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/*******************************************************************************
 * Copyright (c) 2012, 2020 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.osgi.container;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
import org.eclipse.osgi.container.Module.Settings;
import org.eclipse.osgi.container.Module.State;
import org.eclipse.osgi.container.ModuleContainerAdaptor.ContainerEvent;
import org.eclipse.osgi.container.ModuleRevisionBuilder.GenericInfo;
import org.eclipse.osgi.container.namespaces.EquinoxModuleDataNamespace;
import org.eclipse.osgi.framework.util.ObjectPool;
import org.eclipse.osgi.internal.container.Capabilities;
import org.eclipse.osgi.internal.container.ComputeNodeOrder;
import org.eclipse.osgi.internal.framework.EquinoxConfiguration;
import org.osgi.framework.BundleException;
import org.osgi.framework.Constants;
import org.osgi.framework.Version;
import org.osgi.framework.namespace.PackageNamespace;
import org.osgi.framework.wiring.BundleRevision;
import org.osgi.resource.Namespace;
import org.osgi.resource.Requirement;
import org.osgi.resource.Wire;
import org.osgi.service.resolver.Resolver;

/**
 * A database for storing modules, their revisions and wiring states.  The
 * database is responsible for assigning ids and providing access to the
 * capabilities provided by the revisions currently installed as well as
 * the wiring states.
 * 

* Concurrent Semantics
* * Implementations must be thread safe. The database allows for concurrent * read operations and all read operations are protected by the * {@link #readLock() read} lock. All write operations are * protected by the {@link #writeLock() write} lock. The read and write * locks are reentrant and follow the semantics of the * {@link ReentrantReadWriteLock}. Just like the {@code ReentrantReadWriteLock} * the lock on a database can not be upgraded from a read to a write. Doing so will result in an * {@link IllegalMonitorStateException} being thrown. This is behavior is different from * the {@code ReentrantReadWriteLock} which results in a deadlock if an attempt is made * to upgrade from a read to a write lock. *

* A database is associated with a {@link ModuleContainer container}. The container * associated with a database provides public API for manipulating the modules * and their wiring states. For example, installing, updating, uninstalling, * resolving and unresolving modules. Except for the {@link #load(DataInputStream)}, * all other methods that perform write operations are intended to be used by * the associated container. * @since 3.10 */ public class ModuleDatabase { /** * The adaptor for this database */ final ModuleContainerAdaptor adaptor; /** * A map of modules by location. */ private final Map modulesByLocations; /** * A map of modules by id. */ private final Map modulesById; /** * A map of revision wiring objects. */ final Map wirings; /** * Holds the next id to be assigned to a module when it is installed */ final AtomicLong nextId; /** * Holds the current timestamp for revisions of this database. */ final AtomicLong revisionsTimeStamp; /** * Holds the current timestamp for all changes to this database. * This includes changes to revisions and changes to module settings. */ final AtomicLong allTimeStamp; /** * Holds the construction time which is used to check for empty database on * load. This is necessary to ensure the loaded database is consistent with * what was persisted. */ final long constructionTime; private final Capabilities capabilities; /** * A map of module settings keyed by module id. */ final Map> moduleSettings; /** * The initial module start level. */ private int initialModuleStartLevel = 1; /** * Monitors read and write access to this database */ private final ReentrantReadWriteLock monitor = new ReentrantReadWriteLock(false); static enum Sort { BY_DEPENDENCY, BY_START_LEVEL, BY_ID; /** * Tests if this option is contained in the specified options */ public boolean isContained(Sort... options) { for (Sort option : options) { if (equals(option)) { return true; } } return false; } } /** * Constructs a new empty database. * @param adaptor the module container adaptor */ public ModuleDatabase(ModuleContainerAdaptor adaptor) { this.adaptor = adaptor; this.modulesByLocations = new HashMap<>(); this.modulesById = new HashMap<>(); this.wirings = new HashMap<>(); // Start at id 1 because 0 is reserved for the system bundle this.nextId = new AtomicLong(1); // seed with current time to avoid duplicate timestamps after using -clean this.constructionTime = System.currentTimeMillis(); this.revisionsTimeStamp = new AtomicLong(constructionTime); this.allTimeStamp = new AtomicLong(constructionTime); this.moduleSettings = new HashMap<>(); this.capabilities = new Capabilities(); } /** * Returns the module at the given location or null if no module exists * at the given location. *

* A read operation protected by the {@link #readLock() read} lock. * @param location the location of the module. * @return the module at the given location or null. */ final Module getModule(String location) { readLock(); try { return modulesByLocations.get(location); } finally { readUnlock(); } } /** * Returns the module at the given id or null if no module exists * at the given location. *

* A read operation protected by the {@link #readLock() read} lock. * @param id the id of the module. * @return the module at the given id or null. */ final Module getModule(long id) { readLock(); try { return modulesById.get(id); } finally { readUnlock(); } } /** * Installs a new revision using the specified builder, location and module. *

