Copyright (c) 2008, http://www.snakeyaml.org
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.
/**
 * Copyright (c) 2008, http://www.snakeyaml.org
 *
 * 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.yaml.snakeyaml.constructor;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.UUID;

import org.yaml.snakeyaml.LoaderOptions;
import org.yaml.snakeyaml.TypeDescription;
import org.yaml.snakeyaml.error.YAMLException;
import org.yaml.snakeyaml.introspector.Property;
import org.yaml.snakeyaml.nodes.MappingNode;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.nodes.NodeId;
import org.yaml.snakeyaml.nodes.NodeTuple;
import org.yaml.snakeyaml.nodes.ScalarNode;
import org.yaml.snakeyaml.nodes.SequenceNode;
import org.yaml.snakeyaml.nodes.Tag;

Construct a custom Java instance.
/**
 * Construct a custom Java instance.
 */
public class Constructor extends SafeConstructor {

    public Constructor() {
        this(Object.class);
    }

    public Constructor(LoaderOptions loadingConfig) {
        this(Object.class, loadingConfig);
    }

    
Create Constructor for the specified class as the root.
Params:
theRoot – 
           - the class (usually JavaBean) to be constructed/**
     * Create Constructor for the specified class as the root.
     *
     * @param theRoot
     *            - the class (usually JavaBean) to be constructed
     */
    public Constructor(Class<? extends Object> theRoot) {
        this(new TypeDescription(checkRoot(theRoot)));
    }

    public Constructor(Class<? extends Object> theRoot, LoaderOptions loadingConfig) {
        this(new TypeDescription(checkRoot(theRoot)), loadingConfig);
    }

    
Ugly Java way to check the argument in the constructor
/**
     * Ugly Java way to check the argument in the constructor
     */
    private static Class<? extends Object> checkRoot(Class<? extends Object> theRoot) {
        if (theRoot == null) {
            throw new NullPointerException("Root class must be provided.");
        } else
            return theRoot;
    }

    public Constructor(TypeDescription theRoot) {
        this(theRoot, null, new LoaderOptions());
    }

    public Constructor(TypeDescription theRoot, LoaderOptions loadingConfig) {
        this(theRoot, null, loadingConfig);
    }

    public Constructor(TypeDescription theRoot, Collection<TypeDescription> moreTDs) {
    	this(theRoot, moreTDs, new LoaderOptions());
    }

    public Constructor(TypeDescription theRoot, Collection<TypeDescription> moreTDs, LoaderOptions loadingConfig) {
    	super(loadingConfig);
        if (theRoot == null) {
            throw new NullPointerException("Root type must be provided.");
        }
        this.yamlConstructors.put(null, new ConstructYamlObject());
        if (!Object.class.equals(theRoot.getType())) {
            rootTag = new Tag(theRoot.getType());
        }
        yamlClassConstructors.put(NodeId.scalar, new ConstructScalar());
        yamlClassConstructors.put(NodeId.mapping, new ConstructMapping());
        yamlClassConstructors.put(NodeId.sequence, new ConstructSequence());
        addTypeDescription(theRoot);
        if (moreTDs != null) {
            for (TypeDescription td : moreTDs) {
                addTypeDescription(td);
            }
        }
    }

    
Create Constructor for a class which does not have to be in the classpath
or for a definition from a Spring ApplicationContext.
Params:
theRoot – 
           fully qualified class name of the root class (usually
           JavaBean)
Throws:
ClassNotFoundException – if cannot be loaded by the classloader/**
     * Create Constructor for a class which does not have to be in the classpath
     * or for a definition from a Spring ApplicationContext.
     *
     * @param theRoot
     *            fully qualified class name of the root class (usually
     *            JavaBean)
     * @throws ClassNotFoundException if cannot be loaded by the classloader
     */
    public Constructor(String theRoot) throws ClassNotFoundException {
        this(Class.forName(check(theRoot)));
    }

    public Constructor(String theRoot, LoaderOptions loadingConfig) throws ClassNotFoundException {
        this(Class.forName(check(theRoot)), loadingConfig);
    }

    private static final String check(String s) {
        if (s == null) {
            throw new NullPointerException("Root type must be provided.");
        }
        if (s.trim().length() == 0) {
            throw new YAMLException("Root type must be provided.");
        }
        return s;
    }

