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PicoContainer example source code file (SetterInjector.java)

This example PicoContainer source code file (SetterInjector.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - PicoContainer tags/keywords

class, constructor, io, list, method, object, object, parameter, parameter, parametername, picocompositionexception, picocompositionexception, reflection, security, string, string, threadlocalcyclicdependencyguard, util

The PicoContainer SetterInjector.java source code

/*****************************************************************************
 * Copyright (C) PicoContainer Organization. All rights reserved.            *
 * ------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the BSD      *
 * style license a copy of which has been included with this distribution in *
 * the LICENSE.txt file.                                                     *
 *                                                                           *
 * Original code by                                                          *
 *****************************************************************************/
package org.picocontainer.injectors;

import org.picocontainer.ComponentMonitor;
import org.picocontainer.Parameter;
import org.picocontainer.PicoContainer;
import org.picocontainer.PicoCompositionException;
import org.picocontainer.ParameterName;
import org.picocontainer.LifecycleStrategy;
import org.picocontainer.behaviors.PropertyApplyingBehavior;
import org.picocontainer.behaviors.CachingBehavior;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Member;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.io.Serializable;

/**
 * Instantiates components using empty constructors and
 * <a href="http://docs.codehaus.org/display/PICO/Setter+Injection">Setter Injection.
 * For easy setting of primitive properties, also see {@link PropertyApplyingBehavior}.
 * <p/>
 * <em>
 * Note that this class doesn't cache instances. If you want caching,
 * use a {@link CachingBehavior} around this one.
 * </em>
 * </p>
 *
 * @author Aslak Hellesøy
 * @author Jörg Schaible
 * @author Mauro Talevi
 * @author Paul Hammant
 * @version $Revision: 3587 $
 */
public class SetterInjector extends AbstractInjector {
    private transient ThreadLocalCyclicDependencyGuard instantiationGuard;
    protected transient List<Member> injectionMembers;
    protected transient Class[] injectionTypes;

    /**
     * Constructs a SetterInjectionComponentAdapter
     *
     * @param componentKey            the search key for this implementation
     * @param componentImplementation the concrete implementation
     * @param parameters              the parameters to use for the initialization
     * @param monitor                 the component monitor used by this addAdapter
     * @param lifecycleStrategy       the component lifecycle strategy used by this addAdapter
     * @throws org.picocontainer.injectors.AbstractInjector.NotConcreteRegistrationException
     *                              if the implementation is not a concrete class.
     * @throws NullPointerException if one of the parameters is <code>null
     */
    public SetterInjector(final Object componentKey, final Class componentImplementation, Parameter[] parameters, ComponentMonitor monitor, LifecycleStrategy lifecycleStrategy) throws  NotConcreteRegistrationException {
        super(componentKey, componentImplementation, parameters, monitor, lifecycleStrategy);
    }

    private Constructor getConstructor()  {
        Object retVal = AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                try {
                    return getComponentImplementation().getConstructor((Class[])null);
                } catch (NoSuchMethodException e) {
                    return new PicoCompositionException(e);
                } catch (SecurityException e) {
                    return new PicoCompositionException(e);
                }
            }
        });
        if (retVal instanceof Constructor) {
            return (Constructor) retVal;
        } else {
            throw (PicoCompositionException) retVal;
        }
    }

    private Parameter[] getMatchingParameterListForSetters(PicoContainer container) throws PicoCompositionException {
        if (injectionMembers == null) {
            initializeInjectionMembersAndTypeLists();
        }

        final List<Object> matchingParameterList = new ArrayList(Collections.nCopies(injectionMembers.size(), null));
        final Set<Integer> nonMatchingParameterPositions = new HashSet();
        final Parameter[] currentParameters = parameters != null ? parameters : createDefaultParameters(injectionTypes);
        for (int i = 0; i < currentParameters.length; i++) {
            final Parameter parameter = currentParameters[i];
            boolean failedDependency = true;
            for (int j = 0; j < injectionTypes.length; j++) {
                if (matchingParameterList.get(j) == null && parameter.isResolvable(container, this, injectionTypes[j], new ParameterName() {
                    public String getParameterName() {
                        return ""; // TODO 
                    }
                })) {
                    matchingParameterList.set(j, parameter);
                    failedDependency = false;
                    break;
                }
            }
            if (failedDependency) {
                nonMatchingParameterPositions.add(i);
            }
        }

        final Set<Class> unsatisfiableDependencyTypes = new HashSet();
        for (int i = 0; i < matchingParameterList.size(); i++) {
            if (matchingParameterList.get(i) == null) {
                unsatisfiableDependencyTypes.add(injectionTypes[i]);
            }
        }
        if (unsatisfiableDependencyTypes.size() > 0) {
            throw new UnsatisfiableDependenciesException(this, null, unsatisfiableDependencyTypes, container);
        } else if (nonMatchingParameterPositions.size() > 0) {
            throw new PicoCompositionException("Following parameters do not match any of the injectionMembers for " + getComponentImplementation() + ": " + nonMatchingParameterPositions.toString());
        }
        return matchingParameterList.toArray(new Parameter[matchingParameterList.size()]);
    }

