formpropertyconfig.java.svn-base

MVC开源框架

/*
 * $Id$
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.struts.config;

import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;

/**
 * <p>A JavaBean representing the configuration information of a
 * <code>&lt;form-property&gt;</code> element in a Struts configuration
 * file.<p>
 *
 * @version $Rev$ $Date: 2005-11-12 11:52:08 -0500 (Sat, 12 Nov 2005)$
 * @since Struts 1.1
 */
public class FormPropertyConfig extends BaseConfig {
    /**
     * The logging instance
     */
    private static final Log log = LogFactory.getLog(FormPropertyConfig.class);

    // ----------------------------------------------------- Instance Variables
    // ------------------------------------------------------------- Properties

    /**
     * String representation of the initial value for this property.
     */
    protected String initial = null;

    /**
     * The JavaBean property name of the property described by this element.
     */
    protected String name = null;

    /**
     * <p>The conditions under which the property described by this element
     * should be reset to its <code>initial</code> value when the form's
     * <code>reset</code> method is called.</p> <p>This may be set to true (to
     * always reset the property) or a comma-separated list of HTTP request
     * methods.</p>
     *
     * @since Struts 1.3
     */
    protected String reset = null;

    /**
     * <p>The size of the array to be created if this property is an array
     * type and there is no specified <code>initial</code> value.  This value
     * must be non-negative.</p>
     *
     * @since Struts 1.1
     */
    protected int size = 0;

    /**
     * The fully qualified Java class name of the implementation class of this
     * bean property, optionally followed by <code>[]</code> to indicate that
     * the property is indexed.
     */
    protected String type = null;

    // ----------------------------------------------------------- Constructors

    /**
     * Standard no-arguments constructor for dynamic instantiation.
     */
    public FormPropertyConfig() {
        super();
    }

    /**
     * Constructor that preconfigures the relevant properties.
     *
     * @param name    Name of this property
     * @param type    Fully qualified class name of this property
     * @param initial Initial value of this property (if any)
     */
    public FormPropertyConfig(String name, String type, String initial) {
        this(name, type, initial, 0);
    }

    /**
     * Constructor that preconfigures the relevant properties.
     *
     * @param name    Name of this property
     * @param type    Fully qualified class name of this property
     * @param initial Initial value of this property (if any)
     * @param reset   The conditions under which this property will be reset
     *                to its initial value.
     */
    public FormPropertyConfig(String name, String type, String initial,
        String reset) {
        this(name, type, initial, reset, 0);
    }

    /**
     * Constructor that preconfigures the relevant properties.
     *
     * @param name    Name of this property
     * @param type    Fully qualified class name of this property
     * @param initial Initial value of this property (if any)
     * @param size    Size of the array to be created if this property is an
     *                array with no defined initial value
     */
    public FormPropertyConfig(String name, String type, String initial, int size) {
        this(name, type, initial, null, size);
    }

    /**
     * Constructor that preconfigures the relevant properties.
     *
     * @param name    Name of this property
     * @param type    Fully qualified class name of this property
     * @param initial Initial value of this property (if any)
     * @param size    Size of the array to be created if this property is an
     *                array with no defined initial value
     * @param reset   The conditions under which this property will be reset
     *                to its initial value.
     */
    public FormPropertyConfig(String name, String type, String initial,
        String reset, int size) {
        super();
        setName(name);
        setType(type);
        setInitial(initial);
        setReset(reset);
        setSize(size);
    }

    public String getInitial() {
        return (this.initial);
    }

    public void setInitial(String initial) {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        this.initial = initial;
    }

    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        this.name = name;
    }

    public String getReset() {
        return (this.reset);
    }

    public void setReset(String reset) {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        this.reset = reset;
    }

    public int getSize() {
        return (this.size);
    }

    public void setSize(int size) {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        if (size < 0) {
            throw new IllegalArgumentException("size < 0");
        }

        this.size = size;
    }

    public String getType() {
        return (this.type);
    }

    public void setType(String type) {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        this.type = type;
    }

    /**
     * Return a Class corresponds to the value specified for the
     * <code>type</code> property, taking into account the trailing "[]" for
     * arrays (as well as the ability to specify primitive Java types).
     */
    public Class getTypeClass() {
        // Identify the base class (in case an array was specified)
        String baseType = getType();
        boolean indexed = false;

        if (baseType.endsWith("[]")) {
            baseType = baseType.substring(0, baseType.length() - 2);
            indexed = true;
        }

