com.bigdata.gom.gpo.GPO Maven / Gradle / Ivy
package com.bigdata.gom.gpo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import org.apache.log4j.Logger;
import org.openrdf.model.BNode;
import org.openrdf.model.Literal;
import org.openrdf.model.Resource;
import org.openrdf.model.Statement;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.model.ValueFactory;
import org.openrdf.model.impl.LiteralImpl;
import org.openrdf.model.impl.StatementImpl;
import org.openrdf.model.impl.URIImpl;
import org.openrdf.query.BindingSet;
import com.bigdata.gom.om.IObjectManager;
import com.bigdata.gom.om.ObjectMgrModel;
import com.bigdata.gom.skin.GenericSkinRegistry;
import com.bigdata.rdf.model.BigdataLiteralImpl;
import com.bigdata.rdf.model.BigdataResource;
import com.bigdata.rdf.model.BigdataStatement;
import cutthecrap.utils.striterators.EmptyIterator;
import cutthecrap.utils.striterators.ICloseableIterator;
/**
* A TripleStore backed GPO yields a number of challenges.
*
*
* - We need a property mechanism to track the statement assertion and
* retractions required for efficient update. The GPOEntry class provides
* support for this with its linked lists of GPOValues, also supporting multiple
* values per predicate.
*
* - A strategy for lazy materialization. This turns out to be fairly
* straightforward, with the GPO created unmaterialized and requesting as
* necessary
*
* - Most importantly we have a consistency/referential integrity issue since
* the GPO state is not kept in sync with the underlying triple store. The
* simple solution is to ensure that any update is immediately pushed through to
* the underlying store, but this loses the advantage of the localised cache.
* Although it could be argued that a general query is made against committed
* data the same case cannot be made when building GPO models. It seems we need
* a mechanism to lazily flush updates relevant to a specific property.
*
* - An alternate solution is to view the ObjectManager transactions as
* transactional updates to the GPO structures and that when these are committed
* then the model is consistent. Separating the GPO commit from any underlying
* TripleStore commit. So the GPO processing inside the GPO transaction is
* restricted and referential integrity is not maintained. This is similar to
* the read-committed query semantics of most databases, which is not to commend
* it in any way. I am keen to find a solution to this.
*
* - One option is to force GPO related updates through to the underlying
* store, not necessarily a problem since a rollback already performs a
* TripleStore abort anyhow.
*
*
* @author Martyn Cutcher
*
*/
public class GPO implements IGPO {
private static final Logger log = Logger.getLogger(GPO.class);
// final private ReentrantReadWriteLock m_lock = new ReentrantReadWriteLock();
/**
* When the GPO is removed m_removed is set to true and any attempt to access
* the IGPO methods will throw an IllegalStateException
*/
private boolean m_removed = false;
/**
* The owning {@link IObjectManager}.
*/
private final ObjectMgrModel m_om;
/**
* The identifier for this {@link IGPO}.
*/
private final BigdataResource m_id;
private final BigdataStatement m_stmt;
/**
* true iff the forward link set has been materialized.
*/
private volatile boolean m_materialized = false;
private boolean m_clean = true;
/**
* Head of the double-linked list of values for each predicate. There is one
* double-linked list of {@link GPOEntry}s and this is the head of that
* list. There is one {@link GPOEntry} for each predicate that either has
* (or had) a bound value. Each {@link GPOEntry} models all values for a
* given predicate for this subject and tracks the edit list for the values
* for that predicate.
*/
private GPOEntry m_headEntry = null;
/**
* Tail of the double-linked list of values for each predicate. There is one
* double-linked list of {@link GPOEntry}s and this is the head of that
* list. There is one {@link GPOEntry} for each predicate that either has
* (or had) a bound value. Each {@link GPOEntry} models all values for a
* given predicate for this subject and tracks the edit list for the values
* for that predicate.
*/
private GPOEntry m_tailEntry = null;
/**
* The DESCRIBE cache may eagerly load linksIn linkSets. To support this
* {@link GPOEntry}s can be maintained for linksIn.
