Made BaseUnit a subclass of LinearUnit and made an expression parser

2 files changed, 0 insertions, 421 deletions

diff --git a/src/org/unitConverter/expressionParser/ExpressionParser.java b/src/org/unitConverter/expressionParser/ExpressionParser.java
deleted file mode 100644
index 804ea87..0000000
--- a/src/org/unitConverter/expressionParser/ExpressionParser.java
+++ /dev/null
@@ -1,398 +0,0 @@
-/**
- * Copyright (C) 2019 Adrien Hopkins
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-package org.unitConverter.expressionParser;
-
-import java.util.ArrayDeque;
-import java.util.Deque;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.function.BinaryOperator;
-import java.util.function.Function;
-import java.util.function.UnaryOperator;
-
-/**
- * An object that can parse expressions with unary or binary operators.
- * 
- * @author Adrien Hopkins
- * @param <T>
- *            type of object that exists in parsed expressions
- * @since 2019-03-14
- */
-// TODO: possibly make this class non-final?
-public final class ExpressionParser<T> {
-	/**
-	 * A builder that can create {@code ExpressionParser<T>} instances.
-	 * 
-	 * @author Adrien Hopkins
-	 * @param <T>
-	 *            type of object that exists in parsed expressions
-	 * @since 2019-03-17
-	 */
-	public static final class Builder<T> {
-		/**
-		 * A function that obtains a parseable object from a string. For example, an integer {@code ExpressionParser}
-		 * would use {@code Integer::parseInt}.
-		 * 
-		 * @since 2019-03-14
-		 */
-		private final Function<String, T> objectObtainer;
-
-		/**
-		 * A map mapping operator strings to operator functions, for unary operators.
-		 * 
-		 * @since 2019-03-14
-		 */
-		private final Map<String, PriorityUnaryOperator<T>> unaryOperators;
-
-		/**
-		 * A map mapping operator strings to operator functions, for binary operators.
-		 * 
-		 * @since 2019-03-14
-		 */
-		private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-
-		/**
-		 * Creates the {@code Builder}.
-		 * 
-		 * @param objectObtainer
-		 *            a function that can turn strings into objects of the type handled by the parser.
-		 * @throws NullPointerException
-		 *             if {@code objectObtainer} is null
-		 * @since 2019-03-17
-		 */
-		public Builder(final Function<String, T> objectObtainer) {
-			this.objectObtainer = Objects.requireNonNull(objectObtainer, "objectObtainer must not be null.");
-			this.unaryOperators = new HashMap<>();
-			this.binaryOperators = new HashMap<>();
-		}
-
-		/**
-		 * Adds a binary operator to the builder.
-		 * 
-		 * @param text
-		 *            text used to reference the operator, like '+'
-		 * @param operator
-		 *            operator to add
-		 * @param priority
-		 *            operator's priority, which determines which operators are applied first
-		 * @return this builder
-		 * @throws NullPointerException
-		 *             if {@code text} or {@code operator} is null
-		 * @since 2019-03-17
-		 */
-		public Builder<T> addBinaryOperator(final String text, final BinaryOperator<T> operator, final int priority) {
-			Objects.requireNonNull(text, "text must not be null.");
-			Objects.requireNonNull(operator, "operator must not be null.");
-
-			// Unfortunately, I cannot use a lambda because the PriorityBinaryOperator requires arguments.
-			final PriorityBinaryOperator<T> priorityOperator = new PriorityBinaryOperator<T>(priority) {
-				@Override
-				public T apply(final T t, final T u) {
-					return operator.apply(t, u);
-				}
-
-			};
-			this.binaryOperators.put(text, priorityOperator);
-			return this;
-		}
-
-		/**
-		 * Adds a unary operator to the builder.
-		 * 
-		 * @param text
-		 *            text used to reference the operator, like '-'
-		 * @param operator
-		 *            operator to add
-		 * @param priority
-		 *            operator's priority, which determines which operators are applied first
-		 * @return this builder
-		 * @throws NullPointerException
-		 *             if {@code text} or {@code operator} is null
-		 * @since 2019-03-17
-		 */
-		public Builder<T> addUnaryOperator(final String text, final UnaryOperator<T> operator, final int priority) {
-			Objects.requireNonNull(text, "text must not be null.");
-			Objects.requireNonNull(operator, "operator must not be null.");
-
-			// Unfortunately, I cannot use a lambda because the PriorityUnaryOperator requires arguments.
