Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.beans; import java.util.Map; import org.springframework.core.convert.TypeDescriptor; import org.springframework.lang.Nullable; /** * Common interface for classes that can access named properties * (such as bean properties of an object or fields in an object) * Serves as base interface for {@link BeanWrapper}. * * @author Juergen Hoeller * @since 1.1 * @see BeanWrapper * @see PropertyAccessorFactory#forBeanPropertyAccess * @see PropertyAccessorFactory#forDirectFieldAccess */ public interface PropertyAccessor { /** * Path separator for nested properties. * Follows normal Java conventions: getFoo().getBar() would be "foo.bar". */ String NESTED_PROPERTY_SEPARATOR = "."; /** * Path separator for nested properties. * Follows normal Java conventions: getFoo().getBar() would be "foo.bar". */ char NESTED_PROPERTY_SEPARATOR_CHAR = '.'; /** * Marker that indicates the start of a property key for an * indexed or mapped property like "person.addresses[0]". */ String PROPERTY_KEY_PREFIX = "["; /** * Marker that indicates the start of a property key for an * indexed or mapped property like "person.addresses[0]". */ char PROPERTY_KEY_PREFIX_CHAR = '['; /** * Marker that indicates the end of a property key for an * indexed or mapped property like "person.addresses[0]". */ String PROPERTY_KEY_SUFFIX = "]"; /** * Marker that indicates the end of a property key for an * indexed or mapped property like "person.addresses[0]". */ char PROPERTY_KEY_SUFFIX_CHAR = ']'; /** * Determine whether the specified property is readable. * <p>Returns {@code false} if the property doesn't exist. * @param propertyName the property to check * (may be a nested path and/or an indexed/mapped property) * @return whether the property is readable */ boolean isReadableProperty(String propertyName); /** * Determine whether the specified property is writable. * <p>Returns {@code false} if the property doesn't exist. * @param propertyName the property to check * (may be a nested path and/or an indexed/mapped property) * @return whether the property is writable */ boolean isWritableProperty(String propertyName); /** * Determine the property type for the specified property, * either checking the property descriptor or checking the value * in case of an indexed or mapped element. * @param propertyName the property to check * (may be a nested path and/or an indexed/mapped property) * @return the property type for the particular property, * or {@code null} if not determinable * @throws PropertyAccessException if the property was valid but the * accessor method failed */ @Nullable Class<?> getPropertyType(String propertyName) throws BeansException; /** * Return a type descriptor for the specified property: * preferably from the read method, falling back to the write method. * @param propertyName the property to check * (may be a nested path and/or an indexed/mapped property) * @return the property type for the particular property, * or {@code null} if not determinable * @throws PropertyAccessException if the property was valid but the * accessor method failed */ @Nullable TypeDescriptor getPropertyTypeDescriptor(String propertyName) throws BeansException; /** * Get the current value of the specified property. * @param propertyName the name of the property to get the value of * (may be a nested path and/or an indexed/mapped property) * @return the value of the property * @throws InvalidPropertyException if there is no such property or * if the property isn't readable * @throws PropertyAccessException if the property was valid but the * accessor method failed */ @Nullable Object getPropertyValue(String propertyName) throws BeansException; /** * Set the specified value as current property value. * @param propertyName the name of the property to set the value of * (may be a nested path and/or an indexed/mapped property) * @param value the new value * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyAccessException if the property was valid but the * accessor method failed or a type mismatch occurred */ void setPropertyValue(String propertyName, @Nullable Object value) throws BeansException; /** * Set the specified value as current property value. * @param pv an object containing the new property value * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyAccessException if the property was valid but the * accessor method failed or a type mismatch occurred */ void setPropertyValue(PropertyValue pv) throws BeansException; /** * Perform a batch update from a Map. * <p>Bulk updates from PropertyValues are more powerful: This method is * provided for convenience. Behavior will be identical to that of * the {@link #setPropertyValues(PropertyValues)} method. * @param map a Map to take properties from. Contains property value objects, * keyed by property name * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions * occurred for specific properties during the batch update. This exception bundles * all individual PropertyAccessExceptions. All other properties will have been * successfully updated. */ void setPropertyValues(Map<?, ?> map) throws BeansException; /** * The preferred way to perform a batch update. * <p>Note that performing a batch update differs from performing a single update, * in that an implementation of this class will continue to update properties * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an * invalid field name or the like) is encountered, throwing a * {@link PropertyBatchUpdateException} containing all the individual errors. * This exception can be examined later to see all binding errors. * Properties that were successfully updated remain changed. * <p>Does not allow unknown fields or invalid fields. * @param pvs a PropertyValues to set on the target object * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions * occurred for specific properties during the batch update. This exception bundles * all individual PropertyAccessExceptions. All other properties will have been * successfully updated. * @see #setPropertyValues(PropertyValues, boolean, boolean) */ void setPropertyValues(PropertyValues pvs) throws BeansException; /** * Perform a batch update with more control over behavior. * <p>Note that performing a batch update differs from performing a single update, * in that an implementation of this class will continue to update properties * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an * invalid field name or the like) is encountered, throwing a * {@link PropertyBatchUpdateException} containing all the individual errors. * This exception can be examined later to see all binding errors. * Properties that were successfully updated remain changed. * @param pvs a PropertyValues to set on the target object * @param ignoreUnknown should we ignore unknown properties (not found in the bean) * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions * occurred for specific properties during the batch update. This exception bundles * all individual PropertyAccessExceptions. All other properties will have been * successfully updated. * @see #setPropertyValues(PropertyValues, boolean, boolean) */ void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown) throws BeansException; /** * Perform a batch update with full control over behavior. * <p>Note that performing a batch update differs from performing a single update, * in that an implementation of this class will continue to update properties * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an * invalid field name or the like) is encountered, throwing a * {@link PropertyBatchUpdateException} containing all the individual errors. * This exception can be examined later to see all binding errors. * Properties that were successfully updated remain changed. * @param pvs a PropertyValues to set on the target object * @param ignoreUnknown should we ignore unknown properties (not found in the bean) * @param ignoreInvalid should we ignore invalid properties (found but not accessible) * @throws InvalidPropertyException if there is no such property or * if the property isn't writable * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions * occurred for specific properties during the batch update. This exception bundles * all individual PropertyAccessExceptions. All other properties will have been * successfully updated. */ void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown, boolean ignoreInvalid) throws BeansException; }