*/
private GPOEntry m_headLinkEntry = null;
private GPOEntry m_tailLinkEntry = null;
private ArrayList m_skins = null;
/**
* A {@link Value} on any of the {@link GPOEntry} links (values, removed,
* and added). The {@link LinkValue}s are organized as a single-linked list.
*/
static class LinkValue {
/**
* The RDF {@link Value}.
*/
final Value m_value;
/**
* The next {@link LinkValue} in the list -or- null if this
* is the last {@link LinkValue} in the list.
*/
LinkValue m_next;
LinkValue(final Value value) {
if (value == null)
throw new IllegalArgumentException();
m_value = value;
}
public boolean contains(BigdataResource id) {
LinkValue tst = this;
while (tst != null) {
if (tst.m_value.equals(id)) {
return true;
}
tst = tst.m_next;
}
return false;
}
}
/**
* The GPOEntry retains the state necessary for providing delta updates to
* the underlying triple data. It supports multi-values against the same
* property and records values removed and added.
*/
static class GPOEntry {
/**
* This is the predicate.
*/
private final URI m_key;
/**
* This is the next entry for a different predicate.
*/
private GPOEntry m_next;
/**
* This is the collection of bound values at the time the owning
* {@link GPO} was materialized or last committed. The total set of
* current bindings is {@link #m_values} PLUS {@link #m_addedValues}.
*
* TODO We need to improve the documentation here. Ideally, I would like
* to see the pre-/post-conditions for add(), and remove() as well as
* initValue() and commit().
*/
private LinkValue m_values;
/**
* Values added to this predicate and subject since the last commit.
*/
private LinkValue m_addedValues;
/**
* Values removed from this predicate and subject since the last commit.
*/
private LinkValue m_removedValues;
/**
* Keep track of entry size
*/
private int m_size = 0;
GPOEntry(final URI key) {
if (key == null)
throw new IllegalArgumentException();
m_key = key;
}
/**
* initValue is called by ObjectManager materialize and resets the GPO
* to its read state. Therefore the value is added to the m_values list
* and not m_addedValues.
*/
public void initValue(final GPO owner, final Value value) {
final LinkValue newValue = new LinkValue(value);
newValue.m_next = m_values;
m_values = newValue;
m_size++;
}
public void set(final GPO owner, final Value value) {
m_addedValues = new LinkValue(value);
// move m_values to m_removedValues
LinkValue nxt = m_values;
while (nxt != null) {
final LinkValue rem = nxt;
nxt = nxt.m_next;
rem.m_next = m_removedValues;
m_removedValues = rem;
}
// and clear any current values
m_values = null;
m_size = 1;
}
/**
* Remove the statement for the predicate and value if found, returning
* true IFF the statement was removed.
*
* @return true iff the statement was removed.
*/
public boolean remove(final GPO owner, final Value value) {
if (value == null)
throw new IllegalArgumentException();
// if on m_values then move to m_removed
LinkValue test = m_values;
LinkValue prev = null;
while (test != null) {
if (value.equals(test.m_value)) {
if (prev == null) {
m_values = test.m_next;
} else {
prev.m_next = test.m_next;
}
// add to removed values
test.m_next = m_removedValues;
m_removedValues = test;
m_size--;
return true;
}
prev = test;
test = test.m_next;
}
// if on m_added then just remove it
test = m_addedValues;
prev = null;
while (test != null) {
if (value.equals(test.m_value)) {
if (prev == null) {
m_addedValues = test.m_next;
} else {
prev.m_next = test.m_next;
}
m_size--;
return true;
}
prev = test;
test = test.m_next;
}
return false;
}
/**
* Remove all statements for this predicate on the owning {@link IGPO}.
*
* @return true iff any statements were removed.
