https://openjdk.java.net/ 
/*
 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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 *
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package java.io;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.Security;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;

import jdk.internal.misc.SharedSecrets;
import jdk.internal.util.StaticProperty;


Filter classes, array lengths, and graph metrics during deserialization.

Warning: Deserialization of untrusted data is inherently dangerous
and should be avoided. Untrusted data should be carefully validated according to the
"Serialization and Deserialization" section of the
{@extLink secure_coding_guidelines_javase Secure Coding Guidelines for Java SE}.
{@extLink serialization_filter_guide Serialization Filtering} describes best
practices for defensive use of serial filters.

 If set on an ObjectInputStream, the checkInput(FilterInfo) method is called to validate classes, the length of each array, the number of objects being read from the stream, the depth of the graph, and the total number of bytes read from the stream. 
 A filter can be set via setObjectInputFilter for an individual ObjectInputStream. A filter can be set via Config.setSerialFilter to affect every ObjectInputStream that does not otherwise set a filter. 
 A filter determines whether the arguments are ALLOWED or REJECTED and should return the appropriate status. If the filter cannot determine the status it should return UNDECIDED. Filters should be designed for the specific use case and expected types. A filter designed for a particular use may be passed a class that is outside of the scope of the filter. If the purpose of the filter is to black-list classes then it can reject a candidate class that matches and report UNDECIDED for others. A filter may be called with class equals null, arrayLength equal -1, the depth, number of references, and stream size and return a status that reflects only one or only some of the values. This allows a filter to specific about the choice it is reporting and to use other filters without forcing either allowed or rejected status. 

Typically, a custom filter should check if a process-wide filter
is configured and defer to it if so. For example,


ObjectInputFilter.Status checkInput(FilterInfo info) {
    ObjectInputFilter serialFilter = ObjectInputFilter.Config.getSerialFilter();
    if (serialFilter != null) {
        ObjectInputFilter.Status status = serialFilter.checkInput(info);
        if (status != ObjectInputFilter.Status.UNDECIDED) {
            // The process-wide filter overrides this filter
            return status;
        }
    }
    if (info.serialClass() != null &&
        Remote.class.isAssignableFrom(info.serialClass())) {
        return Status.REJECTED;      // Do not allow Remote objects
    }
    return Status.UNDECIDED;
 }



 Unless otherwise noted, passing a null argument to a method in this interface and its nested classes will cause a NullPointerException to be thrown. 
See Also:
Since:9
/**
 * Filter classes, array lengths, and graph metrics during deserialization.
 *
 * <p><strong>Warning: Deserialization of untrusted data is inherently dangerous
 * and should be avoided. Untrusted data should be carefully validated according to the
 * "Serialization and Deserialization" section of the
 * {@extLink secure_coding_guidelines_javase Secure Coding Guidelines for Java SE}.
 * {@extLink serialization_filter_guide Serialization Filtering} describes best
 * practices for defensive use of serial filters.
 * </strong></p>
 *
 * If set on an {@link ObjectInputStream}, the {@link #checkInput checkInput(FilterInfo)}
 * method is called to validate classes, the length of each array,
 * the number of objects being read from the stream, the depth of the graph,
 * and the total number of bytes read from the stream.
 * <p>
 * A filter can be set via {@link ObjectInputStream#setObjectInputFilter setObjectInputFilter}
 * for an individual ObjectInputStream.
 * A filter can be set via {@link Config#setSerialFilter(ObjectInputFilter) Config.setSerialFilter}
 * to affect every {@code ObjectInputStream} that does not otherwise set a filter.
 * <p>
 * A filter determines whether the arguments are {@link Status#ALLOWED ALLOWED}
 * or {@link Status#REJECTED REJECTED} and should return the appropriate status.
 * If the filter cannot determine the status it should return
 * {@link Status#UNDECIDED UNDECIDED}.
 * Filters should be designed for the specific use case and expected types.
 * A filter designed for a particular use may be passed a class that is outside
 * of the scope of the filter. If the purpose of the filter is to black-list classes
 * then it can reject a candidate class that matches and report UNDECIDED for others.
 * A filter may be called with class equals {@code null}, {@code arrayLength} equal -1,
 * the depth, number of references, and stream size and return a status
 * that reflects only one or only some of the values.
 * This allows a filter to specific about the choice it is reporting and
 * to use other filters without forcing either allowed or rejected status.
 *
 * <p>
 * Typically, a custom filter should check if a process-wide filter
 * is configured and defer to it if so. For example,
 * <pre>{@code
 * ObjectInputFilter.Status checkInput(FilterInfo info) {
 *     ObjectInputFilter serialFilter = ObjectInputFilter.Config.getSerialFilter();
 *     if (serialFilter != null) {
 *         ObjectInputFilter.Status status = serialFilter.checkInput(info);
 *         if (status != ObjectInputFilter.Status.UNDECIDED) {
 *             // The process-wide filter overrides this filter
 *             return status;
 *         }
 *     }
 *     if (info.serialClass() != null &&
 *         Remote.class.isAssignableFrom(info.serialClass())) {
 *         return Status.REJECTED;      // Do not allow Remote objects
 *     }
 *     return Status.UNDECIDED;
 * }
 *}</pre>
 * <p>
 * Unless otherwise noted, passing a {@code null} argument to a
 * method in this interface and its nested classes will cause a
 * {@link NullPointerException} to be thrown.
 *
 * @see ObjectInputStream#setObjectInputFilter(ObjectInputFilter)
 * @since 9
 */
@FunctionalInterface
public interface ObjectInputFilter {

