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Merge pull request #37 from DanilaFe/more-exceptions 

Replace some more cases where null is used with Exceptions.
This commit is contained in:
Danila Fedorin 2017-09-23 15:53:37 -07:00 committed by GitHub
parent f385a48aa2 ea4588be44
commit e0ccb67ad3
15 changed files with 128 additions and 42 deletions
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24
core/src/main/java/org/nwapw/abacus/exception/ContextException.java Normal file
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@ -0,0 +1,24 @@
package org.nwapw.abacus.exception;
/**
* Exception thrown by the Context in cases where lookup fails
* where it should not.
*/
public class ContextException extends AbacusException {
/**
* Creates a new ContextException without an extra message.
*/
public ContextException() {
this("");
}
/**
* Creates a ContextException with the given message.
* @param message the message to use.
*/
public ContextException(String message){
super("Context exception", message);
}
}

25
core/src/main/java/org/nwapw/abacus/exception/NumberReducerException.java Normal file
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@ -0,0 +1,25 @@
package org.nwapw.abacus.exception;
/**
* Exception thrown by the NumberReducer if something goes wrong when
* transforming a parse tree into a single value.
*/
public class NumberReducerException extends AbacusException {
/**
* Creates a new NumberReducerException with
* no additional message.
*/
public NumberReducerException() {
this("");
}
/**
* Creates a new NumberReducerException with the given message.
* @param message the message.
*/
public NumberReducerException(String message) {
super("Error evaluating expression", message);
}
}

23
core/src/main/java/org/nwapw/abacus/exception/ParseException.java Normal file
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@ -0,0 +1,23 @@
package org.nwapw.abacus.exception;
/**
* Exception thrown by parsers.
*/
public class ParseException extends AbacusException {
/**
* Creates a new ParseException with no additional message.
*/
public ParseException(){
this("");
}
/**
* Creates a new ParseException with the given additional message.
* @param message the message.
*/
public ParseException(String message){
super("Failed to parse string", message);
}
}

10
core/src/main/java/org/nwapw/abacus/exception/EvaluationException.java → core/src/main/java/org/nwapw/abacus/exception/ReductionException.java
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@ -1,16 +1,14 @@
package org.nwapw.abacus.exception;
/**
* An exception thrown primarily from Tree Value operators and functions,
* which have to deal with the result of a Reducer as well as the results
* of Applicable.
* An exception thrown from TreeReducers.
*/
public class EvaluationException extends AbacusException {
public class ReductionException extends AbacusException {
/**
* Creates a new EvaluationException with the default string.
*/
public EvaluationException() {
public ReductionException() {
this("");
}
@ -18,7 +16,7 @@ public class EvaluationException extends AbacusException {
* Creates a new EvaluationError with the given message string.
* @param message the message string.
*/
public EvaluationException(String message) {
public ReductionException(String message) {
super("Evaluation error", message);
}

23
core/src/main/java/org/nwapw/abacus/exception/TokenizeException.java Normal file
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@ -0,0 +1,23 @@
package org.nwapw.abacus.exception;
/**
* Exception thrown by Lexers when they are unable to tokenize the input string.
*/
public class TokenizeException extends AbacusException {
/**
* Create a new tokenize exception with no additional data.
*/
public TokenizeException() {
this("");
}
/**
* Create a new tokenize exception with the given message.
* @param message the message to use.
*/
public TokenizeException(String message){
super("Failed to tokenize string", message);
}
}

5
core/src/main/java/org/nwapw/abacus/parsing/LexerTokenizer.java
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@ -1,5 +1,6 @@
package org.nwapw.abacus.parsing;
import org.nwapw.abacus.exception.TokenizeException;
import org.nwapw.abacus.lexing.Lexer;
import org.nwapw.abacus.lexing.pattern.Match;
import org.nwapw.abacus.lexing.pattern.Pattern;
@ -42,7 +43,9 @@ public class LexerTokenizer implements Tokenizer<Match<TokenType>>, PluginListen
@Override
public List<Match<TokenType>> tokenizeString(String string) {
return lexer.lexAll(string, 0, TOKEN_SORTER);
List<Match<TokenType>> tokens = lexer.lexAll(string, 0, TOKEN_SORTER);
if(tokens == null) throw new TokenizeException();
return tokens;
}
@Override