    
Construct mapping instance (Map, JavaBean) when the runtime class is
known.
/**
     * Construct mapping instance (Map, JavaBean) when the runtime class is
     * known.
     */
    protected class ConstructMapping implements Construct {

        
Construct JavaBean. If type safe collections are used please look at
TypeDescription.
Params:
node – 
           node where the keys are property names (they can only be
           Strings) and values are objects to be created
Returns:
constructed JavaBean/**
         * Construct JavaBean. If type safe collections are used please look at
         * <code>TypeDescription</code>.
         *
         * @param node
         *            node where the keys are property names (they can only be
         *            <code>String</code>s) and values are objects to be created
         * @return constructed JavaBean
         */
        public Object construct(Node node) {
            MappingNode mnode = (MappingNode) node;
            if (Map.class.isAssignableFrom(node.getType())) {
                if (node.isTwoStepsConstruction()) {
                    return newMap(mnode);
                } else {
                    return constructMapping(mnode);
                }
            } else if (Collection.class.isAssignableFrom(node.getType())) {
                if (node.isTwoStepsConstruction()) {
                    return newSet(mnode);
                } else {
                    return constructSet(mnode);
                }
            } else {
                Object obj = Constructor.this.newInstance(mnode);
                if (node.isTwoStepsConstruction()) {
                    return obj;
                } else {
                    return constructJavaBean2ndStep(mnode, obj);
                }
            }
        }

        @SuppressWarnings("unchecked")
        public void construct2ndStep(Node node, Object object) {
            if (Map.class.isAssignableFrom(node.getType())) {
                constructMapping2ndStep((MappingNode) node, (Map<Object, Object>) object);
            } else if (Set.class.isAssignableFrom(node.getType())) {
                constructSet2ndStep((MappingNode) node, (Set<Object>) object);
            } else {
                constructJavaBean2ndStep((MappingNode) node, object);
            }
        }

        // protected Object createEmptyJavaBean(MappingNode node) {
        // try {
        // Object instance = Constructor.this.newInstance(node);
        // if (instance != null) {
        // return instance;
        // }
        //
        // /**
        // * Using only default constructor. Everything else will be
        // * initialized on 2nd step. If we do here some partial
        // * initialization, how do we then track what need to be done on
        // * 2nd step? I think it is better to get only object here (to
        // * have it as reference for recursion) and do all other thing on
        // * 2nd step.
        // */
        // java.lang.reflect.Constructor<?> c =
        // node.getType().getDeclaredConstructor();
        // c.setAccessible(true);
        // return c.newInstance();
        // } catch (Exception e) {
        // throw new YAMLException(e);
        // }
        // }

        protected Object constructJavaBean2ndStep(MappingNode node, Object object) {
            flattenMapping(node);
            Class<? extends Object> beanType = node.getType();
            List<NodeTuple> nodeValue = node.getValue();
            for (NodeTuple tuple : nodeValue) {
                ScalarNode keyNode;
                if (tuple.getKeyNode() instanceof ScalarNode) {
                    // key must be scalar
                    keyNode = (ScalarNode) tuple.getKeyNode();
                } else {
                    throw new YAMLException(
                            "Keys must be scalars but found: " + tuple.getKeyNode());
                }
                Node valueNode = tuple.getValueNode();
                // keys can only be Strings
                keyNode.setType(String.class);
                String key = (String) constructObject(keyNode);
                try {
                    TypeDescription memberDescription = typeDefinitions.get(beanType);
                    Property property = memberDescription == null ? getProperty(beanType, key)
                            : memberDescription.getProperty(key);

                    if (!property.isWritable()) {
                        throw new YAMLException("No writable property '" + key + "' on class: "
                                + beanType.getName());
                    }

