/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
* own identifying information: Portions Copyright [yyyy]
* [name of copyright owner]
*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
*/
package javax.servlet.jsp.jstl.core;
import java.util.Iterator;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Map;
import java.util.StringTokenizer;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ValueExpression;
import javax.servlet.jsp.JspTagException;
import org.apache.taglibs.standard.resources.Resources;
/**
* @author Kin-man Chung
* @version $Id: IteratedExpression.java,v 1.3 2005/12/08 01:20:43 kchung Exp $
*/
public final class IteratedExpression {
private static final long serialVersionUID = 1L;
protected final ValueExpression orig;
protected final String delims;
private Object base;
private int index;
private Iterator iter;
public IteratedExpression(ValueExpression orig, String delims) {
this.orig = orig;
this.delims = delims;
}
/**
* Evaluates the stored ValueExpression and return the indexed item.
* @param context The ELContext used to evaluate the ValueExpression
* @param i The index of the item to be retrieved
*/
public Object getItem(ELContext context, int i) {
if (base == null) {
base = orig.getValue(context);
if (base == null) {
return null;
}
iter = toIterator(base);
index = 0;
}
if (index > i) {
// Restart from index 0
iter = toIterator(base);
index = 0;
}
while (iter.hasNext()) {
Object item = iter.next();
if (index++ == i) {
return item;
}
}
return null;
}
public ValueExpression getValueExpression() {
return orig;
}
private Iterator toIterator(final Object obj) {
Iterator iter;
if (obj instanceof String) {
iter = toIterator(new StringTokenizer((String)obj, delims));
}
else if (obj instanceof Iterator) {
iter = (Iterator)obj;
}
else if (obj instanceof Collection) {
iter = toIterator(((Collection) obj).iterator());
}
else if (obj instanceof Enumeration) {
iter = toIterator((Enumeration)obj);
}
else if (obj instanceof Map) {
iter = ((Map)obj).entrySet().iterator();
} else {
throw new ELException(Resources.getMessage("FOREACH_BAD_ITEMS"));
}
return iter;
}
private Iterator toIterator(final Enumeration obj) {
return new Iterator() {
public boolean hasNext() {
return obj.hasMoreElements();
}
public Object next() {
return obj.nextElement();
}
public void remove() {}
};
}
}