com.dpslink.base.util

Class TemplateEncoder

java.lang.Object

com.dpslink.base.util.TemplateEncoder

All Implemented Interfaces:

java.io.Serializable, org.apache.velocity.app.event.EventHandler, org.apache.velocity.app.event.InvalidReferenceEventHandler, org.apache.velocity.app.event.NullSetEventHandler, org.apache.velocity.app.event.ReferenceInsertionEventHandler, org.apache.velocity.util.ContextAware

public class TemplateEncoder
extends java.lang.Object
implements org.apache.velocity.util.ContextAware, org.apache.velocity.app.event.InvalidReferenceEventHandler, org.apache.velocity.app.event.ReferenceInsertionEventHandler, org.apache.velocity.app.event.NullSetEventHandler, java.io.Serializable

An event handler for encoding Velocity template data string values. An instance of this class is automatically attached to the processing of a template by the TemplateProcessor class.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.velocity.app.event.InvalidReferenceEventHandler

org.apache.velocity.app.event.InvalidReferenceEventHandler.InvalidGetMethodExecutor, org.apache.velocity.app.event.InvalidReferenceEventHandler.InvalidMethodExecutor, org.apache.velocity.app.event.InvalidReferenceEventHandler.InvalidSetMethodExecutor

Nested classes/interfaces inherited from interface org.apache.velocity.app.event.ReferenceInsertionEventHandler

org.apache.velocity.app.event.ReferenceInsertionEventHandler.referenceInsertExecutor

Nested classes/interfaces inherited from interface org.apache.velocity.app.event.NullSetEventHandler

org.apache.velocity.app.event.NullSetEventHandler.ShouldLogOnNullSetExecutor

Field Summary

Fields

Modifier and Type	Field and Description
private static org.apache.log4j.Logger	cvLogger A reference to the Velocity log writer.
private int	ivEncoderType The encoder's type code.
private org.apache.velocity.context.InternalContextAdapter	ivInternalContext A reference to the Velocity internal context.
private java.util.ArrayList<java.lang.String>	ivTemplateErrors A collection of template error message text.
private static long	serialVersionUID The class' serialization version id.
static int	TYPE_HTML The type code for an html template encoder.
static int	TYPE_TEXT The type code for a text template encoder.
static int	TYPE_XML The type code for an xml template encoder.

Constructor Summary

Constructors

Constructor and Description
TemplateEncoder(int type) Constructs a template encoder for the given template type.

Method Summary

Modifier and Type	Method and Description
java.util.ArrayList<java.lang.String>	getTemplateErrors() Returns the collection of template error message text.
java.lang.Object	invalidGetMethod(org.apache.velocity.context.Context context, java.lang.String reference, java.lang.Object object, java.lang.String property, org.apache.velocity.util.introspection.Info info) A call-back that is invoked during Velocity template processing.
java.lang.Object	invalidMethod(org.apache.velocity.context.Context context, java.lang.String reference, java.lang.Object object, java.lang.String method, org.apache.velocity.util.introspection.Info info) A call-back that is invoked during Velocity template processing.
boolean	invalidSetMethod(org.apache.velocity.context.Context context, java.lang.String leftreference, java.lang.String rightreference, org.apache.velocity.util.introspection.Info info) A call-back that is invoked during Velocity template processing.
private boolean	isDateFormatter(java.lang.String reference) Answers if a reference is for a date or time formatter.
private boolean	isHtmlExclusion(java.lang.String reference) Answers if a reference should be excluded from html string encoding.
private boolean	isHtmlJavaScript(java.lang.String reference) Answers if a reference should be included in html script encoding.
private boolean	isJDBCObjectReturned(java.lang.Object object, java.lang.reflect.Method method) Answers if an object is a JDBC object controller and if the method being invoked on the controller returns a JDBC object.
private boolean	isTextExclusion(java.lang.String reference) Answers if a reference should be excluded from text string encoding.
private boolean	isXmlExclusion(java.lang.String reference) Answers if a reference should be excluded from xml string encoding.
private void	logInvalidMethod(java.lang.String reference, org.apache.velocity.util.introspection.Info info) Writes a log entry to the Velocity log for an invalid reference.
private void	logInvalidReference(java.lang.String reference, org.apache.velocity.util.introspection.Info info) Writes a log entry to the Velocity log for an invalid reference.
private void	logNullInsertion(java.lang.String reference) Writes a log entry to the Velocity log for a null value insertion.
java.lang.Object	referenceInsert(java.lang.String reference, java.lang.Object value) A call-back that is invoked during Velocity template processing.
void	setContext(org.apache.velocity.context.Context context) Sets the Velocity internal context.
boolean	shouldLogOnNullSet(java.lang.String lhs, java.lang.String rhs) A null reference in a #set directive should not log extra messages.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

The class' serialization version id.

