src/main/java/org/apache/maven/shared/utils/introspection/ReflectionValueExtractor.java - maven-shared-utils - Git at Google

 package org.apache.maven.shared.utils.introspection;

 /*
  * 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.
  */

 import java.lang.reflect.Array;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Map;
 import java.util.WeakHashMap;

 import org.apache.maven.shared.utils.StringUtils;
 import org.apache.maven.shared.utils.introspection.MethodMap.AmbiguousException;

 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;


 /**
  * <p>Using simple dotted expressions to extract the values from an Object instance,
  * For example we might want to extract a value like: <code>project.build.sourceDirectory</code></p>
  * <p/>
  * <p>The implementation supports indexed, nested and mapped properties similar to the JSP way.</p>
  *
  * @author <a href="mailto:jason@maven.org">Jason van Zyl </a>
  * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
  * @see <a href="http://struts.apache.org/1.x/struts-taglib/indexedprops.html">
  * http://struts.apache.org/1.x/struts-taglib/indexedprops.html</a>
  */
 public class ReflectionValueExtractor
 {
     private static final Class<?>[] CLASS_ARGS = new Class[0];

     private static final Object[] OBJECT_ARGS = new Object[0];

     /**
      * Use a WeakHashMap here, so the keys (Class objects) can be garbage collected.
      * This approach prevents permgen space overflows due to retention of discarded
      * classloaders.
      */
     private static final Map<Class<?>, ClassMap> CLASS_MAPS = new WeakHashMap<Class<?>, ClassMap>();

     static final int EOF = -1;

     static final char PROPERTY_START = '.';

     static final char INDEXED_START = '[';

     static final char INDEXED_END = ']';

     static final char MAPPED_START = '(';

     static final char MAPPED_END = ')';

     static class Tokenizer
     {
         final String expression;

         int idx;

         Tokenizer( String expression )
         {
             this.expression = expression;
         }

         public int peekChar()
         {
             return idx < expression.length() ? expression.charAt( idx ) : EOF;
         }

         public int skipChar()
         {
             return idx < expression.length() ? expression.charAt( idx++ ) : EOF;
         }

         public String nextToken( char delimiter )
         {
             int start = idx;

             while ( idx < expression.length() && delimiter != expression.charAt( idx ) )
             {
                 idx++;
             }

             // delimiter MUST be present
             if ( idx <= start || idx >= expression.length() )
             {
                 return null;
             }

             return expression.substring( start, idx++ );
         }

         public String nextPropertyName()
         {
             final int start = idx;

             while ( idx < expression.length() && Character.isJavaIdentifierPart( expression.charAt( idx ) ) )
             {
                 idx++;
             }

             // property name does not require delimiter
             if ( idx <= start || idx > expression.length() )
             {
                 return null;
             }

             return expression.substring( start, idx );
         }

         public int getPosition()
         {
             return idx < expression.length() ? idx : EOF;
         }

         // to make tokenizer look pretty in debugger
         @Override
         public String toString()
         {
             return idx < expression.length() ? expression.substring( idx ) : "<EOF>";
         }
     }

     private ReflectionValueExtractor()
     {
     }

     /**
      * <p>The implementation supports indexed, nested and mapped properties.</p>
      * <p/>
      * <ul>
      * <li>nested properties should be defined by a dot, i.e. "user.address.street"</li>
      * <li>indexed properties (java.util.List or array instance) should be contains <code>(\\w+)\\[(\\d+)\\]</code>
      * pattern, i.e. "user.addresses[1].street"</li>
      * <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code> pattern,
      *  i.e. "user.addresses(myAddress).street"</li>
      * <ul>
      *
      * @param expression not null expression
      * @param root       not null object
      * @return the object defined by the expression
      * @throws IntrospectionException if any
      */
     public static Object evaluate( @Nonnull String expression, @Nullable Object root )
         throws IntrospectionException
     {
         return evaluate( expression, root, true );
     }

