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org.codehaus.jackson.map.deser.SettableBeanProperty Maven / Gradle / Ivy

package org.codehaus.jackson.map.deser;

import java.io.IOException;
import java.lang.reflect.*;

import org.codehaus.jackson.*;
import org.codehaus.jackson.map.*;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.util.InternCache;

/**
 * Base class for settable properties of a bean: contains
 * both type and name definitions, and reflection-based set functionality.
 * Concrete sub-classes implement details, so that both field- and
 * setter-backed properties can be handled
 */
public abstract class SettableBeanProperty
{
    /**
     * Logical name of the property (often but not always derived
     * from the setter method name)
     */
    final String _propName;

    final JavaType _type;

    protected JsonDeserializer _valueDeserializer;

    /**
     * Value to be used when 'null' literal is encountered in Json.
     * For most types simply Java null, but for primitive types must
     * be a non-null value (like Integer.valueOf(0) for int).
     */
    protected Object _nullValue;

    /*
    ////////////////////////////////////////////////////////
    // Life-cycle (construct & configure)
    ////////////////////////////////////////////////////////
     */

    public SettableBeanProperty(String propName, JavaType type)
    {
        /* 09-Jan-2009, tatu: Intern()ing makes sense since Jackson parsed
         *   field names are interned too, hence lookups will be faster.
         */
        if (propName == null || propName.length() == 0) {
            _propName = "";
        } else {
            _propName = InternCache.instance.intern(propName);
        }
        _type = type;
    }

    public void setValueDeserializer(JsonDeserializer deser)
    {
        if (_valueDeserializer != null) { // sanity check
            throw new IllegalStateException("Already had assigned deserializer for property '"+_propName+"' (class "+getDeclaringClass().getName()+")");
        }
        _valueDeserializer = deser;
        _nullValue = _valueDeserializer.getNullValue();
    }

    protected abstract Class getDeclaringClass();

    /*
    ////////////////////////////////////////////////////////
    // Accessors
    ////////////////////////////////////////////////////////
     */

    public String getPropertyName() { return _propName; }
    public JavaType getType() { return _type; }

    public boolean hasValueDeserializer() { return (_valueDeserializer != null); }

    /**
     * Method to use for accessing index of the property (related to
     * other properties in the same context); currently only applicable
     * to "Creator properties".
     *