See Also:

Constant Field Values

cvLogger

private static org.apache.log4j.Logger cvLogger

A reference to the Velocity log writer.

TYPE_HTML

public static final int TYPE_HTML

The type code for an html template encoder.

See Also:

Constant Field Values

TYPE_TEXT

public static final int TYPE_TEXT

The type code for a text template encoder.

See Also:

Constant Field Values

TYPE_XML

public static final int TYPE_XML

The type code for an xml template encoder.

See Also:

Constant Field Values

ivTemplateErrors

private java.util.ArrayList<java.lang.String> ivTemplateErrors

A collection of template error message text.

ivInternalContext

private org.apache.velocity.context.InternalContextAdapter ivInternalContext

A reference to the Velocity internal context.

ivEncoderType

private int ivEncoderType

The encoder's type code.

Constructor Detail

TemplateEncoder

public TemplateEncoder(int type)

Constructs a template encoder for the given template type.

Parameters:

type - (int) The type of encoder to process. Must be one of the TYPE_* constants defined by this class.

Method Detail

setContext

public void setContext(org.apache.velocity.context.Context context)

Sets the Velocity internal context. Invoked by Velocity just prior to the invoking of an event. Implements setContext in ContextAware.

Specified by:

setContext in interface org.apache.velocity.util.ContextAware

Parameters:

context - (Context) The internal context.

invalidGetMethod

public java.lang.Object invalidGetMethod(org.apache.velocity.context.Context context,
                                         java.lang.String reference,
                                         java.lang.Object object,
                                         java.lang.String property,
                                         org.apache.velocity.util.introspection.Info info)

A call-back that is invoked during Velocity template processing. Invoked when object is null or there is no getter for the given property. Also invoked for invalid references without properties. invalidGetMethod() will be invoked in sequence for each link in the chain until the first non-null value is returned. Implements invalidGetMethod in InvalidReferenceEventHandler.

Specified by:

invalidGetMethod in interface org.apache.velocity.app.event.InvalidReferenceEventHandler

Parameters:

context - (Context) The context when the invalid reference was found.

reference - (String) The complete invalid reference.

object - (Object) The object referred to, or null if not found.

property - (String) The property name from the reference.

info - (Info) Contains template, line and column details.

Returns:

Object - A substitute return value for the invalid reference, or null if no substitute.

invalidSetMethod

public boolean invalidSetMethod(org.apache.velocity.context.Context context,
                                java.lang.String leftreference,
                                java.lang.String rightreference,
                                org.apache.velocity.util.introspection.Info info)

A call-back that is invoked during Velocity template processing. Invoked when object is null or there is no setter for the given property. invalidSetMethod() will be invoked in sequence for each link in the chain until a true value is returned. It's recommended that false be returned as a default to allow for easy chaining. Implements invalidSetMethod in InvalidReferenceEventHandler.

Specified by:

invalidSetMethod in interface org.apache.velocity.app.event.InvalidReferenceEventHandler

Parameters:

context - (Context) The context when the invalid reference was found.

leftreference - (String) The left reference being assigned to.

rightreference - (String) The invalid reference on the right.

info - (Info) Contains template, line and column details.

Returns:

boolean - If true then stop invoking invalidSetMethod along the chain.

invalidMethod

public java.lang.Object invalidMethod(org.apache.velocity.context.Context context,
                                      java.lang.String reference,
                                      java.lang.Object object,
                                      java.lang.String method,
                                      org.apache.velocity.util.introspection.Info info)

A call-back that is invoked during Velocity template processing. Invoked when object is null or the given method does not exist. invalidMethod() will be invoked in sequence for each link in the chain until the first non-null value is returned.

Velocity seems to invoke this method for reasons other than what the javadocs state, which indicate this method is invoked when object or method don't exist. However, this method also seems to get invoked when both object and method are valid but the resulting return value is null. This implementation attempts to determine if object or method really don't exist so false errors don't get reported. It isn't possible to completely verify the existence of method since parameter types aren't supplied and therefore actual method signatures can't be checked, but most erroneous errors can be eliminated by just determining that a method name exists.

Implements invalidMethod in InvalidReferenceEventHandler.

Specified by:

invalidMethod in interface org.apache.velocity.app.event.InvalidReferenceEventHandler

Parameters:

context - (Context) The context when the invalid reference was found.

reference - (String) The complete invalid reference.

object - (Object) The object referred to, or null if not found.

method - (String) The name of the (non-existent) method.

info - (Info) Contains template, line and column details.