19
core/src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java
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@ -1,5 +1,6 @@
package org.nwapw.abacus.parsing;
import org.nwapw.abacus.exception.ParseException;
import org.nwapw.abacus.function.Operator;
import org.nwapw.abacus.function.OperatorAssociativity;
import org.nwapw.abacus.function.OperatorType;
@ -99,7 +100,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
while (!tokenStack.empty() && tokenStack.peek().getType() != TokenType.OPEN_PARENTH) {
output.add(tokenStack.pop());
}
if (tokenStack.empty()) return null;
if (tokenStack.empty()) throw new ParseException("mismatched parentheses");
if (matchType == TokenType.CLOSE_PARENTH) {
tokenStack.pop();
}
@ -111,7 +112,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
if (!(newMatchType == TokenType.OP ||
newMatchType == TokenType.TREE_VALUE_OP ||
newMatchType == TokenType.FUNCTION ||
newMatchType == TokenType.TREE_VALUE_FUNCTION)) return null;
newMatchType == TokenType.TREE_VALUE_FUNCTION)) throw new ParseException("mismatched parentheses");
output.add(tokenStack.pop());
}
return output;
@ -124,7 +125,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
* @return the construct tree expression.
*/
public TreeNode constructRecursive(List<Match<TokenType>> matches) {
if (matches.size() == 0) return null;
if (matches.size() == 0) throw new ParseException("no tokens left in input");
Match<TokenType> match = matches.remove(0);
TokenType matchType = match.getType();
if (matchType == TokenType.OP || matchType == TokenType.TREE_VALUE_OP) {
@ -133,7 +134,6 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
if (type == OperatorType.BINARY_INFIX) {
TreeNode right = constructRecursive(matches);
TreeNode left = constructRecursive(matches);
if (left == null || right == null) return null;
if (matchType == TokenType.OP) {
return new NumberBinaryNode(operator, left, right);
} else {
@ -141,7 +141,6 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
}
} else {
TreeNode applyTo = constructRecursive(matches);
if (applyTo == null) return null;
if (matchType == TokenType.OP) {
return new NumberUnaryNode(operator, applyTo);
} else {
@ -157,10 +156,9 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
List<TreeNode> children = new ArrayList<>();
while (!matches.isEmpty() && matches.get(0).getType() != TokenType.INTERNAL_FUNCTION_END) {
TreeNode argument = constructRecursive(matches);
if (argument == null) return null;
children.add(0, argument);
}
if (matches.isEmpty()) return null;
if (matches.isEmpty()) throw new ParseException("incorrectly formatted function call");
matches.remove(0);
CallNode node;
if (matchType == TokenType.FUNCTION) {
@ -170,16 +168,17 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
}
return node;
}
return null;
throw new ParseException("unrecognized token");
}
@Override
public TreeNode constructTree(List<Match<TokenType>> tokens) {
if (tokens.isEmpty()) throw new ParseException("no input tokens");
tokens = intoPostfix(new ArrayList<>(tokens));
if (tokens == null) return null;
Collections.reverse(tokens);
TreeNode constructedTree = constructRecursive(tokens);
return tokens.size() == 0 ? constructedTree : null;
if(tokens.size() == 0) return constructedTree;
throw new ParseException("could not parse all input");
}
@Override

4
core/src/main/java/org/nwapw/abacus/parsing/TreeBuilder.java
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@ -42,9 +42,7 @@ public class TreeBuilder<T> {
* @return the resulting tree.
*/
public TreeNode fromString(String input) {
List<T> tokens = tokenizer.tokenizeString(input);
if (tokens == null) return null;
return parser.constructTree(tokens);
return parser.constructTree(tokenizer.tokenizeString(input));
}
}

4
core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
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@ -332,7 +332,7 @@ public class StandardPlugin extends Plugin {
//We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
//In the following, a=1/3^n, b=1/4^n, c = 1/n.
//a is also an error bound.
NumberInterface a = implementation.instanceForString("1"), b = a, c = a;
NumberInterface a = implementation.instanceForString("1"), b = a, c;
NumberInterface sum = implementation.instanceForString("0");
NumberInterface one = implementation.instanceForString("1");
int n = 0;
@ -715,7 +715,7 @@ public class StandardPlugin extends Plugin {
* @return the value of the series
*/
private static NumberInterface sinTaylor(MutableEvaluationContext context, NumberInterface x) {
NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm = x, sum = x;
NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm, sum = x;
NumberInterface maxError = x.getMaxError();
int n = 1;
do {

2
core/src/main/kotlin/org/nwapw/abacus/Abacus.kt
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@ -88,7 +88,7 @@ class Abacus(val configuration: Configuration) {
* @param input the input string to parse
* @return the resulting tree, null if the tree builder or the produced tree are null.
*/
fun parseString(input: String): TreeNode? = treeBuilder.fromString(input)
fun parseString(input: String): TreeNode = treeBuilder.fromString(input)
/**
* Evaluates the given tree.
*

