Initial code checkin

org.springframework.expression/src/main/java/org/springframework/expression/EvaluationException.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ * 
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * Indicates an expression evaluation failed.
+ * 
+ * @author Keith Donald
+ */
+public class EvaluationException extends RuntimeException {
+
+	private Class contextClass;
+
+	private String expressionString;
+
+	/**
+	 * Creates a new evaluation exception.
+	 * @param contextClass the class of object upon which evaluation was attempted
+	 * @param expressionString the string form of the expression that failed to evaluate
+	 * @param message the exception message
+	 */
+	public EvaluationException(Class contextClass, String expressionString, String message) {
+		this(contextClass, expressionString, message, null);
+	}
+
+	/**
+	 * Creates a new evaluation exception.
+	 * @param contextClass the class of object upon which evaluation was attempted
+	 * @param expressionString the string form of the expression that failed to evaluate
+	 * @param message the exception message
+	 * @param cause the underlying cause of this evaluation exception
+	 */
+	public EvaluationException(Class contextClass, String expressionString, String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	/**
+	 * The class of object upon which evaluation was attempted and failed.
+	 * @return the context class
+	 */
+	public Class getContextClass() {
+		return contextClass;
+	}
+
+	/**
+	 * The string form of the expression that failed to evaluate against an instance of the the context class.
+	 * @return the expression string
+	 */
+	public String getExpressionString() {
+		return expressionString;
+	}
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/Expression.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ * 
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * An expression capable of evaluating itself against context objects. Encapsulates the details of a previously parsed
+ * expression string. Provides a common abstraction for expression evaluation independent of any language like OGNL or
+ * the Unified EL.
+ * 
+ * @author Keith Donald
+ */
+public interface Expression {
+
+	/**
+	 * Evaluate this expression in the provided context and return the result of evaluation.
+	 * @param context the context to evaluate this expression in
+	 * @return the evaluation result
+	 * @throws EvaluationException an exception occurred during expression evaluation
+	 */
+	public Object getValue(Object context) throws EvaluationException;
+
+	/**
+	 * Set this expression in the provided context to the value provided.
+	 * @param context the context on which the new value should be set
+	 * @param value the new value to set
+	 * @throws EvaluationException an exception occurred during expression evaluation
+	 */
+	public void setValue(Object context, Object value) throws EvaluationException;
+
+	/**
+	 * Returns the most general type that can be passed to the {@link #setValue(Object, Object)} method for the given
+	 * context.
+	 * @param context the context to evaluate
+	 * @return the most general type of value that can be set on this context
+	 * @throws EvaluationException an exception occurred during expression evaluation
+	 */
+	public Class getValueType(Object context) throws EvaluationException;
+
+	/**
+	 * Returns the original string used to create this expression, unmodified.
+	 * @return the original expression string
+	 */
+	public String getExpressionString();
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/ExpressionParser.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ * 
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * Parses expression strings into compiled expressions that can be evaluated. Supports parsing templates as well as
+ * standard expression strings.
+ * 
+ * @author Keith Donald
+ */
+public interface ExpressionParser {
+
+	/**
+	 * Parse the expression string and return a compiled Expression object you can use for evaluation. Some examples:
+	 * 
+	 * <pre>
+	 *     3 + 4
+	 *     name.firstName
+	 * </pre>
+	 * 
+	 * @param expressionString the raw expression string to parse
+	 * @param context a context for influencing this expression parsing routine (optional)
+	 * @return an evaluator for the parsed expression
+	 * @throws ParserException an exception occurred during parsing
+	 */
+	public Expression parseExpression(String expressionString, ParserContext context) throws ParserException;
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/ExpressionVariable.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ *
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * An expression variable.
+ * @author Keith Donald
+ */
+public class ExpressionVariable {
+
+	private String name;
+
+	private String valueExpression;
+
+	private ParserContext parserContext;
+
+	/**
+	 * Creates a new expression variable.
+	 * @param name the name of the variable, acting as an convenient alias (required)
+	 * @param valueExpression the value expression (required)
+	 */
+	public ExpressionVariable(String name, String valueExpression) {
+		init(name, valueExpression, null);
+	}
+
+	/**
+	 * Creates a new expression variable with a populated parser context.
+	 * @param name the name of the variable, acting as an convenient alias (required)
+	 * @param valueExpression the value expression (required)
+	 * @param parserContext the parser context to use to parse the value expression (optional)
+	 */
+	public ExpressionVariable(String name, String valueExpression, ParserContext parserContext) {
+		init(name, valueExpression, parserContext);
+	}
+
+	/**
+	 * Returns the variable name.
+	 * @return the variable name
+	 */
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * Returns the expression that will be evaluated when the variable is referenced by its name in another expression.
+	 * @return the expression value.
+	 */
+	public String getValueExpression() {
+		return valueExpression;
+	}
+
+	/**
+	 * Returns the parser context to use to parse the variable's value expression.
+	 * @return the value expression parser context
+	 */
+	public ParserContext getParserContext() {
+		return parserContext;
+	}
+
+	public boolean equals(Object o) {
+		if (!(o instanceof ExpressionVariable)) {
+			return false;
+		}
+		ExpressionVariable var = (ExpressionVariable) o;
+		return name.equals(var.name);
+	}
+
+	public int hashCode() {
+		return name.hashCode();
+	}
+
+	public String toString() {
+		return "[Expression Variable '" + name + "']";
+	}
+
+	private void init(String name, String valueExpression, ParserContext parserContext) {
+		this.name = name;
+		this.valueExpression = valueExpression;
+		this.parserContext = parserContext;
+	}
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/ParserContext.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ *
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * Input provided to an expression parser that can influence an expression parsing/compilation routine.
+ * @author Keith Donald
+ */
+public interface ParserContext {
+
+	/**
+	 * Returns the type of context object the parsed expression will evaluate in. An expression parser may use this
+	 * value to install custom variable resolves for that particular type of context.
+	 * @return the evaluation context type
+	 */
+	public Class getEvaluationContextType();
+
+	/**
+	 * Returns the expected type of object returned from evaluating the parsed expression. An expression parser may use
+	 * this value to coerce an raw evaluation result before it is returned.
+	 * @return the expected evaluation result type
+	 */
+	public Class getExpectedEvaluationResultType();
+
+	/**
+	 * Returns additional expression variables or aliases that can be referenced during expression evaluation. An
+	 * expression parser will register these variables for reference during evaluation.
+	 */
+	public ExpressionVariable[] getExpressionVariables();
+
+	/**
+	 * Whether or not the expression being parsed is a template. A template expression consists of literal text that can
+	 * be mixed with evaluatable blocks. Some examples:
+	 * 
+	 * <pre>
+	 * 	   Some literal text
+	 *     Hello #{name.firstName}!
+	 *     #{3 + 4}
+	 * </pre>
+	 * 
+	 * @return true if the expression is a template, false otherwise
+	 */
+	public boolean isTemplate();
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/ParserException.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ * 
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * Base class for exceptions thrown during expression parsing.
+ * 
+ * @author Keith Donald
+ */
+public class ParserException extends RuntimeException {
+
+	/**
+	 * The expression string that could not be parsed.
+	 */
+	private String expressionString;
+
+	/**
+	 * Creates a new expression parsing exception.
+	 * @param expressionString the expression string that could not be parsed
+	 * @param cause the underlying cause of this exception
+	 */
+	public ParserException(String expressionString, Throwable cause) {
+		this(expressionString, "Unable to parse expression string '" + expressionString + "'", cause);
+	}
+
+	/**
+	 * Creates a new expression parsing exception.
+	 * @param expressionString the expression string that could not be parsed
+	 * @param message a descriptive message
+	 * @param cause the underlying cause of this exception
+	 */
+	public ParserException(String expressionString, String message, Throwable cause) {
+		super(message, cause);
+		this.expressionString = expressionString;
+	}
+
+	/**
+	 * Returns the expression string that could not be parsed.
+	 */
+	public Object getExpressionString() {
+		return expressionString;
+	}
+}