     /**
      * <p>
      * The implementation supports indexed, nested and mapped properties.
      * </p>
      * <p/>
      * <ul>
      * <li>nested properties should be defined by a dot, i.e. "user.address.street"</li>
      * <li>indexed properties (java.util.List or array instance) should be contains <code>(\\w+)\\[(\\d+)\\]</code>
      * pattern, i.e. "user.addresses[1].street"</li>
      * <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code> pattern, i.e.
      * "user.addresses(myAddress).street"</li>
      * <ul>
      *
      * @param expression not null expression
      * @param root not null object
      * @param trimRootToken trim root token yes/no.
      * @return the object defined by the expression
      * @throws IntrospectionException if any
      */
     public static Object evaluate( @Nonnull String expression, @Nullable Object root, boolean trimRootToken )
         throws IntrospectionException
     {
         Object value = root;

         // ----------------------------------------------------------------------
         // Walk the dots and retrieve the ultimate value desired from the
         // MavenProject instance.
         // ----------------------------------------------------------------------

         if ( StringUtils.isEmpty( expression ) || !Character.isJavaIdentifierStart( expression.charAt( 0 ) ) )
         {
             return null;
         }

         boolean hasDots = expression.indexOf( PROPERTY_START ) >= 0;

         final Tokenizer tokenizer;
         if ( trimRootToken && hasDots )
         {
             tokenizer = new Tokenizer( expression );
             tokenizer.nextPropertyName();
             if ( tokenizer.getPosition() == EOF )
             {
                 return null;
             }
         }
         else
         {
             tokenizer = new Tokenizer( "." + expression );
         }

         int propertyPosition = tokenizer.getPosition();
         while ( value != null && tokenizer.peekChar() != EOF )
         {
             switch ( tokenizer.skipChar() )
             {
                 case INDEXED_START:
                     value =
                         getIndexedValue( expression, propertyPosition, tokenizer.getPosition(), value,
                                          tokenizer.nextToken( INDEXED_END ) );
                     break;
                 case MAPPED_START:
                     value =
                         getMappedValue( expression, propertyPosition, tokenizer.getPosition(), value,
                                         tokenizer.nextToken( MAPPED_END ) );
                     break;
                 case PROPERTY_START:
                     propertyPosition = tokenizer.getPosition();
                     value = getPropertyValue( value, tokenizer.nextPropertyName() );
                     break;
                 default:
                     // could not parse expression
                     return null;
             }
         }

         return value;
     }

     private static Object getMappedValue( final String expression, final int from, final int to, final Object value,
                                           final String key )
         throws IntrospectionException
     {
         if ( value == null || key == null )
         {
             return null;
         }

         if ( value instanceof Map )
         {
             Object[] localParams = new Object[] { key };
             ClassMap classMap = getClassMap( value.getClass() );
             try
             {
                 Method method = classMap.findMethod( "get", localParams );
                 return method.invoke( value, localParams );
             }
             catch ( AmbiguousException e )
             {
                 throw new IntrospectionException( e );
             }
             catch ( IllegalAccessException e )
             {
                 throw new IntrospectionException( e );
             }
             catch ( InvocationTargetException e )
             {
                 throw new IntrospectionException( e.getTargetException() );
             }

         }

         final String message =
             String.format( "The token '%s' at position '%d' refers to a java.util.Map, but the value "
                 + "seems is an instance of '%s'", expression.subSequence( from, to ), from, value.getClass() );

         throw new IntrospectionException( message );
     }

     private static Object getIndexedValue( final String expression, final int from, final int to, final Object value,
                                            final String indexStr )
         throws IntrospectionException
     {
         try
         {
             int index = Integer.parseInt( indexStr );

             if ( value.getClass().isArray() )
             {
                 return Array.get( value, index );
             }

             if ( value instanceof List )
             {
                 ClassMap classMap = getClassMap( value.getClass() );
                 // use get method on List interface
                 Object[] localParams = new Object[] { index };
                 Method method = null;
                 try
                 {
                     method = classMap.findMethod( "get", localParams );
                     return method.invoke( value, localParams );
                 }
                 catch ( AmbiguousException e )
                 {
                     throw new IntrospectionException( e );
                 }
                 catch ( IllegalAccessException e )
                 {
                     throw new IntrospectionException( e );
                 }
             }
         }
         catch ( NumberFormatException e )
         {
             return null;
         }
         catch ( InvocationTargetException e )
         {
             // catch array index issues gracefully, otherwise release
             if ( e.getCause() instanceof IndexOutOfBoundsException )
             {
                 return null;
             }