7
core/src/main/kotlin/org/nwapw/abacus/context/ChainSearchDelegate.kt
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@ -1,5 +1,6 @@
package org.nwapw.abacus.context
import org.nwapw.abacus.exception.ContextException
import kotlin.reflect.KProperty
/**
@ -16,14 +17,14 @@ import kotlin.reflect.KProperty
*/
class ChainSearchDelegate<out V>(private val valueGetter: EvaluationContext.() -> V?) {
operator fun getValue(selfRef: Any, property: KProperty<*>): V? {
var currentRef = selfRef as? EvaluationContext ?: return null
operator fun getValue(selfRef: Any, property: KProperty<*>): V {
var currentRef = selfRef as EvaluationContext
var returnedValue = currentRef.valueGetter()
while (returnedValue == null) {
currentRef = currentRef.parent ?: break
returnedValue = currentRef.valueGetter()
}
return returnedValue
return returnedValue ?: throw ContextException("context chain does not contain value")
}
}

6
core/src/main/kotlin/org/nwapw/abacus/context/EvaluationContext.kt
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@ -43,13 +43,13 @@ open class EvaluationContext(val parent: EvaluationContext? = null,
/**
* The implementation inherited from this context's parent.
*/
val inheritedNumberImplementation: NumberImplementation?
by ChainSearchDelegate { numberImplementation}
val inheritedNumberImplementation: NumberImplementation
by ChainSearchDelegate { numberImplementation }
/**
* The reducer inherited from this context's parent.
*/
val inheritedReducer: Reducer<NumberInterface>?
val inheritedReducer: Reducer<NumberInterface>
by ChainSearchDelegate { reducer }
/**

10
core/src/main/kotlin/org/nwapw/abacus/tree/NumberReducer.kt
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@ -2,7 +2,8 @@ package org.nwapw.abacus.tree
import org.nwapw.abacus.Abacus
import org.nwapw.abacus.context.EvaluationContext
import org.nwapw.abacus.exception.EvaluationException
import org.nwapw.abacus.exception.NumberReducerException
import org.nwapw.abacus.exception.ReductionException
import org.nwapw.abacus.number.NumberInterface
class NumberReducer(val abacus: Abacus, context: EvaluationContext) : Reducer<NumberInterface> {
@ -17,15 +18,14 @@ class NumberReducer(val abacus: Abacus, context: EvaluationContext) : Reducer<Nu
val promotionManager = abacus.promotionManager
return when(treeNode){
is NumberNode -> {
context.inheritedNumberImplementation?.instanceForString(treeNode.number)
?: throw EvaluationException("no number implementation selected.")
context.inheritedNumberImplementation.instanceForString(treeNode.number)
}
is VariableNode -> {
val variable = context.getVariable(treeNode.variable)
if(variable != null) return variable
val definition = context.getDefinition(treeNode.variable)
if(definition != null) return definition.reduce(this)
throw EvaluationException("variable is not defined.")
throw NumberReducerException("variable is not defined.")
}
is NumberUnaryNode -> {
val child = children[0] as NumberInterface
@ -58,7 +58,7 @@ class NumberReducer(val abacus: Abacus, context: EvaluationContext) : Reducer<Nu
abacus.pluginManager.treeValueFunctionFor(treeNode.callTo)
.apply(context, *treeNode.children.toTypedArray())
}
else -> throw EvaluationException("unrecognized tree node.")
else -> throw ReductionException("unrecognized tree node.")
}
}

2
core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java
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@ -22,7 +22,6 @@ public class CalculationTests {
private void testOutput(String input, String parseOutput, String output) {
TreeNode parsedTree = abacus.parseString(input);
Assert.assertNotNull(parsedTree);
Assert.assertEquals(parsedTree.toString(), parseOutput);
NumberInterface result = abacus.evaluateTree(parsedTree).getValue();
Assert.assertNotNull(result);
@ -31,7 +30,6 @@ public class CalculationTests {
private void testDomainException(String input, String parseOutput) {
TreeNode parsedTree = abacus.parseString(input);
Assert.assertNotNull(parsedTree);
Assert.assertEquals(parsedTree.toString(), parseOutput);
try {
abacus.evaluateTree(parsedTree);

6
fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
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@ -13,11 +13,8 @@ import javafx.util.StringConverter;
import org.nwapw.abacus.Abacus;
import org.nwapw.abacus.config.Configuration;
import org.nwapw.abacus.exception.AbacusException;
import org.nwapw.abacus.exception.ComputationInterruptedException;
import org.nwapw.abacus.function.Documentation;
import org.nwapw.abacus.function.DocumentationType;
import org.nwapw.abacus.exception.DomainException;
import org.nwapw.abacus.exception.EvaluationException;
import org.nwapw.abacus.number.*;
import org.nwapw.abacus.plugin.ClassFinder;
import org.nwapw.abacus.plugin.PluginListener;
@ -145,9 +142,6 @@ public class AbacusController implements PluginListener {
private String attemptCalculation() {
try {
TreeNode constructedTree = abacus.parseString(inputField.getText());
if (constructedTree == null) {
return ERR_SYNTAX;
}
EvaluationResult result = abacus.evaluateTree(constructedTree);
NumberInterface evaluatedNumber = result.getValue();
String resultingString = evaluatedNumber.toString();