Package org.apache.groovy.json.internal

Class LazyMap

java.lang.Object
java.util.AbstractMap<String,Object>
org.apache.groovy.json.internal.LazyMap
All Implemented Interfaces:
Map<String,Object>
public class LazyMap extends AbstractMap<String,Object>
A map that defers creating its backing map, so the small objects that dominate JSON documents do not incur that overhead. Entries are held in parallel key/value arrays until the first lookup, or until the entry count passes the linear-scan threshold, whichever comes first.

  • Constructor Details

    • LazyMap

      public LazyMap()
      Creates a lazy map with the default key and value buffer size.

    • LazyMap

      public LazyMap(int initialSize)
      Creates a lazy map with a caller-supplied key and value buffer size.
      Parameters:
      initialSize - initial buffer size

  • Method Details

    • put

      public Object put(String key, Object value)
      Stores a mapping while keeping the compact array-backed representation until hydration is needed. Once the entry count passes the linear-scan threshold, the backing map is built and delegated to, keeping insertion amortized constant-time for wide objects.
      Specified by:
      put in interface Map<String,Object>
      Overrides:
      put in class AbstractMap<String,Object>
      Parameters:
      key - entry key
      value - entry value
      Returns:
      previous value for key, or null

    • entrySet

      public Set<Map.Entry<String,Object>> entrySet()
      Returns the hydrated entry set, building the backing map if necessary.
      Specified by:
      entrySet in interface Map<String,Object>
      Specified by:
      entrySet in class AbstractMap<String,Object>
      Returns:
      hydrated entry set

    • size

      public int size()
      Returns the current size without hydrating when the compact representation is still active.
      Specified by:
      size in interface Map<String,Object>
      Overrides:
      size in class AbstractMap<String,Object>
      Returns:
      map size

    • isEmpty

      public boolean isEmpty()
      Returns whether the map currently contains any entries.
      Specified by:
      isEmpty in interface Map<String,Object>
      Overrides:
      isEmpty in class AbstractMap<String,Object>
      Returns:
      true when no entries are stored

    • containsValue

      public boolean containsValue(Object value)
      Hydrates the backing map if needed and tests whether the value is present.
      Specified by:
      containsValue in interface Map<String,Object>
      Overrides:
      containsValue in class AbstractMap<String,Object>
      Parameters:
      value - value to test
      Returns:
      true when the value is present

    • containsKey

      public boolean containsKey(Object key)
      Hydrates the backing map if needed and tests whether the key is present.
      Specified by:
      containsKey in interface Map<String,Object>
      Overrides:
      containsKey in class AbstractMap<String,Object>
      Parameters:
      key - key to test
      Returns:
      true when the key is present

    • get

      public Object get(Object key)
      Hydrates the backing map if needed and returns the value for the supplied key.
      Specified by:
      get in interface Map<String,Object>
      Overrides:
      get in class AbstractMap<String,Object>
      Parameters:
      key - key to look up
      Returns:
      mapped value, or null

    • remove

      public Object remove(Object key)
      Hydrates the backing map if needed and removes the supplied key.
      Specified by:
      remove in interface Map<String,Object>
      Overrides:
      remove in class AbstractMap<String,Object>
      Parameters:
      key - key to remove
      Returns:
      removed value, or null

    • putAll

      public void putAll(Map m)
      Hydrates the backing map if needed and copies all supplied entries into it.
      Specified by:
      putAll in interface Map<String,Object>
      Overrides:
      putAll in class AbstractMap<String,Object>
      Parameters:
      m - entries to copy

    • clear

      public void clear()
      Clears the compact buffers or hydrated map, depending on the current state.
      Specified by:
      clear in interface Map<String,Object>
      Overrides:
      clear in class AbstractMap<String,Object>

    • keySet

      public Set<String> keySet()
      Hydrates the backing map if needed and returns its key set.
      Specified by:
      keySet in interface Map<String,Object>
      Overrides:
      keySet in class AbstractMap<String,Object>
      Returns:
      hydrated key set

    • values

      public Collection<Object> values()
      Hydrates the backing map if needed and returns its values collection.
      Specified by:
      values in interface Map<String,Object>
      Overrides:
      values in class AbstractMap<String,Object>
      Returns:
      hydrated values collection

    • equals

      public boolean equals(Object o)
      Hydrates the backing map if needed and compares it with another object.
      Specified by:
      equals in interface Map<String,Object>
      Overrides:
      equals in class AbstractMap<String,Object>
      Parameters:
      o - other object
      Returns:
      true when equal

    • hashCode

      public int hashCode()
      Hydrates the backing map if needed and returns its hash code.
      Specified by:
      hashCode in interface Map<String,Object>
      Overrides:
      hashCode in class AbstractMap<String,Object>
      Returns:
      hydrated hash code

    • toString

      public String toString()
      Hydrates the backing map if needed and returns its string form.
      Overrides:
      toString in class AbstractMap<String,Object>
      Returns:
      hydrated map text

    • clone

      protected Object clone() throws CloneNotSupportedException
      Clones the hydrated backing map when one already exists.
      Overrides:
      clone in class AbstractMap<String,Object>
      Returns:
      a clone of the hydrated backing map, or null when still compact
      Throws:
      CloneNotSupportedException - never thrown by the current implementation

    • clearAndCopy

      public LazyMap clearAndCopy()
      Copies the compact entries into a new LazyMap and clears this instance.
      Returns:
      a copy containing the current compact entries

    • grow

      public static <V> V[] grow(V[] array)
      Doubles the capacity of the supplied array while preserving its component type.
      Type Parameters:
      V - component type
      Parameters:
      array - array to grow
      Returns:
      the expanded array