             throw new IntrospectionException( e.getTargetException() );
         }

         final String message =
             String.format( "The token '%s' at position '%d' refers to a java.util.List or an array, but the value "
                 + "seems is an instance of '%s'", expression.subSequence( from, to ), from, value.getClass() );

         throw new IntrospectionException( message );
     }

     private static Object getPropertyValue( Object value, String property )
         throws IntrospectionException
     {
         if ( value == null || property == null )
         {
             return null;
         }

         ClassMap classMap = getClassMap( value.getClass() );
         String methodBase = StringUtils.capitalizeFirstLetter( property );
         String methodName = "get" + methodBase;
         try
         {
             Method method = classMap.findMethod( methodName, CLASS_ARGS );

             if ( method == null )
             {
                 // perhaps this is a boolean property??
                 methodName = "is" + methodBase;

                 method = classMap.findMethod( methodName, CLASS_ARGS );
             }

             if ( method == null )
             {
                 return null;
             }

             return method.invoke( value, OBJECT_ARGS );
         }
         catch ( InvocationTargetException e )
         {
             throw new IntrospectionException( e.getTargetException() );
         }
         catch ( AmbiguousException e )
         {
             throw new IntrospectionException( e );
         }
         catch ( IllegalAccessException e )
         {
             throw new IntrospectionException( e );
         }
     }

     private static ClassMap getClassMap( Class<?> clazz )
     {
         ClassMap classMap = CLASS_MAPS.get( clazz );

         if ( classMap == null )
         {
             classMap = new ClassMap( clazz );

             CLASS_MAPS.put( clazz, classMap );
         }

         return classMap;
     }
 }
	package org.apache.maven.shared.utils.introspection;

	/*
	* 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.
	*/

	import java.lang.reflect.Array;
	import java.lang.reflect.InvocationTargetException;
	import java.lang.reflect.Method;
	import java.util.List;
	import java.util.Map;
	import java.util.WeakHashMap;

	import org.apache.maven.shared.utils.StringUtils;
	import org.apache.maven.shared.utils.introspection.MethodMap.AmbiguousException;

	import javax.annotation.Nonnull;
	import javax.annotation.Nullable;


	/**
	* <p>Using simple dotted expressions to extract the values from an Object instance,
	* For example we might want to extract a value like: <code>project.build.sourceDirectory</code></p>
	* <p/>
	* <p>The implementation supports indexed, nested and mapped properties similar to the JSP way.</p>
	*
	* @author <a href="mailto:jason@maven.org">Jason van Zyl </a>
	* @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
	* @see <a href="http://struts.apache.org/1.x/struts-taglib/indexedprops.html">
	* http://struts.apache.org/1.x/struts-taglib/indexedprops.html</a>
	*/
	public class ReflectionValueExtractor
	{
	private static final Class<?>[] CLASS_ARGS = new Class[0];

	private static final Object[] OBJECT_ARGS = new Object[0];

	/**
	* Use a WeakHashMap here, so the keys (Class objects) can be garbage collected.
	* This approach prevents permgen space overflows due to retention of discarded
	* classloaders.
	*/
	private static final Map<Class<?>, ClassMap> CLASS_MAPS = new WeakHashMap<Class<?>, ClassMap>();

	static final int EOF = -1;

	static final char PROPERTY_START = '.';

	static final char INDEXED_START = '[';

	static final char INDEXED_END = ']';

	static final char MAPPED_START = '(';

	static final char MAPPED_END = ')';

	static class Tokenizer
	{
	final String expression;

	int idx;

