this.desiredContext = desiredContext;
    }

    @Override
    public boolean isSatisfiedBy(DaemonContext potentialContext) {
        return whyUnsatisfied(potentialContext) == null;
    }

    @Override
    public String whyUnsatisfied(DaemonContext context) {
        if (!jvmCompatible(context)) {
            return "JVM is incompatible.\n" + description(context);
        } else if (!daemonOptsMatch(context)) {

        @Override
        public boolean isSatisfiedBy(Object element) {
            return true;
        }
        @Override
        public String whyUnsatisfied(Object element) {
            return null;
        }
    };

    public static <T> ExplainingSpec<T> satisfyAll() {
        return Cast.uncheckedNonnullCast(SATISFIES_ALL);
    }

     * Explains why the spec is not satisfied.
     *
     * @param element candidate
     * @return the description. Must not be null if the spec is not satisfied. Is null if spec is satisfied.
     */
    String whyUnsatisfied(T element);

        connector.daemonRegistry
    }

    def getNumAllDaemons() {
        registry.all.size()
    }

    abstract static class DummyExplainingSpec implements ExplainingSpec {
        String whyUnsatisfied(Object element) {
            ""
        }
    }

    def "maybeConnect() returns connection to any daemon that matches spec"() {
        given:
        startIdleDaemon()
        startIdleDaemon()

        final Set<String> seen = new HashSet<String>();

        ExplainingSpec<DaemonContext> spec = new ExplainingSpec<DaemonContext>() {
            @Override
            public String whyUnsatisfied(DaemonContext element) {
                return "already seen";
            }

            @Override
            public boolean isSatisfiedBy(DaemonContext element) {

                compatibleDaemons.add(daemon);
            } else {
                LOGGER.info("Found daemon {} however its context does not match the desired criteria.\n"
                    + constraint.whyUnsatisfied(daemon.getContext()) + "\n"
                    + "  Looking for a different daemon...", daemon);
            }
        }
        return compatibleDaemons;
    }

    }

    private boolean isCompatible() {
        new DaemonCompatibilitySpec(request).isSatisfiedBy(candidate)
    }

    private String getUnsatisfiedReason() {
        new DaemonCompatibilitySpec(request).whyUnsatisfied(candidate)
    }

    def "contexts with different java homes are incompatible"() {
        clientWants(Jvm.forHome(javaHome))

        def daemonJdkHome = tmp.createDir("daemon-jdk")