                    valueNode.setType(property.getType());
                    final boolean typeDetected = (memberDescription != null)
                            ? memberDescription.setupPropertyType(key, valueNode)
                            : false;
                    if (!typeDetected && valueNode.getNodeId() != NodeId.scalar) {
                        // only if there is no explicit TypeDescription
                        Class<?>[] arguments = property.getActualTypeArguments();
                        if (arguments != null && arguments.length > 0) {
                            // type safe (generic) collection may contain the
                            // proper class
                            if (valueNode.getNodeId() == NodeId.sequence) {
                                Class<?> t = arguments[0];
                                SequenceNode snode = (SequenceNode) valueNode;
                                snode.setListType(t);
                            } else if (Set.class.isAssignableFrom(valueNode.getType())) {
                                Class<?> t = arguments[0];
                                MappingNode mnode = (MappingNode) valueNode;
                                mnode.setOnlyKeyType(t);
                                mnode.setUseClassConstructor(true);
                            } else if (Map.class.isAssignableFrom(valueNode.getType())) {
                                Class<?> keyType = arguments[0];
                                Class<?> valueType = arguments[1];
                                MappingNode mnode = (MappingNode) valueNode;
                                mnode.setTypes(keyType, valueType);
                                mnode.setUseClassConstructor(true);
                            }
                        }
                    }

                    Object value = (memberDescription != null)
                            ? newInstance(memberDescription, key, valueNode)
                            : constructObject(valueNode);
                    // Correct when the property expects float but double was
                    // constructed
                    if (property.getType() == Float.TYPE || property.getType() == Float.class) {
                        if (value instanceof Double) {
                            value = ((Double) value).floatValue();
                        }
                    }
                    // Correct when the property a String but the value is binary
                    if (property.getType() == String.class && Tag.BINARY.equals(valueNode.getTag())
                            && value instanceof byte[]) {
                        value = new String((byte[]) value);
                    }

                    if (memberDescription == null
                            || !memberDescription.setProperty(object, key, value)) {
                        property.set(object, value);
                    }
                } catch (DuplicateKeyException e) {
                    throw e;
                } catch (Exception e) {
                    throw new ConstructorException(
                            "Cannot create property=" + key + " for JavaBean=" + object,
                            node.getStartMark(), e.getMessage(), valueNode.getStartMark(), e);
                }
            }
            return object;
        }

        private Object newInstance(TypeDescription memberDescription, String propertyName,
                Node node) {
            Object newInstance = memberDescription.newInstance(propertyName, node);
            if (newInstance != null) {
                constructedObjects.put(node, newInstance);
                return constructObjectNoCheck(node);
            }
            return constructObject(node);
        }

        protected Property getProperty(Class<? extends Object> type, String name) {
            return getPropertyUtils().getProperty(type, name);
        }
    }

    
Construct an instance when the runtime class is not known but a global
tag with a class name is defined. It delegates the construction to the
appropriate constructor based on the node kind (scalar, sequence,
mapping)
/**
     * Construct an instance when the runtime class is not known but a global
     * tag with a class name is defined. It delegates the construction to the
     * appropriate constructor based on the node kind (scalar, sequence,
     * mapping)
     */
    protected class ConstructYamlObject implements Construct {

        private Construct getConstructor(Node node) {
            Class<?> cl = getClassForNode(node);
            node.setType(cl);
            // call the constructor as if the runtime class is defined
            Construct constructor = yamlClassConstructors.get(node.getNodeId());
            return constructor;
        }

        public Object construct(Node node) {
            try {
                return getConstructor(node).construct(node);
            } catch (ConstructorException e) {
                throw e;
            } catch (Exception e) {
                throw new ConstructorException(null, null, "Can't construct a java object for "
                        + node.getTag() + "; exception=" + e.getMessage(), node.getStartMark(), e);
            }
        }

        public void construct2ndStep(Node node, Object object) {
            try {
                getConstructor(node).construct2ndStep(node, object);
            } catch (Exception e) {
                throw new ConstructorException(
                        null, null, "Can't construct a second step for a java object for "
                                + node.getTag() + "; exception=" + e.getMessage(),
                        node.getStartMark(), e);
            }
        }
    }

