Class DefaultConfigurationKey
- java.lang.Object
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- org.apache.commons.configuration.tree.DefaultConfigurationKey
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public class DefaultConfigurationKey extends java.lang.Object
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
- Version:
- $Id: DefaultConfigurationKey.java 1231724 2012-01-15 18:40:31Z oheger $
- Author:
- Commons Configuration team
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Nested Class Summary
Nested Classes Modifier and Type Class Description class
DefaultConfigurationKey.KeyIterator
A specialized iterator class for tokenizing a configuration key.
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Constructor Summary
Constructors Constructor Description DefaultConfigurationKey(DefaultExpressionEngine engine)
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine.DefaultConfigurationKey(DefaultExpressionEngine engine, java.lang.String key)
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine and an initial key.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description DefaultConfigurationKey
append(java.lang.String property)
Appends the name of a property to this key.DefaultConfigurationKey
append(java.lang.String property, boolean escape)
Appends the name of a property to this key.DefaultConfigurationKey
appendAttribute(java.lang.String attr)
Appends an attribute to this configuration key.DefaultConfigurationKey
appendIndex(int index)
Appends an index to this configuration key.java.lang.String
attributeName(java.lang.String key)
Extracts the name of the attribute from the given attribute key.java.lang.String
constructAttributeKey(java.lang.String key)
Decorates the given key so that it represents an attribute.boolean
equals(java.lang.Object c)
Checks if twoConfigurationKey
objects are equal.DefaultExpressionEngine
getExpressionEngine()
Returns the associated default expression engine.int
hashCode()
Returns the hash code for this object.boolean
isAttributeKey(java.lang.String key)
Tests if the specified key represents an attribute according to the current expression engine.DefaultConfigurationKey.KeyIterator
iterator()
Returns an iterator for iterating over the single components of this configuration key.int
length()
Returns the actual length of this configuration key.void
setExpressionEngine(DefaultExpressionEngine expressionEngine)
Sets the associated expression engine.void
setLength(int len)
Sets the new length of this configuration key.java.lang.String
toString()
Returns a string representation of this object.java.lang.String
trim(java.lang.String key)
Removes delimiters at the beginning and the end of the specified key.java.lang.String
trimLeft(java.lang.String key)
Removes leading property delimiters from the specified key.java.lang.String
trimRight(java.lang.String key)
Removes trailing property delimiters from the specified key.
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Constructor Detail
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DefaultConfigurationKey
public DefaultConfigurationKey(DefaultExpressionEngine engine)
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine.- Parameters:
engine
- the expression engine
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DefaultConfigurationKey
public DefaultConfigurationKey(DefaultExpressionEngine engine, java.lang.String key)
Creates a new instance ofDefaultConfigurationKey
and sets the associated expression engine and an initial key.- Parameters:
engine
- the expression enginekey
- the key to be wrapped
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Method Detail
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getExpressionEngine
public DefaultExpressionEngine getExpressionEngine()
Returns the associated default expression engine.- Returns:
- the associated expression engine
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setExpressionEngine
public void setExpressionEngine(DefaultExpressionEngine expressionEngine)
Sets the associated expression engine.- Parameters:
expressionEngine
- the expression engine (must not be null)
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append
public DefaultConfigurationKey append(java.lang.String property, boolean escape)
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
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append
public DefaultConfigurationKey append(java.lang.String property)
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
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appendIndex
public DefaultConfigurationKey appendIndex(int index)
Appends an index to this configuration key.- Parameters:
index
- the index to be appended- Returns:
- a reference to this object
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appendAttribute
public DefaultConfigurationKey appendAttribute(java.lang.String attr)
Appends an attribute to this configuration key.- Parameters:
attr
- the name of the attribute to be appended- Returns:
- a reference to this object
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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
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equals
public boolean equals(java.lang.Object c)
Checks if twoConfigurationKey
objects are equal. The method can be called with strings or other objects, too.- Overrides:
equals
in classjava.lang.Object
- Parameters:
c
- the object to compare- Returns:
- a flag if both objects are equal
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hashCode
public int hashCode()
Returns the hash code for this object.- Overrides:
hashCode
in classjava.lang.Object
- Returns:
- the hash code
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toString
public java.lang.String toString()
Returns a string representation of this object. This is the configuration key as a plain string.- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string for this object
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isAttributeKey
public boolean isAttributeKey(java.lang.String key)
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
public java.lang.String constructAttributeKey(java.lang.String key)
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
public java.lang.String attributeName(java.lang.String key)
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
public java.lang.String trimLeft(java.lang.String key)
Removes leading property delimiters from the specified key.- Parameters:
key
- the key- Returns:
- the key with removed leading property delimiters
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trimRight
public java.lang.String trimRight(java.lang.String key)
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
public java.lang.String trim(java.lang.String key)
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
public DefaultConfigurationKey.KeyIterator iterator()
Returns an iterator for iterating over the single components of this configuration key.- Returns:
- an iterator for this key
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