* A write operation protected by the {@link #writeLock() write} lock. * @param location the location to use for the installation * @param builder the builder to use to create the new revision * @param revisionInfo the revision info for the new revision, may be {@code null}. * @return the installed module */ final Module install(String location, ModuleRevisionBuilder builder, Object revisionInfo) { writeLock(); try { int startlevel = Constants.SYSTEM_BUNDLE_LOCATION.equals(location) ? 0 : getInitialModuleStartLevel(); long id = Constants.SYSTEM_BUNDLE_LOCATION.equals(location) ? 0 : builder.getId(); if (id == -1) { // the id is not set by the builder; get and increment the next ID id = getAndIncrementNextId(); } if (getModule(id) != null) { throw new IllegalStateException("Duplicate module id: " + id + " used by module: " + getModule(id)); //$NON-NLS-1$//$NON-NLS-2$ } EnumSet settings = getActivationPolicySettings(builder); Module module = load(location, builder, revisionInfo, id, settings, startlevel); long currentTime = System.currentTimeMillis(); module.setlastModified(currentTime); setSystemLastModified(currentTime); incrementTimestamps(true); return module; } finally { writeUnlock(); } } private EnumSet getActivationPolicySettings(ModuleRevisionBuilder builder) { // do not do this for fragment bundles if ((builder.getTypes() & BundleRevision.TYPE_FRAGMENT) != 0) { return null; } for (GenericInfo info : builder.getCapabilities()) { if (EquinoxModuleDataNamespace.MODULE_DATA_NAMESPACE.equals(info.getNamespace())) { if (EquinoxModuleDataNamespace.CAPABILITY_ACTIVATION_POLICY_LAZY.equals(info.getAttributes().get(EquinoxModuleDataNamespace.CAPABILITY_ACTIVATION_POLICY))) { String compatibilityStartLazy = adaptor.getProperty(EquinoxConfiguration.PROP_COMPATIBILITY_START_LAZY); if (compatibilityStartLazy == null || Boolean.valueOf(compatibilityStartLazy)) { // TODO hack until p2 is fixed (bug 177641) EnumSet settings = EnumSet.noneOf(Settings.class); settings.add(Settings.USE_ACTIVATION_POLICY); settings.add(Settings.AUTO_START); return settings; } } return null; } } return null; } final Module load(String location, ModuleRevisionBuilder builder, Object revisionInfo, long id, EnumSet settings, int startlevel) { // sanity check checkWrite(); if (modulesByLocations.containsKey(location)) throw new IllegalArgumentException("Location is already used: " + location); //$NON-NLS-1$ if (modulesById.containsKey(id)) throw new IllegalArgumentException("Id is already used: " + id); //$NON-NLS-1$ Module module; if (id == 0) { module = adaptor.createSystemModule(); } else { module = adaptor.createModule(location, id, settings, startlevel); } builder.addRevision(module, revisionInfo); modulesByLocations.put(location, module); modulesById.put(id, module); if (settings != null) moduleSettings.put(id, settings); ModuleRevision newRevision = module.getCurrentRevision(); addCapabilities(newRevision); return module; } /** * Uninstalls the specified module from this database. * Uninstalling a module will attempt to clean up any removal pending * revisions possible. *

* A write operation protected by the {@link #writeLock() write} lock. * @param module the module to uninstall */ final void uninstall(Module module) { writeLock(); try { ModuleRevisions uninstalling = module.getRevisions(); // mark the revisions as uninstalled before removing the revisions uninstalling.uninstall(); // remove the location modulesByLocations.remove(module.getLocation()); modulesById.remove(module.getId()); moduleSettings.remove(module.getId()); // remove the revisions by name List revisions = uninstalling.getModuleRevisions(); for (ModuleRevision revision : revisions) { // if the revision does not have a wiring it can safely be removed // from the revisions for the module ModuleWiring oldWiring = wirings.get(revision); if (oldWiring == null) { module.getRevisions().removeRevision(revision); removeCapabilities(revision); } } // attempt to cleanup any removal pendings cleanupRemovalPending(); long currentTime = System.currentTimeMillis(); module.setlastModified(currentTime); setSystemLastModified(currentTime); incrementTimestamps(true); } finally { writeUnlock(); } } /** * Updates the specified module with anew revision using the specified builder. *

* A write operation protected by the {@link #writeLock() write} lock. * @param module the module for which the revision provides an update for * @param builder the builder to use to create the new revision * @param revisionInfo the revision info for the new revision, may be {@code null}. */ final void update(Module module, ModuleRevisionBuilder builder, Object revisionInfo) { writeLock(); try { ModuleRevision oldRevision = module.getCurrentRevision(); ModuleRevision newRevision = builder.addRevision(module, revisionInfo); addCapabilities(newRevision); // if the old revision does not have a wiring it can safely be removed ModuleWiring oldWiring = wirings.get(oldRevision); if (oldWiring == null) { module.getRevisions().removeRevision(oldRevision); removeCapabilities(oldRevision); } // attempt to clean up removal pendings cleanupRemovalPending(); long currentTime = System.currentTimeMillis(); module.setlastModified(currentTime); setSystemLastModified(currentTime); incrementTimestamps(true); } finally { writeUnlock(); } } /** * Examines the wirings to determine if there are any removal * pending wiring objects that can be removed. We consider * a removal pending wiring as removable if all dependent * wiring are also removal pending. */ void cleanupRemovalPending() { // sanity check checkWrite(); Collection removalPending = getRemovalPending(); for (ModuleRevision removed : removalPending) { if (wirings.get(removed) == null) continue; Collection dependencyClosure = ModuleContainer.getDependencyClosure(removed, wirings); boolean allPendingRemoval = true; for (ModuleRevision pendingRemoval : dependencyClosure) { if (pendingRemoval.isCurrent()) { allPendingRemoval = false; break; } } if (allPendingRemoval) { Collection toRemoveWirings = new ArrayList<>(); Map> toRemoveWireLists = new HashMap<>(); for (ModuleRevision pendingRemoval : dependencyClosure) { ModuleWiring removedWiring = wirings.get(pendingRemoval); if (removedWiring == null) { continue; } toRemoveWirings.add(removedWiring); List removedWires = removedWiring.getRequiredModuleWires(null); for (ModuleWire wire : removedWires) { Collection providerWires = toRemoveWireLists.get(wire.getProviderWiring()); if (providerWires == null) { providerWires = new ArrayList<>(); toRemoveWireLists.put(wire.getProviderWiring(), providerWires); } providerWires.add(wire); } } for (ModuleRevision pendingRemoval : dependencyClosure) { pendingRemoval.getRevisions().removeRevision(pendingRemoval); removeCapabilities(pendingRemoval); wirings.remove(pendingRemoval); } // remove any wires from unresolved wirings that got removed for (Map.Entry> entry : toRemoveWireLists.entrySet()) { List provided = entry.getKey().getProvidedModuleWires(null); // No null checks; we are holding the write lock here. provided.removeAll(entry.getValue()); entry.getKey().setProvidedWires(provided); for (ModuleWire removedWire : entry.getValue()) { // invalidate the wire removedWire.invalidate(); } } // invalidate any removed wiring objects for (ModuleWiring moduleWiring : toRemoveWirings) { moduleWiring.invalidate(); } } } } /** * Gets all revisions with a removal pending wiring. *

* A read operation protected by the {@link #readLock() read} lock. * @return all revisions with a removal pending wiring. */ final Collection getRemovalPending() { Collection removalPending = new ArrayList<>(); readLock(); try { for (ModuleWiring wiring : wirings.values()) { if (!wiring.isCurrent()) removalPending.add(wiring.getRevision()); } } finally { readUnlock(); } return removalPending; } /** * Returns the current wiring for the specified revision or * null of no wiring exists for the revision. *

