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throw UnsupportedOperationException vs null return #26

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b72d076
add throw UnsupportedOperationException instead of null returns. Upda…
JaredDavis22 Jun 10, 2026
e16c113
add throw UnsupportedOperationException instead of null returns. Upda…
JaredDavis22 Jun 10, 2026
9efea3f
Merge remote-tracking branch 'origin/exceptionmessages' into exceptio…
JaredDavis22 Jun 10, 2026
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71 changes: 41 additions & 30 deletions src/main/java/org/scijava/parsington/eval/AbstractStandardEvaluator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -110,14 +110,25 @@ public Object function(final Object a, final Object b) {
}

// NB: Unknown function type.
return null;
throw new UnsupportedOperationException("function " + a + " was not found");
}

private static Object throwUnsupportedImplementation(final String op) {
throw new UnsupportedOperationException("Operation " + op + " is not implemented");
}
private static Object throwUnsupportedParameters(String op, Object a, Object b) {
throw new UnsupportedOperationException("Operation " + op + " did not complete with parameters A= [" + a + "] type " + type(a) + " B = [" + b + "] type " + type(b));
}
private static String type(Object o) {
return o == null ? "<null>" : o.getClass().getSimpleName();
}


// -- dot --

@Override
public Object dot(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dot");
}

// -- groups --
Expand All @@ -142,12 +153,12 @@ public Object braces(final Object... args) {

@Override
public Object transpose(final Object a) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("transpose");
}

@Override
public Object dotTranspose(final Object a) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dotTranspose");
}

@Override
Expand All @@ -156,15 +167,15 @@ public Object pow(final Object a, final Object b) {
if (isD(av) && isD(bv)) return pow(d(av), d(bv));
if (isBI(av) && isI(bv)) return pow(bi(av), i(bv));
if (isBD(av) && isI(bv)) return pow(bd(av), i(bv));
return null;
return throwUnsupportedParameters("pow", av, bv);
}
public double pow(final double av, final double bv) { return Math.pow(av, bv); }
public BigInteger pow(final BigInteger av, final int bv) { return av.pow(bv); }
public BigDecimal pow(final BigDecimal av, final int bv) { return av.pow(bv); }

@Override
public Object dotPow(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dotPow");
}

// -- unary --
Expand Down Expand Up @@ -206,7 +217,7 @@ public Object complement(final Object a) {
final Object av = value(a);
if (isI(av)) return complement(i(av));
if (isL(av)) return complement(l(av));
return null;
return throwUnsupportedParameters("complement", av, null);
}
public int complement(final int a) { return ~a; }
public long complement(final long a) { return ~a; }
Expand All @@ -226,7 +237,7 @@ public Object mul(final Object a, final Object b) {
if (isD(av) && isD(bv)) return mul(d(av), d(bv));
if (isBI(av) && isBI(bv)) return mul(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return mul(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("mul", av, bv);
}
public int mul(final int av, final int bv) { return av * bv; }
public long mul(final long av, final long bv) { return av * bv; }
Expand All @@ -248,7 +259,7 @@ public Object div(final Object a, final Object b) {
if (isD(av) && isD(bv)) return div(d(av), d(bv));
if (isBI(av) && isBI(bv)) return div(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return div(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("div", av, bv);
}
public int div(final int av, final int bv) { return av / bv; }
public long div(final long av, final long bv) { return av / bv; }
Expand All @@ -270,7 +281,7 @@ public Object mod(final Object a, final Object b) {
if (isD(av) && isD(bv)) return mod(d(av), d(bv));
if (isBI(av) && isBI(bv)) return mod(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return mod(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("mod", av, bv);
}
public int mod(final int av, final int bv) { return av % bv; }
public long mod(final long av, final long bv) { return av % bv; }
Expand All @@ -285,22 +296,22 @@ public BigDecimal mod(final BigDecimal av, final BigDecimal bv) {

@Override
public Object rightDiv(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("rightDiv");
}

@Override
public Object dotMul(Object a, Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dotMul");
}

@Override
public Object dotDiv(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dotDiv");
}

@Override
public Object dotRightDiv(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("dotRightDiv");
}

