COMMONS_JEXL_2_0/src/main/java/org/apache/commons/jexl2/internal/Introspector.java - commons-jexl - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You 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.apache.commons.jexl2.internal;

 import java.lang.ref.SoftReference;
 import java.lang.reflect.Method;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;

 import org.apache.commons.jexl2.internal.introspection.IntrospectorBase;
 import org.apache.commons.jexl2.internal.introspection.MethodKey;

 import org.apache.commons.logging.Log;

 /**
  *  Default introspection services.
  *  <p>Finding methods as well as property getters & setters.</p>
  * @since 1.0
  */
 public class Introspector {
     /** The logger to use for all warnings & errors. */
     protected final Log rlog;
     /** The soft reference to the introspector currently in use. */
     private volatile SoftReference<IntrospectorBase> ref;

     /**
      * Creates an introspector.
      * @param log the logger to use for warnings.
      */
     protected Introspector(Log log) {
         rlog = log;
         ref = new SoftReference<IntrospectorBase>(null);
     }

     /**
      * Coerce an Object  to an Integer.
      * @param arg the Object to coerce
      * @return an Integer if it can be converted, null otherwise
      */
     protected Integer toInteger(Object arg) {
         if (arg == null) {
             return null;
         }
         if (arg instanceof Number) {
             return Integer.valueOf(((Number) arg).intValue());
         }
         try {
             return Integer.valueOf(arg.toString());
         } catch (NumberFormatException xnumber) {
             return null;
         }
     }

     /**
      * Coerce an Object to a String.
      * @param arg the Object to coerce
      * @return a String if it can be converted, null otherwise
      */
     protected String toString(Object arg) {
         return arg == null ? null : arg.toString();
     }

     /**
      * Gets the current introspector base.
      * <p>If the reference has been collected, this method will recreate the underlying introspector.</p>
      * @return the introspector
      */
     // CSOFF: DoubleCheckedLocking
     protected final IntrospectorBase base() {
         IntrospectorBase intro = ref.get();
         if (intro == null) {
             // double checked locking (fixed by Java 5 memory model).
             synchronized(this) {
                 intro = ref.get();
                 if (intro == null) {
                     intro = new IntrospectorBase(rlog);
                     ref = new SoftReference<IntrospectorBase>(intro);
                 }
             }
         }
         return intro;
     }
     // CSON: DoubleCheckedLocking

     /**
      * Sets the underlying class loader for class solving resolution.
      * @param loader the loader to use
      */
     public void setClassLoader(ClassLoader loader) {
         base().setLoader(loader);
     }


     /**
      * Gets the field named by <code>key</code> for the class <code>c</code>.
      *
      * @param c     Class in which the field search is taking place
      * @param key   Name of the field being searched for
      * @return the desired field or null if it does not exist or is not accessible
      * */
     protected final Field getField(Class<?> c, String key) {
         return base().getField(c, key);
     }

     /**
      * Gets the accessible field names known for a given class.
      * @param c the class
      * @return the class field names
      */
     public final String[] getFieldNames(Class<?> c) {
         return base().getFieldNames(c);
     }

     /**
      * Gets the method defined by <code>name</code> and
      * <code>params</code> for the Class <code>c</code>.
      *
      * @param c Class in which the method search is taking place
      * @param name Name of the method being searched for
      * @param params An array of Objects (not Classes) that describe the
      *               the parameters
      *
      * @return The desired Method object.
      * @throws IllegalArgumentException When the parameters passed in can not be used for introspection.
      * CSOFF: RedundantThrows
      */
     protected final Method getMethod(Class<?> c, String name, Object[] params) throws IllegalArgumentException {
         return base().getMethod(c, new MethodKey(name, params));
     }

     /**
      * Gets the method defined by <code>key</code> and for the Class <code>c</code>.
      *
      * @param c Class in which the method search is taking place
      * @param key MethodKey of the method being searched for
      *
      * @return The desired Method object.
      * @throws IllegalArgumentException When the parameters passed in can not be used for introspection.
      * CSOFF: RedundantThrows
      */
     protected final Method getMethod(Class<?> c, MethodKey key) throws IllegalArgumentException {
         return base().getMethod(c, key);
     }