* A read operation protected by the {@link #readLock() read} lock. * @param revision the revision to get the wiring for * @return the current wiring for the specified revision. */ final ModuleWiring getWiring(ModuleRevision revision) { readLock(); try { return wirings.get(revision); } finally { readUnlock(); } } /** * Returns a snapshot of the wirings for all revisions. This * performs a shallow copy of each entry in the wirings map. *

* A read operation protected by the {@link #readLock() read} lock. * @return a snapshot of the wirings for all revisions. */ final Map getWiringsCopy() { readLock(); try { return new HashMap<>(wirings); } finally { readUnlock(); } } /** * Returns a cloned snapshot of the wirings of all revisions. This * performs a clone of each {@link ModuleWiring}. The * {@link ModuleWiring#getRevision() revision}, * {@link ModuleWiring#getModuleCapabilities(String) capabilities}, * {@link ModuleWiring#getModuleRequirements(String) requirements}, * {@link ModuleWiring#getProvidedModuleWires(String) provided wires}, * {@link ModuleWiring#getRequiredModuleWires(String) required wires}, and * {@link ModuleWiring#getSubstitutedNames()} of * each wiring are copied into a cloned copy of the wiring. *

* The returned map of wirings may be safely read from while not holding * any read or write locks on this database. This is useful for doing * {@link Resolver#resolve(org.osgi.service.resolver.ResolveContext) resolve} * operations without holding the read or write lock on this database. *

* A read operation protected by the {@link #readLock() read} lock. * @return a cloned snapshot of the wirings of all revisions. */ final Map getWiringsClone() { readLock(); try { Map clonedWirings = new HashMap<>(); for (Map.Entry entry : wirings.entrySet()) { ModuleWiring wiring = new ModuleWiring(entry.getKey(), entry.getValue().getModuleCapabilities(null), entry.getValue().getModuleRequirements(null), entry.getValue().getProvidedModuleWires(null), entry.getValue().getRequiredModuleWires(null), entry.getValue().getSubstitutedNames()); clonedWirings.put(entry.getKey(), wiring); } return clonedWirings; } finally { readUnlock(); } } /** * Replaces the complete wiring map with the specified wiring *

* A write operation protected by the {@link #writeLock() write} lock. * @param newWiring the new wiring to take effect. The values * from the new wiring are copied. */ final void setWiring(Map newWiring) { writeLock(); try { wirings.clear(); wirings.putAll(newWiring); incrementTimestamps(true); } finally { writeUnlock(); } } /** * Adds all the values from the specified delta wirings to the * wirings current wirings *

* A write operation protected by the {@link #writeLock() write} lock. * @param deltaWiring the new wiring values to take effect. * The values from the delta wiring are copied. */ final void mergeWiring(Map deltaWiring) { writeLock(); try { wirings.putAll(deltaWiring); incrementTimestamps(true); } finally { writeUnlock(); } } /** * Returns a snapshot of all modules ordered by module ID. *

* A read operation protected by the {@link #readLock() read} lock. * @return a snapshot of all modules. */ final List getModules() { return getSortedModules(); } /** * Returns a snapshot of all modules ordered according to the sort options * @param sortOptions options for sorting * @return a snapshot of all modules ordered according to the sort options */ final List getSortedModules(Sort... sortOptions) { readLock(); try { List modules = new ArrayList<>(modulesByLocations.values()); sortModules(modules, sortOptions); return modules; } finally { readUnlock(); } } final void sortModules(List modules, Sort... sortOptions) { if (modules.size() < 2) return; if (sortOptions == null || Sort.BY_ID.isContained(sortOptions) || sortOptions.length == 0) { Collections.sort(modules, new Comparator() { @Override public int compare(Module m1, Module m2) { return m1.getId().compareTo(m2.getId()); } }); return; } // first sort by start-level if (Sort.BY_START_LEVEL.isContained(sortOptions)) { Collections.sort(modules); } if (Sort.BY_DEPENDENCY.isContained(sortOptions)) { if (Sort.BY_START_LEVEL.isContained(sortOptions)) { // sort each sublist that has modules of the same start level int currentSL = modules.get(0).getStartLevel(); int currentSLindex = 0; boolean lazy = false; for (int i = 0; i < modules.size(); i++) { Module module = modules.get(i); if (currentSL != module.getStartLevel()) { if (lazy) sortByDependencies(modules.subList(currentSLindex, i)); currentSL = module.getStartLevel(); currentSLindex = i; lazy = false; } lazy |= module.isLazyActivate(); } // sort the last set of bundles if (lazy) sortByDependencies(modules.subList(currentSLindex, modules.size())); } else { // sort the whole list by dependency sortByDependencies(modules); } } } private Collection> sortByDependencies(List toSort) { // Build references so we can sort List references = new ArrayList<>(toSort.size()); for (Module module : toSort) { ModuleRevision current = module.getCurrentRevision(); if (current == null) { continue; } ModuleWiring wiring = current.getWiring(); if (wiring == null) { continue; } // No null check; we are holding the database lock here. for (ModuleWire wire : wiring.getRequiredModuleWires(null)) { ModuleRequirement req = wire.getRequirement(); // Add all requirements that are not package requirements. // Only add package requirements that are not dynamic // TODO may want to consider only adding package, bundle and host requirements, other generic requirement are not that interesting if (!PackageNamespace.PACKAGE_NAMESPACE.equals(req.getNamespace()) || !PackageNamespace.RESOLUTION_DYNAMIC.equals(req.getDirectives().get(Namespace.REQUIREMENT_RESOLUTION_DIRECTIVE))) { references.add(new Module[] {wire.getRequirer().getRevisions().getModule(), wire.getProvider().getRevisions().getModule()}); } } } // Sort an array using the references Module[] sorted = toSort.toArray(new Module[toSort.size()]); Object[][] cycles = ComputeNodeOrder.computeNodeOrder(sorted, references.toArray(new Module[references.size()][])); // Apply the sorted array to the list toSort.clear(); toSort.addAll(Arrays.asList(sorted)); if (cycles.length == 0) return Collections.emptyList(); Collection> moduleCycles = new ArrayList<>(cycles.length); for (Object[] cycle : cycles) { List moduleCycle = new ArrayList<>(cycle.length); for (Object module : cycle) { moduleCycle.add((Module) module); } moduleCycles.add(moduleCycle); } return moduleCycles; } private void checkWrite() { if (monitor.getWriteHoldCount() == 0) throw new IllegalMonitorStateException("Must hold the write lock."); //$NON-NLS-1$ } /** * returns the next module ID. *