    
Check the class, array length, number of object references, depth, stream size, and other available filtering information. Implementations of this method check the contents of the object graph being created during deserialization. The filter returns Status.ALLOWED, Status.REJECTED, or Status.UNDECIDED. 
Params:
  • filterInfo – provides information about the current object being deserialized, if any, and the status of the ObjectInputStream
Returns: Status.ALLOWED if accepted, Status.REJECTED if rejected, Status.UNDECIDED if undecided.
/**
     * Check the class, array length, number of object references, depth,
     * stream size, and other available filtering information.
     * Implementations of this method check the contents of the object graph being created
     * during deserialization. The filter returns {@link Status#ALLOWED Status.ALLOWED},
     * {@link Status#REJECTED Status.REJECTED}, or {@link Status#UNDECIDED Status.UNDECIDED}.
     *
     * @param filterInfo provides information about the current object being deserialized,
     *             if any, and the status of the {@link ObjectInputStream}
     * @return  {@link Status#ALLOWED Status.ALLOWED} if accepted,
     *          {@link Status#REJECTED Status.REJECTED} if rejected,
     *          {@link Status#UNDECIDED Status.UNDECIDED} if undecided.
     */
    Status checkInput(FilterInfo filterInfo);

    
FilterInfo provides access to information about the current object being deserialized and the status of the ObjectInputStream. 
Since:9
/**
     * FilterInfo provides access to information about the current object
     * being deserialized and the status of the {@link ObjectInputStream}.
     * @since 9
     */
    interface FilterInfo {
        
The class of an object being deserialized. For arrays, it is the array type. For example, the array class name of a 2 dimensional array of strings is "[[Ljava.lang.String;". To check the array's element type, iteratively use Class.getComponentType while the result is an array and then check the class. The serialClass is null in the case where a new object is not being created and to give the filter a chance to check the depth, number of references to existing objects, and the stream size. 
Returns:class of an object being deserialized; may be null
/**
         * The class of an object being deserialized.
         * For arrays, it is the array type.
         * For example, the array class name of a 2 dimensional array of strings is
         * "{@code [[Ljava.lang.String;}".
         * To check the array's element type, iteratively use
         * {@link Class#getComponentType() Class.getComponentType} while the result
         * is an array and then check the class.
         * The {@code serialClass is null} in the case where a new object is not being
         * created and to give the filter a chance to check the depth, number of
         * references to existing objects, and the stream size.
         *
         * @return class of an object being deserialized; may be null
         */
        Class<?> serialClass();

        
The number of array elements when deserializing an array of the class.

