abstractmulebeandefinitionparser.java

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/*
 * $Id:AbstractMuleBeanDefinitionParser.java 5187 2007-02-16 18:00:42Z rossmason $
 * --------------------------------------------------------------------------------------
 * Copyright (c) MuleSource, Inc.  All rights reserved.  http://www.mulesource.com
 *
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.config.spring.parsers;

import org.mule.api.lifecycle.Disposable;
import org.mule.api.lifecycle.Initialisable;
import org.mule.config.spring.MuleHierarchicalBeanDefinitionParserDelegate;
import org.mule.config.spring.parsers.assembly.BeanAssembler;
import org.mule.config.spring.parsers.assembly.BeanAssemblerFactory;
import org.mule.config.spring.parsers.assembly.DefaultBeanAssemblerFactory;
import org.mule.config.spring.parsers.assembly.configuration.ReusablePropertyConfiguration;
import org.mule.config.spring.parsers.assembly.configuration.ValueMap;
import org.mule.config.spring.parsers.generic.AutoIdUtils;
import org.mule.util.ClassUtils;
import org.mule.util.XMLUtils;

import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;

/**
 * This parser extends the Spring provided {@link AbstractBeanDefinitionParser} to provide additional features for
 * consistently customising bean representations for Mule bean definition parsers.  Most custom bean definition parsers
 * in Mule will use this base class. The following enhancements are made -
 *
 * <ol>
 * <li>A property name which ends with the suffix "-ref" is assumed to be a reference to another bean.
 * Alternatively, a property can be explicitly registered as a bean reference via registerBeanReference()
 *
 * <p>For example,
 * <code> &lt;bpm:connector bpms-ref=&quot;testBpms&quot;/&gt;</code>
 * will automatically set a property "bpms" on the connector to reference a bean named "testBpms"
 * </p></li>
 *
 * <li>Attribute mappings can be registered to control how an attribute name in Mule Xml maps to the bean name in the
 * object being created.
 *
 * <p>For example -
 * <code>addAlias("poolExhaustedAction", "poolExhaustedActionString");</code>
 * Maps the 'poolExhaustedAction' to the 'poolExhaustedActionString' property on the bean being created.
 * </p></li>
 *
 * <li>Value Mappings can be used to map key value pairs from selection lists in the XML schema to property values on the
 * bean being created. These are a comma-separated list of key=value pairs.
 *
 * <p>For example -
 * <code>addMapping("action", "NONE=0,ALWAYS_BEGIN=1,BEGIN_OR_JOIN=2,JOIN_IF_POSSIBLE=3");</code>
 * The first argument is the bean name to set, the second argument is the set of possible key=value pairs
 * </p></li>
 *
 * <li>Provides an automatic way of setting the 'init-method' and 'destroy-method' for this object. This will then automatically
 * wire the bean into the lifecycle of the Application context.</li>
 *
 * <li>The 'singleton' property provides a fixed way to make sure the bean is always a singleton or not.</li>
 *
 * <li>Collections will be automatically created and extended if the setter matches "property+s".</li>
 * </ol>
 *
 * <p>Note that this class is not multi-thread safe.  The internal state is reset before each "use"
 * by {@link #preProcess(org.w3c.dom.Element)} which assumes sequential access.</p>
 *
 * @see  AbstractBeanDefinitionParser
 */
public abstract class AbstractMuleBeanDefinitionParser extends AbstractBeanDefinitionParser
    implements MuleDefinitionParser
{

    public static final String ROOT_ELEMENT = "mule";
    public static final String ATTRIBUTE_ID = "id";
    public static final String ATTRIBUTE_NAME = "name";
    public static final String ATTRIBUTE_CLASS = "class";
    public static final String ATTRIBUTE_REF = "ref";
    public static final String ATTRIBUTE_REFS = "refs";
    public static final String ATTRIBUTE_REF_SUFFIX = "-" + ATTRIBUTE_REF;
    public static final String ATTRIBUTE_REFS_SUFFIX = "-" + ATTRIBUTE_REFS;

    /**
     * logger used by this class
     */
    protected transient Log logger = LogFactory.getLog(getClass());

    private BeanAssemblerFactory beanAssemblerFactory = new DefaultBeanAssemblerFactory();
    protected ReusablePropertyConfiguration beanPropertyConfiguration = new ReusablePropertyConfiguration();
    private ParserContext parserContext;
    private BeanDefinitionRegistry registry;
    private LinkedList preProcessors = new LinkedList();
    private List postProcessors = new LinkedList();
    private Set beanAttributes = new HashSet();
    // By default Mule objects are not singletons
    protected boolean singleton = false;

