com.google.gdata.data

Class AttributeHelper

java.lang.Object

com.google.gdata.data.AttributeHelper

public class AttributeHelper
extends Object

Helps accessing tag attributes. The helper only checks attributes in the default namespace ("") and rejects unknown attributes. The idea is to remove (consume) attributes as they are read from the list and at the end make sure that all attributes have been read, to detect whether unknown attributes have been specified. This is done by the method assertAllConsumed() usually called from XmlParser.ElementHandler.processEndElement().

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AttributeHelper.EnumToAttributeValue<T extends Enum<T>> Defines a custom mapping of an enum value to an attribute value (similar to a closure).
static class	AttributeHelper.LowerCaseEnumToAttributeValue<T extends Enum<T>> Implements the most common custom mapping of an enum value to an attribute value using the lower-case form of the enum name.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,String>	attrs Maps attribute local name to string value.

Constructor Summary

Constructors

Constructor and Description
AttributeHelper(Attributes attrs) Creates a helper tied to a specific set of SAX attributes.

Method Summary

Methods

Modifier and Type	Method and Description
void	assertAllConsumed() Makes sure all attributes have been removed from the list.
String	consume(String name, boolean required) Gets the value of an attribute and remove it from the list.
BigDecimal	consumeBigDecimal(String name, boolean required) Gets the value of a big decimal attribute and remove it from the list.
BigDecimal	consumeBigDecimal(String name, boolean required, BigDecimal defaultValue) Gets the value of a big decimal attribute and remove it from the list.
BigInteger	consumeBigInteger(String name, boolean required) Gets the value of a big integer attribute and remove it from the list.
BigInteger	consumeBigInteger(String name, boolean required, BigInteger defaultValue) Gets the value of a big integer attribute and remove it from the list.
boolean	consumeBoolean(String name, boolean required) Gets the value of a boolean attribute and remove it from the list.
boolean	consumeBoolean(String name, boolean required, boolean defaultValue) Gets the value of a boolean attribute and remove it from the list.
byte	consumeByte(String name, boolean required) Gets the value of a byte attribute and remove it from the list.
byte	consumeByte(String name, boolean required, byte defaultValue) Gets the value of a byte attribute and remove it from the list.
String	consumeContent(boolean required) Gets the element's text content and removes it from the list.
DateTime	consumeDateTime(String name, boolean required) Gets the value of a DateTime attribute and remove it from the list.
double	consumeDouble(String name, boolean required) Gets the value of a double attribute and remove it from the list.
double	consumeDouble(String name, boolean required, double defaultValue) Gets the value of a double attribute and remove it from the list.
<T extends Enum<T>> T	consumeEnum(String name, boolean required, Class<T> enumClass) Gets the value of an enumerated attribute and remove it from the list.
<T extends Enum<T>> T	consumeEnum(String name, boolean required, Class<T> enumClass, T defaultValue) Gets the value of an enumerated attribute and remove it from the list.
<T extends Enum<T>> T	consumeEnum(String name, boolean required, Class<T> enumClass, T defaultValue, AttributeHelper.EnumToAttributeValue<T> enumToAttributeValue) Gets the value of an enumerated attribute and remove it from the list, using a custom mapping of enum to attribute value.
float	consumeFloat(String name, boolean required) Gets the value of a float attribute and remove it from the list.
float	consumeFloat(String name, boolean required, float defaultValue) Gets the value of a float attribute and remove it from the list.
int	consumeInteger(String name, boolean required) Gets the value of an integer attribute and remove it from the list.
int	consumeInteger(String name, boolean required, int defaultValue) Gets the value of an integer attribute and remove it from the list.
long	consumeLong(String name, boolean required) Gets the value of a long attribute and remove it from the list.
long	consumeLong(String name, boolean required, long defaultValue) Gets the value of a long attribute and remove it from the list.
short	consumeShort(String name, boolean required) Gets the value of a short attribute and remove it from the list.
short	consumeShort(String name, boolean required, short defaultValue) Gets the value of a short attribute and remove it from the list.

Methods inherited from class java.lang.Object

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

Field Detail

attrs

protected final Map<String,String> attrs

Maps attribute local name to string value.

Constructor Detail

AttributeHelper

public AttributeHelper(Attributes attrs)

Creates a helper tied to a specific set of SAX attributes.

Parameters:

attrs - the SAX attributes to be processed

Method Detail

consumeContent

public String consumeContent(boolean required)
                      throws ParseException

Gets the element's text content and removes it from the list.