Returns:the non-negative number of array elements when deserializing
an array of the class, otherwise -1
/**
         * The number of array elements when deserializing an array of the class.
         *
         * @return the non-negative number of array elements when deserializing
         * an array of the class, otherwise -1
         */
        long arrayLength();

        
The current depth. The depth starts at 1 and increases for each nested object and decrements when each nested object returns. 
Returns:the current depth
/**
         * The current depth.
         * The depth starts at {@code 1} and increases for each nested object and
         * decrements when each nested object returns.
         *
         * @return the current depth
         */
        long depth();

        
The current number of object references.

Returns:the non-negative current number of object references
/**
         * The current number of object references.
         *
         * @return the non-negative current number of object references
         */
        long references();

        
The current number of bytes consumed.

Implementation Requirements: streamBytes is implementation specific and may not be directly related to the object in the stream that caused the callback.
Returns:the non-negative current number of bytes consumed
/**
         * The current number of bytes consumed.
         * @implSpec  {@code streamBytes} is implementation specific
         * and may not be directly related to the object in the stream
         * that caused the callback.
         *
         * @return the non-negative current number of bytes consumed
         */
        long streamBytes();
    }

    
The status of a check on the class, array length, number of references,
depth, and stream size.

Since:9
/**
     * The status of a check on the class, array length, number of references,
     * depth, and stream size.
     *
     * @since 9
     */
    enum Status {
        
The status is undecided, not allowed and not rejected.

/**
         * The status is undecided, not allowed and not rejected.
         */
        UNDECIDED,
        
The status is allowed.

/**
         * The status is allowed.
         */
        ALLOWED,
        
The status is rejected.

/**
         * The status is rejected.
         */
        REJECTED;
    }

    
A utility class to set and get the process-wide filter or create a filter from a pattern string. If a process-wide filter is set, it will be used for each ObjectInputStream that does not set its own filter. 

When setting the filter, it should be stateless and idempotent,
reporting the same result when passed the same arguments.

 The filter is configured during the initialization of the ObjectInputFilter.Config class. For example, by calling Config.getSerialFilter. If the system property jdk.serialFilter is defined, it is used to configure the filter. If the system property is not defined, and the Security property jdk.serialFilter is defined then it is used to configure the filter. Otherwise, the filter is not configured during initialization. The syntax for each property is the same as for the createFilter method. If a filter is not configured, it can be set with Config.setSerialFilter. 
Since:9
/**
     * A utility class to set and get the process-wide filter or create a filter
     * from a pattern string. If a process-wide filter is set, it will be
     * used for each {@link ObjectInputStream} that does not set its own filter.
     * <p>
     * When setting the filter, it should be stateless and idempotent,
     * reporting the same result when passed the same arguments.
     * <p>
     * The filter is configured during the initialization of the {@code ObjectInputFilter.Config}
     * class. For example, by calling {@link #getSerialFilter() Config.getSerialFilter}.
     * If the system property {@code jdk.serialFilter} is defined, it is used
     * to configure the filter.
     * If the system property is not defined, and the {@link java.security.Security}
     * property {@code jdk.serialFilter} is defined then it is used to configure the filter.
     * Otherwise, the filter is not configured during initialization.
     * The syntax for each property is the same as for the
     * {@link #createFilter(String) createFilter} method.
     * If a filter is not configured, it can be set with
     * {@link #setSerialFilter(ObjectInputFilter) Config.setSerialFilter}.
     *
     * @since 9
     */
    final class Config {
        /* No instances. */
        private Config() {}

        
Lock object for process-wide filter.

/**
         * Lock object for process-wide filter.
         */
        private final static Object serialFilterLock = new Object();

        
Debug: Logger

/**
         * Debug: Logger
         */
        private final static System.Logger configLog;

        
Logger for debugging.

/**
         * Logger for debugging.
         */
        static void filterLog(System.Logger.Level level, String msg, Object... args) {
            if (configLog != null) {
                configLog.log(level, msg, args);
            }
        }

        
The name for the process-wide deserialization filter.
Used as a system property and a java.security.Security property.

