Example usage for java.util.concurrent.locks ReadWriteLock readLock

List of usage examples for java.util.concurrent.locks ReadWriteLock readLock

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Introduction

In this page you can find the example usage for java.util.concurrent.locks ReadWriteLock readLock.

Prototype

Lock readLock();

Source Link

Document

Returns the lock used for reading.

Usage

From source file:Main.java

public static void main(String[] args) {
    System.out.println("read to write test");
    ReadWriteLock lock = new ReentrantReadWriteLock();

    lock.readLock().lock(); // get our own read lock
    lock.writeLock().lock(); // upgrade to write lock
    System.out.println("passed");
}

From source file:org.apache.directory.fortress.core.impl.UsoUtil.java

/**
 *
 * @return handle to simple digraph containing user ou hierarchies.
 *///  w  ww.  j av a  2  s.c o m
private static SimpleDirectedGraph<String, Relationship> getGraph(String contextId) {
    ReadWriteLock hierLock = HierUtil.getLock(contextId, HierUtil.Type.USO);
    String key = getKey(contextId);

    try {
        hierLock.readLock().lock();
        SimpleDirectedGraph<String, Relationship> graph = (SimpleDirectedGraph<String, Relationship>) usoCache
                .get(key);

        if (graph == null) {
            try {
                hierLock.readLock().unlock();
                hierLock.writeLock().lock();

                // TODO: determine why this (code that was commented out) creates a deadlock:
                //graph = ( SimpleDirectedGraph<String, Relationship> ) usoCache.get( key );

                //if ( graph == null )
                //{
                graph = loadGraph(contextId);
                //}
                hierLock.readLock().lock();
            } finally {
                hierLock.writeLock().unlock();
            }
        }

        return graph;
    } finally {
        hierLock.readLock().unlock();
    }
}

From source file:org.apache.directory.fortress.core.impl.PsoUtil.java

/**
 * @param contextId maps to sub-tree in DIT, for example ou=contextId, dc=jts, dc = com.
 * @return handle to simple digraph containing perm ou hierarchies.
 *//*from ww  w . java  2 s  .  co m*/
private static SimpleDirectedGraph<String, Relationship> getGraph(String contextId) {
    ReadWriteLock hierLock = HierUtil.getLock(contextId, HierUtil.Type.PSO);
    String key = getKey(contextId);

    try {
        hierLock.readLock().lock();
        SimpleDirectedGraph<String, Relationship> graph = (SimpleDirectedGraph<String, Relationship>) psoCache
                .get(key);

        if (graph == null) {
            try {
                hierLock.readLock().unlock();
                hierLock.writeLock().lock();

                // TODO: determine why this (code that was commented out) creates a deadlock:
                //graph = ( SimpleDirectedGraph<String, Relationship> ) psoCache.get( key );

                //if ( graph == null )
                //{
                graph = loadGraph(contextId);
                //}

                hierLock.readLock().lock();
            } finally {
                hierLock.writeLock().unlock();
            }
        }

        return graph;
    } finally {
        hierLock.readLock().unlock();
    }
}

From source file:org.apache.directory.fortress.core.impl.AdminRoleUtil.java

/**
 * Read this ldap record,{@code cn=Hierarchies, ou=OS-P} into this entity, {@link Hier}, before loading into this collection class,{@code org.jgrapht.graph.SimpleDirectedGraph}
 * using 3rd party lib, <a href="http://www.jgrapht.org/">JGraphT</a>.
 *
 * @param contextId maps to sub-tree in DIT, for example ou=contextId, dc=jts, dc = com.
 * @return handle to simple digraph containing adminRole hierarchies.
 *//*from w  w w.  ja v  a2 s .co m*/
private static SimpleDirectedGraph<String, Relationship> getGraph(String contextId) {
    ReadWriteLock hierLock = HierUtil.getLock(contextId, HierUtil.Type.ARLE);
    String key = getKey(contextId);

    try {
        hierLock.readLock().lock();
        SimpleDirectedGraph<String, Relationship> graph = (SimpleDirectedGraph<String, Relationship>) adminRoleCache
                .get(key);

        if (graph == null) {
            try {
                hierLock.readLock().unlock();
                hierLock.writeLock().lock();

                // TODO: determine why this (code that was commented out) creates a deadlock:
                //graph = ( SimpleDirectedGraph<String, Relationship> ) adminRoleCache.get( key );