    
Construct scalar instance when the runtime class is known. Recursive
structures are not supported.
/**
     * Construct scalar instance when the runtime class is known. Recursive
     * structures are not supported.
     */
    protected class ConstructScalar extends AbstractConstruct {
        public Object construct(Node nnode) {
            ScalarNode node = (ScalarNode) nnode;
            Class<?> type = node.getType();

            try {
                return newInstance(type, node, false);
            } catch (InstantiationException e1) {
            }

            Object result;
            if (type.isPrimitive() || type == String.class || Number.class.isAssignableFrom(type)
                    || type == Boolean.class || Date.class.isAssignableFrom(type)
                    || type == Character.class || type == BigInteger.class
                    || type == BigDecimal.class || Enum.class.isAssignableFrom(type)
                    || Tag.BINARY.equals(node.getTag()) || Calendar.class.isAssignableFrom(type)
                    || type == UUID.class) {
                // standard classes created directly
                result = constructStandardJavaInstance(type, node);
            } else {
                // there must be only 1 constructor with 1 argument
                java.lang.reflect.Constructor<?>[] javaConstructors = type
                        .getDeclaredConstructors();
                int oneArgCount = 0;
                java.lang.reflect.Constructor<?> javaConstructor = null;
                for (java.lang.reflect.Constructor<?> c : javaConstructors) {
                    if (c.getParameterTypes().length == 1) {
                        oneArgCount++;
                        javaConstructor = c;
                    }
                }
                Object argument;
                if (javaConstructor == null) {
                    try {
                        return newInstance(type, node, false);
                    } catch (InstantiationException ie) {
                        throw new YAMLException("No single argument constructor found for " + type
                                + " : " + ie.getMessage());
                    }
                } else if (oneArgCount == 1) {
                    argument = constructStandardJavaInstance(javaConstructor.getParameterTypes()[0],
                            node);
                } else {
                    // TODO it should be possible to use implicit types instead
                    // of forcing String. Resolver must be available here to
                    // obtain the implicit tag. Then we can set the tag and call
                    // callConstructor(node) to create the argument instance.
                    // On the other hand it may be safer to require a custom
                    // constructor to avoid guessing the argument class
                    argument = constructScalar(node);
                    try {
                        javaConstructor = type.getDeclaredConstructor(String.class);
                    } catch (Exception e) {
                        throw new YAMLException("Can't construct a java object for scalar "
                                + node.getTag() + "; No String constructor found. Exception="
                                + e.getMessage(), e);
                    }
                }
                try {
                    javaConstructor.setAccessible(true);
                    result = javaConstructor.newInstance(argument);
                } catch (Exception e) {
                    throw new ConstructorException(null, null,
                            "Can't construct a java object for scalar " + node.getTag()
                                    + "; exception=" + e.getMessage(),
                            node.getStartMark(), e);
                }
            }
            return result;
        }