/**
         * The name for the process-wide deserialization filter.
         * Used as a system property and a java.security.Security property.
         */
        private final static String SERIAL_FILTER_PROPNAME = "jdk.serialFilter";

        
The process-wide filter; may be null.
Lookup the filter in java.security.Security or
the system property.

/**
         * The process-wide filter; may be null.
         * Lookup the filter in java.security.Security or
         * the system property.
         */
        private final static ObjectInputFilter configuredFilter;

        static {
            configuredFilter = AccessController
                    .doPrivileged((PrivilegedAction<ObjectInputFilter>) () -> {
                        String props = StaticProperty.jdkSerialFilter();
                        if (props == null) {
                            props = Security.getProperty(SERIAL_FILTER_PROPNAME);
                        }
                        if (props != null) {
                            System.Logger log =
                                    System.getLogger("java.io.serialization");
                            log.log(System.Logger.Level.INFO,
                                    "Creating serialization filter from {0}", props);
                            try {
                                return createFilter(props);
                            } catch (RuntimeException re) {
                                log.log(System.Logger.Level.ERROR,
                                        "Error configuring filter: {0}", re);
                            }
                        }
                        return null;
                    });
            configLog = (configuredFilter != null) ? System.getLogger("java.io.serialization") : null;

            // Setup shared secrets for RegistryImpl to use.
            SharedSecrets.setJavaObjectInputFilterAccess(Config::createFilter2);
        }

        
Current configured filter.

/**
         * Current configured filter.
         */
        private static volatile ObjectInputFilter serialFilter = configuredFilter;

        
Returns the process-wide serialization filter or null if not configured. 
Returns:the process-wide serialization filter or null if not configured
/**
         * Returns the process-wide serialization filter or {@code null} if not configured.
         *
         * @return the process-wide serialization filter or {@code null} if not configured
         */
        public static ObjectInputFilter getSerialFilter() {
            return serialFilter;
        }

        
Set the process-wide filter if it has not already been configured or set.

Params:
  • filter – the serialization filter to set as the process-wide filter; not null
Throws:
/**
         * Set the process-wide filter if it has not already been configured or set.
         *
         * @param filter the serialization filter to set as the process-wide filter; not null
         * @throws SecurityException if there is security manager and the
         *       {@code SerializablePermission("serialFilter")} is not granted
         * @throws IllegalStateException if the filter has already been set {@code non-null}
         */
        public static void setSerialFilter(ObjectInputFilter filter) {
            Objects.requireNonNull(filter, "filter");
            SecurityManager sm = System.getSecurityManager();
            if (sm != null) {
                sm.checkPermission(ObjectStreamConstants.SERIAL_FILTER_PERMISSION);
            }
            synchronized (serialFilterLock) {
                if (serialFilter != null) {
                    throw new IllegalStateException("Serial filter can only be set once");
                }
                serialFilter = filter;
            }
        }

        
Returns an ObjectInputFilter from a string of patterns.

 Patterns are separated by ";" (semicolon). Whitespace is significant and is considered part of the pattern. If a pattern includes an equals assignment, "=" it sets a limit. If a limit appears more than once the last value is used. 
    
    
  • maxdepth=value - the maximum depth of a graph
    • 
    
  • maxrefs=value - the maximum number of internal references
    • 
    
  • maxbytes=value - the maximum number of bytes in the input stream
    • 
    
  • maxarray=value - the maximum array length allowed
    • 



 Other patterns match or reject class or package name as returned from Class.getName() and if an optional module name is present class.getModule().getName(). Note that for arrays the element type is used in the pattern, not the array type. 
    

  • If the pattern starts with "!", the class is rejected if the remaining pattern is matched;
    otherwise the class is allowed if the pattern matches.

  • If the pattern contains "/", the non-empty prefix up to the "/" is the module name;
    if the module name matches the module name of the class then
    the remaining pattern is matched with the class name.
    If there is no "/", the module name is not compared.

  • If the pattern ends with ".**" it matches any class in the package and all subpackages.

  • If the pattern ends with ".*" it matches any class in the package.

  • If the pattern ends with "*", it matches any class with the pattern as a prefix.