     /**
      * Gets the accessible methods names known for a given class.
      * @param c the class
      * @return the class method names
      */
     public final String[] getMethodNames(Class<?> c) {
         return base().getMethodNames(c);
     }

     /**
      * Returns a general constructor.
      * @param ctorHandle the object
      * @param args contrusctor arguments
      * @return a {@link java.lang.reflect.Constructor}
      */
     public final Constructor<?> getConstructor(Object ctorHandle, Object[] args) {
         String className = null;
         Class<?> clazz = null;
         if (ctorHandle instanceof Class<?>) {
             clazz = (Class<?>) ctorHandle;
             className = clazz.getName();
         } else if (ctorHandle != null) {
             className = ctorHandle.toString();
         } else {
             return null;
         }
         return base().getConstructor(clazz, new MethodKey(className, args));
     }

     /**
      * Returns a general method.
      * @param obj the object
      * @param name the method name
      * @param args method arguments
      * @return a {@link AbstractExecutor.Method}.
      */
     public final AbstractExecutor.Method getMethodExecutor(Object obj, String name, Object[] args) {
         AbstractExecutor.Method me = new MethodExecutor(this, obj, name, args);
         return me.isAlive() ? me : null;
     }

     /**
      * Return a property getter.
      * @param obj the object to base the property from.
      * @param identifier property name
      * @return a {@link AbstractExecutor.Get}.
      */
     public final AbstractExecutor.Get getGetExecutor(Object obj, Object identifier) {
         final Class<?> claz = obj.getClass();
         final String property = toString(identifier);
         AbstractExecutor.Get executor;
         // first try for a getFoo() type of property (also getfoo() )
         if (property != null) {
             executor = new PropertyGetExecutor(this, claz, property);
             if (executor.isAlive()) {
                 return executor;
             }
         }
         // look for boolean isFoo()
         if (property != null) {
             executor = new BooleanGetExecutor(this, claz, property);
             if (executor.isAlive()) {
                 return executor;
             }
         }
         // let's see if we are a map...
         executor = new MapGetExecutor(this, claz, identifier);
         if (executor.isAlive()) {
             return executor;
         }
         // let's see if we can convert the identifier to an int,
         // if obj is an array or a list, we can still do something
         Integer index = toInteger(identifier);
         if (index != null) {
             executor = new ListGetExecutor(this, claz, index);
             if (executor.isAlive()) {
                 return executor;
             }
         }
         // if that didn't work, look for set("foo")
         executor = new DuckGetExecutor(this, claz, identifier);
         if (executor.isAlive()) {
             return executor;
         }
         return null;
     }

     /**
      * Return a property setter.
      * @param obj the object to base the property from.
      * @param identifier property name (or identifier)
      * @param arg value to set
      * @return a {@link AbstractExecutor.Set}.
      */
     public final AbstractExecutor.Set getSetExecutor(final Object obj, final Object identifier, Object arg) {
         final Class<?> claz = obj.getClass();
         final String property = toString(identifier);
         AbstractExecutor.Set executor;
         // first try for a setFoo() type of property (also setfoo() )
         if (property != null) {
             executor = new PropertySetExecutor(this, claz, property, arg);
             if (executor.isAlive()) {
                 return executor;
             }
         }
         // let's see if we are a map...
         executor = new MapSetExecutor(this, claz, identifier, arg);
         if (executor.isAlive()) {
             return executor;
         }
         // let's see if we can convert the identifier to an int,
         // if obj is an array or a list, we can still do something
         Integer index = toInteger(identifier);
         if (index != null) {
             executor = new ListSetExecutor(this, claz, index, arg);
             if (executor.isAlive()) {
                 return executor;
             }
         }
         // if that didn't work, look for set("foo")
         executor = new DuckSetExecutor(this, claz, property, arg);
         if (executor.isAlive()) {
             return executor;
         }
         return null;
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You 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.apache.commons.jexl2.internal;

	import java.lang.ref.SoftReference;
	import java.lang.reflect.Method;
	import java.lang.reflect.Constructor;
	import java.lang.reflect.Field;

	import org.apache.commons.jexl2.internal.introspection.IntrospectorBase;
	import org.apache.commons.jexl2.internal.introspection.MethodKey;

	import org.apache.commons.logging.Log;