*/
public boolean removeAll(final GPO owner) {
if (m_size == 0) {
return false;
}
// just move m_values to tail of m_removedValues
if (m_removedValues == null) {
m_removedValues = m_values;
} else {
LinkValue tail = m_removedValues;
while (tail.m_next != null)
tail = tail.m_next;
tail.m_next = m_values;
}
m_values = null; // clear values
m_addedValues = null; // remove any additions
m_size = 0;
return true;
}
public Iterator values() {
return new Iterator() {
LinkValue m_cur = m_values;
LinkValue m_added = m_addedValues;
@Override
public boolean hasNext() {
return m_cur != null || m_added != null;
}
@Override
public Value next() {
final LinkValue ret = m_cur != null ? m_cur : m_added;
if (ret == null) {
throw new NoSuchElementException();
}
if (m_cur != null) {
m_cur = m_cur.m_next;
} else {
m_added = m_added.m_next;
}
return ret.m_value;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
static class ValueIterator implements Iterator {
LinkValue m_cur;
ValueIterator(final LinkValue cur) {
m_cur = cur;
}
@Override
public boolean hasNext() {
return m_cur != null;
}
@Override
public Value next() {
final LinkValue ret = m_cur;
m_cur = m_cur.m_next;
return ret.m_value;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
public Iterator removes() {
Iterator ret = new ValueIterator(m_removedValues);
return ret;
}
public Iterator additions() {
Iterator ret = new ValueIterator(m_addedValues);
return ret;
}
public Value getValue() {
if (m_values != null) {
return m_values.m_value;
} else if (m_addedValues != null) {
return m_addedValues.m_value;
} else {
return null;
}
}
/**
* Committing the entry checks for any added values and moves this to
* the values chain.
*/
public void commit() {
if (m_addedValues != null) {
if (m_values == null) {
m_values = m_addedValues;
} else {
LinkValue tail = m_values;
while (tail.m_next != null)
tail = tail.m_next;
tail.m_next = m_addedValues;
}
m_addedValues = null;
}
m_removedValues = null;
}
/**
* A new value is only added if it does not already exist, ensuring the
* GPO maintains semantics with the underlying TripleStore.
*
* @return true if value was added
*/
public boolean add(final GPO owner, final Value value) {
final Iterator values = values();
while (values.hasNext()) {
if (values.next().equals(value)) {
return false;
}
}
final LinkValue nv = new LinkValue(value);
nv.m_next = m_addedValues;
m_addedValues = nv;
m_size++;
return true;
}
public boolean hasValues() {
return m_values != null || m_addedValues != null;
}
public int size() {
return m_size;
}
public boolean contains(BigdataResource id) {
return (m_values != null && m_values.contains(id))
|| (m_addedValues != null && m_addedValues.contains(id));
}
}
/**
* Make sure that there is a {@link GPOEntry} for that property. If one is
* found, return it. Otherwise create and return a new {@link GPOEntry}.
*
* @param key
* The property.
* @return The {@link GPOEntry} and never null.
*/
GPOEntry establishEntry(final URI key) {
final URI fkey = m_om.internKey(key);
if (m_headEntry == null) {
m_headEntry = m_tailEntry = new GPOEntry(fkey);
} else {
GPOEntry entry = m_headEntry;
while (entry != null) {
if (entry.m_key == fkey) {
return entry;
}
entry = entry.m_next;
}
m_tailEntry = m_tailEntry.m_next = new GPOEntry(fkey);
}
return m_tailEntry;
}
/**
* Make sure that there is a {@link GPOEntry} for that link property. If one
* is found, return it. Otherwise create and return a new {@link GPOEntry}.
*
* @param key
* The link property.
* @return The {@link GPOEntry} and never null.
*/
GPOEntry establishLinkEntry(final URI key) {
final URI fkey = m_om.internKey(key);
if (m_headLinkEntry == null) {
m_headLinkEntry = m_tailLinkEntry = new GPOEntry(fkey);
} else {
GPOEntry entry = m_headLinkEntry;
while (entry != null) {
if (entry.m_key == fkey) {
return entry;
}
entry = entry.m_next;
}
m_tailLinkEntry = m_tailLinkEntry.m_next = new GPOEntry(fkey);
}
return m_tailLinkEntry;
}
/**
* The entry is interned to provide a unique Object and allow '==' testing.