* Base implementation returns -1 to indicate that no index exists * for the property. */ public int getCreatorIndex() { return -1; } /* //////////////////////////////////////////////////////// // Public API //////////////////////////////////////////////////////// */ /** * Method called to deserialize appropriate value, given parser (and * context), and set it using appropriate mechanism */ public abstract void deserializeAndSet(JsonParser jp, DeserializationContext ctxt, Object instance) throws IOException, JsonProcessingException; public abstract void set(Object instance, Object value) throws IOException; /** * This method is needed by some specialized bean deserializers, * and also called by some {@link #deserializeAndSet} implementations. */ public final Object deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException { JsonToken t = jp.nextToken(); if (t == JsonToken.VALUE_NULL) { return _nullValue; } return _valueDeserializer.deserialize(jp, ctxt); } /* //////////////////////////////////////////////////////// // Helper methods //////////////////////////////////////////////////////// */ /** * Method that takes in exception of any type, and casts or wraps it * to an IOException or its subclass. */ protected void _throwAsIOE(Exception e, Object value) throws IOException { if (e instanceof IllegalArgumentException) { String actType = (value == null) ? "[NULL]" : value.getClass().getName(); StringBuilder msg = new StringBuilder("Problem deserializing property '").append(getPropertyName()); msg.append("' (expected type: ").append(getType()); msg.append("; actual type: ").append(actType).append(")"); String origMsg = e.getMessage(); if (origMsg != null) { msg.append(", problem: ").append(origMsg); } else { msg.append(" (no error message provided)"); } throw new JsonMappingException(msg.toString(), null, e); } _throwAsIOE(e); } protected IOException _throwAsIOE(Exception e) throws IOException { if (e instanceof IOException) { throw (IOException) e; } if (e instanceof RuntimeException) { throw (RuntimeException) e; } // let's wrap the innermost problem Throwable th = e; while (th.getCause() != null) { th = th.getCause(); } throw new JsonMappingException(th.getMessage(), null, th); } @Override public String toString() { return "[property '"+_propName+"']"; } /* //////////////////////////////////////////////////////// // Impl classes //////////////////////////////////////////////////////// */ /** * This concrete sub-class implements property that is set * using regular "setter" method. */ public final static class MethodProperty extends SettableBeanProperty { /** * Setter method for modifying property value; used for * "regular" method-accessible properties. */ protected final Method _setter; public MethodProperty(String propName, JavaType type, Method setter) { super(propName, type); _setter = setter; } protected Class getDeclaringClass() { return _setter.getDeclaringClass(); } public void deserializeAndSet(JsonParser jp, DeserializationContext ctxt, Object instance) throws IOException, JsonProcessingException { set(instance, deserialize(jp, ctxt)); } public final void set(Object instance, Object value) throws IOException { try { _setter.invoke(instance, value); } catch (Exception e) { _throwAsIOE(e, value); } } } /** * This concrete sub-class implements Collection or Map property that is * indirectly by getting the property value and directly modifying it. */ public final static class SetterlessProperty extends SettableBeanProperty { /** * Get method for accessing property value used to access property * (of Collection or Map type) to modify. */ protected final Method _getter; public SetterlessProperty(String propName, JavaType type, Method getter) { super(propName, type); _getter = getter; } protected Class getDeclaringClass() { return _getter.getDeclaringClass(); } public final void deserializeAndSet(JsonParser jp, DeserializationContext ctxt, Object instance) throws IOException, JsonProcessingException { JsonToken t = jp.nextToken(); if (t == JsonToken.VALUE_NULL) { /* Hmmh. Is this a problem? We won't be setting anything, so it's * equivalent of empty Collection/Map in this case */ return; } // Ok: then, need to fetch Collection/Map to modify: Object toModify; try { toModify = _getter.invoke(instance); } catch (Exception e) { _throwAsIOE(e); return; // never gets here } /* Note: null won't work, since we can't then inject anything * in. At least that's not good in common case. However, * theoretically the case where we get Json null might * be compatible. If so, implementation could be changed. */ if (toModify == null) { throw new JsonMappingException("Problem deserializing 'setterless' property '"+getPropertyName()+"': get method returned null"); } _valueDeserializer.deserialize(jp, ctxt, toModify); } public final void set(Object instance, Object value) throws IOException { throw new UnsupportedOperationException("Should never call 'set' onn setterless property"); } } /** * This concrete sub-class implements property that is set * directly assigning to a Field. */ public final static class FieldProperty extends SettableBeanProperty { /** * Actual field to set when deserializing this property. */ protected final Field _field; public FieldProperty(String propName, JavaType type, Field f) { super(propName, type); _field = f; } protected Class getDeclaringClass() { return _field.getDeclaringClass(); } public void deserializeAndSet(JsonParser jp, DeserializationContext ctxt, Object instance) throws IOException, JsonProcessingException { set(instance, deserialize(jp, ctxt)); } public final void set(Object instance, Object value) throws IOException { try { _field.set(instance, value); } catch (Exception e) { _throwAsIOE(e, value); } } } /** * This concrete sub-class implements property that is passed * via Creator (constructor or static factory method). */ public final static class CreatorProperty extends SettableBeanProperty { final Class _declaringClass; /** * Index of the property */ final int _index; public CreatorProperty(String propName, JavaType type, Class declaringClass, int index) { super(propName, type); _declaringClass = declaringClass; _index = index; } /** * Method to use for accessing index of the property (related to * other properties in the same context); currently only applicable * to "Creator properties". *

* Base implementation returns -1 to indicate that no index exists * for the property. */ public int getCreatorIndex() { return _index; } protected Class getDeclaringClass() { return _declaringClass; } public void deserializeAndSet(JsonParser jp, DeserializationContext ctxt, Object instance) throws IOException, JsonProcessingException { set(instance, deserialize(jp, ctxt)); } public void set(Object instance, Object value) throws IOException { /* Hmmmh. Should we return quietly (NOP), or error? * For now, let's just bail out without fuss. */ //throw new IllegalStateException("Method should never be called on a "+getClass().getName()); } } }