Returns:

Object - A substitute return value for the invalid reference, or null if no substitute.

referenceInsert

public java.lang.Object referenceInsert(java.lang.String reference,
                                        java.lang.Object value)

A call-back that is invoked during Velocity template processing. This method is automatically invoked by the Velocity API before a reference value is inserted into the output stream. Provides default string- encoded values for the current encoder type. Implements referenceInsert in ReferenceInsertionEventHandler.

Specified by:

referenceInsert in interface org.apache.velocity.app.event.ReferenceInsertionEventHandler

Parameters:

reference - (String) The reference from the template that is about to be inserted.

value - (Object) The value that is about to be inserted (after its toString method is invoked).

Returns:

Object - The object on which toString can be invoked for output.

shouldLogOnNullSet

public boolean shouldLogOnNullSet(java.lang.String lhs,
                                  java.lang.String rhs)

A null reference in a #set directive should not log extra messages. This class will already log the invalid reference, so no extra noise is needed in the Velocity log. Called when the RHS of a #set() is null, which will result in a null LHS. All NullSetEventHandlers are called in sequence until a false is returned. If no NullSetEventHandler is registered all nulls will be logged.

Specified by:

shouldLogOnNullSet in interface org.apache.velocity.app.event.NullSetEventHandler

Parameters:

lhs - (String) The left reference being assigned to.

rhs - (String) The invalid reference on the right.

Returns:

boolean - true If log message should be written.

isDateFormatter

private boolean isDateFormatter(java.lang.String reference)

Answers if a reference is for a date or time formatter.

Parameters:

reference - (String) The reference from the template that is about to be inserted.

Returns:

boolean - true if the reference is a date or time formatter, otherwise false.

isHtmlExclusion

private boolean isHtmlExclusion(java.lang.String reference)

Answers if a reference should be excluded from html string encoding.

Parameters:

reference - (String) The reference from the template that is about to be inserted.

Returns:

boolean - true if the reference should be excluded, otherwise false.

isHtmlJavaScript

private boolean isHtmlJavaScript(java.lang.String reference)

Answers if a reference should be included in html script encoding.

Parameters:

reference - (String) The reference from the template that is about to be inserted.

Returns:

boolean - true if the reference should be included, otherwise false.

isJDBCObjectReturned

private boolean isJDBCObjectReturned(java.lang.Object object,
                                     java.lang.reflect.Method method)

Answers if an object is a JDBC object controller and if the method being invoked on the controller returns a JDBC object.

Parameters:

object - (Object) The object to check.

method - (Method) The method being invoked.

Returns:

boolean - true if object is a JDBC object controller and the method returns a JDBC object, otherwise false.

isTextExclusion

private boolean isTextExclusion(java.lang.String reference)

Answers if a reference should be excluded from text string encoding.

Parameters:

reference - (String) The reference from the template that is about to be inserted.

Returns:

boolean - true if the reference should be excluded, otherwise false.

isXmlExclusion

private boolean isXmlExclusion(java.lang.String reference)

Answers if a reference should be excluded from xml string encoding.

Parameters:

reference - (String) The reference from the template that is about to be inserted.

Returns:

boolean - true if the reference should be excluded, otherwise false.

getTemplateErrors

public java.util.ArrayList<java.lang.String> getTemplateErrors()

Returns the collection of template error message text.

CURRENTLY ALWAYS RETURNS AN EMPTY VECTOR DUE TO A DEFICIENCY IN VELOCITY THAT RESULTS IN ERRONEOUS INVALID REFERENCES BEING RECORDED.

Returns:

ArrayList - The message text. Each element in the collection is the full message text for an invalid reference occurrence.

logInvalidMethod

private void logInvalidMethod(java.lang.String reference,
                              org.apache.velocity.util.introspection.Info info)

Writes a log entry to the Velocity log for an invalid reference. Does not add the invalid method message text to the collection of message text.

Parameters:

reference - (String) The invalid reference.

info - (Info) Contains template, line and column details.

logInvalidReference

private void logInvalidReference(java.lang.String reference,
                                 org.apache.velocity.util.introspection.Info info)

Writes a log entry to the Velocity log for an invalid reference. Also adds the invalid reference message text to the collection of message text.

Parameters:

reference - (String) The invalid reference.

info - (Info) Contains template, line and column details.

logNullInsertion

private void logNullInsertion(java.lang.String reference)

Writes a log entry to the Velocity log for a null value insertion. Also adds the null insertion message text to the collection of message text.

Parameters:

reference - (String) The reference that resulted in a null value.