Class DefaultConfigurationKey
A simple class that supports creation of and iteration on configuration keys supported by a
DefaultExpressionEngine
object.
For key creation the class works similar to a StringBuffer: There are several appendXXXX()
methods with which
single parts of a key can be constructed. All these methods return a reference to the actual object so they can be
written in a chain. When using this methods the exact syntax for keys need not be known.
This class also defines a specialized iterator for configuration keys. With such an iterator a key can be tokenized into its single parts. For each part it can be checked whether it has an associated index.
Instances of this class are always associated with an instance of DefaultExpressionEngine
, from which the
current delimiters are obtained. So key creation and parsing is specific to this associated expression engine.
- Since:
- 1.3
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionclass
A specialized iterator class for tokenizing a configuration key. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final DefaultExpressionEngine
Stores a reference to the associated expression engine.private static final int
Constant for the initial StringBuffer size.private final StringBuilder
Holds a buffer with the so far created key. -
Constructor Summary
ConstructorsConstructorDescriptionCreates a new instance ofDefaultConfigurationKey
and sets the associated expression engine.DefaultConfigurationKey
(DefaultExpressionEngine engine, String key) Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine and an initial key. -
Method Summary
Modifier and TypeMethodDescriptionAppends the name of a property to this key.Appends the name of a property to this key.appendAttribute
(String attr) Appends an attribute to this configuration key.appendIndex
(int index) Appends an index to this configuration key.attributeName
(String key) Extracts the name of the attribute from the given attribute key.commonKey
(DefaultConfigurationKey other) Returns a configuration key object that is initialized with the part of the key that is common to this key and the passed in key.Decorates the given key so that it represents an attribute.Returns the "difference key" to a given key.boolean
Checks if twoConfigurationKey
objects are equal.private String
escapeDelimiters
(String key) Escapes the delimiters in the specified string.Gets the associated default expression engine.private DefaultExpressionEngineSymbols
Gets the symbols object from the associated expression engine.int
hashCode()
Returns the hash code for this object.private boolean
Helper method that checks if the specified key starts with a property delimiter.private boolean
Helper method that checks if the specified key ends with a property delimiter.boolean
isAttributeKey
(String key) Tests if the specified key represents an attribute according to the current expression engine.iterator()
Returns an iterator for iterating over the single components of this configuration key.int
length()
Returns the actual length of this configuration key.private static boolean
Helper method for comparing two key parts.private String
Helper method for removing attribute markers from a key.void
setLength
(int len) Sets the new length of this configuration key.toString()
Returns a string representation of this object.Removes delimiters at the beginning and the end of the specified key.Removes leading property delimiters from the specified key.Removes trailing property delimiters from the specified key.private String
unescapeDelimiters
(String key) Unescapes the delimiters in the specified string.
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Field Details
-
INITIAL_SIZE
private static final int INITIAL_SIZEConstant for the initial StringBuffer size.- See Also:
-
expressionEngine
Stores a reference to the associated expression engine. -
keyBuffer
Holds a buffer with the so far created key.
