Package groovy.lang

Class GString

java.lang.Object
groovy.lang.GroovyObjectSupport
groovy.lang.GString
All Implemented Interfaces:
Buildable, GroovyObject, Writable, Serializable, CharSequence, Comparable
Direct Known Subclasses:
GStringImpl
public abstract class GString extends GroovyObjectSupport implements Comparable, CharSequence, Writable, Buildable, Serializable
Represents a String which contains embedded values such as "hello there ${user} how are you?" which can be evaluated lazily. Advanced users can iterate over the text and values to perform special processing, such as for performing SQL operations, the values can be substituted for ? and the actual value objects can be bound to a JDBC statement.

James Strachan: The lovely name of this class was suggested by Jules Gosnell and was such a good idea, I couldn't resist :)

See Also:

  • Field Details

    • EMPTY_STRING_ARRAY

      public static final String[] EMPTY_STRING_ARRAY
      Shared empty string array.

    • EMPTY_OBJECT_ARRAY

      public static final Object[] EMPTY_OBJECT_ARRAY
      Shared empty object array.

    • EMPTY

      public static final GString EMPTY
      A GString containing a single empty String and no values.

  • Constructor Details

    • GString

      public GString(Object values)
      Creates a GString from the supplied values array reference.
      Parameters:
      values - the interpolated values

    • GString

      public GString(Object[] values)
      Creates a GString from the supplied values.
      Parameters:
      values - the interpolated values

  • Method Details

    • getStrings

      public abstract String[] getStrings()
      Returns the string segments surrounding the interpolated values.
      Returns:
      the string segments

    • invokeMethod

      public Object invokeMethod(String name, Object args)
      Overloaded to implement duck typing for Strings so that any method that can't be evaluated on this object will be forwarded to the toString() object instead.
      Specified by:
      invokeMethod in interface GroovyObject
      Parameters:
      name - the name of the method to call
      args - the arguments to use for the method call
      Returns:
      the result of invoking the method

    • getValues

      public Object[] getValues()
      Returns the interpolated values.
      Returns:
      the interpolated values

    • plus

      public GString plus(GString that)
      Concatenates this GString with another GString.
      Parameters:
      that - the other GString
      Returns:
      the concatenated GString

    • plus

      public GString plus(String that)
      Concatenates this GString with a String.
      Parameters:
      that - the string to append
      Returns:
      the concatenated GString

    • getValueCount

      public int getValueCount()
      Returns the number of interpolated values.
      Returns:
      the value count

    • getValue

      public Object getValue(int idx)
      Returns the interpolated value at the supplied index.
      Parameters:
      idx - the value index
      Returns:
      the interpolated value

    • toString

      public String toString()
      Specified by:
      toString in interface CharSequence
      Overrides:
      toString in class Object

    • calcInitialCapacity

      protected int calcInitialCapacity()
      Calculates the initial buffer capacity for rendering this GString.
      Returns:
      the initial capacity

    • writeTo

      public Writer writeTo(Writer out) throws IOException
      Writes this object to the given writer.

      This is used to defer content creation until the point when it is streamed to the output destination. Oftentimes, content will be defined but not necessarily created (as it may be the case with a Closure definition.) In that case, the output is then 'deferred' to the point when it is serialized to the writer. This class may be used whenever an object should be responsible for creating its own textual representation, but creating the entire output as a single String would be inefficient (such as outputting a multi-gigabyte XML document.)

      Specified by:
      writeTo in interface Writable
      Parameters:
      out - the Writer to which this Writable should output its data.
      Returns:
      the Writer that was passed
      Throws:
      IOException - if an error occurred while outputting data to the writer

    • build

      public void build(GroovyObject builder)
      Builds this object into the supplied builder.
      Specified by:
      build in interface Buildable
      Parameters:
      builder - the target builder

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object that)
      Overrides:
      equals in class Object

    • equals

      public boolean equals(GString that)
      Compares this GString with another GString by rendered content.
      Parameters:
      that - the other GString
      Returns:
      true if the rendered strings are equal

    • compareTo

      public int compareTo(Object that)
      Specified by:
      compareTo in interface Comparable

    • charAt

      public char charAt(int index)
      Specified by:
      charAt in interface CharSequence

    • length

      public int length()
      Specified by:
      length in interface CharSequence

    • subSequence

      public CharSequence subSequence(int start, int end)
      Specified by:
      subSequence in interface CharSequence

    • negate

      public Pattern negate()
      Turns a String into a regular expression pattern
      Returns:
      the regular expression pattern

    • getBytes

      public byte[] getBytes()
      Returns the rendered string as a byte array using the platform default charset.
      Returns:
      the rendered bytes

    • getBytes

      public byte[] getBytes(String charset) throws UnsupportedEncodingException
      Returns the rendered string as a byte array using the supplied charset.
      Parameters:
      charset - the charset name
      Returns:
      the rendered bytes
      Throws:
      UnsupportedEncodingException - if the charset is unsupported