    /** Allow the bean class to be set explicitly via the "class" attribute. */
    private boolean allowClassAttribute = true;
    private Class classConstraint = null;

    public AbstractMuleBeanDefinitionParser()
    {
        addIgnored(ATTRIBUTE_ID);
        addBeanFlag(MuleHierarchicalBeanDefinitionParserDelegate.MULE_FORCE_RECURSE);
    }

    public MuleDefinitionParserConfiguration addReference(String propertyName)
    {
        beanPropertyConfiguration.addReference(propertyName);
        return this;
    }

    public MuleDefinitionParserConfiguration addMapping(String propertyName, Map mappings)
    {
        beanPropertyConfiguration.addMapping(propertyName, mappings);
        return this;
    }

    public MuleDefinitionParserConfiguration addMapping(String propertyName, String mappings)
    {
        beanPropertyConfiguration.addMapping(propertyName, mappings);
        return this;
    }

    public MuleDefinitionParserConfiguration addMapping(String propertyName, ValueMap mappings)
    {
        beanPropertyConfiguration.addMapping(propertyName, mappings);
        return this;
    }

    /**
     * @param alias The attribute name
     * @param propertyName The bean property name
     * @return This instance, allowing chaining during use, avoiding subclasses
     */
    public MuleDefinitionParserConfiguration addAlias(String alias, String propertyName)
    {
        beanPropertyConfiguration.addAlias(alias, propertyName);
        return this;
    }

    /**
     * @param propertyName Property that is a collection
     * @return This instance, allowing chaining during use, avoiding subclasses
     */
    public MuleDefinitionParserConfiguration addCollection(String propertyName)
    {
        beanPropertyConfiguration.addCollection(propertyName);
        return this;
    }

    /**
     * @param propertyName Property that is to be ignored
     * @return This instance, allowing chaining during use, avoiding subclasses
     */
    public MuleDefinitionParserConfiguration addIgnored(String propertyName)
    {
        beanPropertyConfiguration.addIgnored(propertyName);
        return this;
    }

    public MuleDefinitionParserConfiguration removeIgnored(String propertyName)
    {
        beanPropertyConfiguration.removeIgnored(propertyName);
        return this;
    }

    public MuleDefinitionParserConfiguration setIgnoredDefault(boolean ignoreAll)
    {
        beanPropertyConfiguration.setIgnoredDefault(ignoreAll);
        return this;
    }

    protected void processProperty(Attr attribute, BeanAssembler assembler)
    {
        assembler.extendBean(attribute);
    }

    /**
     * Hook method that derived classes can implement to inspect/change a
     * bean definition after parsing is complete.
     *
     * @param assembler the parsed (and probably totally defined) bean definition being built
     * @param element   the XML element that was the source of the bean definition's metadata
     */
    protected void postProcess(ParserContext context, BeanAssembler assembler, Element element)
    {
        element.setAttribute(ATTRIBUTE_NAME, getBeanName(element));
        for (Iterator attributes = beanAttributes.iterator(); attributes.hasNext();)
        {
            assembler.setBeanFlag((String) attributes.next());
        }
        for (Iterator processes = postProcessors.iterator(); processes.hasNext();)
        {
            ((PostProcessor) processes.next()).postProcess(context, assembler, element);
        }
    }

    /**
     * Hook method that derived classes can implement to modify internal state before processing.
     *
     * Here we make sure that the internal property configuration state is reset to the
     * initial configuration for each element (it may be modified by the BeanAssembler)
     * and that other mutable instance variables are cleared.
     */
    protected void preProcess(Element element)
    {
        parserContext = null;
        registry = null;
        beanPropertyConfiguration.reset();
        Iterator processes = preProcessors.iterator();
        while (processes.hasNext())
        {
            ((PreProcessor) processes.next()).preProcess(beanPropertyConfiguration, element);
        }
    }

    /**
     * Creates a {@link BeanDefinitionBuilder} instance for the
     * {@link #getBeanClass bean Class} and passes it to the
     * {@link #doParse} strategy method.
     *
     * @param element       the element that is to be parsed into a single BeanDefinition
     * @param parserContext the object encapsulating the current state of the parsing process
     * @return the BeanDefinition resulting from the parsing of the supplied {@link Element}
     * @throws IllegalStateException if the bean {@link Class} returned from
     *                               {@link #getBeanClass(org.w3c.dom.Element)} is <code>null</code>
     * @see #doParse
     */
    protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext)
    {
        preProcess(element);
        setParserContext(parserContext);