  • If the pattern is equal to the class name, it matches.

  • Otherwise, the pattern is not matched.



 The resulting filter performs the limit checks and then tries to match the class, if any. If any of the limits are exceeded, the filter returns Status.REJECTED. If the class is an array type, the class to be matched is the element type. Arrays of any number of dimensions are treated the same as the element type. For example, a pattern of "!example.Foo", rejects creation of any instance or array of example.Foo. The first pattern that matches, working from left to right, determines the Status.ALLOWED or Status.REJECTED result. If the limits are not exceeded and no pattern matches the class, the result is Status.UNDECIDED. 
Params:
  • pattern – the pattern string to parse; not null
Throws:
  • IllegalArgumentException – if the pattern string is illegal or
        malformed and cannot be parsed.
        In particular, if any of the following is true:

      

    •    if a limit is missing the name or the name is not one of
       "maxdepth", "maxrefs", "maxbytes", or "maxarray"

    •  if the value of the limit can not be parsed by Long.parseLong or is negative 
    •    if the pattern contains "/" and the module name is missing
       or the remaining pattern is empty

    •    if the package is missing for ".*" and ".**"

Returns:a filter to check a class being deserialized; null if no patterns
/**
         * Returns an ObjectInputFilter from a string of patterns.
         * <p>
         * Patterns are separated by ";" (semicolon). Whitespace is significant and
         * is considered part of the pattern.
         * If a pattern includes an equals assignment, "{@code =}" it sets a limit.
         * If a limit appears more than once the last value is used.
         * <ul>
         *     <li>maxdepth={@code value} - the maximum depth of a graph</li>
         *     <li>maxrefs={@code value}  - the maximum number of internal references</li>
         *     <li>maxbytes={@code value} - the maximum number of bytes in the input stream</li>
         *     <li>maxarray={@code value} - the maximum array length allowed</li>
         * </ul>
         * <p>
         * Other patterns match or reject class or package name
         * as returned from {@link Class#getName() Class.getName()} and
         * if an optional module name is present
         * {@link Module#getName() class.getModule().getName()}.
         * Note that for arrays the element type is used in the pattern,
         * not the array type.
         * <ul>
         * <li>If the pattern starts with "!", the class is rejected if the remaining pattern is matched;
         *     otherwise the class is allowed if the pattern matches.
         * <li>If the pattern contains "/", the non-empty prefix up to the "/" is the module name;
         *     if the module name matches the module name of the class then
         *     the remaining pattern is matched with the class name.
         *     If there is no "/", the module name is not compared.
         * <li>If the pattern ends with ".**" it matches any class in the package and all subpackages.
         * <li>If the pattern ends with ".*" it matches any class in the package.
         * <li>If the pattern ends with "*", it matches any class with the pattern as a prefix.
         * <li>If the pattern is equal to the class name, it matches.
         * <li>Otherwise, the pattern is not matched.
         * </ul>
         * <p>
         * The resulting filter performs the limit checks and then
         * tries to match the class, if any. If any of the limits are exceeded,
         * the filter returns {@link Status#REJECTED Status.REJECTED}.
         * If the class is an array type, the class to be matched is the element type.
         * Arrays of any number of dimensions are treated the same as the element type.
         * For example, a pattern of "{@code !example.Foo}",
         * rejects creation of any instance or array of {@code example.Foo}.
         * The first pattern that matches, working from left to right, determines
         * the {@link Status#ALLOWED Status.ALLOWED}
         * or {@link Status#REJECTED Status.REJECTED} result.
         * If the limits are not exceeded and no pattern matches the class,
         * the result is {@link Status#UNDECIDED Status.UNDECIDED}.
         *
         * @param pattern the pattern string to parse; not null
         * @return a filter to check a class being deserialized;
         *          {@code null} if no patterns
         * @throws IllegalArgumentException if the pattern string is illegal or
         *         malformed and cannot be parsed.
         *         In particular, if any of the following is true:
         * <ul>
         * <li>   if a limit is missing the name or the name is not one of
         *        "maxdepth", "maxrefs", "maxbytes", or "maxarray"
         * <li>   if the value of the limit can not be parsed by
         *        {@link Long#parseLong Long.parseLong} or is negative
         * <li>   if the pattern contains "/" and the module name is missing
         *        or the remaining pattern is empty
         * <li>   if the package is missing for ".*" and ".**"
         * </ul>
         */
        public static ObjectInputFilter createFilter(String pattern) {
            Objects.requireNonNull(pattern, "pattern");
            return Global.createFilter(pattern, true);
        }

        
Returns an ObjectInputFilter from a string of patterns that
checks only the length for arrays, not the component type.

