org.apache.jackrabbit.oak.segment

Class SegmentNodeState

java.lang.Object

org.apache.jackrabbit.oak.segment.SegmentNodeState

All Implemented Interfaces:

NodeState

public class SegmentNodeState
extends Object
implements NodeState

A record of type "NODE". This class can read a node record from a segment. It currently doesn't cache data (but the template is fully loaded).

Field Summary

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

EXISTS

Constructor Summary

Constructors

Constructor and Description
SegmentNodeState(@NotNull SegmentReader reader, @NotNull SegmentWriter writer, @Nullable BlobStore blobStore, @NotNull RecordId id)
SegmentNodeState(@NotNull SegmentReader reader, @NotNull SegmentWriter writer, @Nullable BlobStore blobStore, @NotNull RecordId id, MeterStats readStats)

Method Summary

Modifier and Type	Method and Description
@NotNull SegmentNodeBuilder	builder() Returns a builder for constructing a new node state based on this state, i.e.
boolean	compareAgainstBaseState(NodeState base, NodeStateDiff diff) Compares this node state against the given base state.
boolean	equals(Object object)
boolean	exists() Checks whether this node exists.
static boolean	fastEquals(NodeState a, NodeState b) Indicates whether two NodeState instances are equal to each other.
boolean	getBoolean(@NotNull String name) Returns the boolean value of the named property.
@NotNull NodeState	getChildNode(@NotNull String name) Returns the named, possibly non-existent, child node.
long	getChildNodeCount(long max) Returns the number of iterable child nodes of this node.
@NotNull Iterable<? extends ChildNodeEntry>	getChildNodeEntries() Returns the iterable child node entries of this instance.
@NotNull Iterable<String>	getChildNodeNames() Returns the names of all iterable child nodes.
@NotNull GCGeneration	getGcGeneration() Get the underlying segment's gc generation.
long	getLong(String name) Returns the long value of the named property.
@Nullable String	getName(@NotNull String name) Returns the name value of the named property.
@NotNull Iterable<String>	getNames(@NotNull String name) Returns the name values of the named property.
@NotNull Iterable<PropertyState>	getProperties() Returns an iterable of the properties of this node.
@Nullable PropertyState	getProperty(@NotNull String name) Returns the named property, or null if no such property exists.
long	getPropertyCount() Returns the number of properties of this node.
RecordId	getRecordId() Returns the identifier of this record.
protected int	getRecordNumber()
protected Segment	getSegment() Returns the segment that contains this record.
String	getStableId() Returns the stable id of this node.
Buffer	getStableIdBytes() Returns the stable ID of this node, non parsed.
@Nullable String	getString(String name) Returns the string value of the named property.
@NotNull Iterable<String>	getStrings(@NotNull String name) Returns the string values of the named property.
boolean	hasChildNode(@NotNull String name) Checks whether the named child node exists.
int	hashCode()
boolean	hasProperty(@NotNull String name) Checks whether the named property exists.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SegmentNodeState

public SegmentNodeState(@NotNull
                        @NotNull SegmentReader reader,
                        @NotNull
                        @NotNull SegmentWriter writer,
                        @Nullable
                        @Nullable BlobStore blobStore,
                        @NotNull
                        @NotNull RecordId id)

SegmentNodeState

public SegmentNodeState(@NotNull
                        @NotNull SegmentReader reader,
                        @NotNull
                        @NotNull SegmentWriter writer,
                        @Nullable
                        @Nullable BlobStore blobStore,
                        @NotNull
                        @NotNull RecordId id,
                        MeterStats readStats)

Method Detail

getStableId

public String getStableId()

Returns the stable id of this node. In contrast to the node's record id (which is technically the node's address) the stable id doesn't change after an online gc cycle. It might though change after an offline gc cycle.

Returns:

stable id

getStableIdBytes

public Buffer getStableIdBytes()

Returns the stable ID of this node, non parsed. In contrast to the node's record id (which is technically the node's address) the stable id doesn't change after an online gc cycle. It might though change after an offline gc cycle.

Returns:

the stable ID of this node.

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

getProperties

@NotNull
public @NotNull Iterable<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

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

@Nullable
public @Nullable 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

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

@NotNull
public @NotNull 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 SegmentNodeBuilder 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)

fastEquals

public static boolean fastEquals(NodeState a,
                                 NodeState b)

Indicates whether two NodeState instances are equal to each other. A return value of true clearly means that the instances are equal, while a return value of false doesn't necessarily mean the instances are not equal. These "false negatives" are an implementation detail and callers cannot rely on them being stable.

Parameters:

a - the first NodeState instance

b - the second NodeState instance

Returns:

true, if these two instances are equal.

hashCode

public int hashCode()

equals

public boolean equals(Object object)

toString

public String toString()

getSegment

protected Segment getSegment()

Returns the segment that contains this record.

Returns:

segment that contains this record

getRecordNumber

protected int getRecordNumber()

getRecordId

public RecordId getRecordId()

Returns the identifier of this record.

Returns:

record identifier

getGcGeneration

@NotNull
public @NotNull GCGeneration getGcGeneration()

Get the underlying segment's gc generation. Might cause the segment to get loaded if the generation info is missing

Returns:

the segment's gc generation