Java tutorial
/** * Copyright 2009-2019 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 * * 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 org.apache.ibatis.binding; import java.lang.reflect.Array; import java.lang.reflect.Method; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Optional; import org.apache.ibatis.annotations.Flush; import org.apache.ibatis.annotations.MapKey; import org.apache.ibatis.cursor.Cursor; import org.apache.ibatis.mapping.MappedStatement; import org.apache.ibatis.mapping.SqlCommandType; import org.apache.ibatis.mapping.StatementType; import org.apache.ibatis.reflection.MetaObject; import org.apache.ibatis.reflection.ParamNameResolver; import org.apache.ibatis.reflection.TypeParameterResolver; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.session.ResultHandler; import org.apache.ibatis.session.RowBounds; import org.apache.ibatis.session.SqlSession; /** * @author Clinton Begin * @author Eduardo Macarron * @author Lasse Voss * @author Kazuki Shimizu */ public class MapperMethod { private final SqlCommand command; private final MethodSignature method; public MapperMethod(Class<?> mapperInterface, Method method, Configuration config) { this.command = new SqlCommand(config, mapperInterface, method); this.method = new MethodSignature(config, mapperInterface, method); } public Object execute(SqlSession sqlSession, Object[] args) { Object result; switch (command.getType()) { case INSERT: { Object param = method.convertArgsToSqlCommandParam(args); result = rowCountResult(sqlSession.insert(command.getName(), param)); break; } case UPDATE: { Object param = method.convertArgsToSqlCommandParam(args); result = rowCountResult(sqlSession.update(command.getName(), param)); break; } case DELETE: { Object param = method.convertArgsToSqlCommandParam(args); result = rowCountResult(sqlSession.delete(command.getName(), param)); break; } case SELECT: if (method.returnsVoid() && method.hasResultHandler()) { executeWithResultHandler(sqlSession, args); result = null; } else if (method.returnsMany()) { result = executeForMany(sqlSession, args); } else if (method.returnsMap()) { result = executeForMap(sqlSession, args); } else if (method.returnsCursor()) { result = executeForCursor(sqlSession, args); } else { Object param = method.convertArgsToSqlCommandParam(args); result = sqlSession.selectOne(command.getName(), param); if (method.returnsOptional() && (result == null || !method.getReturnType().equals(result.getClass()))) { result = Optional.ofNullable(result); } } break; case FLUSH: result = sqlSession.flushStatements(); break; default: throw new BindingException("Unknown execution method for: " + command.getName()); } if (result == null && method.getReturnType().isPrimitive() && !method.returnsVoid()) { throw new BindingException("Mapper method '" + command.getName() + " attempted to return null from a method with a primitive return type (" + method.getReturnType() + ")."); } return result; } private Object rowCountResult(int rowCount) { final Object result; if (method.returnsVoid()) { result = null; } else if (Integer.class.equals(method.getReturnType()) || Integer.TYPE.equals(method.getReturnType())) { result = rowCount; } else if (Long.class.equals(method.getReturnType()) || Long.TYPE.equals(method.getReturnType())) { result = (long) rowCount; } else if (Boolean.class.equals(method.getReturnType()) || Boolean.TYPE.equals(method.getReturnType())) { result = rowCount > 0; } else { throw new BindingException("Mapper method '" + command.getName() + "' has an unsupported return type: " + method.getReturnType()); } return result; } private void executeWithResultHandler(SqlSession sqlSession, Object[] args) { MappedStatement ms = sqlSession.getConfiguration().getMappedStatement(command.getName()); if (!StatementType.CALLABLE.equals(ms.getStatementType()) && void.class.equals(ms.getResultMaps().get(0).getType())) { throw new BindingException("method " + command.getName() + " needs either a @ResultMap annotation, a @ResultType annotation," + " or a resultType attribute in XML so a ResultHandler can be used as a parameter."); } Object param = method.convertArgsToSqlCommandParam(args); if (method.hasRowBounds()) { RowBounds rowBounds = method.extractRowBounds(args); sqlSession.select(command.getName(), param, rowBounds, method.extractResultHandler(args)); } else { sqlSession.select(command.getName(), param, method.extractResultHandler(args)); } } private <E> Object executeForMany(SqlSession sqlSession, Object[] args) { List<E> result; Object param = method.convertArgsToSqlCommandParam(args); if (method.hasRowBounds()) { RowBounds rowBounds = method.extractRowBounds(args); result = sqlSession.selectList(command.getName(), param, rowBounds); } else { result = sqlSession.selectList(command.getName(), param); } // issue #510 Collections & arrays support if (!method.getReturnType().isAssignableFrom(result.getClass())) { if (method.getReturnType().isArray()) { return convertToArray(result); } else { return convertToDeclaredCollection(sqlSession.getConfiguration(), result); } } return result; } private <T> Cursor<T> executeForCursor(SqlSession sqlSession, Object[] args) { Cursor<T> result; Object param = method.convertArgsToSqlCommandParam(args); if (method.hasRowBounds()) { RowBounds rowBounds = method.extractRowBounds(args); result = sqlSession.selectCursor(command.getName(), param, rowBounds); } else { result = sqlSession.selectCursor(command.getName(), param); } return result; } private <E> Object convertToDeclaredCollection(Configuration config, List<E> list) { Object collection = config.getObjectFactory().create(method.getReturnType()); MetaObject metaObject = config.newMetaObject(collection); metaObject.addAll(list); return collection; } @SuppressWarnings("unchecked") private <E> Object convertToArray(List<E> list) { Class<?