Params:
  • pattern – the pattern string to parse; not null
Returns:a filter to check a class being deserialized; null if no patterns
/**
         * Returns an ObjectInputFilter from a string of patterns that
         * checks only the length for arrays, not the component type.
         *
         * @param pattern the pattern string to parse; not null
         * @return a filter to check a class being deserialized;
         *          {@code null} if no patterns
         */
        static ObjectInputFilter createFilter2(String pattern) {
            Objects.requireNonNull(pattern, "pattern");
            return Global.createFilter(pattern, false);
        }

        
Implementation of ObjectInputFilter that performs the checks of
the process-wide serialization filter. If configured, it will be
used for all ObjectInputStreams that do not set their own filters.

/**
         * Implementation of ObjectInputFilter that performs the checks of
         * the process-wide serialization filter. If configured, it will be
         * used for all ObjectInputStreams that do not set their own filters.
         *
         */
        final static class Global implements ObjectInputFilter {
            
The pattern used to create the filter.

/**
             * The pattern used to create the filter.
             */
            private final String pattern;
            
The list of class filters.

/**
             * The list of class filters.
             */
            private final List<Function<Class<?>, Status>> filters;
            
Maximum allowed bytes in the stream.

/**
             * Maximum allowed bytes in the stream.
             */
            private long maxStreamBytes;
            
Maximum depth of the graph allowed.

/**
             * Maximum depth of the graph allowed.
             */
            private long maxDepth;
            
Maximum number of references in a graph.

/**
             * Maximum number of references in a graph.
             */
            private long maxReferences;
            
Maximum length of any array.

/**
             * Maximum length of any array.
             */
            private long maxArrayLength;
            
True to check the component type for arrays.

/**
             * True to check the component type for arrays.
             */
            private final boolean checkComponentType;

            
Returns an ObjectInputFilter from a string of patterns.

Params:
  • pattern – the pattern string to parse
  • checkComponentType – true if the filter should check
                          the component type of arrays
Throws:
  • IllegalArgumentException – if the parameter is malformed
               if the pattern is missing the name, the long value
               is not a number or is negative.
Returns:a filter to check a class being deserialized; null if no patterns
/**
             * Returns an ObjectInputFilter from a string of patterns.
             *
             * @param pattern the pattern string to parse
             * @param checkComponentType true if the filter should check
             *                           the component type of arrays
             * @return a filter to check a class being deserialized;
             *          {@code null} if no patterns
             * @throws IllegalArgumentException if the parameter is malformed
             *                if the pattern is missing the name, the long value
             *                is not a number or is negative.
             */
            static ObjectInputFilter createFilter(String pattern, boolean checkComponentType) {
                try {
                    return new Global(pattern, checkComponentType);
                } catch (UnsupportedOperationException uoe) {
                    // no non-empty patterns
                    return null;
                }
            }

            
Construct a new filter from the pattern String.

Params:
  • pattern – a pattern string of filters
  • checkComponentType – true if the filter should check
                          the component type of arrays
Throws:
/**
             * Construct a new filter from the pattern String.
             *
             * @param pattern a pattern string of filters
             * @param checkComponentType true if the filter should check
             *                           the component type of arrays
             * @throws IllegalArgumentException if the pattern is malformed
             * @throws UnsupportedOperationException if there are no non-empty patterns
             */
            private Global(String pattern, boolean checkComponentType) {
                boolean hasLimits = false;
                this.pattern = pattern;
                this.checkComponentType = checkComponentType;

                maxArrayLength = Long.MAX_VALUE; // Default values are unlimited
                maxDepth = Long.MAX_VALUE;
                maxReferences = Long.MAX_VALUE;
                maxStreamBytes = Long.MAX_VALUE;