* A read operation protected by the {@link #readLock() read} lock. * @return the next module ID */ public final long getNextId() { readLock(); try { return nextId.get(); } finally { readUnlock(); } } /** * Atomically increments by one the next module ID. *

* A write operation protected by the {@link #writeLock()} lock. * @return the previous module ID * @since 3.13 */ public final long getAndIncrementNextId() { writeLock(); try { return nextId.getAndIncrement(); } finally { writeUnlock(); } } /** * Returns the current timestamp for the revisions of this database. * The timestamp is incremented any time a modification * is made to the revisions in this database. For example: *

    *
  • installing a module *
  • updating a module *
  • uninstalling a module *
  • modifying the wirings *
*

* A read operation protected by the {@link #readLock() read} lock. * @return the current timestamp of this database. */ final public long getRevisionsTimestamp() { readLock(); try { return revisionsTimeStamp.get(); } finally { readUnlock(); } } /** * Returns the current timestamp for this database. * The timestamp is incremented any time a modification * is made to this database. This includes the modifications * described in {@link #getRevisionsTimestamp() revisions timestamp} * and the following modifications related to modules: *

    *
  • modifying the initial module start level *
  • modifying a module start level *
  • modifying a module settings *
*

* A read operation protected by the {@link #readLock() read} lock. * @return the current timestamp of this database. */ final public long getTimestamp() { readLock(); try { return allTimeStamp.get(); } finally { readUnlock(); } } /** * Increments the timestamps of this database. * @param incrementRevision indicates if the revision timestamp should change */ private void incrementTimestamps(boolean incrementRevision) { // sanity check checkWrite(); if (incrementRevision) { revisionsTimeStamp.incrementAndGet(); } allTimeStamp.incrementAndGet(); adaptor.updatedDatabase(); } private void setSystemLastModified(long currentTime) { // sanity check checkWrite(); Module systemModule = getModule(0); if (systemModule != null) { systemModule.setlastModified(currentTime); } } /** * Acquires the read lock for this database. * @see ReadLock#lock() */ public final void readLock() { monitor.readLock().lock(); } /** * Acquires the write lock for this database. * Same as {@link WriteLock#lock()} except an illegal * state exception is thrown if the current thread holds * one or more read locks. * @see WriteLock#lock() * @throws IllegalMonitorStateException if the current thread holds * one or more read locks. */ public final void writeLock() { if (monitor.getReadHoldCount() > 0) { // this is not supported and will cause deadlock if allowed to proceed. // fail fast instead of deadlocking throw new IllegalMonitorStateException("Requesting upgrade to write lock."); //$NON-NLS-1$ } monitor.writeLock().lock(); } /** * Attempts to release the read lock for this database. * @see ReadLock#unlock() */ public final void readUnlock() { monitor.readLock().unlock(); } /** * Attempts to release the write lock for this database. * @see WriteLock#unlock() */ public final void writeUnlock() { monitor.writeLock().unlock(); } /** * Adds the {@link ModuleRevision#getModuleCapabilities(String) capabilities} * provided by the specified revision to this database. These capabilities must * become available for lookup with the {@link ModuleDatabase#findCapabilities(Requirement)} * method. *

* This method must be called while holding the {@link #writeLock() write} lock. * @param revision the revision which has capabilities to add */ final void addCapabilities(ModuleRevision revision) { checkWrite(); Collection packageNames = capabilities.addCapabilities(revision); // Clear the dynamic miss caches for all the package names added for (ModuleWiring wiring : wirings.values()) { wiring.removeDynamicPackageMisses(packageNames); } } /** * Removes the {@link ModuleRevision#getModuleCapabilities(String) capabilities} * provided by the specified revision from this database. These capabilities * must no longer be available for lookup with the * {@link ModuleDatabase#findCapabilities(Requirement)} method. *

* This method must be called while holding the {@link #writeLock() write} lock. * @param revision */ protected void removeCapabilities(ModuleRevision revision) { checkWrite(); capabilities.removeCapabilities(revision); } /** * Returns a mutable snapshot of capabilities that are candidates for * satisfying the specified requirement. *

* A read operation protected by the {@link #readLock() read} lock. * Implementers of this method should acquire the read lock while * finding capabilities. * @param requirement the requirement * @return the candidates for the requirement */ final List findCapabilities(Requirement requirement) { readLock(); try { return capabilities.findCapabilities(requirement); } finally { readUnlock(); } } /** * Writes this database in a format suitable for using the {@link #load(DataInputStream)} * method. All modules are stored which have a current {@link ModuleRevision revision}. * Only the current revision of each module is stored (no removal pending revisions * are stored). Optionally the {@link ModuleWiring wiring} of each current revision * may be stored. Wiring can only be stored if there are no {@link #getRemovalPending() * removal pending} revisions. *

* This method acquires the {@link #readLock() read} lock while writing this * database. *

* After this database have been written, the output stream is flushed. * The output stream remains open after this method returns. * @param out the data output steam. * @param persistWirings true if wirings should be persisted. This option will be ignored * if there are {@link #getRemovalPending() removal pending} revisions. * @throws IOException if writing this database to the specified output stream throws an IOException */ public final void store(DataOutputStream out, boolean persistWirings) throws IOException { readLock(); try { Persistence.store(this, out, persistWirings); } finally { readUnlock(); } } /** * Loads information into this database from the input data stream. This data * base must be empty and never been modified (the {@link #getRevisionsTimestamp() timestamp} is zero). * All stored modules are loaded into this database. If the input stream contains * wiring then it will also be loaded into this database. *

* Since this method modifies this database it is considered a write operation. * This method acquires the {@link #writeLock() write} lock while loading * the information into this database. *

