Class DefaultConfigurationKey


  • 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
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      class  DefaultConfigurationKey.KeyIterator
      A specialized iterator class for tokenizing a configuration key.
    • 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 two ConfigurationKey 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.
      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait
    • Constructor Detail

      • DefaultConfigurationKey

        public DefaultConfigurationKey​(DefaultExpressionEngine engine)
        Creates a new instance of DefaultConfigurationKey and sets the associated expression engine.
        Parameters:
        engine - the expression engine
      • DefaultConfigurationKey

        public DefaultConfigurationKey​(DefaultExpressionEngine engine,
                                       java.lang.String key)
        Creates a new instance of DefaultConfigurationKey and sets the associated expression engine and an initial key.
        Parameters:
        engine - the expression engine
        key - the key to be wrapped
    • Method Detail

      • getExpressionEngine

        public DefaultExpressionEngine getExpressionEngine()
        Returns the associated default expression engine.
        Returns:
        the associated expression engine
      • setExpressionEngine

        public void setExpressionEngine​(DefaultExpressionEngine expressionEngine)
        Sets the associated expression engine.
        Parameters:
        expressionEngine - the expression engine (must not be null)
      • 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 added
        escape - a flag if property delimiters in the passed in property name should be escaped
        Returns:
        a reference to this object
      • 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
      • 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
      • 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
      • length

        public int length()
        Returns the actual length of this configuration key.
        Returns:
        the length of this key
      • 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 some append() methods. The semantic is the same as the setLength() method of StringBuilder.
        Parameters:
        len - the new length of the key
      • equals

        public boolean equals​(java.lang.Object c)
        Checks if two ConfigurationKey objects are equal. The method can be called with strings or other objects, too.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        c - the object to compare
        Returns:
        a flag if both objects are equal
      • hashCode

        public int hashCode()
        Returns the hash code for this object.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        the hash code
      • 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 class java.lang.Object
        Returns:
        a string for this object
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • iterator

        public DefaultConfigurationKey.KeyIterator iterator()
        Returns an iterator for iterating over the single components of this configuration key.
        Returns:
        an iterator for this key