odata2-lib/odata-api/src/main/java/org/apache/olingo/odata2/api/uri/expression/CommonExpression.java

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package org.apache.olingo.odata2.api.uri.expression;

import org.apache.olingo.odata2.api.edm.EdmType;

/**
 * Parent class of all classes used to build the expression tree
 * <br>
 * <br>
 * <p>This interface defines the default methods for all expression tree nodes
 * <br>
 * <br>
 * 
 */
public interface CommonExpression extends Visitable {
  /**
   * @return Kind of this expression
   * @see ExpressionKind
   */
  ExpressionKind getKind();

  /**
   * @return The return type of the value represented with
   * this expression. For example the {@link #getEdmType()} method
   * for an expression representing the "concat" method will return always
   * "Edm.String".<br>
   * <br>
   * <p>This type information is set while parsing the $filter or $orderby
   * expressions and used to do a first validation of the expression.
   * For calculating operators like "add, sub, mul" this type
   * information is purely based on input and output types of the
   * operator as defined in the OData specification.
   * So for $filter=2 add 7 the {@link #getEdmType()} method of the binary expression
   * will return Edm.Byte and not Edm.Int16 because the parser performs no real
   * addition.<br>
   * <br>
   * <p>However, the application may change this type while evaluating the
   * expression tree.
   */
  EdmType getEdmType();

  /**
   * Set the edmType of this expression node
   * @param edmType Type to be set
   * @return A self reference for method chaining"
   */
  CommonExpression setEdmType(EdmType edmType);

  /**
   * Returns the URI literal which lead to the creation of this expression.
   * @return URI literal
   */
  String getUriLiteral();
}