beanutilsbean.java

apache beanutils开源项目源码

    public String getProperty(Object bean, String name)
            throws IllegalAccessException, InvocationTargetException,
            NoSuchMethodException {

        return (getNestedProperty(bean, name));

    }


    /**
     * Return the value of the specified simple property of the specified
     * bean, converted to a String.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Name of the property to be extracted
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     * @exception NoSuchMethodException if an accessor method for this
     *  property cannot be found
     */
    public String getSimpleProperty(Object bean, String name)
            throws IllegalAccessException, InvocationTargetException,
            NoSuchMethodException {

        Object value = getPropertyUtils().getSimpleProperty(bean, name);
        return (getConvertUtils().convert(value));

    }


    /**
     * <p>Populate the JavaBeans properties of the specified bean, based on
     * the specified name/value pairs.  This method uses Java reflection APIs
     * to identify corresponding "property setter" method names, and deals
     * with setter arguments of type <code>String</code>, <code>boolean</code>,
     * <code>int</code>, <code>long</code>, <code>float</code>, and
     * <code>double</code>.  In addition, array setters for these types (or the
     * corresponding primitive types) can also be identified.</p>
     * 
     * <p>The particular setter method to be called for each property is
     * determined using the usual JavaBeans introspection mechanisms.  Thus,
     * you may identify custom setter methods using a BeanInfo class that is
     * associated with the class of the bean itself.  If no such BeanInfo
     * class is available, the standard method name conversion ("set" plus
     * the capitalized name of the property in question) is used.</p>
     * 
     * <p><strong>NOTE</strong>:  It is contrary to the JavaBeans Specification
     * to have more than one setter method (with different argument
     * signatures) for the same property.</p>
     *
     * <p><strong>WARNING</strong> - The logic of this method is customized
     * for extracting String-based request parameters from an HTTP request.
     * It is probably not what you want for general property copying with
     * type conversion.  For that purpose, check out the
     * <code>copyProperties()</code> method instead.</p>
     *
     * @param bean JavaBean whose properties are being populated
     * @param properties Map keyed by property name, with the
     *  corresponding (String or String[]) value(s) to be set
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     */
    public void populate(Object bean, Map properties)
        throws IllegalAccessException, InvocationTargetException {

        // Do nothing unless both arguments have been specified
        if ((bean == null) || (properties == null)) {
            return;
        }
        if (log.isDebugEnabled()) {
            log.debug("BeanUtils.populate(" + bean + ", " +
                    properties + ")");
        }

        // Loop through the property name/value pairs to be set
        Iterator names = properties.keySet().iterator();
        while (names.hasNext()) {

            // Identify the property name and value(s) to be assigned
            String name = (String) names.next();
            if (name == null) {
                continue;
            }
            Object value = properties.get(name);

            // Perform the assignment for this property
            setProperty(bean, name, value);

        }

    }


    /**
     * <p>Set the specified property value, performing type conversions as
     * required to conform to the type of the destination property.</p>
     *
     * <p>If the property is read only then the method returns 
     * without throwing an exception.</p>
     *
     * <p>If <code>null</code> is passed into a property expecting a primitive value,
     * then this will be converted as if it were a <code>null</code> string.</p>
     *
     * <p><strong>WARNING</strong> - The logic of this method is customized
     * to meet the needs of <code>populate()</code>, and is probably not what
     * you want for general property copying with type conversion.  For that
     * purpose, check out the <code>copyProperty()</code> method instead.</p>
     *
     * <p><strong>WARNING</strong> - PLEASE do not modify the behavior of this
     * method without consulting with the Struts developer community.  There
     * are some subtleties to its functionality that are not documented in the
     * Javadoc description above, yet are vital to the way that Struts utilizes
     * this method.</p>
     *
     * @param bean Bean on which setting is to be performed
     * @param name Property name (can be nested/indexed/mapped/combo)
     * @param value Value to be set
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     */
    public void setProperty(Object bean, String name, Object value)
        throws IllegalAccessException, InvocationTargetException {

        // Trace logging (if enabled)
        if (log.isTraceEnabled()) {
            StringBuffer sb = new StringBuffer("  setProperty(");
            sb.append(bean);
            sb.append(", ");
            sb.append(name);
            sb.append(", ");
            if (value == null) {
                sb.append("<NULL>");
            } else if (value instanceof String) {
                sb.append((String) value);
            } else if (value instanceof String[]) {
                String values[] = (String[]) value;
                sb.append('[');
                for (int i = 0; i < values.length; i++) {
                    if (i > 0) {
                        sb.append(',');
                    }
                    sb.append(values[i]);
                }
                sb.append(']');
            } else {
                sb.append(value.toString());
            }
            sb.append(')');
            log.trace(sb.toString());
        }

        // Resolve any nested expression to get the actual target bean
        Object target = bean;
        int delim = findLastNestedIndex(name);
        if (delim >= 0) {
            try {
                target =
                    getPropertyUtils().getProperty(bean, name.substring(0, delim));
            } catch (NoSuchMethodException e) {
                return; // Skip this property setter
            }
            name = name.substring(delim + 1);
            if (log.isTraceEnabled()) {
                log.trace("    Target bean = " + target);
                log.trace("    Target name = " + name);
            }
        }

