/*
* $Id: MakeIterator.java 721947 2008-12-01 02:25:47Z wesw $
*
* 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.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* MakeIterator.
*
*/
public class MakeIterator {
/**
* Determine whether a given object can be made into an <code>Iterator</code>
*
* @param object the object to check
* @return <code>true</code> if the object can be converted to an iterator and
* <code>false</code> otherwise
*/
public static boolean isIterable(Object object) {
if (object == null) {
return false;
}
if (object instanceof Map) {
return true;
} else if (object instanceof Iterable) {
return true;
} else if (object.getClass().isArray()) {
return true;
} else if (object instanceof Enumeration) {
return true;
} else if (object instanceof Iterator) {
return true;
} else {
return false;
}
}
public static Iterator convert(Object value) {
Iterator iterator;
if (value instanceof Iterator) {
return (Iterator) value;
}
if (value instanceof Map) {
value = ((Map) value).entrySet();
}
if (value == null) {
return null;
}
if (value instanceof Iterable) {
iterator = ((Iterable) value).iterator();
} else if (value.getClass().isArray()) {
//need ability to support primitives; therefore, cannot
//use Object[] casting.
ArrayList list = new ArrayList(Array.getLength(value));
for (int j = 0; j < Array.getLength(value); j++) {
list.add(Array.get(value, j));
}
iterator = list.iterator();
} else if (value instanceof Enumeration) {
Enumeration enumeration = (Enumeration) value;
ArrayList list = new ArrayList();
while (enumeration.hasMoreElements()) {
list.add(enumeration.nextElement());
}
iterator = list.iterator();
} else {
List list = new ArrayList(1);
list.add(value);
iterator = list.iterator();
}
return iterator;
}
}
|