                String[] patterns = pattern.split(";");
                filters = new ArrayList<>(patterns.length);
                for (int i = 0; i < patterns.length; i++) {
                    String p = patterns[i];
                    int nameLen = p.length();
                    if (nameLen == 0) {
                        continue;
                    }
                    if (parseLimit(p)) {
                        // If the pattern contained a limit setting, i.e. type=value
                        hasLimits = true;
                        continue;
                    }
                    boolean negate = p.charAt(0) == '!';
                    int poffset = negate ? 1 : 0;

                    // isolate module name, if any
                    int slash = p.indexOf('/', poffset);
                    if (slash == poffset) {
                        throw new IllegalArgumentException("module name is missing in: \"" + pattern + "\"");
                    }
                    final String moduleName = (slash >= 0) ? p.substring(poffset, slash) : null;
                    poffset = (slash >= 0) ? slash + 1 : poffset;

                    final Function<Class<?>, Status> patternFilter;
                    if (p.endsWith("*")) {
                        // Wildcard cases
                        if (p.endsWith(".*")) {
                            // Pattern is a package name with a wildcard
                            final String pkg = p.substring(poffset, nameLen - 2);
                            if (pkg.isEmpty()) {
                                throw new IllegalArgumentException("package missing in: \"" + pattern + "\"");
                            }
                            if (negate) {
                                // A Function that fails if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> matchesPackage(c, pkg) ? Status.REJECTED : Status.UNDECIDED;
                            } else {
                                // A Function that succeeds if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> matchesPackage(c, pkg) ? Status.ALLOWED : Status.UNDECIDED;
                            }
                        } else if (p.endsWith(".**")) {
                            // Pattern is a package prefix with a double wildcard
                            final String pkgs = p.substring(poffset, nameLen - 2);
                            if (pkgs.length() < 2) {
                                throw new IllegalArgumentException("package missing in: \"" + pattern + "\"");
                            }
                            if (negate) {
                                // A Function that fails if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> c.getName().startsWith(pkgs) ? Status.REJECTED : Status.UNDECIDED;
                            } else {
                                // A Function that succeeds if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> c.getName().startsWith(pkgs) ? Status.ALLOWED : Status.UNDECIDED;
                            }
                        } else {
                            // Pattern is a classname (possibly empty) with a trailing wildcard
                            final String className = p.substring(poffset, nameLen - 1);
                            if (negate) {
                                // A Function that fails if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> c.getName().startsWith(className) ? Status.REJECTED : Status.UNDECIDED;
                            } else {
                                // A Function that succeeds if the class starts with the pattern, otherwise don't care
                                patternFilter = c -> c.getName().startsWith(className) ? Status.ALLOWED : Status.UNDECIDED;
                            }
                        }
                    } else {
                        final String name = p.substring(poffset);
                        if (name.isEmpty()) {
                            throw new IllegalArgumentException("class or package missing in: \"" + pattern + "\"");
                        }
                        // Pattern is a class name
                        if (negate) {
                            // A Function that fails if the class equals the pattern, otherwise don't care
                            patternFilter = c -> c.getName().equals(name) ? Status.REJECTED : Status.UNDECIDED;
                        } else {
                            // A Function that succeeds if the class equals the pattern, otherwise don't care
                            patternFilter = c -> c.getName().equals(name) ? Status.ALLOWED : Status.UNDECIDED;
                        }
                    }
                    // If there is a moduleName, combine the module name check with the package/class check
                    if (moduleName == null) {
                        filters.add(patternFilter);
                    } else {
                        filters.add(c -> moduleName.equals(c.getModule().getName()) ? patternFilter.apply(c) : Status.UNDECIDED);
                    }
                }
                if (filters.isEmpty() && !hasLimits) {
                    throw new UnsupportedOperationException("no non-empty patterns");
                }
            }

            
Parse out a limit for one of maxarray, maxdepth, maxbytes, maxreferences.