-			final PriorityUnaryOperator<T> priorityOperator = new PriorityUnaryOperator<T>(priority) {
-				@Override
-				public T apply(final T t) {
-					return operator.apply(t);
-				}
-			};
-			this.unaryOperators.put(text, priorityOperator);
-			return this;
-		}
-
-		/**
-		 * @return an {@code ExpressionParser<T>} instance with the properties given to this builder
-		 * @since 2019-03-17
-		 */
-		public ExpressionParser<T> build() {
-			return new ExpressionParser<>(this.objectObtainer, this.unaryOperators, this.binaryOperators);
-		}
-	}
-
-	/**
-	 * A binary operator with a priority field that determines which operators apply first.
-	 * 
-	 * @author Adrien Hopkins
-	 * @param <T>
-	 *            type of operand and result
-	 * @since 2019-03-17
-	 */
-	private static abstract class PriorityBinaryOperator<T>
-			implements BinaryOperator<T>, Comparable<PriorityBinaryOperator<T>> {
-		/**
-		 * The operator's priority. Higher-priority operators are applied before lower-priority operators
-		 */
-		private final int priority;
-
-		/**
-		 * Creates the {@code PriorityBinaryOperator}.
-		 * 
-		 * @param priority
-		 *            operator's priority
-		 * @since 2019-03-17
-		 */
-		public PriorityBinaryOperator(final int priority) {
-			this.priority = priority;
-		}
-
-		/**
-		 * Compares this object to another by priority.
-		 */
-		@Override
-		public int compareTo(final PriorityBinaryOperator<T> o) {
-			if (this.priority < o.priority)
-				return -1;
-			else if (this.priority > o.priority)
-				return 1;
-			else
-				return 0;
-		}
-	}
-
-	/**
-	 * A unary operator with a priority field that determines which operators apply first.
-	 * 
-	 * @author Adrien Hopkins
-	 * @param <T>
-	 *            type of operand and result
-	 * @since 2019-03-17
-	 */
-	private static abstract class PriorityUnaryOperator<T>
-			implements UnaryOperator<T>, Comparable<PriorityUnaryOperator<T>> {
-		/**
-		 * The operator's priority. Higher-priority operators are applied before lower-priority operators
-		 */
-		private final int priority;
-
-		/**
-		 * Creates the {@code PriorityUnaryOperator}.
-		 * 
-		 * @param priority
-		 *            operator's priority
-		 * @since 2019-03-17
-		 */
-		public PriorityUnaryOperator(final int priority) {
-			this.priority = priority;
-		}
-
-		/**
-		 * Compares this object to another by priority.
-		 */
-		@Override
-		public int compareTo(final PriorityUnaryOperator<T> o) {
-			if (this.priority < o.priority)
-				return -1;
-			else if (this.priority > o.priority)
-				return 1;
-			else
-				return 0;
-		}
-	}
-
-	/**
-	 * The types of tokens that are available.
-	 * 
-	 * @author Adrien Hopkins
-	 * @since 2019-03-14
-	 */
-	private static enum TokenType {
-		OBJECT, UNARY_OPERATOR, BINARY_OPERATOR;
-	}
-
-	/**
-	 * A function that obtains a parseable object from a string. For example, an integer {@code ExpressionParser} would
-	 * use {@code Integer::parseInt}.
-	 * 
-	 * @since 2019-03-14
-	 */
-	private final Function<String, T> objectObtainer;
-
-	/**
-	 * A map mapping operator strings to operator functions, for unary operators.
-	 * 
-	 * @since 2019-03-14
-	 */
-	private final Map<String, PriorityUnaryOperator<T>> unaryOperators;
-
-	/**
-	 * A map mapping operator strings to operator functions, for binary operators.
-	 * 
-	 * @since 2019-03-14
-	 */
-	private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-
-	/**
-	 * Creates the {@code ExpressionParser}.
-	 * 
-	 * @param objectObtainer
-	 *            function to get objects from strings
-	 * @param unaryOperators
-	 *            operators available to the parser
-	 * @since 2019-03-14
-	 */
-	private ExpressionParser(final Function<String, T> objectObtainer,
-			final Map<String, PriorityUnaryOperator<T>> unaryOperators,
-			final Map<String, PriorityBinaryOperator<T>> binaryOperators) {
-		this.objectObtainer = objectObtainer;
-		this.unaryOperators = unaryOperators;
-		this.binaryOperators = binaryOperators;
-	}
-
-	/**
-	 * Converts a given mathematical expression to reverse Polish notation (operators after operands).