> arrayComponentType = method.getReturnType().getComponentType(); Object array = Array.newInstance(arrayComponentType, list.size()); if (arrayComponentType.isPrimitive()) { for (int i = 0; i < list.size(); i++) { Array.set(array, i, list.get(i)); } return array; } else { return list.toArray((E[]) array); } } private <K, V> Map<K, V> executeForMap(SqlSession sqlSession, Object[] args) { Map<K, V> result; Object param = method.convertArgsToSqlCommandParam(args); if (method.hasRowBounds()) { RowBounds rowBounds = method.extractRowBounds(args); result = sqlSession.selectMap(command.getName(), param, method.getMapKey(), rowBounds); } else { result = sqlSession.selectMap(command.getName(), param, method.getMapKey()); } return result; } public static class ParamMap<V> extends HashMap<String, V> { private static final long serialVersionUID = -2212268410512043556L; @Override public V get(Object key) { if (!super.containsKey(key)) { throw new BindingException( "Parameter '" + key + "' not found. Available parameters are " + keySet()); } return super.get(key); } } public static class SqlCommand { private final String name; private final SqlCommandType type; public SqlCommand(Configuration configuration, Class<?> mapperInterface, Method method) { final String methodName = method.getName(); final Class<?> declaringClass = method.getDeclaringClass(); MappedStatement ms = resolveMappedStatement(mapperInterface, methodName, declaringClass, configuration); if (ms == null) { if (method.getAnnotation(Flush.class) != null) { name = null; type = SqlCommandType.FLUSH; } else { throw new BindingException( "Invalid bound statement (not found): " + mapperInterface.getName() + "." + methodName); } } else { name = ms.getId(); type = ms.getSqlCommandType(); if (type == SqlCommandType.UNKNOWN) { throw new BindingException("Unknown execution method for: " + name); } } } public String getName() { return name; } public SqlCommandType getType() { return type; } private MappedStatement resolveMappedStatement(Class<?> mapperInterface, String methodName, Class<?> declaringClass, Configuration configuration) { String statementId = mapperInterface.getName() + "." + methodName; if (configuration.hasStatement(statementId)) { return configuration.getMappedStatement(statementId); } else if (mapperInterface.equals(declaringClass)) { return null; } for (Class<?> superInterface : mapperInterface.getInterfaces()) { if (declaringClass.isAssignableFrom(superInterface)) { MappedStatement ms = resolveMappedStatement(superInterface, methodName, declaringClass, configuration); if (ms != null) { return ms; } } } return null; } } public static class MethodSignature { private final boolean returnsMany; private final boolean returnsMap; private final boolean returnsVoid; private final boolean returnsCursor; private final boolean returnsOptional; private final Class<?> returnType; private final String mapKey; private final Integer resultHandlerIndex; private final Integer rowBoundsIndex; private final ParamNameResolver paramNameResolver; public MethodSignature(Configuration configuration, Class<?> mapperInterface, Method method) { Type resolvedReturnType = TypeParameterResolver.resolveReturnType(method, mapperInterface); if (resolvedReturnType instanceof Class<?>) { this.returnType = (Class<?>) resolvedReturnType; } else if (resolvedReturnType instanceof ParameterizedType) { this.returnType = (Class<?>) ((ParameterizedType) resolvedReturnType).getRawType(); } else { this.returnType = method.getReturnType(); } this.returnsVoid = void.class.equals(this.returnType); this.returnsMany = configuration.getObjectFactory().isCollection(this.returnType) || this.returnType.isArray(); this.returnsCursor = Cursor.class.equals(this.returnType); this.returnsOptional = Optional.class.equals(this.returnType); this.mapKey = getMapKey(method); this.returnsMap = this.mapKey != null; this.rowBoundsIndex = getUniqueParamIndex(method, RowBounds.class); this.resultHandlerIndex = getUniqueParamIndex(method, ResultHandler.class); this.paramNameResolver = new ParamNameResolver(configuration, method); } public Object convertArgsToSqlCommandParam(Object[] args) { return paramNameResolver.getNamedParams(args); } public boolean hasRowBounds() { return rowBoundsIndex != null; } public RowBounds extractRowBounds(Object[] args) { return hasRowBounds() ? (RowBounds) args[rowBoundsIndex] : null; } public boolean hasResultHandler() { return resultHandlerIndex != null; } public ResultHandler extractResultHandler(Object[] args) { return hasResultHandler() ? (ResultHandler) args[resultHandlerIndex] : null; } public String getMapKey() { return mapKey; } public Class<?> getReturnType() { return returnType; } public boolean returnsMany() { return returnsMany; } public boolean returnsMap() { return returnsMap; } public boolean returnsVoid() { return returnsVoid; } public boolean returnsCursor() { return returnsCursor; } /** * return whether return type is {@code java.util.Optional}. * @return return {@code true}, if return type is {@code java.util.Optional} * @since 3.5.0 */ public boolean returnsOptional() { return returnsOptional; } private Integer getUniqueParamIndex(Method method, Class<?> paramType) { Integer index = null; final Class<?>[] argTypes = method.getParameterTypes(); for (int i = 0; i < argTypes.length; i++) { if (paramType.isAssignableFrom(argTypes[i])) { if (index == null) { index = i; } else { throw new BindingException(method.getName() + " cannot have multiple " + paramType.getSimpleName() + " parameters"); } } } return index; } private String getMapKey(Method method) { String mapKey = null; if (Map.class.isAssignableFrom(method.getReturnType())) { final MapKey mapKeyAnnotation = method.getAnnotation(MapKey.class); if (mapKeyAnnotation != null) { mapKey = mapKeyAnnotation.value(); } } return mapKey; } } }