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/*
* $Id: ActionMessages.java 54929 2004-10-16 16:38:42Z germuska $
*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed 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.action;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.HashMap;
import java.util.List;
/**
* A class that encapsulates messages. Messages can be either global
* or they are specific to a particular bean property.
*
* Each individual message is described by an ActionMessage
* object, which contains a message key (to be looked up in an appropriate
* message resources database), and up to four placeholder arguments used for
* parametric substitution in the resulting message.
*
* IMPLEMENTATION NOTE - It is assumed that these objects
* are created and manipulated only within the context of a single thread.
* Therefore, no synchronization is required for access to internal
* collections.
*
* @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
* @since Struts 1.1
*/
public class ActionMessages implements Serializable {
/**
* Compares ActionMessageItem objects.
*/
private static final Comparator actionItemComparator = new Comparator() {
public int compare(Object o1, Object o2) {
return ((ActionMessageItem) o1).getOrder()
- ((ActionMessageItem) o2).getOrder();
}
};
// ----------------------------------------------------- Manifest Constants
/**
* The "property name" marker to use for global messages, as opposed to
* those related to a specific property.
*/
public static final String GLOBAL_MESSAGE =
"org.apache.struts.action.GLOBAL_MESSAGE";
// ----------------------------------------------------- Instance Variables
/**
* Have the messages been retrieved from this object?
*
* The controller uses this property to determine if session-scoped
* messages can be removed.
*
* @since Struts 1.2
*/
protected boolean accessed = false;
/**
* The accumulated set of ActionMessage objects (represented
* as an ArrayList) for each property, keyed by property name.
*/
protected HashMap messages = new HashMap();
/**
* The current number of the property/key being added. This is used
* to maintain the order messages are added.
*/
protected int iCount = 0;
// --------------------------------------------------------- Public Methods
/**
* Create an empty ActionMessages object.
*/
public ActionMessages() {
super();
}
/**
* Create an ActionMessages object initialized with the given
* messages.
*
* @param messages The messages to be initially added to this object.
* This parameter can be null.
* @since Struts 1.1
*/
public ActionMessages(ActionMessages messages) {
super();
this.add(messages);
}
/**
* Add a message to the set of messages for the specified property. An
* order of the property/key is maintained based on the initial addition
* of the property/key.
*
* @param property Property name (or ActionMessages.GLOBAL_MESSAGE)
* @param message The message to be added
*/
public void add(String property, ActionMessage message) {
ActionMessageItem item = (ActionMessageItem) messages.get(property);
List list = null;
if (item == null) {
list = new ArrayList();
item = new ActionMessageItem(list, iCount++, property);
messages.put(property, item);
} else {
list = item.getList();
}
list.add(message);
}
/**
* Adds the messages from the given ActionMessages object to
* this set of messages. The messages are added in the order they are returned from
* the properties method. If a message's property is already in the current
* ActionMessages object, it is added to the end of the list for that
* property. If a message's property is not in the current list it is added to the end
* of the properties.
*
* @param messages The ActionMessages object to be added.
* This parameter can be null.
* @since Struts 1.1
*/
public void add(ActionMessages messages) {
if (messages == null) {
return;
}
// loop over properties
Iterator props = messages.properties();
while (props.hasNext()) {
String property = (String) props.next();
// loop over messages for each property
Iterator msgs = messages.get(property);
while (msgs.hasNext()) {
ActionMessage msg = (ActionMessage) msgs.next();
this.add(property, msg);
}
}
}
/**
* Clear all messages recorded by this object.
*/
public void clear() {
messages.clear();
}
/**
* Return true if there are no messages recorded
* in this collection, or false otherwise.
*
* @since Struts 1.1
*/
public boolean isEmpty(){
return (messages.isEmpty());
}
/**
* Return the set of all recorded messages, without distinction
* by which property the messages are associated with. If there are
* no messages recorded, an empty enumeration is returned.
