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 * 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
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package org.springframework.expression.spel.ast;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import org.springframework.expression.EvaluationException;
import org.springframework.expression.spel.ExpressionState;
import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.SpelMessage;
import org.springframework.expression.spel.support.BooleanTypedValue;

Implements the matches operator. Matches takes two operands: The first is a String and the second is a Java regex. It will return true when SpelNodeImpl.getValue is called if the first operand matches the regex.
Author:Andy Clement, Juergen Hoeller
Since:3.0
/** * Implements the matches operator. Matches takes two operands: * The first is a String and the second is a Java regex. * It will return {@code true} when {@link #getValue} is called * if the first operand matches the regex. * * @author Andy Clement * @author Juergen Hoeller * @since 3.0 */
public class OperatorMatches extends Operator { private static final int PATTERN_ACCESS_THRESHOLD = 1000000; private final ConcurrentMap<String, Pattern> patternCache = new ConcurrentHashMap<>(); public OperatorMatches(int startPos, int endPos, SpelNodeImpl... operands) { super("matches", startPos, endPos, operands); }
Check the first operand matches the regex specified as the second operand.
Params:
  • state – the expression state
Throws:
  • EvaluationException – if there is a problem evaluating the expression (e.g. the regex is invalid)
Returns:true if the first operand matches the regex specified as the second operand, otherwise false
/** * Check the first operand matches the regex specified as the second operand. * @param state the expression state * @return {@code true} if the first operand matches the regex specified as the * second operand, otherwise {@code false} * @throws EvaluationException if there is a problem evaluating the expression * (e.g. the regex is invalid) */
@Override public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException { SpelNodeImpl leftOp = getLeftOperand(); SpelNodeImpl rightOp = getRightOperand(); String left = leftOp.getValue(state, String.class); Object right = getRightOperand().getValue(state); if (left == null) { throw new SpelEvaluationException(leftOp.getStartPosition(), SpelMessage.INVALID_FIRST_OPERAND_FOR_MATCHES_OPERATOR, (Object) null); } if (!(right instanceof String)) { throw new SpelEvaluationException(rightOp.getStartPosition(), SpelMessage.INVALID_SECOND_OPERAND_FOR_MATCHES_OPERATOR, right); } try { String rightString = (String) right; Pattern pattern = this.patternCache.get(rightString); if (pattern == null) { pattern = Pattern.compile(rightString); this.patternCache.putIfAbsent(rightString, pattern); } Matcher matcher = pattern.matcher(new MatcherInput(left, new AccessCount())); return BooleanTypedValue.forValue(matcher.matches()); } catch (PatternSyntaxException ex) { throw new SpelEvaluationException( rightOp.getStartPosition(), ex, SpelMessage.INVALID_PATTERN, right); } catch (IllegalStateException ex) { throw new SpelEvaluationException( rightOp.getStartPosition(), ex, SpelMessage.FLAWED_PATTERN, right); } } private static class AccessCount { private int count; public void check() throws IllegalStateException { if (this.count++ > PATTERN_ACCESS_THRESHOLD) { throw new IllegalStateException("Pattern access threshold exceeded"); } } } private static class MatcherInput implements CharSequence { private final CharSequence value; private AccessCount access; public MatcherInput(CharSequence value, AccessCount access) { this.value = value; this.access = access; } @Override public char charAt(int index) { this.access.check(); return this.value.charAt(index); } @Override public CharSequence subSequence(int start, int end) { return new MatcherInput(this.value.subSequence(start, end), this.access); } @Override public int length() { return this.value.length(); } @Override public String toString() { return this.value.toString(); } } }