Parameters:

required - indicates attributes is required

Returns:

element's text content or null for no text content

Throws:

ParseException - if required is set and the text content is not defined

consume

public String consume(String name,
             boolean required)
               throws ParseException

Gets the value of an attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attributes is required

Returns:

attribute value or null if not available

Throws:

ParseException - if required is set and the attribute is not defined

consumeByte

public byte consumeByte(String name,
               boolean required,
               byte defaultValue)
                 throws ParseException

Gets the value of a byte attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the byte value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid byte

consumeByte

public byte consumeByte(String name,
               boolean required)
                 throws ParseException

Gets the value of a byte attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the byte value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid byte

consumeShort

public short consumeShort(String name,
                 boolean required,
                 short defaultValue)
                   throws ParseException

Gets the value of a short attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the short value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid short

consumeShort

public short consumeShort(String name,
                 boolean required)
                   throws ParseException

Gets the value of a short attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the short value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid short

consumeInteger

public int consumeInteger(String name,
                 boolean required,
                 int defaultValue)
                   throws ParseException

Gets the value of an integer attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the integer value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid integer

consumeInteger

public int consumeInteger(String name,
                 boolean required)
                   throws ParseException

Gets the value of an integer attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the integer value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid integer

consumeLong

public long consumeLong(String name,
               boolean required,
               long defaultValue)
                 throws ParseException

Gets the value of a long attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the long value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid long

consumeLong

public long consumeLong(String name,
               boolean required)
                 throws ParseException

Gets the value of a long attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the long value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid long

consumeBigInteger

public BigInteger consumeBigInteger(String name,
                           boolean required,
                           BigInteger defaultValue)
                             throws ParseException

Gets the value of a big integer attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the big integer value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid big integer

consumeBigInteger

public BigInteger consumeBigInteger(String name,
                           boolean required)
                             throws ParseException

Gets the value of a big integer attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the big integer value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid big integer

consumeBigDecimal

public BigDecimal consumeBigDecimal(String name,
                           boolean required,
                           BigDecimal defaultValue)
                             throws ParseException

Gets the value of a big decimal attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the big decimal value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid big decimal

consumeBigDecimal

public BigDecimal consumeBigDecimal(String name,
                           boolean required)
                             throws ParseException

Gets the value of a big decimal attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the big decimal value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid big decimal

consumeDouble

public double consumeDouble(String name,
                   boolean required,
                   double defaultValue)
                     throws ParseException

Gets the value of a double attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the double value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid double

consumeDouble

public double consumeDouble(String name,
                   boolean required)
                     throws ParseException

Gets the value of a double attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the double value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid double

consumeFloat

public float consumeFloat(String name,
                 boolean required,
                 float defaultValue)
                   throws ParseException

Gets the value of a float attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the float value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid float

consumeFloat

public float consumeFloat(String name,
                 boolean required)
                   throws ParseException

Gets the value of a float attribute and remove it from the list.

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the float value of this attribute, 0 by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid float

consumeBoolean

public boolean consumeBoolean(String name,
                     boolean required,
                     boolean defaultValue)
                       throws ParseException

Gets the value of a boolean attribute and remove it from the list. The accepted values are based upon xsd:boolean syntax (true, false, 1, 0).

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

defaultValue - the default value for an optional attribute (used if not present)

Returns:

the boolean value of this attribute

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is neither true nor false.

consumeBoolean

public boolean consumeBoolean(String name,
                     boolean required)
                       throws ParseException

Gets the value of a boolean attribute and remove it from the list. The accepted values are based upon xsd:boolean syntax (true, false, 1, 0).

Parameters:

name - attribute name

required - indicates attribute is required

Returns:

the boolean value of this attribute, false by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is neither true nor false.

consumeDateTime

public DateTime consumeDateTime(String name,
                       boolean required)
                         throws ParseException

Gets the value of a DateTime attribute and remove it from the list.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

Returns:

the date-time value of this attribute, null by default

Throws:

ParseException - if required is set and the attribute is not defined, or if the date-time attribute cannot be parsed

consumeEnum

public <T extends Enum<T>> T consumeEnum(String name,
                                boolean required,
                                Class<T> enumClass,
                                T defaultValue,
                                AttributeHelper.EnumToAttributeValue<T> enumToAttributeValue)
                           throws ParseException

Gets the value of an enumerated attribute and remove it from the list, using a custom mapping of enum to attribute value.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

enumClass - enumeration class

defaultValue - the default value for an optional attribute (used if not present)

enumToAttributeValue - custom mapping of enum to attribute value

Returns:

an enumerated value

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid enumerated value

consumeEnum

public <T extends Enum<T>> T consumeEnum(String name,
                                boolean required,
                                Class<T> enumClass,
                                T defaultValue)
                           throws ParseException

Gets the value of an enumerated attribute and remove it from the list. Enumerated values are case-insensitive.

Parameters:

name - attribute name or null for text content

required - indicates attribute is required

enumClass - enumeration class

defaultValue - the default value for an optional attribute (used if not present)

Returns:

an enumerated value

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid enumerated value

consumeEnum

public <T extends Enum<T>> T consumeEnum(String name,
                                boolean required,
                                Class<T> enumClass)
                           throws ParseException

Gets the value of an enumerated attribute and remove it from the list. Enumerated values are case-insensitive.

Parameters:

name - attribute name

required - indicates attribute is required

enumClass - enumeration class

Returns:

an enumerated value or null if not present

Throws:

ParseException - if required is set and the attribute is not defined, or if the attribute value is not a valid enumerated value

assertAllConsumed

public void assertAllConsumed()
                       throws ParseException

Makes sure all attributes have been removed from the list. To all attribute in the default namespace must correspond exactly one call to consume*().

Throws:

ParseException - if an attribute in the default namespace hasn't been removed