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Struts example source code file (Param.java)

This example Struts source code file (Param.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Struts tags/keywords

body_param_name, class, class, exception, method, nosuchmethodexception, object, object, param, param, parameter, reflection, runtimeexception, string, string

The Struts Param.java source code

/*
 * $Id$
 *
 * 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.struts2.views.gxp;

import com.google.gxp.html.HtmlClosure;

import java.lang.reflect.Method;

/**
 * @author Bob Lee
 */
public class Param {

    public static final String BODY_PARAM_NAME = "body";

    String name;
    Class type;
    Class gxpClass;
    boolean optional;
    Object defaultValue;

    Param(Class gxpClass, String name, Class type) {
        this.gxpClass = gxpClass;
        this.name = name;
        this.type = type;

        // if you specify a default parameter value in a GXP, a getDefaultXxx()
        // method will be present.
        try {
            Method defaultGetter = gxpClass.getMethod("getDefault" + capitalize(name));
            this.defaultValue = defaultGetter.invoke(null);
            this.optional = true;
        } catch (NoSuchMethodException ignored) {
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static String capitalize(String s) {
        if (s.isEmpty()) {
            return s;
        }
        char first = s.charAt(0);
        char capitalized = Character.toUpperCase(first);
        return (first == capitalized) ? s : capitalized + s.substring(1);
    }

    public String getName() {
        return name;
    }

    public Class getType() {
        return type;
    }

    boolean isBody() {
        return name.equals(BODY_PARAM_NAME) && type.equals(HtmlClosure.class);
    }

    public String toString() {
        return "Param[name: " + name
                + ", type: " + type.getName()
                + ", optional: " + optional
                + (optional ? ", defaultValue: " + defaultValue : "")
                + "]";
    }

    public boolean isOptional() {
        return optional;
    }

    public Object getDefaultValue() {
        if (!optional)
            throw new RuntimeException("Parameter '" + name + "' in " + gxpClass.getName() + " is not optional.");
        return defaultValue;
    }

}

Other Struts examples (source code examples)

Here is a short list of links related to this Struts Param.java source code file:

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