* The specified stream remains open after this method returns. * @param in the data input stream. * @throws IOException if an error occurred when reading from the input stream. * @throws IllegalStateException if this database is not empty. */ public final void load(DataInputStream in) throws IOException { writeLock(); try { if (allTimeStamp.get() != constructionTime) throw new IllegalStateException("Can only load into a empty database."); //$NON-NLS-1$ Persistence.load(this, in); } finally { writeUnlock(); } } final void persistSettings(EnumSet settings, Module module) { writeLock(); try { EnumSet existing = moduleSettings.get(module.getId()); if (!settings.equals(existing)) { moduleSettings.put(module.getId(), EnumSet.copyOf(settings)); incrementTimestamps(false); } } finally { writeUnlock(); } } final void setStartLevel(Module module, int startlevel) { writeLock(); try { module.checkValid(); module.storeStartLevel(startlevel); incrementTimestamps(false); } finally { writeUnlock(); } } final int getInitialModuleStartLevel() { readLock(); try { return this.initialModuleStartLevel; } finally { readUnlock(); } } final void setInitialModuleStartLevel(int initialStartlevel) { writeLock(); try { this.initialModuleStartLevel = initialStartlevel; incrementTimestamps(false); } finally { writeUnlock(); } } private static class Persistence { private static final int VERSION = 3; private static final byte NULL = 0; private static final byte OBJECT = 1; private static final byte INDEX = 2; private static final byte LONG_STRING = 3; private static final byte VALUE_STRING = 0; // REMOVED treated as List - private static final byte VALUE_STRING_ARRAY = 1; // REMOVED never was really supported by the OSGi builder - private static final byte VAlUE_BOOLEAN = 2; // REMOVED never was really supported by the OSGi builder - private static final byte VALUE_INTEGER = 3; private static final byte VALUE_LONG = 4; private static final byte VALUE_DOUBLE = 5; private static final byte VALUE_VERSION = 6; // REMOVED treated as type String - private static final byte VALUE_URI = 7; private static final byte VALUE_LIST = 8; private static int addToWriteTable(Object object, Map objectTable) { if (object == null) throw new NullPointerException(); Integer cur = objectTable.get(object); if (cur != null) throw new IllegalStateException("Object is already in the write table: " + object); //$NON-NLS-1$ objectTable.put(object, Integer.valueOf(objectTable.size())); // return the index of the object just added (i.e. size - 1) return (objectTable.size() - 1); } private static void addToReadTable(Object object, int index, List objectTable) { if (index == objectTable.size()) { objectTable.add(object); } else if (index < objectTable.size()) { objectTable.set(index, object); } else { while (objectTable.size() < index) { objectTable.add(null); } objectTable.add(object); } } public static void store(ModuleDatabase moduleDatabase, DataOutputStream out, boolean persistWirings) throws IOException { out.writeInt(VERSION); out.writeLong(moduleDatabase.getRevisionsTimestamp()); out.writeLong(moduleDatabase.getTimestamp()); out.writeLong(moduleDatabase.getNextId()); out.writeInt(moduleDatabase.getInitialModuleStartLevel()); // prime the object table with all the strings, versions and maps Set allStrings = new HashSet<>(); Set allVersions = new HashSet<>(); Set> allMaps = new HashSet<>(); // first gather all the strings, versions and maps from the modules List modules = moduleDatabase.getModules(); for (Module module : modules) { getStringsVersionsAndMaps(module, moduleDatabase, allStrings, allVersions, allMaps); } // outside of the modules the wirings have 'substituted' packages strings Map wirings = moduleDatabase.wirings; for (ModuleWiring wiring : wirings.values()) { Collection substituted = wiring.getSubstitutedNames(); allStrings.addAll(substituted); } // Now persist all the Strings Map objectTable = new HashMap<>(); allStrings.remove(null); out.writeInt(allStrings.size()); for (String string : allStrings) { writeString(string, out, objectTable); out.writeInt(addToWriteTable(string, objectTable)); } // Followed by versions which may reference strings with their qualifier out.writeInt(allVersions.size()); for (Version version : allVersions) { writeVersion(version, out, objectTable); out.writeInt(addToWriteTable(version, objectTable)); } // Followed by maps which may reference the strings and versions out.writeInt(allMaps.size()); for (Map map : allMaps) { writeMap(map, out, objectTable, moduleDatabase); out.writeInt(addToWriteTable(map, objectTable)); } // Followed by modules which reference the strings, versions, and maps out.writeInt(modules.size()); for (Module module : modules) { writeModule(module, moduleDatabase, out, objectTable); } Collection removalPendings = moduleDatabase.getRemovalPending(); // only persist wirings if there are no removals pending persistWirings &= removalPendings.isEmpty(); out.writeBoolean(persistWirings); if (!persistWirings) { return; } // prime the object table with all the required wires which reference the modules out.writeInt(wirings.size()); for (ModuleWiring wiring : wirings.values()) { List requiredWires = wiring.getPersistentRequiredWires(); out.writeInt(requiredWires.size()); for (ModuleWire wire : requiredWires) { writeWire(wire, out, objectTable); } } // now write all the info about each wiring using only indexes from the objectTable for (ModuleWiring wiring : wirings.values()) { writeWiring(wiring, out, objectTable); } out.flush(); } private static void getStringsVersionsAndMaps(Module module, ModuleDatabase moduleDatabase, Set allStrings, Set allVersions, Set> allMaps) { ModuleRevision current = module.getCurrentRevision(); if (current == null) return; allStrings.add(module.getLocation()); allStrings.add(current.getSymbolicName()); allStrings.add(current.getVersion().getQualifier()); allVersions.add(current.getVersion()); EnumSet settings = moduleDatabase.moduleSettings.get(module.getId()); if (settings != null) { for (Settings setting : settings) { allStrings.add(setting.toString()); } } List capabilities = current.getModuleCapabilities(null); for (ModuleCapability capability : capabilities) { allStrings.add(capability.getNamespace()); addMap(capability.getPersistentAttributes(), allStrings, allVersions, allMaps); addMap(capability.getDirectives(), allStrings, allVersions, allMaps); } List requirements = current.getModuleRequirements(null); for (ModuleRequirement requirement : requirements) { allStrings.add(requirement.getNamespace()); addMap(requirement.getAttributes(), allStrings, allVersions, allMaps); addMap(requirement.getDirectives(), allStrings, allVersions, allMaps); } } private static void addMap(Map map, Set allStrings, Set allVersions, Set> allMaps) { if (!allMaps.add(map)) { // map was already added return; } for (Map.Entry entry : map.entrySet()) { allStrings.add(entry.getKey()); Object value = entry.getValue(); if (value instanceof String) { allStrings.add((String) value); } else if (value instanceof Version) { allStrings.add(((Version) value).getQualifier()); allVersions.add((Version) value); } else if (value instanceof List) { switch (getListType((List) value)) { case VALUE_STRING : for (Object string : (List) value) { allStrings.add((String) string); } break; case VALUE_VERSION : for (Object version : (List) value) { allStrings.add(((Version) version).getQualifier()); allVersions.add((Version) version); } break; } } } } public static void load(ModuleDatabase moduleDatabase, DataInputStream in) throws IOException { int version = in.readInt(); if (version > VERSION || VERSION / 1000 != version / 1000) throw new IllegalArgumentException("The version of the persistent framework data is not compatible: " + version + " expecting: " + VERSION); //$NON-NLS-1$ //$NON-NLS-2$ long revisionsTimeStamp = in.readLong(); long allTimeStamp = in.readLong(); moduleDatabase.nextId.set(in.readLong()); moduleDatabase.setInitialModuleStartLevel(in.readInt()); List objectTable = new ArrayList<>(); if (version >= 2) { int numStrings = in.readInt(); for (int i = 0; i < numStrings; i++) { readIndexedString(in, objectTable); } int numVersions = in.readInt(); for (int i = 0; i < numVersions; i++) { readIndexedVersion(in, objectTable); } int numMaps = in.readInt(); for (int i = 0; i < numMaps; i++) { readIndexedMap(in, objectTable); } } int numModules = in.readInt(); ModuleRevisionBuilder builder = new ModuleRevisionBuilder(); for (int i = 0; i < numModules; i++) { readModule(builder, moduleDatabase, in, objectTable, version); } moduleDatabase.revisionsTimeStamp.set(revisionsTimeStamp); moduleDatabase.allTimeStamp.set(allTimeStamp); if (!in.readBoolean()) return; // no wires persisted int numWirings = in.readInt(); // prime the table with all the required wires for (int i = 0; i < numWirings; i++) { int numWires = in.readInt(); for (int j = 0; j < numWires; j++) { readWire(in, objectTable); } } // now read all the info about each wiring using only indexes Map wirings = new HashMap<>(); for (int i = 0; i < numWirings; i++) { ModuleWiring wiring = readWiring(in, objectTable); wirings.put(wiring.getRevision(), wiring); } // TODO need to do this without incrementing the timestamp moduleDatabase.setWiring(wirings); // need to set the resolution state of the modules for (ModuleWiring wiring : wirings.values()) { wiring.getRevision().getRevisions().getModule().setState(State.RESOLVED); } // Setting the timestamp at the end since some operations increment it moduleDatabase.revisionsTimeStamp.set(revisionsTimeStamp); moduleDatabase.allTimeStamp.set(allTimeStamp); } private static void writeModule(Module module, ModuleDatabase moduleDatabase, DataOutputStream out, Map objectTable) throws IOException { ModuleRevision current = module.getCurrentRevision(); if (current == null) return; out.writeInt(addToWriteTable(current, objectTable)); writeString(module.getLocation(), out, objectTable); out.writeLong(module.getId()); writeString(current.getSymbolicName(), out, objectTable); writeVersion(current.getVersion(), out, objectTable); out.writeInt(current.getTypes()); List capabilities = current.getModuleCapabilities(null); out.writeInt(capabilities.size()); for (ModuleCapability capability : capabilities) { out.writeInt(addToWriteTable(capability, objectTable)); writeGenericInfo(capability.getNamespace(), capability.getPersistentAttributes(), capability.getDirectives(), out, objectTable); } List requirements = current.getRequirements(null); out.writeInt(requirements.size()); for (Requirement requirement : requirements) { out.writeInt(addToWriteTable(requirement, objectTable)); writeGenericInfo(requirement.getNamespace(), requirement.getAttributes(), requirement.getDirectives(), out, objectTable); } // settings EnumSet settings = moduleDatabase.moduleSettings.get(module.getId()); out.writeInt(settings == null ? 0 : settings.size()); if (settings != null) { for (Settings setting : settings) { writeString(setting.name(), out, objectTable); } } // startlevel out.writeInt(module.getStartLevel()); // last modified out.writeLong(module.getLastModified()); } private static void readModule(ModuleRevisionBuilder builder, ModuleDatabase moduleDatabase, DataInputStream in, List objectTable, int version) throws IOException { builder.clear(); int moduleIndex = in.readInt(); String location = readString(in, objectTable); long id = in.readLong(); builder.setSymbolicName(readString(in, objectTable)); builder.setVersion(readVersion(in, objectTable)); builder.setTypes(in.readInt()); int numCapabilities = in.readInt(); int[] capabilityIndexes = new int[numCapabilities]; for (int i = 0; i < numCapabilities; i++) { capabilityIndexes[i] = in.readInt(); readGenericInfo(true, in, builder, objectTable, version); } int numRequirements = in.readInt(); int[] requirementIndexes = new int[numRequirements]; for (int i = 0; i < numRequirements; i++) { requirementIndexes[i] = in.readInt(); readGenericInfo(false, in, builder, objectTable, version); } // settings EnumSet settings = null; int numSettings = in.readInt(); if (numSettings > 0) { settings = EnumSet.noneOf(Settings.class); for (int i = 0; i < numSettings; i++) { settings.add(Settings.valueOf(readString(in, objectTable))); } } // startlevel int startlevel = in.readInt(); Object revisionInfo = moduleDatabase.adaptor.getRevisionInfo(location, id); Module module = moduleDatabase.load(location, builder, revisionInfo, id, settings, startlevel); // last modified module.setlastModified(in.readLong()); ModuleRevision current = module.getCurrentRevision(); addToReadTable(current, moduleIndex, objectTable); List capabilities = current.getModuleCapabilities(null); for (int i = 0; i < capabilities.size(); i++) { addToReadTable(capabilities.get(i), capabilityIndexes[i], objectTable); } List requirements = current.getModuleRequirements(null); for (int i = 0; i < requirements.size(); i++) { addToReadTable(requirements.get(i), requirementIndexes[i], objectTable); } } private static void writeWire(ModuleWire wire, DataOutputStream out, Map objectTable) throws IOException { Wire w = wire; Integer capability = objectTable.get(w.getCapability()); Integer provider = objectTable.get(w.getProvider()); Integer requirement = objectTable.get(w.getRequirement()); Integer requirer = objectTable.get(w.getRequirer()); if (capability == null || provider == null || requirement == null || requirer == null) throw new NullPointerException("Could not find the expected indexes"); //$NON-NLS-1$ out.writeInt(addToWriteTable(wire, objectTable)); out.writeInt(capability); out.writeInt(provider); out.writeInt(requirement); out.writeInt(requirer); } private static void readWire(DataInputStream in, List objectTable) throws IOException { int wireIndex = in.readInt(); ModuleCapability capability = (ModuleCapability) objectTable.get(in.readInt()); ModuleRevision provider = (ModuleRevision) objectTable.get(in.readInt()); ModuleRequirement requirement = (ModuleRequirement) objectTable.get(in.readInt()); ModuleRevision requirer = (ModuleRevision) objectTable.get(in.readInt()); if (capability == null || provider == null || requirement == null || requirer == null) throw new NullPointerException("Could not find the expected indexes"); //$NON-NLS-1$ ModuleWire result = new ModuleWire(capability, provider, requirement, requirer); addToReadTable(result, wireIndex, objectTable); } private static void writeWiring(ModuleWiring wiring, DataOutputStream out, Map objectTable) throws IOException { Integer revisionIndex = objectTable.get(wiring.getRevision()); if (revisionIndex == null) throw new NullPointerException("Could not find revision for wiring."); //$NON-NLS-1$ out.writeInt(revisionIndex); List capabilities = wiring.getModuleCapabilities(null); out.writeInt(capabilities.size()); for (ModuleCapability capability : capabilities) { Integer capabilityIndex = objectTable.get(capability); if (capabilityIndex == null) throw new NullPointerException("Could not find capability for wiring."); //$NON-NLS-1$ out.writeInt(capabilityIndex); } List requirements = wiring.getPersistentRequirements(); out.writeInt(requirements.size()); for (ModuleRequirement requirement : requirements) { Integer requirementIndex = objectTable.get(requirement); if (requirementIndex == null) throw new NullPointerException("Could not find requirement for wiring."); //$NON-NLS-1$ out.writeInt(requirementIndex); } List providedWires = wiring.getPersistentProvidedWires(); out.writeInt(providedWires.size()); for (ModuleWire wire : providedWires) { Integer wireIndex = objectTable.get(wire); if (wireIndex == null) throw new NullPointerException("Could not find provided wire for wiring."); //$NON-NLS-1$ out.writeInt(wireIndex); } List requiredWires = wiring.getPersistentRequiredWires(); out.writeInt(requiredWires.size()); for (ModuleWire wire : requiredWires) { Integer wireIndex = objectTable.get(wire); if (wireIndex == null) throw new NullPointerException("Could not find required wire for wiring."); //$NON-NLS-1$ out.writeInt(wireIndex); } Collection substituted = wiring.getSubstitutedNames(); out.writeInt(substituted.size()); for (String pkgName : substituted) { writeString(pkgName, out, objectTable); } } private static ModuleWiring readWiring(DataInputStream in, List objectTable) throws IOException { ModuleRevision revision = (ModuleRevision) objectTable.get(in.readInt()); if (revision == null) throw new NullPointerException("Could not find revision for wiring."); //$NON-NLS-1$ int numCapabilities = in.readInt(); List capabilities = new ArrayList<>(numCapabilities); for (int i = 0; i < numCapabilities; i++) { capabilities.add((ModuleCapability) objectTable.get(in.readInt())); } int numRequirements = in.readInt(); List requirements = new ArrayList<>(numRequirements); for (int i = 0; i < numRequirements; i++) { requirements.add((ModuleRequirement) objectTable.get(in.readInt())); } int numProvidedWires = in.readInt(); List providedWires = new ArrayList<>(numProvidedWires); for (int i = 0; i < numProvidedWires; i++) { providedWires.add((ModuleWire) objectTable.get(in.readInt())); } int numRequiredWires = in.readInt(); List requiredWires = new ArrayList<>(numRequiredWires); for (int i = 0; i < numRequiredWires; i++) { requiredWires.add((ModuleWire) objectTable.get(in.readInt())); } int numSubstitutedNames = in.readInt(); Collection substituted = new ArrayList<>(numSubstitutedNames); for (int i = 0; i < numSubstitutedNames; i++) { substituted.add(readString(in, objectTable)); } return new ModuleWiring(revision, capabilities, requirements, providedWires, requiredWires, substituted); } private static void writeGenericInfo(String namespace, Map attributes, Map directives, DataOutputStream out, Map objectTable) throws IOException { writeString(namespace, out, objectTable); Integer attributesIndex = objectTable.get(attributes); Integer directivesIndex = objectTable.get(directives); if (attributesIndex == null || directivesIndex == null) throw new NullPointerException("Could not find the expected indexes"); //$NON-NLS-1$ out.writeInt(attributesIndex); out.writeInt(directivesIndex); } @SuppressWarnings("unchecked") private static void readGenericInfo(boolean isCapability, DataInputStream in, ModuleRevisionBuilder builder, List objectTable, int version) throws IOException { String namespace = readString(in, objectTable); Map attributes = version >= 2 ? (Map) objectTable.get(in.readInt()) : readMap(in, objectTable); Map directives = version >= 2 ? (Map) objectTable.get(in.readInt()) : readMap(in, objectTable); if (attributes == null || directives == null) throw new NullPointerException("Could not find the expected indexes"); //$NON-NLS-1$ if (isCapability) { builder.basicAddCapability(namespace, (Map) directives, attributes); } else { builder.basicAddRequirement(namespace, (Map) directives, attributes); } } private static void writeMap(Map source, DataOutputStream out, Map objectTable, ModuleDatabase moduleDatabase) throws IOException { if (source == null) { out.writeInt(0); } else { out.writeInt(source.size()); Iterator iter = source.keySet().iterator(); while (iter.hasNext()) { String key = iter.next(); Object value = source.get(key); writeString(key, out, objectTable); if (value instanceof String) { out.writeByte(VALUE_STRING); writeString((String) value, out, objectTable); } else if (value instanceof Long) { out.writeByte(VALUE_LONG); out.writeLong(((Long) value).longValue()); } else if (value instanceof Double) { out.writeByte(VALUE_DOUBLE); out.writeDouble(((Double) value).doubleValue()); } else if (value instanceof Version) { out.writeByte(VALUE_VERSION); writeVersion((Version) value, out, objectTable); } else if (value instanceof List) { out.writeByte(VALUE_LIST); writeList(out, key, (List) value, objectTable, moduleDatabase); } else { // do our best and write a string; post an error. // This will be difficult to debug because we don't know which module it is coming from, but it is better than being silent moduleDatabase.adaptor.publishContainerEvent(ContainerEvent.ERROR, moduleDatabase.getModule(0), new BundleException("Invalid map value: " + key + " = " + value.getClass().getName() + '[' + value + ']')); //$NON-NLS-1$ //$NON-NLS-2$ out.writeByte(VALUE_STRING); writeString(String.valueOf(value), out, objectTable); } } } } private static void readIndexedMap(DataInputStream