	Tokenizer( String expression )
	{
	this.expression = expression;
	}

	public int peekChar()
	{
	return idx < expression.length() ? expression.charAt( idx ) : EOF;
	}

	public int skipChar()
	{
	return idx < expression.length() ? expression.charAt( idx++ ) : EOF;
	}

	public String nextToken( char delimiter )
	{
	int start = idx;

	while ( idx < expression.length() && delimiter != expression.charAt( idx ) )
	{
	idx++;
	}

	// delimiter MUST be present
	if ( idx <= start \|\| idx >= expression.length() )
	{
	return null;
	}

	return expression.substring( start, idx++ );
	}

	public String nextPropertyName()
	{
	final int start = idx;

	while ( idx < expression.length() && Character.isJavaIdentifierPart( expression.charAt( idx ) ) )
	{
	idx++;
	}

	// property name does not require delimiter
	if ( idx <= start \|\| idx > expression.length() )
	{
	return null;
	}

	return expression.substring( start, idx );
	}

	public int getPosition()
	{
	return idx < expression.length() ? idx : EOF;
	}

	// to make tokenizer look pretty in debugger
	@Override
	public String toString()
	{
	return idx < expression.length() ? expression.substring( idx ) : "<EOF>";
	}
	}

	private ReflectionValueExtractor()
	{
	}

	/**
	* <p>The implementation supports indexed, nested and mapped properties.</p>
	* <p/>
	* <ul>
	* <li>nested properties should be defined by a dot, i.e. "user.address.street"</li>
	* <li>indexed properties (java.util.List or array instance) should be contains <code>(\\w+)\\[(\\d+)\\]</code>
	* pattern, i.e. "user.addresses[1].street"</li>
	* <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code> pattern,
	* i.e. "user.addresses(myAddress).street"</li>
	* <ul>
	*
	* @param expression not null expression
	* @param root not null object
	* @return the object defined by the expression
	* @throws IntrospectionException if any
	*/
	public static Object evaluate( @Nonnull String expression, @Nullable Object root )
	throws IntrospectionException
	{
	return evaluate( expression, root, true );
	}

	/**
	* <p>
	* The implementation supports indexed, nested and mapped properties.
	* </p>
	* <p/>
	* <ul>
	* <li>nested properties should be defined by a dot, i.e. "user.address.street"</li>
	* <li>indexed properties (java.util.List or array instance) should be contains <code>(\\w+)\\[(\\d+)\\]</code>
	* pattern, i.e. "user.addresses[1].street"</li>
	* <li>mapped properties should be contains <code>(\\w+)\\((.+)\\)</code> pattern, i.e.
	* "user.addresses(myAddress).street"</li>
	* <ul>
	*
	* @param expression not null expression
	* @param root not null object
	* @param trimRootToken trim root token yes/no.
	* @return the object defined by the expression
	* @throws IntrospectionException if any
	*/
	public static Object evaluate( @Nonnull String expression, @Nullable Object root, boolean trimRootToken )
	throws IntrospectionException
	{
	Object value = root;

	// ----------------------------------------------------------------------
	// Walk the dots and retrieve the ultimate value desired from the
	// MavenProject instance.
	// ----------------------------------------------------------------------

	if ( StringUtils.isEmpty( expression ) \|\| !Character.isJavaIdentifierStart( expression.charAt( 0 ) ) )
	{
	return null;
	}

	boolean hasDots = expression.indexOf( PROPERTY_START ) >= 0;

	final Tokenizer tokenizer;
	if ( trimRootToken && hasDots )
	{
	tokenizer = new Tokenizer( expression );
	tokenizer.nextPropertyName();
	if ( tokenizer.getPosition() == EOF )
	{
	return null;
	}
	}
	else
	{
	tokenizer = new Tokenizer( "." + expression );
	}

	int propertyPosition = tokenizer.getPosition();
	while ( value != null && tokenizer.peekChar() != EOF )
	{
	switch ( tokenizer.skipChar() )
	{
	case INDEXED_START:
	value =
	getIndexedValue( expression, propertyPosition, tokenizer.getPosition(), value,
	tokenizer.nextToken( INDEXED_END ) );
	break;
	case MAPPED_START:
	value =
	getMappedValue( expression, propertyPosition, tokenizer.getPosition(), value,
	tokenizer.nextToken( MAPPED_END ) );
	break;
	case PROPERTY_START:
	propertyPosition = tokenizer.getPosition();
	value = getPropertyValue( value, tokenizer.nextPropertyName() );
	break;
	default:
	// could not parse expression
	return null;
	}
	}