-
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Constructor Details
-
DefaultConfigurationKey
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine.- Parameters:
engine
- the expression engine (must not be null)- Throws:
IllegalArgumentException
- if the expression engine is null
-
DefaultConfigurationKey
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine and an initial key.- Parameters:
engine
- the expression engine (must not be null)key
- the key to be wrapped- Throws:
IllegalArgumentException
- if the expression engine is null
-
-
Method Details
-
getExpressionEngine
Gets the associated default expression engine.- Returns:
- the associated expression engine
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append
Appends the name of a property to this key. If necessary, a property delimiter will be added. If the boolean argument is set to true, property delimiters contained in the property name will be escaped.- Parameters:
property
- the name of the property to be addedescape
- a flag if property delimiters in the passed in property name should be escaped- Returns:
- a reference to this object
-
append
Appends the name of a property to this key. If necessary, a property delimiter will be added. Property delimiters in the given string will not be escaped.- Parameters:
property
- the name of the property to be added- Returns:
- a reference to this object
-
appendIndex
Appends an index to this configuration key.- Parameters:
index
- the index to be appended- Returns:
- a reference to this object
-
appendAttribute
Appends an attribute to this configuration key.- Parameters:
attr
- the name of the attribute to be appended- Returns:
- a reference to this object
-
length
public int length()Returns the actual length of this configuration key.- Returns:
- the length of this key
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setLength
public void setLength(int len) Sets the new length of this configuration key. With this method it is possible to truncate the key, e.g. to return to a state prior calling someappend()
methods. The semantic is the same as thesetLength()
method ofStringBuilder
.- Parameters:
len
- the new length of the key
-
commonKey
Returns a configuration key object that is initialized with the part of the key that is common to this key and the passed in key.- Parameters:
other
- the other key- Returns:
- a key object with the common key part
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differenceKey
Returns the "difference key" to a given key. This value is the part of the passed in key that differs from this key. There is the following relation:other = key.commonKey(other) + key.differenceKey(other)
for an arbitrary configuration keykey
.- Parameters:
other
- the key for which the difference is to be calculated- Returns:
- the difference key
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equals
Checks if twoConfigurationKey
objects are equal. Two instances of this class are considered equal if they have the same content (i.e. their internal string representation is equal). The expression engine property is not taken into account. -
hashCode
public int hashCode()Returns the hash code for this object. -
toString
Returns a string representation of this object. This is the configuration key as a plain string. -
isAttributeKey
Tests if the specified key represents an attribute according to the current expression engine.- Parameters:
key
- the key to be checked- Returns:
- true if this is an attribute key, false otherwise
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constructAttributeKey
Decorates the given key so that it represents an attribute. Adds special start and end markers. The passed in string will be modified only if does not already represent an attribute.- Parameters:
key
- the key to be decorated- Returns:
- the decorated attribute key
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attributeName
Extracts the name of the attribute from the given attribute key. This method removes the attribute markers - if any - from the specified key.- Parameters:
key
- the attribute key- Returns:
- the name of the corresponding attribute
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trimLeft
Removes leading property delimiters from the specified key.- Parameters:
key
- the key- Returns:
- the key with removed leading property delimiters
-
trimRight
Removes trailing property delimiters from the specified key.- Parameters:
key
- the key- Returns:
- the key with removed trailing property delimiters
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trim
Removes delimiters at the beginning and the end of the specified key.- Parameters:
key
- the key- Returns:
- the key with removed property delimiters
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iterator
Returns an iterator for iterating over the single components of this configuration key.- Returns:
- an iterator for this key
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hasTrailingDelimiter
Helper method that checks if the specified key ends with a property delimiter.- Parameters:
key
- the key to check- Returns:
- a flag if there is a trailing delimiter
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hasLeadingDelimiter
Helper method that checks if the specified key starts with a property delimiter.- Parameters:
key
- the key to check- Returns:
- a flag if there is a leading delimiter
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removeAttributeMarkers
Helper method for removing attribute markers from a key.- Parameters:
key
- the key- Returns:
- the key with removed attribute markers
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unescapeDelimiters
Unescapes the delimiters in the specified string.- Parameters:
key
- the key to be unescaped- Returns:
- the unescaped key
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getSymbols
Gets the symbols object from the associated expression engine.- Returns:
- the
DefaultExpressionEngineSymbols
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escapeDelimiters
Escapes the delimiters in the specified string.- Parameters:
key
- the key to be escaped- Returns:
- the escaped key
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partsEqual
private static boolean partsEqual(DefaultConfigurationKey.KeyIterator it1, DefaultConfigurationKey.KeyIterator it2) Helper method for comparing two key parts.- Parameters:
it1
- the iterator with the first partit2
- the iterator with the second part- Returns:
- a flag if both parts are equal
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