// -- additive --
Expand All @@ -315,7 +326,7 @@ public Object add(final Object a, final Object b) {
if (isD(av) && isD(bv)) return add(d(av), d(bv));
if (isBI(av) && isBI(bv)) return add(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return add(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("add", av, bv);
}
public String add(final String av, final String bv) { return av + bv; }
public int add(final int av, final int bv) { return av + bv; }
Expand All @@ -338,7 +349,7 @@ public Object sub(final Object a, final Object b) {
if (isD(av) && isD(bv)) return sub(d(av), d(bv));
if (isBI(av) && isBI(bv)) return sub(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return sub(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("sub", av, bv);
}
public int sub(final int av, final int bv) { return av - bv; }
public long sub(final long av, final long bv) { return av - bv; }
Expand All @@ -359,7 +370,7 @@ public Object leftShift(final Object a, final Object b) {
if (isI(av) && isI(bv)) return leftShift(i(av), i(bv));
if (isL(av) && isL(bv)) return leftShift(l(av), l(bv));
if (isBI(av) && isI(bv)) return leftShift(bi(av), i(bv));
return null;
return throwUnsupportedParameters("leftShift", av, bv);
}
public int leftShift(final int av, final int bv) { return av << bv; }
public long leftShift(final long av, final long bv) { return av << bv; }
Expand All @@ -373,7 +384,7 @@ public Object rightShift(final Object a, final Object b) {
if (isI(av) && isI(bv)) return rightShift(i(av), i(bv));
if (isL(av) && isL(bv)) return rightShift(l(av), l(bv));
if (isBI(av) && isI(bv)) return rightShift(bi(av), i(bv));
return null;
return throwUnsupportedParameters("rightShift", av, bv);
}
public int rightShift(final int av, final int bv) { return av >> bv; }
public long rightShift(final long av, final long bv) { return av >> bv; }
Expand All @@ -386,7 +397,7 @@ public Object unsignedRightShift(final Object a, final Object b) {
final Object av = value(a), bv = value(b);
if (isI(av) && isI(bv)) return unsignedRightShift(i(av), i(bv));
if (isL(av) && isL(bv)) return unsignedRightShift(l(av), l(bv));
return null;
return throwUnsupportedParameters("unsignedRightShift", av, bv);
}
public int unsignedRightShift(final int av, final int bv) { return av >>> bv; }
public long unsignedRightShift(final long av, final long bv) { return av >>> bv; }
Expand All @@ -404,7 +415,7 @@ public Object lessThan(final Object a, final Object b) {
if (isD(av) && isD(bv)) return lessThan(d(av), d(bv));
if (isBI(av) && isBI(bv)) return lessThan(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return lessThan(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("lessThan", av, bv);
}
public <T> boolean lessThan(final Comparable<T> av, final T bv) {
return av.compareTo(bv) < 0;
Expand All @@ -421,7 +432,7 @@ public Object greaterThan(final Object a, final Object b) {
if (isD(av) && isD(bv)) return greaterThan(d(av), d(bv));
if (isBI(av) && isBI(bv)) return greaterThan(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return greaterThan(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("greaterThan", av, bv);
}
public <T> boolean greaterThan(final Comparable<T> av, final T bv) {
return av.compareTo(bv) > 0;
Expand All @@ -438,7 +449,7 @@ public Object lessThanOrEqual(final Object a, final Object b) {
if (isD(av) && isD(bv)) return lessThanOrEqual(d(av), d(bv));
if (isBI(av) && isBI(bv)) return lessThanOrEqual(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return lessThanOrEqual(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("lessThanOrEqual", av, bv);
}
public <T> boolean lessThanOrEqual(final Comparable<T> av, final T bv) {
return av.compareTo(bv) <= 0;
Expand All @@ -455,15 +466,15 @@ public Object greaterThanOrEqual(final Object a, final Object b) {
if (isD(av) && isD(bv)) return greaterThanOrEqual(d(av), d(bv));
if (isBI(av) && isBI(bv)) return greaterThanOrEqual(bi(av), bi(bv));
if (isBD(av) && isBD(bv)) return greaterThanOrEqual(bd(av), bd(bv));
return null;
return throwUnsupportedParameters("greaterThanOrEqual", av, bv);
}
public <T> boolean greaterThanOrEqual(final Comparable<T> av, final T bv) {
return av.compareTo(bv) >= 0;
}

@Override
public Object instanceOf(final Object av, final Object bv) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("instanceOf");
}

// -- equality --
Expand All @@ -486,7 +497,7 @@ public Object bitwiseAnd(final Object a, final Object b) {
if (isI(av) && isI(bv)) return bitwiseAnd(i(av), i(bv));
if (isL(av) && isL(bv)) return bitwiseAnd(l(av), l(bv));
if (isBI(av) && isBI(bv)) return bitwiseAnd(bi(av), bi(bv));
return null;
return throwUnsupportedParameters("bitwiseAnd", av, bv);
}
public int bitwiseAnd(final int av, final int bv) { return av & bv; }
public long bitwiseAnd(final long av, final long bv) { return av & bv; }
Expand All @@ -500,7 +511,7 @@ public Object bitwiseOr(final Object a, final Object b) {
if (isI(av) && isI(bv)) return bitwiseOr(i(av), i(bv));
if (isL(av) && isL(bv)) return bitwiseOr(l(av), l(bv));
if (isBI(av) && isBI(bv)) return bitwiseOr(bi(av), bi(bv));
return null;
return throwUnsupportedParameters("bitwiseOr", av, bv);
}
public int bitwiseOr(final int av, final int bv) { return av | bv; }
public long bitwiseOr(final long av, final long bv) { return av | bv; }
Expand All @@ -514,28 +525,28 @@ public BigInteger bitwiseOr(final BigInteger av, final BigInteger bv) {
public Object logicalAnd(final Object a, final Object b) {
final Object av = value(a), bv = value(b);
if (isBool(av) && isBool(bv)) return logicalAnd(bool(av), bool(bv));
return null;
return throwUnsupportedParameters("logicalAnd", av, bv);
}
public boolean logicalAnd(final boolean av, final boolean bv) { return av && bv; }

@Override
public Object logicalOr(final Object a, final Object b) {
final Object av = value(a), bv = value(b);
if (isBool(av) && isBool(bv)) return logicalOr(bool(av), bool(bv));
return null;
return throwUnsupportedParameters("logicalOr", av, bv);
}
public boolean logicalOr(final boolean av, final boolean bv) { return av || bv; }

// -- ternary --

@Override
public Object question(final Object a, final Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("question");
}

@Override
public Object colon(Object a, Object b) {
throw new UnsupportedOperationException();
return throwUnsupportedImplementation("colon");
}

// -- Helper methods - type matching --
Expand Down
3 changes: 1 addition & 2 deletions src/test/java/org/scijava/parsington/eval/AbstractStandardEvaluatorTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,6 @@
package org.scijava.parsington.eval;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
Expand Down Expand Up @@ -109,7 +108,7 @@ public void testFunction() {
assertEquals("b", e.function(v, Arrays.asList(1)));
assertEquals("c", e.function(v, Arrays.asList(2)));

assertNull(e.function(o(0), o(1)));
assertThrows(UnsupportedOperationException.class, () ->e.function(o(0), o(1)));
}

// -- dot --
Expand Down
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