        // Declare local variables we will require
        String propName = null;          // Simple name of target property
        Class type = null;               // Java type of target property
        int index = -1;                  // Indexed subscript value (if any)
        String key = null;               // Mapped key value (if any)

        // Calculate the property name, index, and key values
        propName = name;
        int i = propName.indexOf(PropertyUtils.INDEXED_DELIM);
        if (i >= 0) {
            int k = propName.indexOf(PropertyUtils.INDEXED_DELIM2);
            try {
                index =
                    Integer.parseInt(propName.substring(i + 1, k));
            } catch (NumberFormatException e) {
                ;
            }
            propName = propName.substring(0, i);
        }
        int j = propName.indexOf(PropertyUtils.MAPPED_DELIM);
        if (j >= 0) {
            int k = propName.indexOf(PropertyUtils.MAPPED_DELIM2);
            try {
                key = propName.substring(j + 1, k);
            } catch (IndexOutOfBoundsException e) {
                ;
            }
            propName = propName.substring(0, j);
        }

        // Calculate the property type
        if (target instanceof DynaBean) {
            DynaClass dynaClass = ((DynaBean) target).getDynaClass();
            DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
            if (dynaProperty == null) {
                return; // Skip this property setter
            }
            type = dynaProperty.getType();
        } else {
            PropertyDescriptor descriptor = null;
            try {
                descriptor =
                    getPropertyUtils().getPropertyDescriptor(target, name);
                if (descriptor == null) {
                    return; // Skip this property setter
                }
            } catch (NoSuchMethodException e) {
                return; // Skip this property setter
            }
            if (descriptor instanceof MappedPropertyDescriptor) {
                if (((MappedPropertyDescriptor) descriptor).getMappedWriteMethod() == null) {
                    if (log.isDebugEnabled()) {
                        log.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = ((MappedPropertyDescriptor) descriptor).
                    getMappedPropertyType();
            } else if (descriptor instanceof IndexedPropertyDescriptor) {
                if (((IndexedPropertyDescriptor) descriptor).getIndexedWriteMethod() == null) {
                    if (log.isDebugEnabled()) {
                        log.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = ((IndexedPropertyDescriptor) descriptor).
                    getIndexedPropertyType();
            } else {
                if (descriptor.getWriteMethod() == null) {
                    if (log.isDebugEnabled()) {
                        log.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = descriptor.getPropertyType();
            }
        }

        // Convert the specified value to the required type
        Object newValue = null;
        if (type.isArray() && (index < 0)) { // Scalar value into array
            if (value == null) {
                String values[] = new String[1];
                values[0] = (String) value;
                newValue = getConvertUtils().convert((String[]) values, type);
            } else if (value instanceof String) {
                String values[] = new String[1];
                values[0] = (String) value;
                newValue = getConvertUtils().convert((String[]) values, type);
            } else if (value instanceof String[]) {
                newValue = getConvertUtils().convert((String[]) value, type);
            } else {
                newValue = value;
            }
        } else if (type.isArray()) {         // Indexed value into array
            if (value instanceof String) {
                newValue = getConvertUtils().convert((String) value,
                                                type.getComponentType());
            } else if (value instanceof String[]) {
                newValue = getConvertUtils().convert(((String[]) value)[0],
                                                type.getComponentType());
            } else {
                newValue = value;
            }
        } else {                             // Value into scalar
            if ((value instanceof String) || (value == null)) {
                newValue = getConvertUtils().convert((String) value, type);
            } else if (value instanceof String[]) {
                newValue = getConvertUtils().convert(((String[]) value)[0],
                                                type);
            } else if (getConvertUtils().lookup(value.getClass()) != null) {
                newValue = getConvertUtils().convert(value.toString(), type);
            } else {
                newValue = value;
            }
        }

        // Invoke the setter method
        try {
            if (index >= 0) {
                getPropertyUtils().setIndexedProperty(target, propName,
                                                 index, newValue);
            } else if (key != null) {
                getPropertyUtils().setMappedProperty(target, propName,
                                                key, newValue);
            } else {
                getPropertyUtils().setProperty(target, propName, newValue);
            }
        } catch (NoSuchMethodException e) {
            throw new InvocationTargetException
                (e, "Cannot set " + propName);
        }

    }
    
    private int findLastNestedIndex(String expression)
    {
        // walk back from the end to the start 
        // and find the first index that 
        int bracketCount = 0;
        for (int i = expression.length() - 1; i>=0 ; i--) {
            char at = expression.charAt(i);
            switch (at) {
                case PropertyUtils.NESTED_DELIM:
                    if (bracketCount < 1) {
                        return i;
                    }
                    break;
                    
                case PropertyUtils.MAPPED_DELIM:
                case PropertyUtils.INDEXED_DELIM:
                    // not bothered which
                    --bracketCount;
                    break;
                
                case PropertyUtils.MAPPED_DELIM2:
                case PropertyUtils.INDEXED_DELIM2:
                    // not bothered which
                    ++bracketCount;
                    break;            
            }
        }
        // can't find any
        return -1;
    }
    
    /** 
     * Gets the <code>ConvertUtilsBean</code> instance used to perform the conversions.
     */
    public ConvertUtilsBean getConvertUtils() {
        return convertUtilsBean;
    }
    
    /**
     * Gets the <code>PropertyUtilsBean</code> instance used to access properties.
     */
    public PropertyUtilsBean getPropertyUtils() {
        return propertyUtilsBean;
    }
}