*/
public Iterator get() {
this.accessed = true;
if (messages.isEmpty()) {
return Collections.EMPTY_LIST.iterator();
}
ArrayList results = new ArrayList();
ArrayList actionItems = new ArrayList();
for (Iterator i = messages.values().iterator(); i.hasNext();) {
actionItems.add(i.next());
}
// Sort ActionMessageItems based on the initial order the
// property/key was added to ActionMessages.
Collections.sort(actionItems, actionItemComparator);
for (Iterator i = actionItems.iterator(); i.hasNext();) {
ActionMessageItem ami = (ActionMessageItem) i.next();
for (Iterator messages = ami.getList().iterator(); messages.hasNext();) {
results.add(messages.next());
}
}
return results.iterator();
}
/**
* Return the set of messages related to a specific property.
* If there are no such messages, an empty enumeration is returned.
*
* @param property Property name (or ActionMessages.GLOBAL_MESSAGE)
*/
public Iterator get(String property) {
this.accessed = true;
ActionMessageItem item = (ActionMessageItem) messages.get(property);
if (item == null) {
return (Collections.EMPTY_LIST.iterator());
} else {
return (item.getList().iterator());
}
}
/**
* Returns true if the get() or
* get(String) methods are called.
*
* @return true if the messages have been accessed one or more
* times.
* @since Struts 1.2
*/
public boolean isAccessed() {
return this.accessed;
}
/**
* Return the set of property names for which at least one message has
* been recorded. If there are no messages, an empty Iterator is returned.
* If you have recorded global messages, the String value of
* ActionMessages.GLOBAL_MESSAGE will be one of the returned
* property names.
*/
public Iterator properties() {
if (messages.isEmpty()) {
return Collections.EMPTY_LIST.iterator();
}
ArrayList results = new ArrayList();
ArrayList actionItems = new ArrayList();
for (Iterator i = messages.values().iterator(); i.hasNext();) {
actionItems.add(i.next());
}
// Sort ActionMessageItems based on the initial order the
// property/key was added to ActionMessages.
Collections.sort(actionItems, actionItemComparator);
for (Iterator i = actionItems.iterator(); i.hasNext();) {
ActionMessageItem ami = (ActionMessageItem) i.next();
results.add(ami.getProperty());
}
return results.iterator();
}
/**
* Return the number of messages recorded for all properties (including
* global messages). NOTE - it is more efficient to call
* isEmpty if all you care about is whether or not there are
* any messages at all.
*/
public int size() {
int total = 0;
for (Iterator i = messages.values().iterator(); i.hasNext();) {
ActionMessageItem ami = (ActionMessageItem) i.next();
total += ami.getList().size();
}
return (total);
}
/**
* Return the number of messages associated with the specified property.
*
* @param property Property name (or ActionMessages.GLOBAL_MESSAGE)
*/
public int size(String property) {
ActionMessageItem item = (ActionMessageItem) messages.get(property);
return (item == null) ? 0 : item.getList().size();
}
/**
* Returns a String representation of this ActionMessages'
* property name=message list mapping.
* @see java.lang.Object#toString()
*/
public String toString() {
return this.messages.toString();
}
/**
* This class is used to store a set of messages associated with a
* property/key and the position it was initially added to list.
*/
protected class ActionMessageItem implements Serializable {
/**
* The list of ActionMessages.
*/
protected List list = null;
/**
* The position in the list of messages.
*/
protected int iOrder = 0;
/**
* The property associated with ActionMessage.
*/
protected String property = null;
public ActionMessageItem(List list, int iOrder, String property) {
this.list = list;
this.iOrder = iOrder;
this.property = property;
}
public List getList() {
return list;
}
public void setList(List list) {
this.list = list;
}
public int getOrder() {
return iOrder;
}
public void setOrder(int iOrder) {
this.iOrder = iOrder;
}
public String getProperty() {
return property;
}
public void setProperty(String property) {
this.property = property;
}
public String toString() {
return this.list.toString();
}
}
}