BeanProperties.java

// $Id$
package org.yajul.reflection;

import org.yajul.collections.CollectionUtil;
import org.yajul.util.ExceptionList;
import org.yajul.util.ReflectionUtil;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;
import java.util.logging.Logger;

import static org.yajul.juli.LogHelper.unexpected;

/**
 * Represents the property accessor methods for a given class, and provides methods
 * for accessing the properties at run-time.
 *
 * @author josh Apr 4, 2004 9:11:19 AM
 */
public class BeanProperties {
    private static Logger log = Logger.getLogger(BeanProperties.class.getName());
    private Map<String, PropertyAccessors> accessorsByName = CollectionUtil.newHashMap();
    private Class clazz;

    /**
     * Constructs a set of property accessors from the class.
     *
     * @param c the class
     */
    public BeanProperties(Class c) {
        clazz = c;
        Method[] methods = c.getMethods();
        Map<String, Method> getters = CollectionUtil.newHashMap();
        Map<String, Method> setters = CollectionUtil.newHashMap();
        for (Method method : methods) {
            String propertyName = ReflectionUtil.getterPropertyName(method);
            if (propertyName != null)
                getters.put(propertyName, method);
            else {
                propertyName = ReflectionUtil.setterPropertyName(method);
                if (propertyName != null)
                    setters.put(propertyName, method);
            }
        }
        Set<String> propertyNames = CollectionUtil.newHashSet(getters.keySet());
        propertyNames.addAll(setters.keySet());
        for (String propertyName : propertyNames) {
            Method getter = getters.get(propertyName);
            Method setter = setters.get(propertyName);
            accessorsByName.put(propertyName,
                    new PropertyAccessors(clazz, propertyName, getter, setter));
        }
    }

    /**
     * Returns the name of the class.
     *
     * @return the name of the class.
     */
    public String getClassName() {
        return clazz.getName();
    }

    /**
     * Returns the number of properties in the class.
     *
     * @return the number of properties in the class.
     */
    public int size() {
        return accessorsByName.size();
    }

    /**
     * Returns the value of the specified property.
     *
     * @param bean         the object
     * @param propertyName the name of the property to get
     * @return the value of the property in the specified bean
     */
    public Object getProperty(Object bean, String propertyName) {
        try {
            PropertyAccessors accessorMethods = getAccessorMethods(bean, propertyName);
            return accessorMethods.invokeGetter(bean);
        } catch (NoSuchMethodException e) {
            unexpected(log, e);
            return null;
        } catch (IllegalAccessException e) {
            unexpected(log, e);
            return null;
        } catch (InvocationTargetException e) {
            unexpected(log, e);
            return null;
        }
    }

    /**
     * Sets the property in the bean to the specified value.
     *
     * @param bean         the object to set the property in
     * @param propertyName the name of the property
     * @param value        the new property value
     * @return the new property value
     */
    public Object setProperty(Object bean, String propertyName, Object value) {
        try {
            PropertyAccessors accessorMethods = getAccessorMethods(bean, propertyName);
            return accessorMethods.invokeSetter(bean, value);
        } catch (Exception e) {
            unexpected(log, e);
            return null;
        }
    }

    /**
     * Returns an iterator that returns the String names of all properties in the class.
     *
     * @return an iterator that returns the String names of all properties in the class.
     */
    public Iterator<String> propertyNames() {
        return accessorsByName.keySet().iterator();
    }

    /**
     * Returns the set of all the property name Strings in the class.
     *
     * @return the set of all the property name Strings in the class.
     */
    public Set<String> getPropertyNames() {
        return accessorsByName.keySet();
    }

    /**
     * Returns the pair of accessor methods for the given property name.
     *
     * @param propertyName the property name.
     * @return the accessor methods for the property
     */
    public PropertyAccessors getAccessorMethods(String propertyName) {
        return accessorsByName.get(propertyName);
    }

    /**
     * Returns an iterator that returns all AccessorMethods for all properties in the class.
     *
     * @return an iterator that returns all AccessorMethods for all properties in the class.
     */
    public Iterator<PropertyAccessors> accessorMethods() {
        return accessorsByName.values().iterator();
    }

    /**
     * Returns a double property value.
     *
     * @param bean         the bean
     * @param propertyName the property name
     * @return the property value as a double
     */
    public double getDoubleProperty(Object bean, String propertyName) {
        return (Double) getProperty(bean, propertyName);
    }

    /**
     * Returns an int property value.
     *
     * @param bean         the bean
     * @param propertyName the property name
     * @return the int property value
     */
    public int getIntProperty(Object bean, String propertyName) {
        return (Integer) getProperty(bean, propertyName);
    }

    /**
     * Returns a collection of all of the property values in the specified bean.
     *
     * @param bean the bean
     * @return a collection of all of the property values in the specified bean
     * @throws Exception if a property cannot be accessed.
     */
    public Collection<Object> values(Object bean) throws Exception {
        ArrayList<Object> values = CollectionUtil.newArrayList(size());
        Iterator iter = accessorMethods();
        ExceptionList exceptions = new ExceptionList();
        while (iter.hasNext()) {
            PropertyAccessors accessorMethods = (PropertyAccessors) iter.next();
            try {
                values.add(accessorMethods.invokeGetter(bean));
            } catch (Exception e) {
                exceptions.add(e);
            }
        }
        exceptions.throwIfException();
        return values;
    }

    /**
     * Copies all of the properties from one bean into another.
     * The two beans must be of the same class.
     *
     * @param bean the source bean.
     * @param copy the target bean.
     * @throws Exception if a property could not be accessed.
     */
    public void copy(Object bean, Object copy) throws Exception {
        Iterator iter = accessorMethods();
        ExceptionList exceptions = new ExceptionList();
        while (iter.hasNext()) {
            PropertyAccessors accessorMethods = (PropertyAccessors) iter.next();
            try {
                Object value = accessorMethods.invokeGetter(bean);
                accessorMethods.invokeSetter(copy, value);
            } catch (Exception e) {
                exceptions.add(e);
            }
        }
        exceptions.throwIfException();
    }

    // --- Implementation methods ---

    private PropertyAccessors getAccessorMethods(Object bean, String key)
            throws NoSuchMethodException {
        checkBean(bean);
        // Look up the Method for the property name.
        PropertyAccessors accessorMethods = getAccessorMethods(key);
        if (accessorMethods == null)
            throw new NoSuchMethodException("No property " + key + " in class " + getClassName());
        return accessorMethods;
    }

    private void checkBean(Object bean) {
        if (bean == null)
            throw new NullPointerException("Bean cannot be null!");
        if (bean.getClass() != clazz)
            throw new IllegalArgumentException("Bean class "
                    + bean.getClass().getName() + " does not match class " + getClassName());
    }
}