                //if ( graph == null )
                //{
                graph = loadGraph(contextId);
                //}

                hierLock.readLock().lock();
            } finally {
                hierLock.writeLock().unlock();
            }
        }

        return graph;
    } finally {
        hierLock.readLock().unlock();
    }
}

From source file:org.apache.directory.fortress.core.impl.RoleUtil.java

/**
 *
 * @param contextId maps to sub-tree in DIT, for example ou=contextId, dc=jts, dc = com.
 * @return handle to simple digraph containing role hierarchies.
 *//* ww  w. jav a  2s  .  c  o  m*/
private static SimpleDirectedGraph<String, Relationship> getGraph(String contextId) {
    ReadWriteLock hierLock = HierUtil.getLock(contextId, HierUtil.Type.ROLE);
    String key = getKey(contextId);

    try {
        hierLock.readLock().lock();
        SimpleDirectedGraph<String, Relationship> graph = (SimpleDirectedGraph<String, Relationship>) roleCache
                .get(key);

        if (graph == null) {
            try {
                hierLock.readLock().unlock();
                hierLock.writeLock().lock();

                // TODO: determine why this (code that was commented out) creates a deadlock:
                //graph = ( SimpleDirectedGraph<String, Relationship> ) roleCache.get( key );

                //if ( graph == null )
                //{
                graph = loadGraph(contextId);
                //}

                hierLock.readLock().lock();
            } finally {
                hierLock.writeLock().unlock();
            }
        }

        return graph;
    } finally {
        hierLock.readLock().unlock();
    }
}

From source file:org.jactr.io.resolver.ASTResolver.java

/**
 * create a version of the model.with the option to generate just the model
 * header (fullResoltuion), or to filter out content when generating a full
 * dump/*  ww  w .  ja v  a 2 s  .  c o  m*/
 * 
 * @param model
 * @param fullResolution
 *          if false, just the model & parameters is generated. filters are
 *          ignored.
 * @param productionFilter
 * @param chunkTypeFilter
 * @param chunkFilter
 * @return
 */
static public CommonTree toAST(IModel model, boolean fullResolution, Predicate<IProduction> productionFilter,
        Predicate<IChunkType> chunkTypeFilter, Predicate<IChunk> chunkFilter) {
    if (productionFilter == null)
        productionFilter = p -> true;
    if (chunkTypeFilter == null)
        chunkTypeFilter = c -> true;
    if (chunkFilter == null)
        chunkFilter = c -> true;

    /**
     * lock so that we are the only one right now
     */
    ReadWriteLock lock = model.getLock();

    lock.readLock().lock();
    try {
        CommonTree md = _support.createModelTree(model.getName());

        // insert all the parameters
        setParameters(ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.PARAMETERS), model);

        if (fullResolution) {
            CommonTree modules = ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.MODULES);
            for (IModule module : model.getModules()) {
                CommonTree modDesc = toAST(module);
                modules.addChild(modDesc);
            }

            // if full we add extensions, buffers, chunks, chunktype, and
            // productions
            CommonTree extensions = ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.EXTENSIONS);

            for (IExtension extension : model.getExtensions()) {
                if (LOGGER.isDebugEnabled())
                    LOGGER.debug("Generating AST for extension " + extension.getClass().getName());

                CommonTree ed = toAST(extension);

                if (LOGGER.isDebugEnabled())
                    LOGGER.debug("Returned ast " + ed.toStringTree());

                extensions.addChild(ed);
            }
            // chunktypes will add the chunks for us
            CommonTree decWrapper = ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.DECLARATIVE_MEMORY);
            Set<IChunkType> resolved = new HashSet<IChunkType>();
            List<CommonTree> chunkTypes = new ArrayList<CommonTree>();
            try {
                for (IChunkType ct : model.getDeclarativeModule().getChunkTypes().get())
                    if (chunkTypeFilter.test(ct)) {
                        List<CommonTree> chunkTypesList = toOrderedAST(ct, resolved, chunkTypeFilter,
                                chunkFilter);
                        chunkTypes.addAll(chunkTypesList);
                    }
            } catch (InterruptedException ie) {
                LOGGER.error("Interrupted ", ie);
            } catch (ExecutionException e) {
                LOGGER.error("Execution ", e);
            }

            // now we can dump them
            for (CommonTree ctNode : chunkTypes)
                decWrapper.addChild(ctNode);

            chunkTypes.clear();