	/**
	* Default introspection services.
	* <p>Finding methods as well as property getters & setters.</p>
	* @since 1.0
	*/
	public class Introspector {
	/** The logger to use for all warnings & errors. */
	protected final Log rlog;
	/** The soft reference to the introspector currently in use. */
	private volatile SoftReference<IntrospectorBase> ref;

	/**
	* Creates an introspector.
	* @param log the logger to use for warnings.
	*/
	protected Introspector(Log log) {
	rlog = log;
	ref = new SoftReference<IntrospectorBase>(null);
	}

	/**
	* Coerce an Object to an Integer.
	* @param arg the Object to coerce
	* @return an Integer if it can be converted, null otherwise
	*/
	protected Integer toInteger(Object arg) {
	if (arg == null) {
	return null;
	}
	if (arg instanceof Number) {
	return Integer.valueOf(((Number) arg).intValue());
	}
	try {
	return Integer.valueOf(arg.toString());
	} catch (NumberFormatException xnumber) {
	return null;
	}
	}

	/**
	* Coerce an Object to a String.
	* @param arg the Object to coerce
	* @return a String if it can be converted, null otherwise
	*/
	protected String toString(Object arg) {
	return arg == null ? null : arg.toString();
	}

	/**
	* Gets the current introspector base.
	* <p>If the reference has been collected, this method will recreate the underlying introspector.</p>
	* @return the introspector
	*/
	// CSOFF: DoubleCheckedLocking
	protected final IntrospectorBase base() {
	IntrospectorBase intro = ref.get();
	if (intro == null) {
	// double checked locking (fixed by Java 5 memory model).
	synchronized(this) {
	intro = ref.get();
	if (intro == null) {
	intro = new IntrospectorBase(rlog);
	ref = new SoftReference<IntrospectorBase>(intro);
	}
	}
	}
	return intro;
	}
	// CSON: DoubleCheckedLocking

	/**
	* Sets the underlying class loader for class solving resolution.
	* @param loader the loader to use
	*/
	public void setClassLoader(ClassLoader loader) {
	base().setLoader(loader);
	}


	/**
	* Gets the field named by <code>key</code> for the class <code>c</code>.
	*
	* @param c Class in which the field search is taking place
	* @param key Name of the field being searched for
	* @return the desired field or null if it does not exist or is not accessible
	* */
	protected final Field getField(Class<?> c, String key) {
	return base().getField(c, key);
	}

	/**
	* Gets the accessible field names known for a given class.
	* @param c the class
	* @return the class field names
	*/
	public final String[] getFieldNames(Class<?> c) {
	return base().getFieldNames(c);
	}

	/**
	* Gets the method defined by <code>name</code> and
	* <code>params</code> for the Class <code>c</code>.
	*
	* @param c Class in which the method search is taking place
	* @param name Name of the method being searched for
	* @param params An array of Objects (not Classes) that describe the
	* the parameters
	*
	* @return The desired Method object.
	* @throws IllegalArgumentException When the parameters passed in can not be used for introspection.
	* CSOFF: RedundantThrows
	*/
	protected final Method getMethod(Class<?> c, String name, Object[] params) throws IllegalArgumentException {
	return base().getMethod(c, new MethodKey(name, params));
	}

	/**
	* Gets the method defined by <code>key</code> and for the Class <code>c</code>.
	*
	* @param c Class in which the method search is taking place
	* @param key MethodKey of the method being searched for
	*
	* @return The desired Method object.
	* @throws IllegalArgumentException When the parameters passed in can not be used for introspection.
	* CSOFF: RedundantThrows
	*/
	protected final Method getMethod(Class<?> c, MethodKey key) throws IllegalArgumentException {
	return base().getMethod(c, key);
	}