        @SuppressWarnings("unchecked")
        private Object constructStandardJavaInstance(@SuppressWarnings("rawtypes") Class type,
                ScalarNode node) {
            Object result;
            if (type == String.class) {
                Construct stringConstructor = yamlConstructors.get(Tag.STR);
                result = stringConstructor.construct(node);
            } else if (type == Boolean.class || type == Boolean.TYPE) {
                Construct boolConstructor = yamlConstructors.get(Tag.BOOL);
                result = boolConstructor.construct(node);
            } else if (type == Character.class || type == Character.TYPE) {
                Construct charConstructor = yamlConstructors.get(Tag.STR);
                String ch = (String) charConstructor.construct(node);
                if (ch.length() == 0) {
                    result = null;
                } else if (ch.length() != 1) {
                    throw new YAMLException(
                            "Invalid node Character: '" + ch + "'; length: " + ch.length());
                } else {
                    result = Character.valueOf(ch.charAt(0));
                }
            } else if (Date.class.isAssignableFrom(type)) {
                Construct dateConstructor = yamlConstructors.get(Tag.TIMESTAMP);
                Date date = (Date) dateConstructor.construct(node);
                if (type == Date.class) {
                    result = date;
                } else {
                    try {
                        java.lang.reflect.Constructor<?> constr = type.getConstructor(long.class);
                        result = constr.newInstance(date.getTime());
                    } catch (RuntimeException e) {
                        throw e;
                    } catch (Exception e) {
                        throw new YAMLException("Cannot construct: '" + type + "'");
                    }
                }
            } else if (type == Float.class || type == Double.class || type == Float.TYPE
                    || type == Double.TYPE || type == BigDecimal.class) {
                if (type == BigDecimal.class) {
                    result = new BigDecimal(node.getValue());
                } else {
                    Construct doubleConstructor = yamlConstructors.get(Tag.FLOAT);
                    result = doubleConstructor.construct(node);
                    if (type == Float.class || type == Float.TYPE) {
                        result = Float.valueOf(((Double) result).floatValue());
                    }
                }
            } else if (type == Byte.class || type == Short.class || type == Integer.class
                    || type == Long.class || type == BigInteger.class || type == Byte.TYPE
                    || type == Short.TYPE || type == Integer.TYPE || type == Long.TYPE) {
                Construct intConstructor = yamlConstructors.get(Tag.INT);
                result = intConstructor.construct(node);
                if (type == Byte.class || type == Byte.TYPE) {
                    result = Integer.valueOf(result.toString()).byteValue();
                } else if (type == Short.class || type == Short.TYPE) {
                    result = Integer.valueOf(result.toString()).shortValue();
                } else if (type == Integer.class || type == Integer.TYPE) {
                    result = Integer.parseInt(result.toString());
                } else if (type == Long.class || type == Long.TYPE) {
                    result = Long.valueOf(result.toString());
                } else {
                    // only BigInteger left
                    result = new BigInteger(result.toString());
                }
            } else if (Enum.class.isAssignableFrom(type)) {
                String enumValueName = node.getValue();
                try {
                    result = Enum.valueOf(type, enumValueName);
                } catch (Exception ex) {
                    throw new YAMLException("Unable to find enum value '" + enumValueName
                            + "' for enum class: " + type.getName());
                }
            } else if (Calendar.class.isAssignableFrom(type)) {
                ConstructYamlTimestamp contr = new ConstructYamlTimestamp();
                contr.construct(node);
                result = contr.getCalendar();
            } else if (Number.class.isAssignableFrom(type)) {
                //since we do not know the exact type we create Float
                ConstructYamlFloat contr = new ConstructYamlFloat();
                result = contr.construct(node);
            } else if (UUID.class == type) {
                result = UUID.fromString(node.getValue());
            } else {
                if (yamlConstructors.containsKey(node.getTag())) {
                    result = yamlConstructors.get(node.getTag()).construct(node);
                } else {
                    throw new YAMLException("Unsupported class: " + type);
                }
            }
            return result;
        }
    }

    
Construct sequence (List, Array, or immutable object) when the runtime
class is known.
/**
     * Construct sequence (List, Array, or immutable object) when the runtime
     * class is known.
     */
    protected class ConstructSequence implements Construct {
        @SuppressWarnings("unchecked")
        public Object construct(Node node) {
            SequenceNode snode = (SequenceNode) node;
            if (Set.class.isAssignableFrom(node.getType())) {
                if (node.isTwoStepsConstruction()) {
                    throw new YAMLException("Set cannot be recursive.");
                } else {
                    return constructSet(snode);
                }
            } else if (Collection.class.isAssignableFrom(node.getType())) {
                if (node.isTwoStepsConstruction()) {
                    return newList(snode);
                } else {
                    return constructSequence(snode);
                }
            } else if (node.getType().isArray()) {
                if (node.isTwoStepsConstruction()) {
                    return createArray(node.getType(), snode.getValue().size());
                } else {
                    return constructArray(snode);
                }
            } else {
                // create immutable object
                List<java.lang.reflect.Constructor<?>> possibleConstructors = new ArrayList<java.lang.reflect.Constructor<?>>(
                        snode.getValue().size());
                for (java.lang.reflect.Constructor<?> constructor : node.getType()
                        .getDeclaredConstructors()) {
                    if (snode.getValue().size() == constructor.getParameterTypes().length) {
                        possibleConstructors.add(constructor);
                    }
                }
                if (!possibleConstructors.isEmpty()) {
                    if (possibleConstructors.size() == 1) {
                        Object[] argumentList = new Object[snode.getValue().size()];
                        java.lang.reflect.Constructor<?> c = possibleConstructors.get(0);
                        int index = 0;
                        for (Node argumentNode : snode.getValue()) {
                            Class<?> type = c.getParameterTypes()[index];
                            // set runtime classes for arguments
                            argumentNode.setType(type);
                            argumentList[index++] = constructObject(argumentNode);
                        }