    public Object getComponentInstance(final PicoContainer container) throws PicoCompositionException {
        final Constructor constructor = getConstructor();
        if (instantiationGuard == null) {
            instantiationGuard = new ThreadLocalCyclicDependencyGuard() {
                public Object run() {
                    final Parameter[] matchingParameters = getMatchingParameterListForSetters(guardedContainer);
                    ComponentMonitor componentMonitor = currentMonitor();
                    Object componentInstance;
                    long startTime = System.currentTimeMillis();
                    Constructor constructorToUse = componentMonitor.instantiating(container,
                                                                                  SetterInjector.this, constructor);
                    try {
                        componentInstance = newInstance(constructorToUse, null);
                    } catch (InvocationTargetException e) {
                        componentMonitor.instantiationFailed(container, SetterInjector.this, constructorToUse, e);
                        if (e.getTargetException() instanceof RuntimeException) {
                            throw (RuntimeException) e.getTargetException();
                        } else if (e.getTargetException() instanceof Error) {
                            throw (Error) e.getTargetException();
                        }
                        throw new PicoCompositionException(e.getTargetException());
                    } catch (InstantiationException e) {
                        return caughtInstantiationException(componentMonitor, constructor, e, container);
                    } catch (IllegalAccessException e) {
                        return caughtIllegalAccessException(componentMonitor, constructor, e, container);                    }
                    Member member = null;
                    Object injected[] = new Object[injectionMembers.size()];
                    try {
                        for (int i = 0; i < injectionMembers.size(); i++) {
                            member = injectionMembers.get(i);
                            componentMonitor.invoking(container, SetterInjector.this, member, componentInstance);
                            Object toInject = matchingParameters[i].resolveInstance(guardedContainer, SetterInjector.this, injectionTypes[i], new ParameterName() {
                                public String getParameterName() {
                                    return ""; // TODO
                                }
                            });
                            injectIntoMember(member, componentInstance, toInject);
                            injected[i] = toInject;
                        }
                        componentMonitor.instantiated(container,
                                                      SetterInjector.this,
                                                      constructorToUse, componentInstance, injected, System.currentTimeMillis() - startTime);
                        return componentInstance;
                    } catch (InvocationTargetException e) {
                        return caughtInvocationTargetException(componentMonitor, member, componentInstance, e);
                    } catch (IllegalAccessException e) {
                        return caughtIllegalAccessException(componentMonitor, member, componentInstance, e);
                    }

                }
            };
        }
        instantiationGuard.setGuardedContainer(container);
        return instantiationGuard.observe(getComponentImplementation());
    }

    protected void injectIntoMember(Member member, Object componentInstance, Object toInject)
        throws IllegalAccessException, InvocationTargetException
    {
        ((Method)member).invoke(componentInstance, toInject);
    }

    public void verify(final PicoContainer container) throws PicoCompositionException {
        if (verifyingGuard == null) {
            verifyingGuard = new ThreadLocalCyclicDependencyGuard() {
                public Object run() {
                    final Parameter[] currentParameters = getMatchingParameterListForSetters(guardedContainer);
                    for (int i = 0; i < currentParameters.length; i++) {
                        currentParameters[i].verify(container, SetterInjector.this, injectionTypes[i], new ParameterName() {
                            public String getParameterName() {
                                return ""; // TODO
                            }
                        });
                    }
                    return null;
                }
            };
        }
        verifyingGuard.setGuardedContainer(container);
        verifyingGuard.observe(getComponentImplementation());
    }

    protected void initializeInjectionMembersAndTypeLists() {
        injectionMembers = new ArrayList<Member>();
        final List<Class> typeList = new ArrayList();
        final Method[] methods = getMethods();
        for (final Method method : methods) {
            final Class[] parameterTypes = method.getParameterTypes();
            // We're only interested if there is only one parameter and the method name is bean-style.
            if (parameterTypes.length == 1) {
                boolean isInjector = isInjectorMethod(method);
                if (isInjector) {
                    injectionMembers.add(method);
                    typeList.add(parameterTypes[0]);
                }
            }
        }
        injectionTypes = typeList.toArray(new Class[0]);
    }

    protected boolean isInjectorMethod(Method method) {
        String methodName = method.getName();
        return methodName.length() >= getInjectorPrefix().length() + 1 && methodName.startsWith(getInjectorPrefix()) && Character.isUpperCase(methodName.charAt(getInjectorPrefix().length()));
    }

    protected String getInjectorPrefix() {
        return "set";
    }

    private Method[] getMethods() {
        return (Method[]) AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                return getComponentImplementation().getMethods();
            }
        });
    }
}




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