com.univocity.parsers.common.fields.AbstractColumnMapping Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of univocity-parsers Show documentation
Show all versions of univocity-parsers Show documentation
univocity's open source parsers for processing different text formats using a consistent API
/*******************************************************************************
* Copyright 2019 Univocity Software Pty Ltd
*
* 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
*
* http://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 com.univocity.parsers.common.fields;
import com.univocity.parsers.annotations.helpers.*;
import java.util.*;
/**
* Basic support operations for mapping attributes/methods to columns in a {@link ColumnMapper}
* @param the type of key (attribute/method names or specific method definition with parameter and return types)
*/
abstract class AbstractColumnMapping implements Cloneable {
final String prefix;
Map mapping;
/**
* Creates a mapping with a prefix.
*
* @param prefix a dot separated sequence of names that represents the nesting of complex attributes inside a class (e.g customer.contact.phone).
* @param parent the parent mapping of columns, relevant only when nested objects' attributes or methods are being mapped.
*/
AbstractColumnMapping(String prefix, AbstractColumnMapping parent) {
if (parent != null) {
mapping = parent.mapping;
this.prefix = parent.prefix.isEmpty() ? prefix : parent.prefix + '.' + prefix;
} else {
mapping = new LinkedHashMap();
this.prefix = prefix;
}
}
/**
* Maps a attribute or method to a column name
* @param key attribute/method name or specific method definition with parameter and return type
* @param columnName name of column associated with the given key
*/
void mapToColumnName(K key, String columnName) {
mapping.put(key, columnName);
}
/**
* Maps a attribute or method to a column name
* @param key attribute/method name or specific method definition with parameter and return type
* @param column enumeration representing the column associated with the given key
*/
void mapToColumn(K key, Enum column) {
mapping.put(key, column);
}
/**
* Maps a attribute or method to a column name
* @param key attribute/method name or specific method definition with parameter and return type
* @param columnIndex number representing the position of the column associated with the given key
*/
void mapToColumnIndex(K key, int columnIndex) {
mapping.put(key, columnIndex);
}
/**
* Maps multiple attributes or methods to multiple column names
* @param mappings the mappings to be added
*/
void mapToColumnNames(Map mappings) {
mapping.putAll(mappings);
}
/**
* Maps multiple attributes or methods to multiple column names
* @param mappings the mappings to be added
*/
void mapToColumns(Map> mappings) {
mapping.putAll(mappings);
}
/**
* Maps multiple attributes or methods to multiple column names
* @param mappings the mappings to be added
*/
void mapToColumnIndexes(Map mappings) {
mapping.putAll(mappings);
}
/**
* Tests whether a given attribute or method is mapped to a column
* @param key the attribute or method name/descriptor
* @return {@code true} if the key is mapped.
*/
boolean isMapped(K key) {
return getMappedColumn(key) != null;
}
/**
* Transforms the key so it can work with the given prefix.
*
* @param prefix the current object nesting level, denoted by a dot-separated string of nested attribute names.
* @param key the key to transform.
* @return the transformed key or {@code null} if the key can't be used with the given prefix
*/
abstract K prefixKey(String prefix, K key);
private Object getMappedColumn(K key) {
if (key == null) {
return null;
}
key = prefixKey(prefix, key);
Object out = mapping.get(key);
return out;
}
/**
* Updates the mapping of a attribute/method so a mapped class member can target
* a user provided column.
*
* @param fieldMapping a class member that has should be mapped to a column
* @param key the attribute name or method specification that matches with the given field.
*
* @return {@code true} if the mapping has been successfully updated.
*/
boolean updateFieldMapping(FieldMapping fieldMapping, K key) {
Object mappedColumn = getMappedColumn(key);
if (mappedColumn != null) {
if (mappedColumn instanceof Enum) {
mappedColumn = ((Enum) mappedColumn).name();
}
if (mappedColumn instanceof String) {
fieldMapping.setFieldName((String) mappedColumn);
fieldMapping.setIndex(-1);
return true;
} else if (mappedColumn instanceof Integer) {
fieldMapping.setIndex((Integer) mappedColumn);
return true;
}
throw new IllegalStateException("Unexpected mapping of '" + key + "' to " + mappedColumn);
}
return false;
}
/**
* Returns all prefixes used by the keys in this mapping. These represent names of
* nested objects that will be navigated through to access their attributes/methods.
* @param out the set of prefixes to populate.
*/
void extractPrefixes(Set out) {
for (K key : mapping.keySet()) {
String keyPrefix = getKeyPrefix(prefix, key);
if (keyPrefix != null) {
out.add(keyPrefix);
}
}
}
/**
* Returns the prefix of a given key, i.e. the current nested object that is
* being targeted.
*
* @param prefix the current prefix - a dot separated string with nested attribute names
* @param key the attribute name or method definition. If its own prefix starts with the given prefix, the next element after the dot will be returned (if any)
* @return the name of the next nested object relative to the current prefix.
*/
abstract String getKeyPrefix(String prefix, K key);
/**
* Creates a deep copy of this mapping that is independent from the original.
* @return the duplicate of this object.
*/
public AbstractColumnMapping clone() {
try {
AbstractColumnMapping out = (AbstractColumnMapping) super.clone();
out.mapping = new LinkedHashMap(mapping);
return out;
} catch (CloneNotSupportedException e) {
throw new IllegalStateException(e);
}
}
/**
* Locates a given key based on an attribute or method name.
*
* @param nameWithPrefix name of the attribute or method, prefixed with nested object names that identify the path to the target class member.
* @return the key formed with the given attribute name or method definition
*/
abstract K findKey(String nameWithPrefix);
/**
* Removes any mappings containing keys that have a given attribute or method name.
*
* @param nameWithPrefix name of the attribute or method, prefixed with nested object names that identify the path to the target class member.
*/
void remove(String nameWithPrefix) {
K key;
while ((key = findKey(nameWithPrefix)) != null) {
if (mapping.remove(key) == null) {
return;
}
}
}
}