                        try {
                            c.setAccessible(true);
                            return c.newInstance(argumentList);
                        } catch (Exception e) {
                            throw new YAMLException(e);
                        }
                    }

                    // use BaseConstructor
                    List<Object> argumentList = (List<Object>) constructSequence(snode);
                    Class<?>[] parameterTypes = new Class[argumentList.size()];
                    int index = 0;
                    for (Object parameter : argumentList) {
                        parameterTypes[index] = parameter.getClass();
                        index++;
                    }

                    for (java.lang.reflect.Constructor<?> c : possibleConstructors) {
                        Class<?>[] argTypes = c.getParameterTypes();
                        boolean foundConstructor = true;
                        for (int i = 0; i < argTypes.length; i++) {
                            if (!wrapIfPrimitive(argTypes[i]).isAssignableFrom(parameterTypes[i])) {
                                foundConstructor = false;
                                break;
                            }
                        }
                        if (foundConstructor) {
                            try {
                                c.setAccessible(true);
                                return c.newInstance(argumentList.toArray());
                            } catch (Exception e) {
                                throw new YAMLException(e);
                            }
                        }
                    }
                }
                throw new YAMLException(
                        "No suitable constructor with " + String.valueOf(snode.getValue().size())
                                + " arguments found for " + node.getType());

            }
        }

        private final Class<? extends Object> wrapIfPrimitive(Class<?> clazz) {
            if (!clazz.isPrimitive()) {
                return clazz;
            }
            if (clazz == Integer.TYPE) {
                return Integer.class;
            }
            if (clazz == Float.TYPE) {
                return Float.class;
            }
            if (clazz == Double.TYPE) {
                return Double.class;
            }
            if (clazz == Boolean.TYPE) {
                return Boolean.class;
            }
            if (clazz == Long.TYPE) {
                return Long.class;
            }
            if (clazz == Character.TYPE) {
                return Character.class;
            }
            if (clazz == Short.TYPE) {
                return Short.class;
            }
            if (clazz == Byte.TYPE) {
                return Byte.class;
            }
            throw new YAMLException("Unexpected primitive " + clazz);
        }

        @SuppressWarnings("unchecked")
        public void construct2ndStep(Node node, Object object) {
            SequenceNode snode = (SequenceNode) node;
            if (List.class.isAssignableFrom(node.getType())) {
                List<Object> list = (List<Object>) object;
                constructSequenceStep2(snode, list);
            } else if (node.getType().isArray()) {
                constructArrayStep2(snode, object);
            } else {
                throw new YAMLException("Immutable objects cannot be recursive.");
            }
        }
    }

    protected Class<?> getClassForNode(Node node) {
        Class<? extends Object> classForTag = typeTags.get(node.getTag());
        if (classForTag == null) {
            String name = node.getTag().getClassName();
            Class<?> cl;
            try {
                cl = getClassForName(name);
            } catch (ClassNotFoundException e) {
                throw new YAMLException("Class not found: " + name);
            }
            typeTags.put(node.getTag(), cl);
            return cl;
        } else {
            return classForTag;
        }
    }

    protected Class<?> getClassForName(String name) throws ClassNotFoundException {
        try {
            return Class.forName(name, true, Thread.currentThread().getContextClassLoader());
        } catch (ClassNotFoundException e) {
            return Class.forName(name);
        }
    }
}