*
* @param key
* @return the found entry, if any
*/
GPOEntry getEntry(final URI key) {
checkLive();
final URI fkey = m_om.internKey(key);
GPOEntry entry = m_headEntry;
while (entry != null) {
if (entry.m_key == fkey) {
return entry;
}
entry = entry.m_next;
}
return null;
}
/**
* The entry is interned to provide a unique Object and allow '==' testing.
*
* @param key
* @return the found link entry, if any
*/
GPOEntry getLinkEntry(final URI key) {
checkLive();
final URI fkey = m_om.internKey(key);
GPOEntry entry = m_headLinkEntry;
while (entry != null) {
if (entry.m_key == fkey) {
return entry;
}
entry = entry.m_next;
}
return null;
}
public void dematerialize() {
m_materialized = false;
m_clean = true;
m_headEntry = m_tailEntry = null;
}
public int hashCode() {
return m_id.hashCode();
}
public GPO(final IObjectManager om, final Resource id) {
if (om == null)
throw new IllegalArgumentException();
if (id == null)
throw new IllegalArgumentException();
m_om = (ObjectMgrModel) om;
m_id = om.getValueFactory().asValue(id);
m_stmt = null;
}
public GPO(final IObjectManager om, final BNode id, final Statement stmt) {
if (om == null)
throw new IllegalArgumentException();
if (id == null)
throw new IllegalArgumentException();
m_om = (ObjectMgrModel) om;
m_id = om.getValueFactory().asValue(id);
final BigdataStatement stmt2 = om.getValueFactory().createStatement(
((ObjectMgrModel)om).bestEffortIntern(stmt.getSubject()),//
((ObjectMgrModel)om).internKey(stmt.getPredicate()), //
((ObjectMgrModel)om).bestEffortIntern(stmt.getObject()) //
);
this.m_stmt = stmt2;
}
private void checkLive() {
if (m_removed)
throw new IllegalStateException("This GPO has been removed");
}
@Override
public IGenericSkin asClass(Class theClassOrInterface) {
/**
* Could simply call through to the GenericSkinRegistry
*
* GenericSkinRegistry.asClass(this, theClassOrInterface);
*
* but this ignores any cached skins already created.
*/
return getSkin(theClassOrInterface);
}
@Override
public IObjectManager getObjectManager() {
checkLive();
return m_om;
}
@Override
public BigdataResource getId() {
checkLive();
return m_id;
}
/**
* Iff this {@link IGPO} represents a statement (aka link), then return that
* {@link Statement}.
*
* @return The {@link Statement} or null if the {@link IGPO}
* does not represent a {@link Statement}.
*/
public BigdataStatement getStatement() {
return m_stmt;
}
/**
* Encode a URL, Literal, or blank node for inclusion in a SPARQL query to
* be sent to the remote service.
*
* @param v
* The resource.
*
* @return The encoded representation of the resource.
*
* @see ObjectMgrModel#encode(Resource)
*/
public String encode(final Resource v) {
checkLive();
return m_om.encode(v);
}
/**
* getLinksIn simply filters the values for Resources and returns a wrapper.