-	 * <p>
-	 * For example,<br>
-	 * {@code 2 * (3 + 4)}<br>
-	 * becomes<br>
-	 * {@code 2 3 4 + *}.
-	 * 
-	 * @param expression
-	 * @return
-	 * @since 2019-03-17
-	 */
-	private String convertExpressionToReversePolish(final String expression) {
-		Objects.requireNonNull(expression, "expression must not be null.");
-
-		// TODO method stub org.unitConverter.expressionParser.ExpressionParser.convertExpressionToPolish(expression)
-		throw new UnsupportedOperationException();
-	}
-
-	/**
-	 * Determines whether an inputted string is an object or an operator
-	 * 
-	 * @param token
-	 *            string to input
-	 * @return type of token it is
-	 * @throws NullPointerException
-	 *             if {@code expression} is null
-	 * @since 2019-03-14
-	 */
-	private TokenType getTokenType(final String token) {
-		Objects.requireNonNull(token, "token must not be null.");
-
-		if (this.unaryOperators.containsKey(token))
-			return TokenType.UNARY_OPERATOR;
-		else if (this.binaryOperators.containsKey(token))
-			return TokenType.BINARY_OPERATOR;
-		else
-			return TokenType.OBJECT;
-	}
-
-	/**
-	 * Parses an expression.
-	 * 
-	 * @param expression
-	 *            expression to parse
-	 * @return result
-	 * @throws NullPointerException
-	 *             if {@code expression} is null
-	 * @since 2019-03-14
-	 */
-	public T parseExpression(final String expression) {
-		return this.parseReversePolishExpression(this.convertExpressionToReversePolish(expression));
-	}
-
-	/**
-	 * Parses an expression expressed in reverse Polish notation.
-	 * 
-	 * @param expression
-	 *            expression to parse
-	 * @return result
-	 * @throws NullPointerException
-	 *             if {@code expression} is null
-	 * @since 2019-03-14
-	 */
-	private T parseReversePolishExpression(final String expression) {
-		Objects.requireNonNull(expression, "expression must not be null.");
-
-		final Deque<T> stack = new ArrayDeque<>();
-
-		// iterate over every item in the expression, then
-		for (final String item : expression.split(" ")) {
-			// choose a path based on what kind of thing was just read
-			switch (this.getTokenType(item)) {
-
-				case BINARY_OPERATOR:
-					if (stack.size() < 2)
-						throw new IllegalStateException(String.format(
-								"Attempted to call binary operator %s with only %d arguments.", item, stack.size()));
-
-					// get two arguments and operator, then apply!
-					final T o1 = stack.pop();
-					final T o2 = stack.pop();
-					final BinaryOperator<T> binaryOperator = this.binaryOperators.get(item);
-
-					stack.push(binaryOperator.apply(o1, o2));
-					break;
-
-				case OBJECT:
-					// just add it to the stack
-					stack.push(this.objectObtainer.apply(item));
-					break;
-
-				case UNARY_OPERATOR:
-					if (stack.size() < 1)
-						throw new IllegalStateException(String.format(
-								"Attempted to call unary operator %s with only %d arguments.", item, stack.size()));
-
-					// get one argument and operator, then apply!
-					final T o = stack.pop();
-					final UnaryOperator<T> unaryOperator = this.unaryOperators.get(item);
-
-					stack.push(unaryOperator.apply(o));
-					break;
-				default:
-					throw new AssertionError(
-							String.format("Internal error: Invalid token type %s.", this.getTokenType(item)));
-
-			}
-		}
-
-		// return answer, or throw an exception if I can't
-		if (stack.size() > 1)
-			throw new IllegalStateException("Computation ended up with more than one answer.");
-		else if (stack.size() == 0)
-			throw new IllegalStateException("Computation ended up without an answer.");
-		return stack.pop();
-	}
-}
diff --git a/src/org/unitConverter/expressionParser/package-info.java b/src/org/unitConverter/expressionParser/package-info.java
deleted file mode 100644
index 28f0cae..0000000
--- a/src/org/unitConverter/expressionParser/package-info.java
+++ /dev/null
@@ -1,23 +0,0 @@
-/**
- * Copyright (C) 2019 Adrien Hopkins
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-/**
- * A module that is capable of parsing expressions of things, like mathematical expressions or unit expressions.
- * 
- * @author Adrien Hopkins
- * @since 2019-03-14
- */
-package org.unitConverter.expressionParser;
\ No newline at end of file