            // productions
            CommonTree proWrapper = ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.PROCEDURAL_MEMORY);
            try {
                for (IProduction p : model.getProceduralModule().getProductions().get()) {
                    if (LOGGER.isDebugEnabled())
                        LOGGER.debug("generating AST for production " + p);
                    CommonTree pd = toAST(p);
                    if (LOGGER.isDebugEnabled())
                        LOGGER.debug("returned ast " + pd.toStringTree());
                    proWrapper.addChild(pd);
                }
            } catch (InterruptedException ie) {
                LOGGER.error("Interrupted ", ie);
            } catch (ExecutionException e) {
                LOGGER.error("Execution ", e);
            }

            // buffers
            CommonTree buffersWrapper = ASTSupport.getFirstDescendantWithType(md, JACTRBuilder.BUFFERS);
            Map<String, CommonTree> chunkTypeNodes = ASTSupport.getMapOfTrees(decWrapper,
                    JACTRBuilder.CHUNK_TYPE);
            for (IActivationBuffer buffer : model.getActivationBuffers()) {
                buffersWrapper.addChild(toAST(buffer));
                /*
                 * since the chunks in the buffer aren't in the model, they won't be
                 * serialized correctly, so we grab them now and stick them under
                 * their respective chunktype
                 */
                for (IChunk source : buffer.getSourceChunks()) {
                    CommonTree sourceChunk = toAST(source, false);
                    CommonTree chunkType = chunkTypeNodes.get(source.getSymbolicChunk().getChunkType()
                            .getSymbolicChunkType().getName().toLowerCase());

                    if (chunkType != null)
                        ASTSupport.getFirstDescendantWithType(chunkType, JACTRBuilder.CHUNKS)
                                .addChild(sourceChunk);
                }
            }
        }
        return md;
    } finally {
        lock.readLock().unlock();
    }
}

From source file:com.cloudera.oryx.als.serving.ServerRecommender.java

private static float[] getFeatures(long longID, LongObjectMap<float[]> matrix, ReadWriteLock lock) {
    float[] features;
    Lock readLock = lock.readLock();
    readLock.lock();// w  w  w.j  a  v a  2  s  .  c o  m
    try {
        features = matrix.get(longID);
        if (features == null) {
            int numFeatures = countFeatures(matrix);
            if (numFeatures > 0) {
                features = new float[numFeatures];
                Lock writeLock = lock.writeLock();
                readLock.unlock();
                writeLock.lock();
                try {
                    matrix.put(longID, features);
                } finally {
                    readLock.lock();
                    writeLock.unlock();
                }
            }
        }
    } finally {
        readLock.unlock();
    }
    return features;
}

From source file:RWStripedHashSet.java

/**
 * Constructor//  w  ww  . java 2  s  .  c  o m
 * @param capacity Initial number of  buckets.
 */
public RWStripedHashSet(int capacity) {
    super(capacity);
    locks = new Lock[capacity];
    for (int j = 0; j < locks.length; j++) {
        locks[j] = new ReentrantLock();
    }
    ReadWriteLock rwLock = new ReentrantReadWriteLock();
    readLock = rwLock.readLock();
    writeLock = rwLock.writeLock();
}

From source file:org.alfresco.repo.content.replication.AggregatingContentStore.java

/**
 * Default constructor //  w w w.j a  v  a2  s  .  co  m
 */
public AggregatingContentStore() {
    ReadWriteLock storeLock = new ReentrantReadWriteLock();
    readLock = storeLock.readLock();
    writeLock = storeLock.writeLock();
}

From source file:org.sonar.core.dryrun.DryRunCache.java

public byte[] getDatabaseForDryRun(@Nullable Long projectId) {
    long notNullProjectId = projectId != null ? projectId.longValue() : 0L;
    ReadWriteLock rwl = getLock(notNullProjectId);
    try {//from ww w .j  ava 2  s  .c  o  m
        rwl.readLock().lock();
        if (!isCacheValid(projectId)) {
            // upgrade lock manually
            // must unlock first to obtain writelock
            rwl.readLock().unlock();
            rwl.writeLock().lock();
            // recheck
            if (!isCacheValid(projectId)) {
                generateNewDB(projectId);
            }
            // downgrade lock
            // reacquire read without giving up write lock
            rwl.readLock().lock();
            // unlock write, still hold read
            rwl.writeLock().unlock();
        }
        File dbFile = new File(getCacheLocation(projectId),
                lastTimestampPerProject.get(notNullProjectId) + DryRunDatabaseFactory.H2_FILE_SUFFIX);
        return fileToByte(dbFile);
    } finally {
        rwl.readLock().unlock();
    }
}