Apache Struts API Documentation: Class ActionMessages

org.apache.struts.action Class ActionMessages

java.lang.Object
  |
  +--org.apache.struts.action.ActionMessages

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

ActionErrors

public class ActionMessages

extends java.lang.Object

implements java.io.Serializable

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.

Since:

Struts 1.1

Version:

$Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $

See Also:

Serialized Form

actionItemComparator

private static final java.util.Comparator actionItemComparator

Compares ActionMessageItem objects.

GLOBAL_MESSAGE

public static final java.lang.String GLOBAL_MESSAGE

The "property name" marker to use for global messages, as opposed to those related to a specific property.

accessed

protected boolean accessed

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

messages

protected java.util.HashMap messages

The accumulated set of ActionMessage objects (represented as an ArrayList) for each property, keyed by property name.

iCount

protected int iCount

The current number of the property/key being added. This is used to maintain the order messages are added.

ActionMessages

public ActionMessages()

Create an empty ActionMessages object.

ActionMessages

public ActionMessages(ActionMessages messages)

Create an ActionMessages object initialized with the given messages.

Parameters:

messages - The messages to be initially added to this object. This parameter can be null.

Since:

Struts 1.1

add

public void add(java.lang.String property,
                ActionMessage message)

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.

Parameters:

property - Property name (or ActionMessages.GLOBAL_MESSAGE)

message - The message to be added

add

public void add(ActionMessages messages)

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.

Parameters:

messages - The ActionMessages object to be added. This parameter can be null.

Since:

Struts 1.1

clear

public void clear()

Clear all messages recorded by this object.

isEmpty

public boolean isEmpty()

Return true if there are no messages recorded in this collection, or false otherwise.

Since:

Struts 1.1

get

public java.util.Iterator get()

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.

get

public java.util.Iterator get(java.lang.String property)

Return the set of messages related to a specific property. If there are no such messages, an empty enumeration is returned.

Parameters:

property - Property name (or ActionMessages.GLOBAL_MESSAGE)

isAccessed

public boolean isAccessed()

Returns true if the get() or get(String) methods are called.

Returns:

true if the messages have been accessed one or more times.

Since:

Struts 1.2

properties

public java.util.Iterator properties()

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.

size

public int size()

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.

size

public int size(java.lang.String property)

Return the number of messages associated with the specified property.

Parameters:

property - Property name (or ActionMessages.GLOBAL_MESSAGE)

toString

public java.lang.String toString()

Returns a String representation of this ActionMessages' property name=message list mapping.

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()