Params:
  • pattern – a string with a type name, '=' and a value
Throws:
Returns:true if a limit was parsed, else false
/**
             * Parse out a limit for one of maxarray, maxdepth, maxbytes, maxreferences.
             *
             * @param pattern a string with a type name, '=' and a value
             * @return {@code true} if a limit was parsed, else {@code false}
             * @throws IllegalArgumentException if the pattern is missing
             *                the name, the Long value is not a number or is negative.
             */
            private boolean parseLimit(String pattern) {
                int eqNdx = pattern.indexOf('=');
                if (eqNdx < 0) {
                    // not a limit pattern
                    return false;
                }
                String valueString = pattern.substring(eqNdx + 1);
                if (pattern.startsWith("maxdepth=")) {
                    maxDepth = parseValue(valueString);
                } else if (pattern.startsWith("maxarray=")) {
                    maxArrayLength = parseValue(valueString);
                } else if (pattern.startsWith("maxrefs=")) {
                    maxReferences = parseValue(valueString);
                } else if (pattern.startsWith("maxbytes=")) {
                    maxStreamBytes = parseValue(valueString);
                } else {
                    throw new IllegalArgumentException("unknown limit: " + pattern.substring(0, eqNdx));
                }
                return true;
            }

            
Parse the value of a limit and check that it is non-negative.

Params:
  • string – inputstring
Throws:
Returns:the parsed value
/**
             * Parse the value of a limit and check that it is non-negative.
             * @param string inputstring
             * @return the parsed value
             * @throws IllegalArgumentException if parsing the value fails or the value is negative
             */
            private static long parseValue(String string) throws IllegalArgumentException {
                // Parse a Long from after the '=' to the end
                long value = Long.parseLong(string);
                if (value < 0) {
                    throw new IllegalArgumentException("negative limit: " + string);
                }
                return value;
            }

            
{@inheritDoc}

/**
             * {@inheritDoc}
             */
            @Override
            public Status checkInput(FilterInfo filterInfo) {
                if (filterInfo.references() < 0
                        || filterInfo.depth() < 0
                        || filterInfo.streamBytes() < 0
                        || filterInfo.references() > maxReferences
                        || filterInfo.depth() > maxDepth
                        || filterInfo.streamBytes() > maxStreamBytes) {
                    return Status.REJECTED;
                }

                Class<?> clazz = filterInfo.serialClass();
                if (clazz != null) {
                    if (clazz.isArray()) {
                        if (filterInfo.arrayLength() >= 0 && filterInfo.arrayLength() > maxArrayLength) {
                            // array length is too big
                            return Status.REJECTED;
                        }
                        if (!checkComponentType) {
                            // As revised; do not check the component type for arrays
                            return Status.UNDECIDED;
                        }
                        do {
                            // Arrays are decided based on the component type
                            clazz = clazz.getComponentType();
                        } while (clazz.isArray());
                    }

                    if (clazz.isPrimitive())  {
                        // Primitive types are undecided; let someone else decide
                        return Status.UNDECIDED;
                    } else {
                        // Find any filter that allowed or rejected the class
                        final Class<?> cl = clazz;
                        Optional<Status> status = filters.stream()
                                .map(f -> f.apply(cl))
                                .filter(p -> p != Status.UNDECIDED)
                                .findFirst();
                        return status.orElse(Status.UNDECIDED);
                    }
                }
                return Status.UNDECIDED;
            }

            
Returns true if the class is in the package. 
Params:
  • c –   a class
  • pkg – a package name
Returns:true if the class is in the package, otherwise false
/**
             * Returns {@code true} if the class is in the package.
             *
             * @param c   a class
             * @param pkg a package name
             * @return {@code true} if the class is in the package,
             * otherwise {@code false}
             */
            private static boolean matchesPackage(Class<?> c, String pkg) {
                return pkg.equals(c.getPackageName());
            }

            
Returns the pattern used to create this filter.

Returns:the pattern used to create this filter
/**
             * Returns the pattern used to create this filter.
             * @return the pattern used to create this filter
             */
            @Override
            public String toString() {
                return pattern;
            }
        }
    }
}