genericobjectfactory.java

JfreeChart 常用图表例子

     * Returns a property definition for the specified tag name.
     * 
     * @param tagName  the tag name.
     * 
     * @return the property definition.
     * 
     * @throws ObjectDescriptionException if there is no such tag defined for this object.
     */
    public PropertyDefinition getPropertyDefinitionByTagName(final String tagName)
        throws ObjectDescriptionException {
        for (int i = 0; i < this.propertyDefinitions.length; i++) {
            final PropertyDefinition pdef = this.propertyDefinitions[i];
            if (pdef.getElementName().equals(tagName)) {
                return pdef;
            }
        }
        throw new ObjectDescriptionException(
            "This tag is not defined for this kind of object. : " + tagName
        );
    }

    /**
     * Returns the constructor definitions.
     * 
     * @return the constructor definitions.
     */
    public ConstructorDefinition[] getConstructorDefinitions() {
        return this.constructorDefinitions;
    }

    /**
     * Returns the attribute definitions.
     * 
     * @return the attribute definitions.
     */
    public AttributeDefinition[] getAttributeDefinitions() {
        return this.attributeDefinitions;
    }

    /**
     * Returns the property definitions.
     * 
     * @return the property definitions.
     */
    public PropertyDefinition[] getPropertyDefinitions() {
        return this.propertyDefinitions;
    }

    /**
     * Returns the property names.
     * 
     * @return the property names.
     */
    public String[] getOrderedPropertyNames() {
        return this.orderedPropertyNames;
    }

    /**
     * Returns the lookup definitions.
     * 
     * @return the lookup definitions.
     */
    public LookupDefinition[] getLookupDefinitions() {
        return this.lookupDefinitions;
    }

    /**
     * Returns the value of the specified property.
     * 
     * @param name  the property name.
     * 
     * @return the property value.
     */
    public Object getProperty(final String name) {
        return this.propertyValues.get(name);
    }

    /**
     * Creates an object according to the definition.
     * 
     * @return the object.
     * 
     * @throws ObjectDescriptionException if there is a problem with the object description.
     */
    public Object createObject() throws ObjectDescriptionException {
        final Class[] cArgs = new Class[this.constructorDefinitions.length];
        final Object[] oArgs = new Object[this.constructorDefinitions.length];
        for (int i = 0; i < cArgs.length; i++) {
            final ConstructorDefinition cDef = this.constructorDefinitions[i];
            cArgs[i] = cDef.getType();
            if (cDef.isNull()) {
                oArgs[i] = null;
            }
            else {
                oArgs[i] = getProperty(cDef.getPropertyName());
            }
        }

        try {
            final Constructor constr = this.baseClass.getConstructor(cArgs);
            final Object o = constr.newInstance(oArgs);
            return o;
        }
        catch (Exception e) {
            throw new ObjectDescriptionException("Ugh! Constructor made a buuuh!", e);
        }
    }

    /**
     * Sets a property value.
     * 
     * @param propertyName  the property name.
     * @param value  the property value.
     * 
     * @throws ObjectDescriptionException if there is a problem with the object description.
     */
    public void setProperty(final String propertyName, final Object value)
        throws ObjectDescriptionException {
        final PropertyDescriptor pdesc = getPropertyDescriptor(propertyName);
        if (pdesc == null) {
            throw new ObjectDescriptionException("Unknown property " + propertyName);
        }

        if (!isAssignableOrPrimitive(pdesc.getPropertyType(), value.getClass())) {
            throw new ObjectDescriptionException(
                "Invalid value: " + pdesc.getPropertyType() + " vs. " + value.getClass()
            );
        }

        this.propertyValues.put(propertyName, value);
    }

    /**
     * Returns <code>true</code> if the base type is a primitive or assignable from the value type.
     * 
     * @param baseType  the base class.
     * @param valueType  the value class.
     * 
     * @return A boolean.
     */
    private boolean isAssignableOrPrimitive(final Class baseType, final Class valueType) {
        if (BasicTypeSupport.isBasicDataType(baseType)) {
            return true;
        }
        // verbose stuff below *should* no longer be needed
        return baseType.isAssignableFrom(valueType);
    }

    /**
     * Returns <code>true<code> if the specified property is...
     * 
     * @param propertyName  the property name.
     * 
     * @return A boolean.
     */
    private boolean isConstructorProperty(final String propertyName) {
        for (int i = 0; i < this.constructorDefinitions.length; i++) {
            final ConstructorDefinition cDef = this.constructorDefinitions[i];
            if (propertyName.equals(cDef.getPropertyName())) {
                return true;
            }
        }
        return false;
    }

    /**
     * Writes the properties for the object.
     * 
     * @param object  the object.
     * 
     * @throws ObjectDescriptionException if there is a problem.
     */
    public void writeObjectProperties(final Object object) throws ObjectDescriptionException {
        // this assumes that the order of setting the attributes does not matter.
        for (int i = 0; i < this.orderedPropertyNames.length; i++) {
            try {
                final String name = this.orderedPropertyNames[i];
                if (isConstructorProperty(name)) {
                    continue;
                }
                final Object value = getProperty(name);
                if (value == null) {
                    // do nothing if value is not defined ...
                    continue;
                }
                final PropertyDescriptor pdescr = getPropertyDescriptor(name);
                final Method setter = pdescr.getWriteMethod();
                setter.invoke(object, new Object[]{value});
            }
            catch (Exception e) {
                throw new ObjectDescriptionException(
                    "Failed to set properties." + getBaseClass(), e
                );
            }
        }
    }

    /**
     * Reads the properties.
     * 
     * @param object  the object.
     * 
     * @throws ObjectDescriptionException if there is a problem.
     */
    public void readProperties(final Object object) throws ObjectDescriptionException {
        // this assumes that the order of setting the attributes does not matter.
        for (int i = 0; i < this.orderedPropertyNames.length; i++) {
            try {
                final String name = this.orderedPropertyNames[i];
                final PropertyDescriptor pdescr = getPropertyDescriptor(name);
                if (pdescr == null) {
                    throw new IllegalStateException("No property defined: " + name);
                }
                final Method setter = pdescr.getReadMethod();
                final Object value = setter.invoke(object, new Object[0]);
                if (value == null) {
                    // do nothing if value is not defined ... or null
                    continue;
                }
                setProperty(name, value);
            }
            catch (Exception e) {
                throw new ObjectDescriptionException("Failed to set properties.", e);
            }
        }
    }

    /**
     * Returns the base class.
     * 
     * @return the base class.
     */
    public Class getBaseClass() {
        return this.baseClass;
    }
    
}