ELExpressionParserTests.java

package org.springframework.binding.expression.el;

import java.beans.FeatureDescriptor;
import java.util.Iterator;

import javax.el.ELContext;
import javax.el.ELResolver;
import javax.el.FunctionMapper;
import javax.el.VariableMapper;

import junit.framework.TestCase;

import org.apache.el.ExpressionFactoryImpl;
import org.springframework.binding.expression.EvaluationException;
import org.springframework.binding.expression.Expression;
import org.springframework.binding.expression.ExpressionVariable;
import org.springframework.binding.expression.ParserException;
import org.springframework.binding.expression.ValueCoercionException;
import org.springframework.binding.expression.support.FluentParserContext;

public class ELExpressionParserTests extends TestCase {

	private ELExpressionParser parser = new ELExpressionParser(new ExpressionFactoryImpl());

	public void setUp() {
		parser.putContextFactory(TestBean.class, new TestELContextFactory());
	}

	public void testParseSimpleEvalExpressionNoParserContext() {
		String expressionString = "3 + 4";
		Expression exp = parser.parseExpression(expressionString, null);
		assertEquals(new Long(7), exp.getValue(null));
	}

	public void testParseNullExpressionString() {
		String expressionString = null;
		try {
			parser.parseExpression(expressionString, null);
			fail("should have thrown iae");
		} catch (IllegalArgumentException e) {

		}
	}

	public void testParseNull() {
		Expression exp = parser.parseExpression("null", null);
		assertEquals(null, exp.getValue(null));
	}

	public void testParseEmptyExpressionString() {
		String expressionString = "";
		try {
			parser.parseExpression(expressionString, null);
			fail("Should have failed");
		} catch (ParserException e) {

		}
	}

	public void testParseSimpleEvalExpressionNoEvalContextWithTypeCoersion() {
		String expressionString = "3 + 4";
		Expression exp = parser
				.parseExpression(expressionString, new FluentParserContext().expectResult(Integer.class));
		assertEquals(new Integer(7), exp.getValue(null));
	}

	public void testParseBeanEvalExpressionNoParserContext() {
		String expressionString = "value";
		Expression exp = parser.parseExpression(expressionString, null);
		assertEquals("foo", exp.getValue(new TestBean()));
	}

	public void testParseEvalExpressionWithContextTypeCoersion() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, new FluentParserContext().expectResult(Long.class));
		assertEquals(new Long(2), exp.getValue(new TestBean()));
	}

	public void testParseEvalExpressionWithContextCustomELVariableResolver() {
		String expressionString = "specialProperty";
		Expression exp = parser.parseExpression(expressionString, new FluentParserContext().evaluate(TestBean.class));
		assertEquals("Custom resolver resolved this special property!", exp.getValue(new TestBean()));
	}

	public void testParseBeanEvalExpressionInvalidELVariable() {
		try {
			String expressionString = "bogus";
			Expression exp = parser.parseExpression(expressionString,
					new FluentParserContext().evaluate(TestBean.class));
			exp.getValue(new TestBean());
			fail("Should have failed");
		} catch (EvaluationException e) {

		}
	}

	public void testParseLiteralExpression() {
		String expressionString = "'value'";
		Expression exp = parser.parseExpression(expressionString, null);
		assertEquals("value", exp.getValue(null));
	}

	public void testParseTemplateExpression() {
		String expressionString = "text text text #{value} text text text#{value}";
		Expression exp = parser.parseExpression(expressionString, new FluentParserContext().template());
		TestBean target = new TestBean();
		assertEquals("text text text foo text text textfoo", exp.getValue(target));
	}

	public void testParseTemplateExpressionWithVariables() {
		String expressionString = "#{value}#{max}";
		Expression exp = parser.parseExpression(expressionString,
				new FluentParserContext().template().variable(new ExpressionVariable("max", "maximum")));
		TestBean target = new TestBean();
		assertEquals("foo2", exp.getValue(target));
	}

	public void testVariablesWithCoersion() {
		Expression exp = parser.parseExpression("max", new FluentParserContext().variable(new ExpressionVariable("max",
				"maximum", new FluentParserContext().expectResult(Long.class))));
		TestBean target = new TestBean();
		assertEquals(new Long(2), exp.getValue(target));
	}

	public void testTemplateNestedVariables() {
		String expressionString = "#{value}#{max}";
		Expression exp = parser.parseExpression(
				expressionString,
				new FluentParserContext().template().variable(
						new ExpressionVariable("max", "#{maximum}#{var}", new FluentParserContext().template()
								.variable(new ExpressionVariable("var", "'bar'")))));
		TestBean target = new TestBean();
		assertEquals("foo2bar", exp.getValue(target));
	}

	// public void testGetValueTypeNullCollectionValue() {
	// String exp = "list[3]";
	// Expression e = parser.parseExpression(exp, null);
	// TestBean target = new TestBean();
	// assertEquals(null, e.getValueType(target));
	// }

	public void testGetExpressionString() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, null);
		assertEquals("maximum", exp.getExpressionString());
	}

	public void testGetExpressionType() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, null);
		TestBean context = new TestBean();
		assertEquals(int.class, exp.getValueType(context));
	}

	public void testGetValueWithCoersion() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, new FluentParserContext().expectResult(String.class));
		TestBean context = new TestBean();
		assertEquals("2", exp.getValue(context));
	}

	public void testGetValueCoersionError() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString,
				new FluentParserContext().expectResult(TestBean.class));
		TestBean context = new TestBean();
		try {
			exp.getValue(context);
			fail("Should have failed with coersion");
		} catch (ValueCoercionException e) {
		}
	}

	public void testSetValue() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, null);
		TestBean context = new TestBean();
		exp.setValue(context, 5);
		assertEquals(5, context.getMaximum());
	}

	public void testSetValueWithTypeCoersion() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, null);
		TestBean context = new TestBean();
		exp.setValue(context, "5");
		assertEquals(5, context.getMaximum());
	}

	public void testSetValueCoersionError() {
		String expressionString = "maximum";
		Expression exp = parser.parseExpression(expressionString, null);
		TestBean context = new TestBean();
		try {
			exp.setValue(context, "bogus");
			fail("Should have failed with coersion");
		} catch (ValueCoercionException e) {
		}
	}

	private static class TestELContextFactory implements ELContextFactory {
		public ELContext getELContext(final Object target) {
			return new ELContext() {
				public ELResolver getELResolver() {
					return new ELResolver() {
						public Class<?> getCommonPropertyType(ELContext arg0, Object arg1) {
							return Object.class;
						}

						public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext arg0, Object arg1) {
							return null;
						}

						public Class<?> getType(ELContext arg0, Object arg1, Object arg2) {
							return String.class;
						}

						public Object getValue(ELContext arg0, Object arg1, Object arg2) {
							if (arg1 == null && arg2.equals("specialProperty")) {
								arg0.setPropertyResolved(true);
								return "Custom resolver resolved this special property!";
							} else {
								return null;
							}
						}

						public boolean isReadOnly(ELContext arg0, Object arg1, Object arg2) {
							return true;
						}

						public void setValue(ELContext arg0, Object arg1, Object arg2, Object arg3) {
							throw new UnsupportedOperationException("Not supported");
						}
					};
				}

				public FunctionMapper getFunctionMapper() {
					return null;
				}

				public VariableMapper getVariableMapper() {
					return null;
				}
			};
		}
	}
}