    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      https://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.beanutils2;
    018
    019import java.beans.IntrospectionException;
    020import java.util.Collection;
    021import java.util.Collections;
    022import java.util.HashSet;
    023import java.util.Objects;
    024import java.util.Set;
    025
    026/**
    027 * <p>
    028 * A specialized {@code BeanIntrospector} implementation which suppresses some properties.
    029 * </p>
    030 * <p>
    031 * An instance of this class is passed a set with the names of the properties it should process. During introspection of a bean class it removes all these
    032 * properties from the {@link IntrospectionContext}. So effectively, properties added by a different {@code BeanIntrospector} are removed again.
    033 * </p>
    034 *
    035 * @since 1.9.2
    036 */
    037public class SuppressPropertiesBeanIntrospector implements BeanIntrospector {
    038
    039    /**
    040     * A specialized instance which is configured to suppress the special {@code class} properties of Java beans. Unintended access to the property
    041     * {@code class} (which is common to all Java objects) can be a security risk because it also allows access to the class loader. Adding this instance as
    042     * {@code BeanIntrospector} to an instance of {@code PropertyUtilsBean} suppresses the {@code class} property; it can then no longer be accessed.
    043     */
    044    public static final SuppressPropertiesBeanIntrospector SUPPRESS_CLASS = new SuppressPropertiesBeanIntrospector(Collections.singleton("class"));
    045
    046    /**
    047     * A specialized instance which is configured to suppress the special {@code class} properties of Java beans. Unintended access to the call for
    048     * {@code declaringClass} (which is common to all Java {@code enum}) can be a security risk because it also allows access to the class loader. Adding this
    049     * instance as {@code BeanIntrospector} to an instance of {@code PropertyUtilsBean} suppresses the {@code class} property; it can then no longer be
    050     * accessed.
    051     *
    052     * @since 2.0.0-M2
    053     */
    054    public static final SuppressPropertiesBeanIntrospector SUPPRESS_DECLARING_CLASS = new SuppressPropertiesBeanIntrospector(
    055            Collections.singleton("declaringClass"));
    056
    057/** A set with the names of the properties to be suppressed. */
    058    private final Set<String> propertyNames;
    059
    060    /**
    061     * Creates a new instance of {@code SuppressPropertiesBeanIntrospector} and sets the names of the properties to be suppressed.
    062     *
    063     * @param propertiesToSuppress the names of the properties to be suppressed (must not be <strong>null</strong>)
    064     * @throws IllegalArgumentException if the collection with property names is <strong>null</strong>
    065     */
    066    public SuppressPropertiesBeanIntrospector(final Collection<String> propertiesToSuppress) {
    067        Objects.requireNonNull(propertiesToSuppress, "propertiesToSuppress");
    068        propertyNames = Collections.unmodifiableSet(new HashSet<>(propertiesToSuppress));
    069    }
    070
    071    /**
    072     * Returns a (unmodifiable) set with the names of the properties which are suppressed by this {@code BeanIntrospector}.
    073     *
    074     * @return a set with the names of the suppressed properties
    075     */
    076    public Set<String> getSuppressedProperties() {
    077        return propertyNames;
    078    }
    079
    080    /**
    081     * {@inheritDoc} This implementation removes all properties from the given context it is configured for.
    082     */
    083    @Override
    084    public void introspect(final IntrospectionContext icontext) throws IntrospectionException {
    085        getSuppressedProperties().forEach(icontext::removePropertyDescriptor);
    086    }
    087}