in, List objectTable) throws IOException { Map result = readMap(in, objectTable); addToReadTable(result, in.readInt(), objectTable); } private static Map readMap(DataInputStream in, List objectTable) throws IOException { int count = in.readInt(); Map result; if (count == 0) { result = Collections.emptyMap(); } else if (count == 1) { String key = readString(in, objectTable); byte type = in.readByte(); Object value = readMapValue(in, type, objectTable); result = Collections.singletonMap(key, value); } else { result = new HashMap<>(count); for (int i = 0; i < count; i++) { String key = readString(in, objectTable); byte type = in.readByte(); Object value = readMapValue(in, type, objectTable); result.put(key, value); } result = Collections.unmodifiableMap(result); } return result; } private static Object readMapValue(DataInputStream in, int type, List objectTable) throws IOException { switch (type) { case VALUE_STRING : return readString(in, objectTable); case VALUE_LONG : return Long.valueOf(in.readLong()); case VALUE_DOUBLE : return Double.valueOf(in.readDouble()); case VALUE_VERSION : return readVersion(in, objectTable); case VALUE_LIST : return readList(in, objectTable); default : throw new IllegalArgumentException("Invalid type: " + type); //$NON-NLS-1$ } } private static void writeList(DataOutputStream out, String key, List list, Map objectTable, ModuleDatabase moduleDatabase) throws IOException { if (list.isEmpty()) { out.writeInt(0); return; } byte type = getListType(list); if (type == -1) { out.writeInt(0); return; // don't understand the list type } out.writeInt(list.size()); out.writeByte(type == -2 ? VALUE_STRING : type); for (Object value : list) { switch (type) { case VALUE_STRING : writeString((String) value, out, objectTable); break; case VALUE_LONG : out.writeLong(((Long) value).longValue()); break; case VALUE_DOUBLE : out.writeDouble(((Double) value).doubleValue()); break; case VALUE_VERSION : writeVersion((Version) value, out, objectTable); break; default : // do our best and write a string; post an error. // This will be difficult to debug because we don't know which module it is coming from, but it is better than being silent moduleDatabase.adaptor.publishContainerEvent(ContainerEvent.ERROR, moduleDatabase.getModule(0), new BundleException("Invalid list element in map: " + key + " = " + value.getClass().getName() + '[' + value + ']')); //$NON-NLS-1$ //$NON-NLS-2$ writeString(String.valueOf(value), out, objectTable); break; } } } private static byte getListType(List list) { if (list.size() == 0) return -1; Object type = list.get(0); if (type instanceof String) return VALUE_STRING; if (type instanceof Long) return VALUE_LONG; if (type instanceof Double) return VALUE_DOUBLE; if (type instanceof Version) return VALUE_VERSION; return -2; } private static List readList(DataInputStream in, List objectTable) throws IOException { int size = in.readInt(); if (size == 0) return Collections.emptyList(); byte listType = in.readByte(); if (size == 1) { return Collections.singletonList(readListValue(listType, in, objectTable)); } List list = new ArrayList<>(size); for (int i = 0; i < size; i++) { list.add(readListValue(listType, in, objectTable)); } return Collections.unmodifiableList(list); } private static Object readListValue(byte listType, DataInputStream in, List objectTable) throws IOException { switch (listType) { case VALUE_STRING : return readString(in, objectTable); case VALUE_LONG : return Long.valueOf(in.readLong()); case VALUE_DOUBLE : return Double.valueOf(in.readDouble()); case VALUE_VERSION : return readVersion(in, objectTable); default : throw new IllegalArgumentException("Invalid type: " + listType); //$NON-NLS-1$ } } private static void writeVersion(Version version, DataOutputStream out, Map objectTable) throws IOException { if (version == null || version.equals(Version.emptyVersion)) { out.writeByte(NULL); return; } Integer index = objectTable.get(version); if (index != null) { out.writeByte(INDEX); out.writeInt(index); return; } out.writeByte(OBJECT); out.writeInt(version.getMajor()); out.writeInt(version.getMinor()); out.writeInt(version.getMicro()); writeQualifier(version.getQualifier(), out, objectTable); } private static void writeQualifier(String string, DataOutputStream out, Map objectTable) throws IOException { if (string != null && string.length() == 0) string = null; writeString(string, out, objectTable); } private static Version readIndexedVersion(DataInputStream in, List objectTable) throws IOException { Version version = readVersion0(in, objectTable, false); addToReadTable(version, in.readInt(), objectTable); return version; } private static Version readVersion(DataInputStream in, List objectTable) throws IOException { return readVersion0(in, objectTable, true); } private static Version readVersion0(DataInputStream in, List objectTable, boolean intern) throws IOException { byte type = in.readByte(); if (type == INDEX) { int index = in.readInt(); return (Version) objectTable.get(index); } if (type == NULL) return Version.emptyVersion; int majorComponent = in.readInt(); int minorComponent = in.readInt(); int serviceComponent = in.readInt(); String qualifierComponent = readString(in, objectTable); Version version = new Version(majorComponent, minorComponent, serviceComponent, qualifierComponent); return intern ? ObjectPool.intern(version) : version; } private static void writeString(String string, DataOutputStream out, Map objectTable) throws IOException { Integer index = string != null ? objectTable.get(string) : null; if (index != null) { out.writeByte(INDEX); out.writeInt(index); return; } if (string == null) out.writeByte(NULL); else { byte[] data = string.getBytes(StandardCharsets.UTF_8); if (data.length > 65535) { out.writeByte(LONG_STRING); out.writeInt(data.length); out.write(data); } else { out.writeByte(OBJECT); out.writeUTF(string); } } } static private String readIndexedString(DataInputStream in, List objectTable) throws IOException { String string = readString0(in, objectTable, false); addToReadTable(string, in.readInt(), objectTable); return string; } static private String readString(DataInputStream in, List objectTable) throws IOException { return readString0(in, objectTable, true); } static private String readString0(DataInputStream in, List objectTable, boolean intern) throws IOException { byte type = in.readByte(); if (type == INDEX) { int index = in.readInt(); return (String) objectTable.get(index); } if (type == NULL) { return null; } String string; if (type == LONG_STRING) { int length = in.readInt(); byte[] data = new byte[length]; in.readFully(data); string = new String(data, StandardCharsets.UTF_8); } else { string = in.readUTF(); } return intern ? ObjectPool.intern(string) : string; } } }