Struts example source code file (IteratorGenerator.java)

This example Struts source code file (IteratorGenerator.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

arraylist, converter, converter, iterator, iteratorgenerator, iteratorgenerator, list, logger, object, object, remove, string, string, unsupportedoperationexception, util

The Struts IteratorGenerator.java source code

/*
 * $Id: IteratorGenerator.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * 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.util;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;


/**
 * A bean that generates an iterator filled with a given object depending on the count,
 * separator and converter defined. It is being used by IteratorGeneratorTag.
 *
 */
public class IteratorGenerator implements Iterator, Action {

    private static final Logger LOG = LoggerFactory.getLogger(IteratorGenerator.class);

    List values;
    Object value;
    String separator;
    Converter converter;

    // Attributes ----------------------------------------------------
    int count = 0;
    int currentCount = 0;


    public void setCount(int aCount) {
        this.count = aCount;
    }

    public boolean getHasNext() {
        return hasNext();
    }

    public Object getNext() {
        return next();
    }

    public void setSeparator(String aChar) {
        separator = aChar;
    }

    public void setConverter(Converter aConverter) {
        converter = aConverter;
    }

    // Public --------------------------------------------------------
    public void setValues(Object aValue) {
        value = aValue;
    }

    // Action implementation -----------------------------------------
    public String execute() {
        if (value == null) {
            return ERROR;
        } else {
            values = new ArrayList();

            if (separator != null) {
                StringTokenizer tokens = new StringTokenizer(value.toString(), separator);

                while (tokens.hasMoreTokens()) {
                    String token = tokens.nextToken().trim();
                    if (converter != null) {
                        try {
                            Object convertedObj = converter.convert(token);
                            values.add(convertedObj);
                        }
                        catch(Exception e) { // make sure things, goes on, we just ignore the bad ones
                            LOG.warn("unable to convert ["+token+"], skipping this token, it will not appear in the generated iterator", e);
                        }
                    }
                    else {
                        values.add(token);
                    }
                }
            } else {
                values.add(value.toString());
            }

            // Count default is the size of the list of values
            if (count == 0) {
                count = values.size();
            }

            return SUCCESS;
        }
    }

    // Iterator implementation ---------------------------------------
    public boolean hasNext() {
        return (value == null) ? false : ((currentCount < count) || (count == -1));
    }

    public Object next() {
        try {
            return values.get(currentCount % values.size());
        } finally {
            currentCount++;
        }
    }

    public void remove() {
        throw new UnsupportedOperationException("Remove is not supported in IteratorGenerator.");
    }


    // Inner class --------------------------------------------------
    /**
     * Interface for converting each separated token into an Object of choice.
     */
    public static interface Converter {
        Object convert(String token) throws Exception;
    }
}