org.springframework.expression/src/main/java/org/springframework/expression/PropertyNotFoundException.java

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+/*
+ * Copyright 2004-2008 the original author or authors.
+ *
+ * Licensed 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.springframework.binding.expression;
+
+/**
+ * An evaluation exception indicating a expression that references a property failed to evaluate because the property
+ * could not be found.
+ * @author Keith Donald
+ */
+public class PropertyNotFoundException extends EvaluationException {
+
+	/**
+	 * Creates a new property not found exception
+	 * @param contextClass the class of object upon which property evaluation was attempted
+	 * @param property the property that could not be found
+	 * @param cause root cause of the failure
+	 */
+	public PropertyNotFoundException(Class contextClass, String property, Throwable cause) {
+		super(contextClass, property, "Property '" + property + "' not found on context of class ["
+				+ contextClass.getName() + "]", cause);
+	}
+
+}

org.springframework.expression/src/main/java/org/springframework/expression/package.html

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+<html>
+<body>
+<p>
+Core expression language abstraction for parsing and evaluating expressions.
+</p>
+</body>
+</html>

org.springframework.expression/src/main/java/overview.html

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+<html>
+<body>
+<p>
+The Spring Data Binding framework, an internal library used by Spring Web Flow.
+</p>
+</body>
+</html>

org.springframework.expression/src/test/resources/log4j.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
+
+<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
+
+	<!-- Appenders -->
+	<appender name="console" class="org.apache.log4j.ConsoleAppender">
+		<param name="Target" value="System.out" />
+		<layout class="org.apache.log4j.PatternLayout">
+			<param name="ConversionPattern" value="%-5p: %c - %m%n" />
+		</layout>
+	</appender>
+
+	<logger name="org.springframework.beans">
+		<level value="warn" />
+	</logger>
+
+	<logger name="org.springframework.binding">
+		<level value="debug" />
+	</logger>
+
+	<!-- Root Logger -->
+	<root>
+		<priority value="warn" />
+		<appender-ref ref="console" />
+	</root>
+	
+</log4j:configuration>