public class Transaction extends java.lang.Object implements java.lang.Iterable<Page>
Modifier and Type | Class and Description |
---|---|
static interface |
Transaction.CallableClosure<R,T extends java.lang.Throwable>
This closure interface is intended for the end user implement callbacks for the Transaction.exectue() method.
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static interface |
Transaction.Closure<T extends java.lang.Throwable>
This closure interface is intended for the end user implement callbacks for the Transaction.exectue() method.
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class |
Transaction.InvalidPageIOException
The InvalidPageIOException is thrown if try to load/store a a page
with an invalid page id.
|
class |
Transaction.PageOverflowIOException
The PageOverflowIOException occurs when a page write is requested
and it's data is larger than what would fit into a single page.
|
Modifier and Type | Method and Description |
---|---|
<T> Page<T> |
allocate()
Allocates a free page that you can write data to.
|
<T> Page<T> |
allocate(int count)
Allocates a block of free pages that you can write data to.
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void |
commit()
Commits the transaction to the PageFile as a single 'Unit of Work'.
|
<R,T extends java.lang.Throwable> |
execute(Transaction.CallableClosure<R,T> closure)
Executes a closure and if it does not throw any exceptions, then it commits the transaction.
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<T extends java.lang.Throwable> |
execute(Transaction.Closure<T> closure)
Executes a closure and if it does not throw any exceptions, then it commits the transaction.
|
void |
free(long pageId)
Frees up a previously allocated page so that it can be re-allocated again.
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void |
free(long pageId,
int count)
Frees up a previously allocated sequence of pages so that it can be re-allocated again.
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<T> void |
free(Page<T> page)
Frees up a previously allocated page so that it can be re-allocated again.
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<T> void |
free(Page<T> page,
int count)
Frees up a previously allocated sequence of pages so that it can be re-allocated again.
|
PageFile |
getPageFile() |
boolean |
isReadOnly() |
java.util.Iterator<Page> |
iterator()
Allows you to iterate through all active Pages in this object.
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java.util.Iterator<Page> |
iterator(boolean includeFreePages)
Allows you to iterate through all active Pages in this object.
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<T> Page<T> |
load(long pageId,
Marshaller<T> marshaller)
Loads a page from disk.
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<T> void |
load(Page<T> page,
Marshaller<T> marshaller)
Loads a page from disk.
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java.io.InputStream |
openInputStream(Page p) |
java.io.OutputStream |
openOutputStream(Page page,
boolean overflow) |
void |
rollback()
Rolls back the transaction.
|
<T> void |
store(Page<T> page,
Marshaller<T> marshaller,
boolean overflow) |
public PageFile getPageFile()
public <T> Page<T> allocate() throws java.io.IOException
java.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic <T> Page<T> allocate(int count) throws java.io.IOException
count
- the number of sequential pages to allocatejava.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic void free(long pageId) throws java.io.IOException
page
- the page to free upjava.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic void free(long pageId, int count) throws java.io.IOException
page
- the initial page of the sequence that will be getting freedcount
- the number of pages in the sequencejava.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic <T> void free(Page<T> page, int count) throws java.io.IOException
page
- the initial page of the sequence that will be getting freedcount
- the number of pages in the sequencejava.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic <T> void free(Page<T> page) throws java.io.IOException
page
- the page to free upjava.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic <T> void store(Page<T> page, Marshaller<T> marshaller, boolean overflow) throws java.io.IOException
page
- the page to write. The Page object must be fully populated with a valid pageId, type, and data.marshaller
- the marshaler to use to load the data portion of the Page, may be null if you do not wish to write the data.overflow
- If true, then if the page data marshalls to a bigger size than can fit in one page, then additional
overflow pages are automatically allocated and chained to this page to store all the data. If false,
and the overflow condition would occur, then the PageOverflowIOException is thrown.java.io.IOException
- If an disk error occurred.Transaction.PageOverflowIOException
- If the page data marshalls to size larger than maximum page size and overflow was false.java.lang.IllegalStateException
- if the PageFile is not loadedpublic java.io.OutputStream openOutputStream(Page page, boolean overflow) throws java.io.IOException
java.io.IOException
public <T> Page<T> load(long pageId, Marshaller<T> marshaller) throws java.io.IOException
pageId
- the id of the page to loadmarshaller
- the marshaler to use to load the data portion of the Page, may be null if you do not wish to load the data.java.io.IOException
- If an disk error occurred.java.lang.IllegalStateException
- if the PageFile is not loadedpublic <T> void load(Page<T> page, Marshaller<T> marshaller) throws java.io.IOException
page
- - The pageId field must be properly setmarshaller
- the marshaler to use to load the data portion of the Page, may be null if you do not wish to load the data.java.io.IOException
- If an disk error occurred.Transaction.InvalidPageIOException
- If the page is is not valid.java.lang.IllegalStateException
- if the PageFile is not loadedpublic java.io.InputStream openInputStream(Page p) throws java.io.IOException
java.io.IOException
load(org.apache.kahadb.page.Page,
org.apache.kahadb.util.Marshaller)
public java.util.Iterator<Page> iterator()
iterator
in interface java.lang.Iterable<Page>
java.lang.IllegalStateException
- if the PageFile is not loadedpublic java.util.Iterator<Page> iterator(boolean includeFreePages)
includeFreePages
- - if true, free pages are included in the iterationtx
- - if not null, then the remove() opeation on the Iterator will operate in scope of that transaction.java.lang.IllegalStateException
- if the PageFile is not loadedpublic void commit() throws java.io.IOException
java.io.IOException
public void rollback() throws java.io.IOException
java.io.IOException
public boolean isReadOnly()
public <T extends java.lang.Throwable> void execute(Transaction.Closure<T> closure) throws T extends java.lang.Throwable, java.io.IOException
T
- closure
- - the work to get exectued.T
- if the closure throws itjava.io.IOException
- If the commit fails.T extends java.lang.Throwable
public <R,T extends java.lang.Throwable> R execute(Transaction.CallableClosure<R,T> closure) throws T extends java.lang.Throwable, java.io.IOException
T
- closure
- - the work to get exectued.T
- if the closure throws itjava.io.IOException
- If the commit fails.T extends java.lang.Throwable
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