*/
@Override
public Set getLinksIn() {
materialize();
final HashSet ret = new HashSet();
GPOEntry linkEntry = this.m_headLinkEntry;
while (linkEntry != null) {
Iterator inlinks = linkEntry.values();
while (inlinks.hasNext()) {
final IGPO mem = m_om.getGPO((Resource) inlinks.next());
ret.add(mem);
}
linkEntry = linkEntry.m_next;
}
return ret;
/*
final String query = "SELECT ?x WHERE {?x ?p <" + encode(getId())
+ ">}";
final ICloseableIterator res = m_om.evaluate(query);
final HashSet ret = new HashSet();
while (res.hasNext()) {
final BindingSet bs = res.next();
ret.add(m_om.getGPO((Resource) bs.getBinding("x").getValue()));
}
return ret;
*/
}
/** All ?y where (?y,p,self). */
@Override
public ILinkSet getLinksIn(final URI property) {
// materialize fully load links in from Describe cache
materialize();
return new LinkSet(this, property, true/* linksIn */);
}
/** All ?y where (self,?,?y). */
@Override
public Set getLinksOut() {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
materialize();
final HashSet ret = new HashSet();
GPOEntry entry = m_headEntry;
while (entry != null) {
final Iterator values = entry.values();
while (values.hasNext()) {
final Value value = values.next();
if (value instanceof Resource) {
ret.add(m_om.getGPO((Resource) value));
}
}
entry = entry.m_next;
}
return ret;
// } finally {
// readLock.unlock();
// }
}
/** All ?y where (self,p,?y). */
@Override
public ILinkSet getLinksOut(final URI property) {
materialize();
return new LinkSet(this, property, false/* linksOut */);
}
@Override
public Map getReverseLinkProperties() {
materialize();
final Map ret = new HashMap();
final String query = "SELECT ?p (COUNT(?o) AS ?count)\n"
+ "WHERE { ?o ?p <" + getId().toString() + "> }\n"
+ "GROUP BY ?p";
final ICloseableIterator res = m_om.evaluate(query);
while (res.hasNext()) {
final BindingSet bs = res.next();
final URI pred = (URI) bs.getBinding("p").getValue();
final Long count = ((Literal) bs.getBinding("count")
.getValue()).longValue();
ret.put(pred, count);
}
return ret;
}
@Override
public Set getStatements() {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
materialize();
final HashSet out = new HashSet();
GPOEntry entry = m_headEntry;
while (entry != null) {
Iterator values = entry.values();
while (values.hasNext())
out.add(makeStatement(m_id, entry.m_key, values.next()));
entry = entry.m_next;
}
return out;
// } finally {
// readLock.unlock();
// }
}
private Statement makeStatement(final Resource id, final URI key,
final Value value) {
return m_om.getValueFactory().createStatement(id, key, value);
}
@Override
public Value getValue(final URI property) {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
materialize();
final GPOEntry entry = getEntry(property);
return entry != null ? entry.getValue() : null;
// } finally {
// readLock.unlock();
// }
}
@Override
public Set getValues(URI property) {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
materialize();
HashSet values = new HashSet();
final GPOEntry entry = getEntry(property);
if (entry != null) {
Iterator vals = entry.values();
while (vals.hasNext()) {
values.add(vals.next());
}
}
return values;
// } finally {
// readLock.unlock();
// }
}
@Override
public boolean isBound(URI property) {
materialize();
return getValue(property) != null;
}
@Override
public boolean isMemberOf(ILinkSet linkSet) {
return linkSet.contains(this);
}
/**
* FIXME This should run a query (unless it is fully materialized, including
* the reverse links and forward links) and build an edit list for the
* retracts. [There could be a separate operation to remove only those
* properties associated with a skin.]
*/
@Override
public void remove() {
materialize();
m_removed = true;
// remove all properties
GPOEntry entry = m_headEntry;
while (entry != null) {
clearReverseLinkSetEntries(entry);
entry.removeAll(this);
entry = entry.m_next;
}
// remove all linksest
entry = m_headLinkEntry;
while (entry != null) {
entry.removeAll(this);
entry = entry.m_next;
}
dirty();
}
public void initValue(final URI predicate, final Value object) {
if (predicate == null)
throw new IllegalArgumentException();
if (object == null)
throw new IllegalArgumentException();
assert !m_materialized;
final GPOEntry entry = establishEntry(predicate);
entry.initValue(this, object);
}
public void initLinkValue(final URI predicate, final Resource object) {
if (predicate == null)
throw new IllegalArgumentException();
if (object == null)
throw new IllegalArgumentException();
assert !m_materialized;
final GPOEntry entry = establishLinkEntry(predicate);
entry.initValue(this, object);
}
@Override
public void setValue(final URI property, final Value newValue) {
if (property == null)
throw new IllegalArgumentException();
if (newValue == null)
throw new IllegalArgumentException();
// final Lock writeLock = m_lock.writeLock();
// writeLock.lock();
// try {
materialize();
// calls reverse removeLinkSetMembers
removeValues(property);
final GPOEntry entry = establishEntry(property);
entry.set(this, newValue);
if (newValue instanceof Resource) {
// add to LinkSet of target
((GPO) m_om.getGPO((Resource) newValue)).addLinkSetMember(property, m_id);
}
dirty();
// } finally {
// writeLock.unlock();
// }
}
/**
* {@inheritDoc}
*
* FIXME This should be conditional, returning null if the link does not
* exist. However, that conditional test needs to be efficient.
