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}