	/**
	* Gets the accessible methods names known for a given class.
	* @param c the class
	* @return the class method names
	*/
	public final String[] getMethodNames(Class<?> c) {
	return base().getMethodNames(c);
	}

	/**
	* Returns a general constructor.
	* @param ctorHandle the object
	* @param args contrusctor arguments
	* @return a {@link java.lang.reflect.Constructor}
	*/
	public final Constructor<?> getConstructor(Object ctorHandle, Object[] args) {
	String className = null;
	Class<?> clazz = null;
	if (ctorHandle instanceof Class<?>) {
	clazz = (Class<?>) ctorHandle;
	className = clazz.getName();
	} else if (ctorHandle != null) {
	className = ctorHandle.toString();
	} else {
	return null;
	}
	return base().getConstructor(clazz, new MethodKey(className, args));
	}

	/**
	* Returns a general method.
	* @param obj the object
	* @param name the method name
	* @param args method arguments
	* @return a {@link AbstractExecutor.Method}.
	*/
	public final AbstractExecutor.Method getMethodExecutor(Object obj, String name, Object[] args) {
	AbstractExecutor.Method me = new MethodExecutor(this, obj, name, args);
	return me.isAlive() ? me : null;
	}

	/**
	* Return a property getter.
	* @param obj the object to base the property from.
	* @param identifier property name
	* @return a {@link AbstractExecutor.Get}.
	*/
	public final AbstractExecutor.Get getGetExecutor(Object obj, Object identifier) {
	final Class<?> claz = obj.getClass();
	final String property = toString(identifier);
	AbstractExecutor.Get executor;
	// first try for a getFoo() type of property (also getfoo() )
	if (property != null) {
	executor = new PropertyGetExecutor(this, claz, property);
	if (executor.isAlive()) {
	return executor;
	}
	}
	// look for boolean isFoo()
	if (property != null) {
	executor = new BooleanGetExecutor(this, claz, property);
	if (executor.isAlive()) {
	return executor;
	}
	}
	// let's see if we are a map...
	executor = new MapGetExecutor(this, claz, identifier);
	if (executor.isAlive()) {
	return executor;
	}
	// let's see if we can convert the identifier to an int,
	// if obj is an array or a list, we can still do something
	Integer index = toInteger(identifier);
	if (index != null) {
	executor = new ListGetExecutor(this, claz, index);
	if (executor.isAlive()) {
	return executor;
	}
	}
	// if that didn't work, look for set("foo")
	executor = new DuckGetExecutor(this, claz, identifier);
	if (executor.isAlive()) {
	return executor;
	}
	return null;
	}

	/**
	* Return a property setter.
	* @param obj the object to base the property from.
	* @param identifier property name (or identifier)
	* @param arg value to set
	* @return a {@link AbstractExecutor.Set}.
	*/
	public final AbstractExecutor.Set getSetExecutor(final Object obj, final Object identifier, Object arg) {
	final Class<?> claz = obj.getClass();
	final String property = toString(identifier);
	AbstractExecutor.Set executor;
	// first try for a setFoo() type of property (also setfoo() )
	if (property != null) {
	executor = new PropertySetExecutor(this, claz, property, arg);
	if (executor.isAlive()) {
	return executor;
	}
	}
	// let's see if we are a map...
	executor = new MapSetExecutor(this, claz, identifier, arg);
	if (executor.isAlive()) {
	return executor;
	}
	// let's see if we can convert the identifier to an int,
	// if obj is an array or a list, we can still do something
	Integer index = toInteger(identifier);
	if (index != null) {
	executor = new ListSetExecutor(this, claz, index, arg);
	if (executor.isAlive()) {
	return executor;
	}
	}
	// if that didn't work, look for set("foo")
	executor = new DuckSetExecutor(this, claz, property, arg);
	if (executor.isAlive()) {
	return executor;
	}
	return null;
	}
	}