*/
@Override
public IGPO getLink(final URI property, final IGPO target) {
// if (getValue(property) != target.getId()) {
//
// // Link does not exist.
// return null;
//
// }
final GPOEntry entry = getEntry(property);
if (entry != null && entry.contains(target.getId())) {
return m_om.getGPO(new StatementImpl(m_id, property, target.getId()));
}
return null;
}
// @Override
// public void addLink(final URI property, final IGPO target) {
//
// addValue(property, target.getId());
//
// }
@Override
public void addValue(final URI property, final Value value) {
if (property == null)
throw new IllegalArgumentException();
if (value == null)
throw new IllegalArgumentException();
// final Lock writeLock = m_lock.writeLock();
// writeLock.lock();
// try {
materialize();
final GPOEntry entry = establishEntry(property);
if (entry.add(this, value)) {
dirty();
}
// } finally {
// writeLock.unlock();
// }
}
/**
* The under the hood method to remove a link set member called from set/removeValue to
* ensure referential integrity for the GPO references.
*
* @param property
* @param resource
*/
private void removeLinkSetMember(final URI property, final Resource resource) {
materialize();
final GPOEntry entry = establishLinkEntry(property);
entry.remove(this, resource);
}
/**
* The under the hood method to add a link set member called from setValue to
* ensure referential integrity for the GPO references.
*
* @param property
* @param resource
*/
private void addLinkSetMember(final URI property, final Resource resource) {
materialize();
final GPOEntry entry = establishLinkEntry(property);
entry.add(this, resource);
}
@Override
public void removeValue(final URI property, final Value value) {
if (property == null)
throw new IllegalArgumentException();
if (value == null)
throw new IllegalArgumentException();
// final Lock writeLock = m_lock.writeLock();
// writeLock.lock();
// try {
materialize();
final GPOEntry entry = establishEntry(property);
if (entry.remove(this, value)) {
if (value instanceof Resource) {
((GPO) m_om.getGPO((Resource) value)).removeLinkSetMember(property, m_id);
}
dirty();
}
// } finally {
// writeLock.unlock();
// }
}
@Override
public void removeValues(final URI property) {
if (property == null)
throw new IllegalArgumentException();
// final Lock writeLock = m_lock.writeLock();
// writeLock.lock();
// try {
materialize();
final GPOEntry entry = establishEntry(property);
if (entry.m_size != 0) {
clearReverseLinkSetEntries(entry);
entry.removeAll(this);
dirty();
}
// } finally {
// writeLock.unlock();
// }
}
private void clearReverseLinkSetEntries(final GPOEntry entry) {
Iterator values = entry.values();
while (values.hasNext()) {
Value value = values.next();
if (value instanceof Resource) {
((GPO) m_om.getGPO((Resource) value)).removeLinkSetMember(entry.m_key, m_id);
}
}
}
/**
* If this {@link GPO} was clean, then mark the {@link GPO} as dirty and add
* it to the object manager's dirty list. This is a NOP if the {@link GPO}
* is already marked as dirty.
*/
private void dirty() {
if (m_clean) {
m_clean = false;
((ObjectMgrModel) m_om).addToDirtyList(this);
}
}
public boolean isDirty() {
return !m_clean;
}
@Override
public IGPO asGeneric() {
return this;
}
@Override
public String pp() {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
// materialize();
final StringBuilder out = new StringBuilder("ID: "
+ m_id.stringValue() + "\n");
GPOEntry entry = m_headEntry;
while (entry != null) {
Iterator values = entry.values();
while (values.hasNext())
out.append(entry.m_key.toString() + ": "
+ values.next().toString() + "\n");
entry = entry.m_next;
}
return out.toString();
// } finally {
// readLock.unlock();
// }
}
@Override
public IGPO getType() {
materialize();
final URI tid = (URI) getValue(new URIImpl("attr:/type"));
if (tid != null) {
return m_om.getGPO(tid);
} else {
return null;
}
}
/**
* Called by the ObjectManager when flushing dirty objects. This can occur
* incrementally or on ObjectManager commit. The object is marked as clean
* once written.
