enhanced mapper subsystem

spring-binding/src/main/java/org/springframework/binding/mapping/Mapping.java

@@ -15,134 +15,12 @@
  */
 package org.springframework.binding.mapping;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.springframework.binding.convert.ConversionException;
-import org.springframework.binding.convert.ConversionExecutor;
 import org.springframework.binding.expression.Expression;
-import org.springframework.binding.message.MessageBuilder;
-import org.springframework.binding.message.MessageResolver;
-import org.springframework.core.style.ToStringCreator;
-import org.springframework.util.Assert;
-import org.springframework.util.ClassUtils;
 
-/**
- * A single mapping definition, encapsulating the information necessary to map the result of evaluating an expression on
- * a source object to a property on a target object, optionally applying a type conversion during the mapping process.
- * 
- * @author Keith Donald
- */
-public class Mapping {
+public interface Mapping {
+	public Expression getSourceExpression();
 
-	private static final Log logger = LogFactory.getLog(Mapping.class);
+	public Expression getTargetExpression();
 
-	/**
-	 * The source expression to evaluate against a source object to map from.
-	 */
-	private final Expression sourceExpression;
-
-	/**
-	 * The target expression to set on a target object to map to.
-	 */
-	private final Expression targetExpression;
-
-	/**
-	 * A type converter to apply during the mapping process.
-	 */
-	private final ConversionExecutor typeConverter;
-
-	/**
-	 * Whether or not this is a required mapping; if true, the source expression must return a non-null value.
-	 */
-	private boolean required;
-
-	/**
-	 * Creates a new mapping.
-	 * @param sourceExpression the source expression
-	 * @param targetExpression the target expression
-	 * @param typeConverter a type converter
-	 * @param required whether or not this mapping is required
-	 */
-	public Mapping(Expression sourceExpression, Expression targetExpression, ConversionExecutor typeConverter,
-			boolean required) {
-		Assert.notNull(sourceExpression, "The source expression is required");
-		Assert.notNull(targetExpression, "The target expression is required");
-		this.sourceExpression = sourceExpression;
-		this.targetExpression = targetExpression;
-		this.typeConverter = typeConverter;
-		this.required = required;
-	}
-
-	/**
-	 * Map the <code>sourceAttribute</code> in to the <code>targetAttribute</code> target map, performing type
-	 * conversion if necessary.
-	 * @param source The source data structure
-	 * @param target The target data structure
-	 */
-	public boolean map(Object source, Object target, MappingContext context) {
-		Assert.notNull(source, "The source to map from is required");
-		Assert.notNull(target, "The target to map to is required");
-		Assert.notNull(context, "The mapping context is required");
-		Object sourceValue = sourceExpression.getValue(source);
-		if (required && (sourceValue == null || isEmptyString(sourceValue))) {
-			String defaultText = "'" + targetExpression.getExpressionString() + "' is required";
-			MessageResolver message = new MessageBuilder().error().source(targetExpression.getExpressionString())
-					.codes(createMessageCodes("required", target, targetExpression)).defaultText(defaultText).build();
-			context.getMessageContext().addMessage(message);
-			return false;
-		}
-		Object targetValue;
-		if (sourceValue != null && typeConverter != null) {
-			try {
-				targetValue = typeConverter.execute(sourceValue);
-			} catch (ConversionException e) {
-				e.printStackTrace();
-				String defaultText = "The '" + targetExpression.getExpressionString() + "' value is the wrong type";
-				MessageResolver message = new MessageBuilder().error().source(targetExpression.getExpressionString())
-						.codes(createMessageCodes("typeMismatch", target, targetExpression)).defaultText(defaultText)
-						.build();
-				context.getMessageContext().addMessage(message);
-				return false;
-			}
-		} else {
-			targetValue = sourceValue;
-		}
-		if (logger.isDebugEnabled()) {
-			logger.debug("Mapping '" + sourceExpression + "' value [" + sourceValue + "] to target '"
-					+ targetExpression + "'; setting target value to [" + targetValue + "]");
-		}
-		targetExpression.setValue(target, targetValue);
-		return true;
-	}
-
-	private boolean isEmptyString(Object sourceValue) {
-		if (sourceValue instanceof CharSequence) {
-			return ((CharSequence) sourceValue).length() == 0;
-		} else {
-			return false;
-		}
-	}
-
-	private String[] createMessageCodes(String errorCode, Object target, Expression targetExpression) {
-		String[] codes = new String[2];
-		codes[0] = ClassUtils.getShortName(target.getClass()) + "." + targetExpression.getExpressionString();
-		codes[1] = errorCode;
-		return codes;
-	}
-
-	public boolean equals(Object o) {
-		if (!(o instanceof Mapping)) {
-			return false;
-		}
-		Mapping other = (Mapping) o;
-		return sourceExpression.equals(other.sourceExpression) && targetExpression.equals(other.targetExpression);
-	}
-
-	public int hashCode() {
-		return sourceExpression.hashCode() + targetExpression.hashCode();
-	}
-
-	public String toString() {
-		return new ToStringCreator(this).append(sourceExpression + " -> " + targetExpression).toString();
-	}
+	public boolean isRequired();
 }