Package org.apache.jackrabbit.oak.plugins.memory

Class EmptyNodeState

java.lang.Object
org.apache.jackrabbit.oak.plugins.memory.EmptyNodeState
All Implemented Interfaces:
NodeState
public final class EmptyNodeState extends Object implements NodeState
Singleton instances of empty and non-existent node states, i.e. ones with neither properties nor child nodes.

  • Field Details

    • EMPTY_NODE

      public static final NodeState EMPTY_NODE

    • MISSING_NODE

      public static final NodeState MISSING_NODE

  • Method Details

    • exists

      public boolean exists()
      Description copied from interface: NodeState
      Checks whether this node exists. See the above discussion about the existence of node states.
      Specified by:
      exists in interface NodeState
      Returns:
      true if this node exists, false if not

    • getPropertyCount

      public long getPropertyCount()
      Description copied from interface: NodeState
      Returns the number of properties of this node.
      Specified by:
      getPropertyCount in interface NodeState
      Returns:
      number of properties

    • hasProperty

      public boolean hasProperty(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Checks whether the named property exists. The implementation is equivalent to getProperty(name) != null, but may be optimized to avoid having to load the property value.
      Specified by:
      hasProperty in interface NodeState
      Parameters:
      name - property name
      Returns:
      true if the named property exists, false otherwise

    • getProperty

      @Nullable public @Nullable PropertyState getProperty(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the named property, or null if no such property exists.
      Specified by:
      getProperty in interface NodeState
      Parameters:
      name - name of the property to return
      Returns:
      named property, or null if not found

    • getBoolean

      public boolean getBoolean(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the boolean value of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 return property != null
     && property.getType() == Type.BOOLEAN
     && property.getValue(Type.BOOLEAN);
      Specified by:
      getBoolean in interface NodeState
      Parameters:
      name - property name
      Returns:
      boolean value of the named property, or false

    • getLong

      public long getLong(String name)
      Description copied from interface: NodeState
      Returns the long value of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 if (property != null && property.getType() == Type.LONG) {
     return property.getValue(Type.LONG);
 } else {
     return 0;
 }
      Specified by:
      getLong in interface NodeState
      Parameters:
      name - property name
      Returns:
      long value of the named property, or zero

    • getString

      public String getString(String name)
      Description copied from interface: NodeState
      Returns the string value of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 if (property != null && property.getType() == Type.STRING) {
     return property.getValue(Type.STRING);
 } else {
     return null;
 }
      Specified by:
      getString in interface NodeState
      Parameters:
      name - property name
      Returns:
      string value of the named property, or null

    • getStrings

      @NotNull public @NotNull Iterable<String> getStrings(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the string values of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 if (property != null && property.getType() == Type.STRINGS) {
     return property.getValue(Type.STRINGS);
 } else {
     return Collections.emptyList();
 }
      Specified by:
      getStrings in interface NodeState
      Parameters:
      name - property name
      Returns:
      string values of the named property, or an empty collection

    • getName

      @Nullable public @Nullable String getName(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the name value of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 if (property != null && property.getType() == Type.NAME) {
     return property.getValue(Type.NAME);
 } else {
     return null;
 }
      Specified by:
      getName in interface NodeState
      Parameters:
      name - property name
      Returns:
      name value of the named property, or null

    • getNames

      @NotNull public @NotNull Iterable<String> getNames(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the name values of the named property. The implementation is equivalent to the following code, but may be optimized. 
       
 PropertyState property = state.getProperty(name);
 if (property != null && property.getType() == Type.NAMES) {
     return property.getValue(Type.NAMES);
 } else {
     return Collections.emptyList();
 }
      Specified by:
      getNames in interface NodeState
      Parameters:
      name - property name
      Returns:
      name values of the named property, or an empty collection

    • getProperties

      @NotNull public @NotNull Iterable<? extends PropertyState> getProperties()
      Description copied from interface: NodeState
      Returns an iterable of the properties of this node. Multiple iterations are guaranteed to return the properties in the same order, but the specific order used is implementation-dependent and may change across different states of the same node.
      Specified by:
      getProperties in interface NodeState
      Returns:
      properties in some stable order

    • getChildNodeCount

      public long getChildNodeCount(long max)
      Description copied from interface: NodeState
      Returns the number of iterable child nodes of this node.

      If an implementation knows the exact value, it returns it (even if the value is higher than max). If the implementation does not know the exact value, and the child node count is higher than max, it may return Long.MAX_VALUE. The cost of the operation is at most O(max).

      Specified by:
      getChildNodeCount in interface NodeState
      Parameters:
      max - the maximum number of entries to traverse
      Returns:
      number of iterable child nodes

    • hasChildNode

      public boolean hasChildNode(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Checks whether the named child node exists. The implementation is equivalent to getChildNode(name).exists(), except that passing an invalid name as argument will result in a false return value instead of an IllegalArgumentException.
      Specified by:
      hasChildNode in interface NodeState
      Parameters:
      name - name of the child node
      Returns:
      true if the named child node exists, false otherwise

    • getChildNode

      @NotNull public @NotNull NodeState getChildNode(@NotNull @NotNull String name)
      Description copied from interface: NodeState
      Returns the named, possibly non-existent, child node. Use the NodeState.exists() method on the returned child node to determine whether the node exists or not.
      Specified by:
      getChildNode in interface NodeState
      Parameters:
      name - name of the child node to return
      Returns:
      named child node

    • getChildNodeNames

      public Iterable<String> getChildNodeNames()
      Description copied from interface: NodeState
      Returns the names of all iterable child nodes.
      Specified by:
      getChildNodeNames in interface NodeState
      Returns:
      child node names in some stable order

    • getChildNodeEntries

      @NotNull public @NotNull Iterable<? extends ChildNodeEntry> getChildNodeEntries()
      Description copied from interface: NodeState
      Returns the iterable child node entries of this instance. Multiple iterations are guaranteed to return the child nodes in the same order, but the specific order used is implementation dependent and may change across different states of the same node.

      Note on cost and performance: while it is possible to iterate over all child NodeStates with the two methods NodeState.getChildNodeNames() and NodeState.getChildNode(String), this method is considered more efficient because an implementation can potentially perform the retrieval of the name and NodeState in one call. This results in O(n) vs. O(n log n) when iterating over the child node names and then look up the NodeState by name.

      Specified by:
      getChildNodeEntries in interface NodeState
      Returns:
      child node entries in some stable order

    • builder

      @NotNull public @NotNull NodeBuilder builder()
      Description copied from interface: NodeState
      Returns a builder for constructing a new node state based on this state, i.e. starting with all the properties and child nodes of this state.
      Specified by:
      builder in interface NodeState
      Returns:
      node builder based on this state

    • compareAgainstBaseState

      public boolean compareAgainstBaseState(NodeState base, NodeStateDiff diff)
      Description copied from interface: NodeState
      Compares this node state against the given base state. Any differences are reported by calling the relevant added/changed/deleted methods of the given handler.

      TODO: Define the behavior of this method with regards to iterability/existence of child nodes.

      Specified by:
      compareAgainstBaseState in interface NodeState
      Parameters:
      base - base state
      diff - handler of node state differences
      Returns:
      true if the full diff was performed, or false if it was aborted as requested by the handler (see the NodeStateDiff contract for more details)

    • compareAgainstEmptyState

      public static boolean compareAgainstEmptyState(NodeState state, NodeStateDiff diff)

    • isEmptyState

      public static boolean isEmptyState(NodeState state)

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

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

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object