	return value;
	}

	private static Object getMappedValue( final String expression, final int from, final int to, final Object value,
	final String key )
	throws IntrospectionException
	{
	if ( value == null \|\| key == null )
	{
	return null;
	}

	if ( value instanceof Map )
	{
	Object[] localParams = new Object[] { key };
	ClassMap classMap = getClassMap( value.getClass() );
	try
	{
	Method method = classMap.findMethod( "get", localParams );
	return method.invoke( value, localParams );
	}
	catch ( AmbiguousException e )
	{
	throw new IntrospectionException( e );
	}
	catch ( IllegalAccessException e )
	{
	throw new IntrospectionException( e );
	}
	catch ( InvocationTargetException e )
	{
	throw new IntrospectionException( e.getTargetException() );
	}

	}

	final String message =
	String.format( "The token '%s' at position '%d' refers to a java.util.Map, but the value "
	+ "seems is an instance of '%s'", expression.subSequence( from, to ), from, value.getClass() );

	throw new IntrospectionException( message );
	}

	private static Object getIndexedValue( final String expression, final int from, final int to, final Object value,
	final String indexStr )
	throws IntrospectionException
	{
	try
	{
	int index = Integer.parseInt( indexStr );

	if ( value.getClass().isArray() )
	{
	return Array.get( value, index );
	}

	if ( value instanceof List )
	{
	ClassMap classMap = getClassMap( value.getClass() );
	// use get method on List interface
	Object[] localParams = new Object[] { index };
	Method method = null;
	try
	{
	method = classMap.findMethod( "get", localParams );
	return method.invoke( value, localParams );
	}
	catch ( AmbiguousException e )
	{
	throw new IntrospectionException( e );
	}
	catch ( IllegalAccessException e )
	{
	throw new IntrospectionException( e );
	}
	}
	}
	catch ( NumberFormatException e )
	{
	return null;
	}
	catch ( InvocationTargetException e )
	{
	// catch array index issues gracefully, otherwise release
	if ( e.getCause() instanceof IndexOutOfBoundsException )
	{
	return null;
	}

	throw new IntrospectionException( e.getTargetException() );
	}

	final String message =
	String.format( "The token '%s' at position '%d' refers to a java.util.List or an array, but the value "
	+ "seems is an instance of '%s'", expression.subSequence( from, to ), from, value.getClass() );

	throw new IntrospectionException( message );
	}

	private static Object getPropertyValue( Object value, String property )
	throws IntrospectionException
	{
	if ( value == null \|\| property == null )
	{
	return null;
	}

	ClassMap classMap = getClassMap( value.getClass() );
	String methodBase = StringUtils.capitalizeFirstLetter( property );
	String methodName = "get" + methodBase;
	try
	{
	Method method = classMap.findMethod( methodName, CLASS_ARGS );

	if ( method == null )
	{
	// perhaps this is a boolean property??
	methodName = "is" + methodBase;

	method = classMap.findMethod( methodName, CLASS_ARGS );
	}

	if ( method == null )
	{
	return null;
	}

	return method.invoke( value, OBJECT_ARGS );
	}
	catch ( InvocationTargetException e )
	{
	throw new IntrospectionException( e.getTargetException() );
	}
	catch ( AmbiguousException e )
	{
	throw new IntrospectionException( e );
	}
	catch ( IllegalAccessException e )
	{
	throw new IntrospectionException( e );
	}
	}

	private static ClassMap getClassMap( Class<?> clazz )
	{
	ClassMap classMap = CLASS_MAPS.get( clazz );

	if ( classMap == null )
	{
	classMap = new ClassMap( clazz );

	CLASS_MAPS.put( clazz, classMap );
	}

	return classMap;
	}
	}