        // Construct an appropriate Class instance for the base class
        Class baseClass = null;

        if ("boolean".equals(baseType)) {
            baseClass = Boolean.TYPE;
        } else if ("byte".equals(baseType)) {
            baseClass = Byte.TYPE;
        } else if ("char".equals(baseType)) {
            baseClass = Character.TYPE;
        } else if ("double".equals(baseType)) {
            baseClass = Double.TYPE;
        } else if ("float".equals(baseType)) {
            baseClass = Float.TYPE;
        } else if ("int".equals(baseType)) {
            baseClass = Integer.TYPE;
        } else if ("long".equals(baseType)) {
            baseClass = Long.TYPE;
        } else if ("short".equals(baseType)) {
            baseClass = Short.TYPE;
        } else {
            ClassLoader classLoader =
                Thread.currentThread().getContextClassLoader();

            if (classLoader == null) {
                classLoader = this.getClass().getClassLoader();
            }

            try {
                baseClass = classLoader.loadClass(baseType);
            } catch (ClassNotFoundException ex) {
                log.error("Class '" + baseType +
                          "' not found for property '" + name + "'");
                baseClass = null;
            }
        }

        // Return the base class or an array appropriately
        if (indexed) {
            return (Array.newInstance(baseClass, 0).getClass());
        } else {
            return (baseClass);
        }
    }

    // --------------------------------------------------------- Public Methods

    /**
     * <p>Return an object representing the initial value of this property.
     * This is calculated according to the following algorithm:</p>
     *
     * <ul>
     *
     * <li>If the value you have specified for the <code>type</code> property
     * represents an array (i.e. it ends with "[]"):
     *
     * <ul>
     *
     * <li>If you have specified a value for the <code>initial</code>
     * property, <code>ConvertUtils.convert</code> will be called to convert
     * it into an instance of the specified array type.</li>
     *
     * <li>If you have not specified a value for the <code>initial</code>
     * property, an array of the length specified by the <code>size</code>
     * property will be created. Each element of the array will be
     * instantiated via the zero-args constructor on the specified class (if
     * any). Otherwise, <code>null</code> will be returned.</li>
     *
     * </ul></li>
     *
     * <li>If the value you have specified for the <code>type</code> property
     * does not represent an array:
     *
     * <ul>
     *
     * <li>If you have specified a value for the <code>initial</code>
     * property, <code>ConvertUtils.convert</code> will be called to convert
     * it into an object instance.</li>
     *
     * <li>If you have not specified a value for the <code>initial</code>
     * attribute, Struts will instantiate an instance via the zero-args
     * constructor on the specified class (if any). Otherwise,
     * <code>null</code> will be returned.</li>
     *
     * </ul></li>
     *
     * </ul>
     */
    public Object initial() {
        Object initialValue = null;

        try {
            Class clazz = getTypeClass();

            if (clazz.isArray()) {
                if (initial != null) {
                    initialValue = ConvertUtils.convert(initial, clazz);
                } else {
                    initialValue =
                        Array.newInstance(clazz.getComponentType(), size);

                    if (!(clazz.getComponentType().isPrimitive())) {
                        for (int i = 0; i < size; i++) {
                            try {
                                Array.set(initialValue, i,
                                    clazz.getComponentType().newInstance());
                            } catch (Throwable t) {
                                log.error("Unable to create instance of "
                                    + clazz.getName() + " for property=" + name
                                    + ", type=" + type + ", initial=" + initial
                                    + ", size=" + size + ".");

                                //FIXME: Should we just dump the entire application/module ?
                            }
                        }
                    }
                }
            } else {
                if (initial != null) {
                    initialValue = ConvertUtils.convert(initial, clazz);
                } else {
                    initialValue = clazz.newInstance();
                }
            }
        } catch (Throwable t) {
            initialValue = null;
        }

        return (initialValue);
    }

    /**
     * <p>Inherit values that have not been overridden from the provided
     * config object.  Subclasses overriding this method should verify that
     * the given parameter is of a class that contains a property it is trying
     * to inherit:</p>
     * <pre>
     * if (config instanceof MyCustomFormPropertyConfig) {
     *     MyCustomFormPropertyConfig myConfig =
     *         (MyCustomFormPropertyConfig) config;
     *
     *     if (getMyCustomProp() == null) {
     *         setMyCustomProp(myConfig.getMyCustomProp());
     *     }
     * }
     * </pre>
     *
     * @param config The object that this instance will be inheriting its
     *               values from.
     */
    public void inheritFrom(FormPropertyConfig config)
        throws IllegalAccessException, InvocationTargetException,
            InstantiationException, ClassNotFoundException {
        if (configured) {
            throw new IllegalStateException("Configuration is frozen");
        }

        if (getInitial() == null) {
            setInitial(config.getInitial());
        }

        if (getName() == null) {
            setName(config.getName());
        }

        if (getSize() == 0) {
            setSize(config.getSize());
        }

        if (getType() == null) {
            setType(config.getType());
        }

        inheritProperties(config);
    }

    /**
     * Return a String representation of this object.
     */
    public String toString() {
        StringBuffer sb = new StringBuffer("FormPropertyConfig[");

        sb.append("name=");
        sb.append(this.name);
        sb.append(",type=");
        sb.append(this.type);
        sb.append(",initial=");
        sb.append(this.initial);
        sb.append(",reset=");
        sb.append(this.reset);
        sb.append("]");

        return (sb.toString());
    }
}