public Entry(BeanProperties accessor, Object bean, String propertyName) {
            this.accessor = accessor;
            this.bean = bean;
            this.propertyName = propertyName;
        }

        public Object getKey() {
            return propertyName;
        }

        public Object getValue() {
            return accessor.getProperty(bean, propertyName);
        }

        public Object setValue(Object value) {
            return accessor.setProperty(bean, propertyName, value);
        }

        public boolean equals(Object o) {
            if (this == o) return true;
            if (!(o instanceof Entry)) return false;

            final Entry entry = (Entry) o;

            if (!propertyName.equals(entry.propertyName)) return false;

            return true;
        }

        public int hashCode() {
            return propertyName.hashCode();
        }

        public String toString() {
            StringBuffer buf = new StringBuffer();
            buf.append("[propertyName=");
            buf.append(propertyName);
            buf.append(", value=");
            buf.append(getValue());
            buf.append("]");
            return buf.toString();
        }
    }
}