org.apache.jackrabbit.oak.plugins.memory

Class ModifiedNodeState

java.lang.Object

org.apache.jackrabbit.oak.spi.state.AbstractNodeState

org.apache.jackrabbit.oak.plugins.memory.ModifiedNodeState

All Implemented Interfaces:

NodeState

public class ModifiedNodeState
extends AbstractNodeState

Immutable snapshot of a mutable node state.

Field Summary

Fields inherited from interface org.apache.jackrabbit.oak.spi.state.NodeState

EXISTS

Method Summary

Methods

Modifier and Type	Method and Description
NodeBuilder	builder() Returns a builder for constructing a new node state based on this state, i.e.
boolean	compareAgainstBaseState(NodeState base, NodeStateDiff diff) Since we keep track of an explicit base node state for a ModifiedNodeState instance, we can do this in two steps: first compare all the modified properties and child nodes to those of the given base state, and then compare the base states to each other, ignoring all changed properties and child nodes that were already covered earlier.
boolean	exists() Checks whether this node exists.
NodeState	getBaseState()
NodeState	getChildNode(String name) Returns the named, possibly non-existent, child node.
long	getChildNodeCount(long max) Returns the number of iterable child nodes of this node.
Iterable<? extends ChildNodeEntry>	getChildNodeEntries() Returns the iterable child node entries of this instance.
Iterable<String>	getChildNodeNames() Returns the names of all iterable child nodes.
Iterable<? extends PropertyState>	getProperties() Returns an iterable of the properties of this node.
PropertyState	getProperty(String name) Returns the named property, or null if no such property exists.
long	getPropertyCount() Returns the number of properties of this node.
boolean	hasChildNode(String name) Checks whether the named child node exists.
boolean	hasProperty(String name) Checks whether the named property exists.
static NodeState	squeeze(NodeState state) "Squeezes" ModifiedNodeState instances into equivalent MemoryNodeStates.

Methods inherited from class org.apache.jackrabbit.oak.spi.state.AbstractNodeState

checkValidName, compareAgainstBaseState, comparePropertiesAgainstBaseState, equals, equals, getBoolean, getBoolean, getLong, getLong, getName, getName, getNames, getNames, getString, getString, getStrings, getStrings, hashCode, isValidName, toString, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

squeeze

public static NodeState squeeze(NodeState state)

"Squeezes" ModifiedNodeState instances into equivalent MemoryNodeStates. Other kinds of states are returned as-is.

getBaseState

public NodeState getBaseState()

builder

public 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.

Returns:

node builder based on this state

exists

public boolean exists()

Description copied from interface: NodeState

Checks whether this node exists. See the above discussion about the existence of node states.

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

Overrides:

getPropertyCount in class AbstractNodeState

Returns:

number of properties

hasProperty

public boolean hasProperty(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

Overrides:

hasProperty in class AbstractNodeState

Parameters:

name - property name

Returns:

true if the named property exists, false otherwise

getProperty

public PropertyState getProperty(String name)

Description copied from interface: NodeState

Returns the named property, or null if no such property exists.

Specified by:

getProperty in interface NodeState

Overrides:

getProperty in class AbstractNodeState

Parameters:

name - name of the property to return

Returns:

named property, or null if not found

getProperties

public 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.

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

Overrides:

getChildNodeCount in class AbstractNodeState

Parameters:

max - the maximum number of entries to traverse

Returns:

number of iterable child nodes

hasChildNode

public boolean hasChildNode(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.

Parameters:

name - name of the child node

Returns:

true if the named child node exists, false otherwise

getChildNode

public NodeState getChildNode(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.

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

Overrides:

getChildNodeNames in class AbstractNodeState

Returns:

child node names in some stable order

getChildNodeEntries

public 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.

Returns:

child node entries in some stable order

compareAgainstBaseState

public boolean compareAgainstBaseState(NodeState base,
                              NodeStateDiff diff)

Since we keep track of an explicit base node state for a ModifiedNodeState instance, we can do this in two steps: first compare all the modified properties and child nodes to those of the given base state, and then compare the base states to each other, ignoring all changed properties and child nodes that were already covered earlier.

Specified by:

compareAgainstBaseState in interface NodeState

Overrides:

compareAgainstBaseState in class AbstractNodeState

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)