*/
public void doCommit() {
assert m_materialized;
GPOEntry entry = m_headEntry;
while (entry != null) {
entry.commit();
entry = entry.m_next;
}
m_clean = true;
}
// private void update(final GPOEntry entry) {
//
// assert m_materialized;
//
// // final Iterator removes = entry.removes();
// // while (removes.hasNext()) {
// // m_om.retract(m_id, entry.m_key, removes.next());
// // }
// //
// // final Iterator inserts = entry.additions();
// // while (inserts.hasNext()) {
// // m_om.insert(m_id, entry.m_key, inserts.next());
// // }
//
// entry.commit();
// }
/**
* Basis for lazy materialization, checks materialize state and if false
* requests matierialization from the ObjectManager
*/
public IGPO materialize() {
checkLive();
if (!m_materialized) {
synchronized (this) {
if (!m_materialized && m_stmt == null) {
m_om.materialize(this);
m_materialized = true;
}
}
}
return this;
}
public void setMaterialized(boolean b) {
m_materialized = true;
}
// public void prepareBatchTerms() {
// final ObjectMgrModel oom = (ObjectMgrModel) m_om;
// GPOEntry entry = m_headEntry;
// while (entry != null) {
// final Iterator inserts = entry.additions();
// while (inserts.hasNext()) {
// final Value v = inserts.next();
// oom.checkValue(v);
// }
//
// entry = entry.m_next;
// }
// }
/**
* Adds statements to be inserted and removed to the appropriate lists based
* on the {@link GPO}s internal edit set.
*
* @param insertList
* The list of statements to be added.
* @param removeList
* The list of statements to be removed.
*/
public void prepareBatchUpdate(final List insertList,
final List removeList) {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
final ObjectMgrModel oom = (ObjectMgrModel) m_om;
final ValueFactory f = oom.getValueFactory();
GPOEntry entry = m_headEntry;
while (entry != null) {
final Iterator inserts = entry.additions();
while (inserts.hasNext()) {
final Value v = inserts.next();
final Statement stmt = f.createStatement(m_id, entry.m_key,
v);
insertList.add(stmt);
}
final Iterator removes = entry.removes();
while (removes.hasNext()) {
final Value v = removes.next();
final Statement stmt = f.createStatement(m_id, entry.m_key,
v);
removeList.add(stmt);
}
entry = entry.m_next;
}
// } finally {
// readLock.unlock();
// }
}
/**
* The getSkin method is inspired somewhat by the Microsoft Win32
* getInterface that allowed an object to return multiple interfaces. The
* difference with the GPO skin is that the skin should be able to interact
* with any underlying GPO object.
*
*
* It may be worthwhile performance wise to cache a skin. I believe of more
* importance is to preserve identity - even of the interface/skin object.
*
* @param skin
* interface required
* @return a skin if available
*/
public IGenericSkin getSkin(final Class intf) {
IGenericSkin ret = null;
if (m_skins != null) {
for (int i = 0; i < m_skins.size(); i++) {
if (intf.isInstance(m_skins.get(i))) {
return m_skins.get(i);
}
}
} else {
m_skins = new ArrayList(2);
}
ret = GenericSkinRegistry.asClass(this, intf);
m_skins.add(ret);
return ret;
}
public Iterator getPropertyURIs() {
// final Lock readLock = m_lock.readLock();
// readLock.lock();
// try {
materialize();
if (m_headEntry == null) {
return new EmptyIterator();
}
ArrayList properties = new ArrayList();
GPOEntry entry = m_headEntry;
while (entry != null) {
properties.add(entry.m_key);
entry = entry.m_next;
}
return properties.iterator();
// } finally {
// readLock.unlock();
// }
}
}
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