| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.commons.configuration2.beanutils; |
| |
| /** |
| * <p> |
| * A class representing an argument for a constructor invocation to be used by a |
| * {@link BeanDeclaration}. |
| * </p> |
| * <p> |
| * A {@code BeanDeclaration} can provide a list of instances of this class to |
| * define the constructor to be invoked on the bean class. Each constructor |
| * argument can either be a simple value or a nested {@code BeanDeclaration}. In |
| * the latter case, the bean is resolved recursively. |
| * </p> |
| * <p> |
| * The constructor to be invoked on the bean class has to be determined based on |
| * the types of the constructor arguments. To avoid ambiguity, the type name can |
| * be explicitly provided. |
| * </p> |
| * |
| * @version $Id$ |
| * @since 2.0 |
| */ |
| public final class ConstructorArg |
| { |
| /** The bean declaration referenced by this constructor argument. */ |
| private final BeanDeclaration beanDeclaration; |
| |
| /** The value of this constructor argument. */ |
| private final Object value; |
| |
| /** The name of the argument type. */ |
| private final String typeName; |
| |
| /** |
| * Creates a new instance of {@code ConstructorArg}. |
| * |
| * @param decl the associated bean declaration |
| * @param val the value of the argument |
| * @param type the type name |
| */ |
| private ConstructorArg(BeanDeclaration decl, Object val, String type) |
| { |
| beanDeclaration = decl; |
| value = val; |
| typeName = type; |
| } |
| |
| /** |
| * Creates a new instance of {@code ConstructorArg} for the specified |
| * {@code BeanDeclaration}. The actual value of this argument is the |
| * resolved {@code BeanDeclaration}. |
| * |
| * @param decl the {@code BeanDeclaration} |
| * @return the newly created instance of this class |
| * @throws NullPointerException if the {@code BeanDeclaration} is |
| * <b>null</b> |
| */ |
| public static ConstructorArg forBeanDeclaration(BeanDeclaration decl) |
| { |
| return forBeanDeclaration(decl, null); |
| } |
| |
| /** |
| * Creates a new instance of {@code ConstructorArg} for the specified |
| * {@code BeanDeclaration} and sets the type name explicitly. The type name |
| * is used to match this argument against the parameter type of a |
| * constructor or the bean class. |
| * |
| * @param decl the {@code BeanDeclaration} |
| * @param typeName the name of the data type of this argument |
| * @return the newly created instance of this class |
| * @throws NullPointerException if the {@code BeanDeclaration} is |
| * <b>null</b> |
| */ |
| public static ConstructorArg forBeanDeclaration(BeanDeclaration decl, |
| String typeName) |
| { |
| if (decl == null) |
| { |
| throw new NullPointerException("BeanDeclaration must not be null!"); |
| } |
| return new ConstructorArg(decl, null, typeName); |
| } |
| |
| /** |
| * Creates a new instance of {@code ConstructorArg} for the specified simple |
| * value. The value is passed to the constructor invocation. |
| * |
| * @param value the value of this constructor argument (may be <b>null</b>) |
| * @return the newly created instance of this class |
| */ |
| public static ConstructorArg forValue(Object value) |
| { |
| return forValue(value, null); |
| } |
| |
| /** |
| * Creates a new instance of {@code ConstructorArg} for the specified simple |
| * value and sets the type name explicitly. The type name is used to match |
| * this argument against the parameter type of a constructor or the bean |
| * class. |
| * |
| * @param value the value of this constructor argument (may be <b>null</b>) |
| * @param typeName the name of the data type of this argument |
| * @return the newly created instance of this class |
| */ |
| public static ConstructorArg forValue(Object value, String typeName) |
| { |
| return new ConstructorArg(null, value, typeName); |
| } |
| |
| /** |
| * Returns the {@code BeanDeclaration} referenced by this constructor |
| * argument. A return value of <b>null</b> means that this constructor |
| * argument does not have a bean declaration as value; in this case, the |
| * value can be queried using the {@link #getValue()} method. |
| * |
| * @return the referenced {@code BeanDeclaration} or <b>null</b> |
| */ |
| public BeanDeclaration getBeanDeclaration() |
| { |
| return beanDeclaration; |
| } |
| |
| /** |
| * Returns a flag whether this constructor argument represents a |
| * {@code BeanDeclaration}. If this method returns <b>true</b>, the actual |
| * value of this argument can be obtained by resolving the bean declaration |
| * returned by {@link #getBeanDeclaration()}. Otherwise, this argument has a |
| * simple value which can be queried using {@link #getValue()}. |
| * |
| * @return a flag whether this constructor argument references a bean |
| * declaration |
| */ |
| public boolean isNestedBeanDeclaration() |
| { |
| return getBeanDeclaration() != null; |
| } |
| |
| /** |
| * Returns the value of this constructor argument. This method can be |
| * queried if {@link #isNestedBeanDeclaration()} returns <b>false</b>. Note |
| * that a return value of <b>null</b> is legal (to pass <b>null</b> to a |
| * constructor argument). |
| * |
| * @return the simple value of this constructor argument |
| */ |
| public Object getValue() |
| { |
| return value; |
| } |
| |
| /** |
| * Returns the optional data type name of this constructor argument. The |
| * type name can be specified as a hint to select a specific constructor if |
| * there are ambiguities. Note that it does not necessarily has to match the |
| * data type of this argument's value because a type conversion may be |
| * performed before invoking the constructor. |
| * |
| * @return the data type name of this argument if defined or <b>null</b> |
| * otherwise |
| */ |
| public String getTypeName() |
| { |
| return typeName; |
| } |
| |
| /** |
| * Checks whether this constructor argument is compatible with the given |
| * class. This method is called to determine a matching constructor. It |
| * compares the argument's data type with the class name if it is defined. |
| * If no type name has been set, result is <b>true</b> as it is assumed that |
| * a type conversion can be performed when calling the constructor. This |
| * means that per default only the number of constructor arguments is |
| * checked to find a matching constructor. Only if there are multiple |
| * constructors with the same number of arguments, explicit type names have |
| * to be provided to select a specific constructor. |
| * |
| * @param argCls the class of the constructor argument to compare with |
| * @return <b>true</b> if this constructor argument is compatible with this |
| * class, <b>false</b> otherwise |
| */ |
| public boolean matches(Class<?> argCls) |
| { |
| if (argCls == null) |
| { |
| return false; |
| } |
| |
| return getTypeName() == null || getTypeName().equals(argCls.getName()); |
| } |
| |
| /** |
| * Returns a string representation of this object. This string contains the |
| * value of this constructor argument and the explicit type if provided. |
| * |
| * @return a string for this object |
| */ |
| @Override |
| public String toString() |
| { |
| StringBuilder buf = new StringBuilder(); |
| buf.append(getClass().getSimpleName()); |
| buf.append(" [ value = "); |
| buf.append(isNestedBeanDeclaration() ? getBeanDeclaration() |
| : getValue()); |
| if (getTypeName() != null) |
| { |
| buf.append(" (").append(getTypeName()).append(')'); |
| } |
| buf.append(" ]"); |
| return buf.toString(); |
| } |
| } |